Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

Low Dropout High Performance Adjustable Positive Voltage Regulator by znr91839

VIEWS: 0 PAGES: 18

									                                                                                                            SC1592
                                                             Low Dropout High Performance
                                                       Adjustable Positive Voltage Regulator
POWER MANAGEMENT
Description                                                       Features
The SC1592 is a 3A low dropout high performance                     Wide input range, VIN = 1.25V to 16V,
linear voltage regulator, that provides a low voltage, high                             VCNTL = 3V to 16V
current output with a minimum of external components,               3A Guaranteed Output Current
utilizing dual supply configuration.                                260mV (typ) @ 3A dropout voltage in dual supply
                                                                    mode
The SC1592 offers a wide input voltage range from 1.25V             1% Initial Accuracy
to 16V and is ideal for applications that need to convert
                                                                    Adjustable output voltage, down to 0.8V
down to 0.8V.
                                                                    Programmable current limiting and thermal
                                                                    shutdown
Additionally, the SC1592 is fully protected with an exter-
nally programmable current limit, and thermal shutdown.             Fast transient response
Also, there is an EN input which enables or shuts down              Excellent line and load regulation
the device.                                                         Power SO-8 and 7-lead DDPAK

The SC1592 voltage regulator is available in 7-lead DDPAK         Applications
and SOIC-8L EDP packages.
                                                                    Low voltage logic supplies
                                                                    Microprocessor and chipset supplies
                                                                    Split plane microprocessor supplies
                                                                    Advanced graphics cards supplies
                                                                    Sound cards and auxiliary power supplies
                                                                    SMPS post regulator
Typical Application Circuit



                    +3.3V Vcntl                                                            +1.8V Vout
                                            CNTL                     OUT
                             C1
                             1uF                                                             C3
                                                                                  R2
                                                                                             47uF(cer)
                                                    SC1592                        66.5
                    +2.5V Vin
                                            IN                      SENSE
                                                       GND                                             R2
                             C2               EN                    ILIM                 VOUT = (1 +      ) • VREF
                             10uF                                                 R3                   R3
                                                                                  53
                                                                                         VREF   = 0.8 V typ.
                                              TTL                      R1
                                                                       100




Revision: January 27, 2004                                    1                                             www.semtech.com
                                                                                                                               SC1592

POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not implied.

 Parameter                                                                Symbol                       Maximum                  Units

 Power Input Voltage                                                          VIN                          18                        V

 Control Input Voltage                                                      VCNTL                          18                        V

 Output Current                                                              IOUT                           5                        A

 Power Dissipation                                                            PD                   Internally Limited             W

 Thermal Resistance Junction to Ambient
 DDPAK (1sq. in.)                                                             θJ A                          29                  °C/W
 SOIC-8L EDP (1sq. in.)                                                                                    36.5

 Thermal Resistance Junction to Case
 DDPAK                                                                        θJ C                          3                   °C/W
 SOIC-8L EDP                                                                                               5.5

 Junction Temperature Range                                                     TJ                    -40 to +125                 °C

 Storage Temperature Range                                                   TSTG                     -65 to +150                 °C

 Lead Temperature (Soldering) 10 Sec.                                       TLEAD                          300                    °C

 ESD Rating (Human Body Model)                                              ESD                             2                     kV

Electrical Characteristics
Unless specified: VIN = 2.5V, VEN = VCNTL = 3.3V, VOUT = 1.8V, IOUT = 10mA, RLIM = 100Ω, TJ = TA = 25°C.
Values in bold indicate -40°C < TJ < +125°C.

 Parameter                             Symbol                        Test Conditions                            Min     Typ    Max        Units

 Control Voltage                         VCNTL                           VOUT = VREF                              3             16            V

 Reference Voltage                       VREF                            VOUT = VREF                            792     800    808            mV

 Control Pin Current                    ICNTL_EN                 VCNTL = VIN = VEN = 16V                                 3       8
                                                                   VOUT = VREF; IO = 0                                                        mA

                                                                 VCNTL = VIN = VEN = 16V                                24
                                                                  VOUT = VREF; IO = 3A

 Control Pin Current in                 ICNTL_DIS                    VCNTL = VIN = 16V                                   1       5            µA
 Shutdown                                                                 V EN = 0

 VIN Line Regulation                   REG(LINE)                     2.5V ≤ VIN ≤ 16V                                   0.01    0.1       %/V

 VCNTL Line Regulation                REG(CNTL)                    3.3V ≤ VCNTL ≤ 16V,                                  0.1     0.4       %/V
                                                                       VOUT = VREF

