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

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

1/10November 2000

ST763A SERIES

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter² Value Unit

V

V

V

SHDN

V

S,VC

I

LX

I

REF

P

TOT

T

T

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

R

thj-amb

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

DC Input Voltage

CC

Switch Pin Voltage -0.3 to (VCC + 0.3)

LX

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)

op

(AB series)

Thermal Resistance Junction-ambient (*)

160 100 °C/W

-0.3 to 12 V
V
V
V

2A

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

CC

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

for normal operation (ON MODE)

CC

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

CC

pins

ST763A SERIES

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ST763A SERIES

ELECTRICAL CHARACTERISTICS (VCC=5V, IO = 0mA, TA = T

MIN

to T

, unless otherwise specified.)

MAX

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

Input Voltage 3.3 11 V

CC

V

Output Voltage VCC = 4 to 11V IO =0 to 300mA

O

∆V
∆V

Line Regulation 0.13 %/V

O

Load Regulatio IO = 1 to 500mA 0.005 %/mA

O

η Power Efficency I

I

SUPPLY

I

SHDN

V

R

DS(on)

I

LEAK

V

∆V

f

Supply Current ON Mode (Including Switch Current)

V

SHDN Input High Threshold 2 V

IH

V

SHDN Input Low Threshold 0.25 V

IL

Shutdown Input Leakage
Current

Under Voltage Lockout VCC Falling 2.7 3 V

LOCK

LX On Resistance ILX=500mA 1 Ω
LX Leakage Current VCC = 12V VLX = 0V 10 nA
Reference Voltage TA = 25°C 1.18 1.25 1.32 V

REF

Temeperature Reference

REF

Drift
Switching Frequency 159 200 212.5 KHz

OSC

R

Compensation Pin

C

Impedance

V

= 4.75 to 11V IO =0 to 500mA

CC

=300mA

O

I

=100mA

O

OFF Mode

TA = T

MIN

to T

MAX

3.135

3.135

3.3

3.465

3.3

3.465

88
90

0.6

0.2

2.5

100

1 µA

50 ppm/°C

7500 Ω

V
V

%
%

mA

µA

TYPICAL APPLICATION CIRCUIT

SHDN

REF

0.047 µF

SS

1500 pF

CC

470 pF

Vcc

Lx

GND

OUT

22 µH

STPS330U

+

100 µF

220 µF

Vout

Vin

+

1 µF

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ST763A SERIES

TYPICAL PERFORMANCE CHARACTERISTICS (unless otherwise specified Tj = 25°C
Figure 1 : Output Voltage vs Temp erature

Figure 2 : Output Voltage vs Input Voltage

Figure 4 : Efficency vs Temperature

Figure 5 : Efficency vs Output Current

Figure 3 : Reference Voltage vs Temperature

Figure 6 : LX Leakage Current vs Temperature

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ST763A SERIES

V

I

A

Figure 7 : LX ON Resistance vs Temperature

Figure 8 : Shutdown Input Threshold vs

Temperature

Figure 10 : Oscillator Freque ncy vs Tem peratu re

Figure 11 : Oscillator Freque ncy vs Input Voltag e

Figure 9 : Shutdown Input Leakage Current vs

Temperature

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Figure 12 : Switching Waveforms, Continuous
Conduction

=6V,

=250m

I

O

ST763A SERIES

V

I

A

i

A

V

I

A

Figure 13 : Switching Waveforms, Discontinuous
Conduction

=6V,

=75m

I

O

Figure 14 : Line Transient

Figure 15 : Load Transient

=5V,

=0 to 500m

I

O

=350m

O

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ST763A SERIES

Plastic DIP-8 MECHANICAL DATA

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A3.3 0.130

a1 0.7 0.028

B 1.39 1.65 0.055 0.065

B1 0.91 1.04 0.036 0.041

b0.5 0.020

b1 0.38 0.5 0.015 0.020

D9.80.386
E8.8 0.346

e2.54 0.100
e3 7.62 0.300
e4 7.62 0.300

F7.10.280

I4.80.189
L3.3 0.130
Z 0.44 1.6 0.017 0.063

mm inch

8/10

P001F

SO-8 MECHANICAL DATA

ST763A SERIES

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A1.750.068
a1 0.1 0.25 0.003 0.009
a2 1.65 0.064
a3 0.65 0.85 0.025 0.033

b 0.35 0.48 0.013 0.018

b1 0.19 0.25 0.007 0.010

C 0.25 0.5 0.010 0.019
c1 45 (typ.)

D 4.8 5.0 0.188 0.196

E 5.8 6.2 0.228 0.244

e1.27 0.050

e3 3.81 0.150

F 3.8 4.0 0.14 0.157

L 0.4 1.27 0.015 0.050
M0.60.023
S8 (max.)

mm inch

0016023

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ST763A SERIES

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mentioned in this publication ar e subject to change without notice. This publication supersedes and replaces all information
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systems without express written approval of STMicroelectronics.

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