SGS Thomson Microelectronics ST763ACN, ST763ACDTR, ST763ACD, ST763ABN, ST763ABDTR Datasheet

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ST763A SERIES

3.3V STEP DOWN

CURRENT MODE PWM DC-DC CONVERTERS

■ OUTPUT VOLTAGE 3.3V

■ SUPPLY VOLTAGE RANGE FROM 3 .3 V TO

11V

■ GUARANT EED OUT P UT CURRENT: 500mA

■ TYPICAL OPERATION FREQUENCY:

200KHz

■ VERY LOW QUIESCENT CURRENT: 0.6mA

ON MODE 0.2µA OFF MODE

■ SWITCH ON/OFF CONTROL

■ TYPICAL EFFICENCY: 90%

■ OPERATING TEMPERATURE RANGE:

-40°C TO 85°C

■ AVAILABLE IN SO-8 AND DIP-8 PACKAGES

DESCRIPTION

The ST763A is a step-down switching regulator . It operates from 3.3V to 11V giving a fixed 3.3V output voltage, delivering up to 500mA. The mainly features are typical efficiency of 90%, quiescent current of 0.6mA, and only 0.2µA in shut-down. The PWM current m ode control provides precise output regulation and very good transient response. Output vo ltage accuracy is gua ranteed to be ±5% over line, load and temperature variations. A minimum number of external

DIP-8 SO-8

components is used and the fixed frequency switching allows easy filtering of output ripple a nd noise. Other features of t his ddevice are cycle-by-clicle current limiting, overcurrent limiting, under voltage lockout and programmable soft-start protection. A 22µH inductor works in most applications, so no sophisticated design is necessary. Package available are SO-8 and DIP-8. Typical application are in 5V to 3.3V converters, cellular phones, portable instruments, hand-held computers, and peripherals.

SCHEMATIC DIAGRAM

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ST763A SERIES

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter² Value Unit

SHDN

S,VC

REF

TOT

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.

THERMAL DATA

Symbol Parameter SO-8 DIP-8 Unit

thj-amb

(*) This value depends from ther m al design of PCB on which the device is mou nt ed.

DC Input Voltage

Switch Pin Voltage -0.3 to (VCC + 0.3)

Shutdown Voltage (SHDN) -0.3 to (VCC + 0.3) Soft Start (SS) and Compensation Capacitor (CC) Pins Voltage -0.3 to (VCC + 0.3) Switching Peak Current Reference Current Continuous Power Dissipation at TA=70°C (DIP-8)

(SO-8) Storage Temperature Range

stg

Operating Junction Temperature Range (AC series)

(AB series)

Thermal Resistance Junction-ambient (*)

160 100 °C/W

-0.3 to 12 V V V V

2.5 mA

550 344

mW mW

-40 to +150 °C 0 to +70

-40 to +85

°C °C

ORDERING CODES

TYPE DIP8 SO-8 SO-8 (T&R)

ST763AB ST763ABN ST763ABD ST763ABDTR ST763AC ST763ACN ST763ACD ST763ACDTR

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CONNECTION DIAGRAM (top view)

PIN DESCRIPTION

Pin N° Symbol Name and Function

1 SHDN

2 REF Reference Output Voltage:(1.25V): Bypass to GND with 47nF capacitor 3 SS Soft Start: a capacitor between SS and GND provides soft-start and short-circuit

4 CC Compensation Capacitor Input: externally compensates the outer (voltage)

5 OUT Output Voltage Sense Input: provides regulation of feedback sensing. Connect to

6 GND Ground 7 LX Switch Output. Drain of internal P-Channel Power MOSFET 8V

Shutdown control (active low): If connected to GND the IC is in shutdown. Connect to V

for normal operation (ON MODE)

protections.

feedback loop. Connect to OUT with 330pF capacitor

3.3V output.

Supply Voltage Input. Bypass to GND with 1µF ceramic capacitance and large value electrolytic capacitor in parallel. The 1µF capacitor must be as close as possible to the GND and V

pins

ST763A SERIES

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