 Load Regulation (1)                  REG(LOAD)               10mA ≤ IOUT ≤ 2A, TJ = 25°C                               0.8     1.5           %

                                                         10mA ≤ IOUT ≤ 3A, -40 < TJ < 125°C                             1.4      3            %

 Dropout Voltage                          V DO                IOUT = 2A; VOUT = 0.98 Vnom                               160    320            mV

                                                              IOUT = 3A; VOUT = 0.98 Vnom                               260    520


 2004 Semtech Corp.                                                        2                                                  www.semtech.com
                                                                                                                       SC1592

POWER MANAGEMENT
Electrical Characteristics (Cont.)
Unless specified: VIN = 2.5V, VEN = VCNTL = 3.3V, VOUT = 1.8V, IOUT = 10mA, RLIM = 100Ω, TJ = TA = 25°C.
Values in bold indicate -40°C < TJ < +125°C.

 Parameter                             Symbol                        Test Conditions                       Min   Typ   Max     Units

 Thermal Shutdown                        TSHUT                                                                   150            °C

 Thermal Shutdown                                                                                                10             °C
 Hysteresis

 SENSE Input Current                                                                                              1             µA

 Low Level EN                                                                                                          0.8       V

 High Level EN                                                                                             2                     V

 EN Input Current                                                    VEN = VCNTL = 5V                            55    100      µA

 EN Impedance                                                                                                    65             KΩ

 Current Limit Accuracy(2)                 ILIM                                                            -20         +20       %

Notes:
(1) For load regulation use a 1ms current pulse width, d.c. ≤ 10% when measuring VOUT.
                                                   240 • VOUT
(2) Current limit is programmable, ILIM ≈
                                                     RLIM




 2004 Semtech Corp.                                                        3                                          www.semtech.com
                                                                                                                            SC1592

POWER MANAGEMENT
Pin Configurations                                                         Ordering Information
                              Top View                                        Part Number          P ackag e   (1)
                                                                                                                         Temp. Range (TJ)

                                                                              SC1592IMTR           TO-263-7L             -40°C to +125°C
               TAB                           Pin Function

                                             1         ILIM
                                                                             SC1592IMTRT(3)
                                             2          IN                    SC1592ISTR          SOIC-8L EDP
                                             3        CNTL
                                                                             SC1592ISTRT(3)
                                             4        GND
                                                                             SC1592EVB(2)                   Evaluation Board
                                             5         OUT

                                             6       SENSE                 Notes:
                                                                           (1) Only available in tape and reel packaging. A reel
                                             7         EN
                                                                           contains 800 devices for TO-263 package and 2500
                                         TAB          GND
                                                                           devices for SOIC package.
                                                                           (2) When ordering Evaluation Board please specify pack-
                       (TO-263-7L DDPAK)
                                                                           age needed (TO-263(DDPAK) or SOIC(EDP)).
                                                                           (3) Lead free product.

                          Top View                                                               Bottom View                   GND

           ILIM           1              8          EN                                  EN         8                 1       ILIM
            IN            2              7          SENSE                         SENSE            7    Exposed      2       IN
                                                                                                        Die Pad
            IN            3              6          OUT                              OUT           6                 3       IN
         CNTL             4              5          OUT                               OUT          5                 4      CNTL


                        (SOIC-8L EDP)                                                           (SOIC-8L EDP)

Pin Descriptions
  Pin #           Pin #        Pin Name                                               Pin Function
 DDPAK            SOIC

     1              1             ILIM           Externally programmable current limit should be set at < 5A.

     2            2, 3            IN             This is the collector input to the power device. The ouput load current is supplied
                                                 through this pin.

     3             4             CNTL            This pin is the bias supply for the control circuitry. The current flow into this pin will
                                                 be approximately 1% of the output current. For the device to regulate, the voltage
                                                 on this pin must be at least 1.5V greater than the output voltage, but no less than
                                                 VCNTL_MIN.

  4, TAB          PAD            GND             Ground.

     5            5, 6           OUT             This is the power output of the device.

     6             7            SENSE            This is a feedback input.

     7             8              EN             Enable input. When high, should be less or equal to VCNTL.
 2004 Semtech Corp.                                                   4                                                    www.semtech.com
                                                                                                     SC1592

POWER MANAGEMENT
Block Diagram




                                                      Figure 1



                 V 
    RLIM ≈ 240 X  OUT 
                  ILIM 


  ILIM = Selected current limit value
  VOUT = Regulated output voltage
  RLIM = Externally programmable current limit resistor.

  Accuracy of the current limit setting is better than ±20% over full operating temperature range.

