Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Holder SOIC 8



      

SLVS141A − JULY 1996 − REVISED JANUARY 1997

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

POST OFFICE BOX 1443

• HOUSTON, TEXAS 77251−1443

D Negative 5-V 200-mA Output (V

≥ 4.5 V)

D 4-V to 6.2-V Input Operating Range

D 78% Typical Efficiency

D 160-kHz Fixed-Frequency Current-Mode

PWM Controller

D EN Input Inhibits Operation and Reduces

Supply Current to 1 µA

D Soft Start

D 8-Pin SOIC and DIP Packages

D −40°C to 85°C Free-Air Temperature Range

D Pin-for-Pin Compatible with MAX735

description

The TPS6735 is a fixed negative 5-V output inverting dc/dc converter capable of delivering 200 mA from inputs

as low as 4.5 V. The only external components required are an inductor, an output filter capacitor, an input filter

capacitor, a reference filter capacitor, and a Schottky rectifier. An enable input is provided to shut down the

inverter when a −5-V output is not needed. The typical supply current is 1.9 mA at no-load and is further reduced

to 1-µA when the enable input is low.

The TPS6735 is a 160-kHz current-mode pulse-width-modulation (PWM) controller with a p-channel MOSFET

power switch. The gate drive uses the −5-V output to reduce the die area needed to realize the 0.4-Ω MOSFET.

Soft start is accomplished with the addition of one small capacitor at SS. A 1.22-V reference is available for

external loads up to 125 µA.

The TPS6735 is attractive for board-level dc/dc conversion in computer peripherals and in battery-powered

equipment requiring high efficiency and low supply current.

The TPS6735 is available in 8-pin DIP and SOIC packages and operates over a free-air temperature range of

−40°C to 85°C.

REF

COMP

OUT

GND

TPS6735

1 µF

47 µF

82 pF

†

10 µF

10 µH

1N5817

100 µF

− 5 V

4 V to 6.2 V

ENABLE

†

Not required for loads of 100 mA or less

Figure 1. Typical Circuit

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications o

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

REF

COMP

OUT

GND

D OR P PACKAGE

(TOP VIEW)

  ! " #$%! "  &$'(#! )!%*

)$#!" # ! "&%##!" &% !+% !%"  %," "!$%!"

"!)) -!.* )$#! &#%""/ )%" ! %#%""(. #($)%

!%"!/  (( &%!%"*

Summary of content (18 pages)