  *Internal ESD structure. In cases where EN is permanently tied to VIN, it’s recommended that a 10-20k
  resistor should be inserted in the link between EN and VIN.




 2004 Semtech Corp.                                       5                                         www.semtech.com
                                                                                                                     SC1592

POWER MANAGEMENT
Application Information
The SC1592 is a 3A low dropout high performance linear
voltage regulator. The SC1592 can be used for voltage                +3.3V Vcntl                                           +1.8V Vout
applications as low as 0.8V and is ideal for down                                          CNTL             OUT
                                                                          C1
conversion utilizing dual supply configuration. This allows              2.2uF
                                                                                                                             C3
                                                                                                  SC1592            R2      100uF
for extremely low dropout voltages with excellent load               +2.5V Vin
                                                                                                                    66.5

and line regulation. The SC1592 can be utilized in high                                    IN              SENSE

voltage applications, with VIN and VCNTL up to 16V, providing             C2
                                                                         22uF
                                                                                     10k    EN     GND     ILIM
                                                                                                                    R3
there is adequate thermal management.                                                                               53
                                                                                                              R1
                                                                                                              100

SC1592 is designed to meet stringent requirements of                                    R2
                                                                          VOUT = (1 +      ) • VREF
current generation microprocessors and other sensitive                                  R3
electronic devices. This is possible by employing an                      VREF   = 0.8 V typ.
additional bias source, VCNTL. The voltage of this supply                                          Figure 2
needs to be at least 1.5V greater than the output voltage
in order to achieve low dropout, typically less then                The circuit in Figure 2 shows a typical application of 2.5V
300mV.                                                              to 1.8V conversion with a 3.3V control supply and the
                                                                    load range of up to 3A steady state. Considering the
Unlike most of the other high current linear regulators,            approximate 2W power being dissipated by the pass
the SC1592 provides a programmable current limit which              element of the SC1592, we are still able to choose an
can be set with a single resistor. The value of the                 SO-8 EDP package with TJA = 36.5°C/W mount on the
programming resistor is:                                            1sq.in. copper pad allocated for adequate heat transfer.

                                240 • VOUT
                                                                    The ambient temperature in this case should not exceed
                       ILIM ≈                                       50°C. If this temperature range is too restrictive, then
                                  RLIM
                                                                    the DDPAK can be utilized, having TJA = 29°C/W mount
                                                                    on the same size copper pad.
where ILIM = selected current limit value
VOUT = regulated output voltage
                                                                    Input capacitor: A minimum of 10µF ceramic capacitor
RLIM = programmable current limit resistor
                                                                    is recommended to be placed directly next to the Vin pin.
The SC1592 has a fast transient response that allows it             This allows for the device being some distance from any
to handle large load changes associated with high current           bulk capacitance on the rail. Additionally, bulk
applications. Proper selection of the of the output                 capacitance may be added closely to the input supply
capacitor and it’s ESR value determines stable operation            pin of the SC1592 to ensure that Vin does not sag,
and optimizes performance.                                          improving load transient response.

The typical application shown in Figure 2 was tested with           Output capacitor: A minimum bulk capacitance of 33µF,
a wide range of different capacitors. The circuit was found         along with a 0.1µF ceramic decoupling capacitor is
to be unconditionally stable with capacitor values from             recommended. Increasing the bulk capacitance will
47µF to 330µF and ESR ranging from 0.5mΩ to greater                 improve the overall transient response. The use of
then 75mΩ.                                                          multiple lower value ceramic capacitors in parallel to
                                                                    achieve the desired bulk capacitance will not cause
It’s recommended to maintain 5-10mA through the output              stability issues. Although designed for use with ceramic
divider network in order to have a tight load and line              output capacitors, the SC1592 is extremely tolerant of
regulation. Initial accuracy of the internal voltage                output capacitor ESR values and thus will also work
reference VREF = 0.8V ±1% over full temperature range.              comfortably with tantalum output capacitors.
This commands the use of 0.5% or better accuracy
resistors to build a precision power supply.


 2004 Semtech Corp.                                            6                                                    www.semtech.com
                                                                                       SC1592

POWER MANAGEMENT
Typical Characteristics



                                  Load Transient Reponse

                       20mV/div                                   V IN      = 2.5V
                         V OUT


                                                                  V OUT = 1.8V

                                                                  V CNTL = 3.3V

                                                                  CIN       = 22uF
                        VIN




                                                                  COUT = 100uF




                                        Istep : 1 5 m A to 3 A
                         Iout




                                        sl              5
                                          ew rate: 2 . A /uS




                                      Time (2ms/div)




                                                                     V IN     = 2.5V
                       20mV/div
                         V OUT




                                                                     V OUT = 1.8V

                                                                     V CNTL = 3.3V

                                                                     CIN      = 22uF
                        VIN




                                                                     COUT = 100uF
                         Iout




                                         Istep : 1 5 m A to 3 A
                                         sl              5
                                           ew rate: 2 . A /uS




                                      Time (200us/div)




 2004 Semtech Corp.                          7                                        www.semtech.com
                                                                                                                        SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)


                                                                                   Load Regulation
                                                 2.00

                                                 1.95         VCNTL = 3.3V
                                                 1.90         VIN = 2.5V
                             OUTPUT VOLTAGE(V)


                                                 1.85

                                                 1.80
                                                 1.75

                                                 1.70

                                                 1.65

                                                 1.60

                                                 1.55

                                                 1.50
                                                        0.0       0.5        1.0        1.5     2.0        2.5    3.0
                                                                             OUTPUT CURRENT (A)




                                                                                Output Voltage
                                                                               vs. Tem perature
                                                   2
                                                 1.95         VCNTL = 3.3V
                                                              VIN = 2.5V
                                                  1.9
                                                              IOUT = 10mA
                       OUTPUT VOLTAGE (V)




                                                 1.85
                                                  1.8
                                                 1.75
                                                  1.7
                                                 1.65
                                                  1.6
                                                 1.55
                                                  1.5
                                                        -40     -20     0      20       40    60      80    100   120
                                                                              TEMPERATURE (oC)




 2004 Semtech Corp.                                                                    8                               www.semtech.com
                                                                                                           SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)



                                                                       EnableThreshold
                                                                       vs. Temperature
                                             2
                                                        VCNTL = 3.3V
                                            1.8
                                                        VIN = 2.5V
                                            1.6         VOUT = 1.8V
                       OUTPUT VOLTAGE (V)




                                                        IOUT = 10mA
                                            1.4

                                            1.2

                                             1

                                            0.8

                                            0.6

                                            0.4
                                                  -40      -20    0     20    40    60    80   100   120
                                                                       TEMPERATURE (oC)




 2004 Semtech Corp.                                                          9                            www.semtech.com
                                                                                                  SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)


                                                                       Dropout Voltage
                                                                       (Control Supply)
                                                1.1

                                                           INITIAL VCNTL = 3.3V
                                                           VIN = 2.5V
                          DROPOUT VOLTAGE (V)

                                                           VOUT = 1.8V
                                                1.0




                                                0.9




                                                0.8
                                                       0                1                 2   3
                                                                       OUTPUT CURRENT (A)




                                                                        Dropout Voltage
                                                                         (Input Supply)
                                                0.50
                                                           VCNTL = 3.3V
                                                0.40       INITIAL VIN = 2.5V
                                                           VOUT = 1.8V
                        DROPOUT VOLTAGE (V)




                                                0.30


                                                0.20


                                                0.10


                                                0.00
                                                       0                 1                2   3
                                                                        OUTPUT CURRENT (A)




 2004 Semtech Corp.                                                            10                www.semtech.com
                                                                                                                                                              SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)

                                                                                                   Contol Current
                                                                                                  vs. Tem perature
                                                                                                   (In Shutdow n)
                                              10000



                                               1000
                       CONTROL CURRENT (nA)




                                                100

                                                                                                                             V CNTL = 3.3V
                                                 10                                                                          V IN = 2.5V
                                                                                                                             V EN = 0V
                                                                                                                             I OUT = 10mA
                                                         1
                                                                        -40   -20         0       20         40        60        80      100     120

                                                                                              TEMPERATURE (oC)




                                                                                                         Control Current
                                                                                                         vs Tem perature
                                                                                                          (In Regulation)
                                                                        100
                                                 CONTROL CURRENT (mA)




                                                                                                                            IOUT = 3A


                                                                                                                                            IOUT = 2A
                                                                         10


                                                                                                                                IOUT = 1A


                                                                                                                                      V CNTL = 3.3V
                                                                                                                                      V IN = 2.5V
                                                                          1
                                                                           -40      -20       0         20        40        60        80      100       120
                                                                                                       TEMPERATURE ( C)     o




 2004 Semtech Corp.                                                                                    11                                                    www.semtech.com
                                                                                                                                  SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)


                                                                                       Dropout Voltage
                                                                                       vs. Temperature
                                                                                         (V CNTL - V OUT)
                                                      1500
                                                      1400                                            INITIAL VCNTL = 3.3V
                                                                                                      VIN = 2.5V
                                                      1300
                       DROPOUT VOLTAGE (mV)