PAGE 1
SLVS141A − JULY 1996 − REVISED JANUARY 1997 D D D D D D D D D Negative 5-V 200-mA Output (VCC ≥ 4.5 V) 4-V to 6.
PAGE 2
SLVS141A − JULY 1996 − REVISED JANUARY 1997 AVAILABLE OPTIONS PACKAGED DEVICES TA SMALL OUTLINE (D) −40°C to 85°C TPS6735ID CHIP FORM (Y) PLASTIC DIP (P) TPS6735IP TPS6735Y The D package is also available taped and reeled (TPS6735IDR). functional block diagram EN 1 EN EN FB COMP GND 5 2 Σ Drive Latch + _ R Driver Q Error Amplifier REF Voltage Reference S PWM Comparator 7 FB 160-kHz Oscillator Power Switch PMOS 1.
PAGE 3
SLVS141A − JULY 1996 − REVISED JANUARY 1997 chip information These chips, when properly assembled, display characteristics similar to the TPS6735. Thermal compression or ultrasonic bonding may be used on the doped aluminum bonding pads. The chips may be mounted with conductive epoxy or a gold-silicon preform.
PAGE 4
SLVS141A − JULY 1996 − REVISED JANUARY 1997 detailed description The following descriptions refer to the functional block diagram. current-sense amplifier The current-sense amplifier, which has a fixed gain of 3, amplifies the slope-compensated current-sense voltage (a summation of the voltage on the current-sense resistor and the oscillator ramp) and feeds it to the PWM comparator.
PAGE 5
SLVS141A − JULY 1996 − REVISED JANUARY 1997 SS clamp The SS clamp circuit limits the signal level on error-amplifier output during start-up. The voltage on SS is amplified and used to override the error-amplifier output until it rises above that output, at which point the error amplifier takes over. This prevents the input to the PWM comparator from exceeding its common-mode range (i.e.
PAGE 6
SLVS141A − JULY 1996 − REVISED JANUARY 1997 electrical characteristics over recommended operating free-air temperature range, VCC = 5 V, IO = 0, EN = 5 V, typical values are at TA = 25°C (unless otherwise noted) (refer to Figure 15) PARAMETER TEST CONDITION MIN Supply current TYP MAX 1.9 Standby current EN = 0.4 V 1 High-level input threshold voltage, EN Low-level input threshold voltage, EN 0.
PAGE 7
SLVS141A − JULY 1996 − REVISED JANUARY 1997 5 0 −5 VI = 5 V VO = − 5 V IO = 100 mA 1 0.5 0 I − Inductor Current − A Voltage at Out − V APPLICATION INFORMATION 2.5 µs/div t − Time − s Figure 2. Switching Waveforms 1 0.5 0 0 −50 Output Voltage − mV I − Inductor Current − A VI = 5 V VO = − 5 V IO = 100 mA 2.5 µs/div t − Time − s Figure 3.
PAGE 8
SLVS141A − JULY 1996 − REVISED JANUARY 1997 VI = 5 V VO = − 5 V IO = 0 mA to 200 mA 200 100 50 0 −50 2 ms/div Output Voltage Ripple − mV I L − Load Current − mA APPLICATION INFORMATION t − Time − s Figure 4. Load Transient Response 5 4 3 10 2 0 1 − 10 0 VI = 4.5 V to 6 V VO = − 5 V IO = 100 mA 2 ms/div t − Time − s Figure 5.
PAGE 9
SLVS141A − JULY 1996 − REVISED JANUARY 1997 4 2 0 VI = 5 V VO = −5 V IO = 100 mA 0 −2 −4 −6 VO − Output Voltage − V Voltage at EN − V APPLICATION INFORMATION 2.5 ms/div t − Time − s Figure 6. Enable Response Time system typical characteristics EFFICIENCY vs LOAD CURRENT PEAK INDUCTOR CURRENT vs LOAD CURRENT 80 1.8 TA = 25°C (see Figure 15) VI = 5 V (see Figure 15) 1.6 78 1.
PAGE 10
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION system typical characteristics (continued) NO-LOAD SUPPLY CURRENT vs SUPPLY VOLTAGE MAXIMUM LOAD CURRENT vs SUPPLY VOLTAGE 2 (see Figure 15) 350 1.6 Maximum Load Current − mA No-Load Supply Current − mA 1.8 400 IO = 0 A (see Figure 15) 1.4 1.2 1 0.8 0.6 0.4 250 200 150 100 50 0.2 0 0.5 1 300 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 0 3.75 4 4.25 4.5 4.75 5 5.25 5.5 5.75 6 6.25 6.
PAGE 11
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION system typical characteristics (continued) SOFT-START DELAY vs CAPACITANCE DRAIN-SOURCE ON-STATE RESISTANCE vs TEMPERATURE r DS(on) − Drain-Source On-State Resistance − Ω 70 C6 varied (see Figure 7) 60 Soft-Start Delay − ms VI = 4 V 50 40 VI = 6 V 30 VI = 5 V 20 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 C − Capacitance − µF 0.7 0.6 VI = 6 V 0.5 0.
PAGE 12
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION output filter capacitor A low equivalent series resistance (ESR) output filter capacitor is necessary to minimize the output-ripple voltage. An ESR of 100 mΩ limits the output ripple to 90 mV or less for output loads up to 200 mA.
PAGE 13
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION Table 1. Bill of Materials QTY REF DES DESCRIPTION 1 IC Power supply 1 Diode Schottky −5 V MANUFACTURER PART NO.
PAGE 14
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION TEXAS INSTRUMENTS C1 P1 SLVP095 P2 C5 R3 U1 D1 C2 R1 J1 C4 L1 C3 R2 TPS6735 EVALUATION BOARD SOLDER PASTE MASK Figure 17. Solder Paste Mask COMPONENT SIDE Figure 18.
PAGE 15
SLVS141A − JULY 1996 − REVISED JANUARY 1997 APPLICATION INFORMATION Figure 19.
PAGE 16
SLVS141A − JULY 1996 − REVISED JANUARY 1997 MECHANICAL DATA D (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PIN SHOWN PINS ** 0.050 (1,27) 8 14 16 A MAX 0.197 (5,00) 0.344 (8,75) 0.394 (10,00) A MIN 0.189 (4,80) 0.337 (8,55) 0.386 (9,80) DIM 0.020 (0,51) 0.014 (0,35) 14 0.010 (0,25) M 8 0.244 (6,20) 0.228 (5,80) 0.008 (0,20) NOM 0.157 (4,00) 0.150 (3,81) 1 Gage Plane 7 A 0.010 (0,25) 0°−ā 8° 0.044 (1,12) 0.
PAGE 17
SLVS141A − JULY 1996 − REVISED JANUARY 1997 MECHANICAL DATA P (R-PDIP-T8) PLASTIC DUAL-IN-LINE PACKAGE 0.400 (10,60) 0.355 (9,02) 8 5 0.260 (6,60) 0.240 (6,10) 1 4 0.070 (1,78) MAX 0.310 (7,87) 0.290 (7,37) 0.020 (0,51) MIN 0.200 (5,08) MAX Seating Plane 0.125 (3,18) MIN 0.100 (2,54) 0.021 (0,53) 0.015 (0,38) 0°−ā 15° 0.010 (0,25) M 0.010 (0,25) NOM 4040082 / B 03/95 NOTES: A. All linear dimensions are in inches (millimeters). B.
PAGE 18
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.