                                                                                                      VOUT = 1.8v
                                                      1200
                                                                                                      IOUT = 3A
                                                      1100
                                                      1000
                                                              900
                                                              800
                                                              700
                                                              600
                                                              500
                                                                 -40                   10               60              110
                                                                                       TEMPERATURE (oC)




                                                                                        Dropout Voltage
                                                                                        vs. Tem perature
                                                                                            (V IN - V OUT)
                                                              500

                                                              450
                                                                       IOUT = 3A
                                                              400
                                       DROPOUT VOLTAGE (mV)




                                                              350

                                                              300

                                                              250

                                                              200

                                                              150
                                                                                                       VCNTL = 3.3V
                                                              100
                                                                       IOUT = 2A                       INITIAL VIN = 2.5V
                                                               50
                                                                                                       VOUT = 1.8v
                                                                0
                                                                 -40    -20        0        20   40     60   80       100   120
                                                                                         TEMPERATURE (oC)




 2004 Semtech Corp.                                                                             12                               www.semtech.com
                                                                                                              SC1592

POWER MANAGEMENT
Typical Characteristics (Cont.)

                                                                 47uF ESR vs. Iout
                                         10

                                                                                     Unstable
                                                                                       Area
                                          1
                       ESR (Ohm)


                                         0.1

                                                       Stable
                                        0.01            Area



                                       0.001
                                               0        0.5     1       1.5     2             2.5     3
                                                                OUTPUT CURRENT (A)


                                                                 150uF ESR vs. Iout
                                          10

                                                                                       Unstable
                                                                                         Area
                                               1
                           ESR (Ohm)




                                          0.1

                                                       Stable
                                         0.01           Area



                                        0.001
                                                   0     0.5    1       1.5     2              2.5    3
                                                                OUTPUT CURRENT (A)



                                                                  330uF ESR vs. Iout
                                          10

                                                                                          Unstable
                                           1                                                Area
                          ESR (Ohm)




                                          0.1

                                                       Stable
                                         0.01           Area


                                        0.001
                                                   0     0.5     1        1.5         2         2.5       3
                                                                OUTPUT CURRENT (A)


 2004 Semtech Corp.                                                 13                                       www.semtech.com
                                                                                                       SC1592

POWER MANAGEMENT
Evaluation Board Schematic




                  +3.3V Vcntl                                                             +1.8V Vout
                                                  CNTL                 OUT
                         C1
                        2.2uF
                                                           U1                                  C3
                                                         SC1592                   R2         100uF
                                                                                              (cer)
                                                                                  66.5
                  +2.5V Vin
                                                  IN                  SENSE
                                          R opt
                         C2               10k      EN          GND    ILIM
                        22uF                                                      R3
                        (cer)                                                     53
                                                                         R1
                                                 R2
                                   VOUT = (1 +      ) • VREF             100
                                                 R3
                                   VREF   = 0.8 V typ.




Evaluation Board Schematic - Bill of Material
  R ef      Qty               Reference                  Part Number/Value                  Manufacturer

    1         1        C1                         2.2uF, 16V, Ceramic, 1206    Murata or similar

    2         1        C2                         22uF, 10V, Ceramic, 1210     Murata or similar

    3         1        C3                         100uF, 6.3V, Ceramic, 1812   Murata or similar

    4         1        R1                         100, ±5%, 0805               Any

    5         1        R2                         66.5, ±0.5%, 0805            Any

    6         1        R3                         53, ±0.5%, 0805              Any

    7         1        Ropt                       10K, ±10%, 0805              Any

    8         1        U1                         S C 1592                     Semtech Corp.




 2004 Semtech Corp.                                             14                                    www.semtech.com
                                     SC1592

POWER MANAGEMENT
Evaluation Board - SOIC-8 EDP




 2004 Semtech Corp.            15   www.semtech.com
                                            SC1592

POWER MANAGEMENT
Evaluation Board - TO-263-7L (DDPAK)




 2004 Semtech Corp.                   16   www.semtech.com
                                     SC1592

POWER MANAGEMENT
Outline Drawing - SOIC-8L EDP




Land Pattern - SOIC-8L EDP




 2004 Semtech Corp.            17   www.semtech.com
                                                                        SC1592

POWER MANAGEMENT
Outline Drawing - TO-263-7L (DDPAK)




Recommended Land Pattern - TO-263-7L (DDPAK)




                                                           (FOR REFERENCE)




Contact Information

                                   Semtech Corporation
                           Power Management Products Division
                           200 Flynn Road, Camarillo, CA 93012
                        Phone: (805)498-2111 FAX (805)498-3804


 2004 Semtech Corp.                      18                            www.semtech.com

								
To top