SGS Thomson Microelectronics ST730ACD-TR, ST730ABN, ST730ACD, ST730ABD-TR, ST730ABD Datasheet
CURRENT-MODE PWM DC-DC CONVERTERS
■ UP TO 450mA LOAD CURRENTS
■ 200kHz HIGH-FREQUENCY
CURRENT-MODE PWM
■ 85% TO 96% EFFICIENCIES
■ 33µHOR100µH PRE-SELECTED
INDUCTOR VALUE, NO COMPONENT
DESIGN REQUIRED
■ 0.8mA QUIESCENT CURRENT
■ 0.3µA SHUTDOWN SUPPLY CURRENT
■ ADJUSTABLE OUTPUT VOLTAGE
■ OVERCURRENT, SOFT-START AND
UNDERVOLTAGE LOCKOUT PROTECTION
■ CYCLE-BY-CYCLE CURRENT LIMITING
■ PACKAGE AVAILABLE: DIP-8 AND SO-8
DESCRIPTION
The ST730A is a 5V output CMOS, step-down
switching regulator. The ST730A accepts inputs
between 5.2V and 11V and delivers 450mA.
Typical efficiencies are 85% to 96%.
Quiescent supply current is0.8mA and o nly 0.3µA
in shutdown mode. The output does not exhibit
frequency over this specified range. Pulse-width
modulation (PWM) current-mode control provides
ST730A
5V STEP-DOWN,
DIP-8 SO-8
precise o utput regulation and excellent transient
responses. Output voltage accuracy is
guaranteed to be ±5% over line, load, and
temperature varations.
Fixed-frequency switching and absence of
subharmonic ruipple allows ea sy filtering of out put
ripple and noise, as well as the use of small
external components. This regul ators require only
a s ingle inductor value to work in most
applications, so no inductor design is necessary.
Typical applications are: Cellular phones & radios,
portable Ins t ru ments, Portable Communications
Equipments and Computer Peripherals.
SCHEMATIC DIAGRAM
1/9January 2003
ST730A
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 thermal design of PCB on which the device is mounted.
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 (C series)
op
Thermal Resistance Junction-ambient (*)
(B series)
160 100 °C/W
-0.3 to 12 V
V
V
V
2A
2.5 mA
550
344
mW
mW
-40 to +150 °C
0to+70
-40 to +85
°C
°C
ORDERING CODES
TYPE DIP8 SO-8 SO-8 (T&R)
ST730AB ST730ABN ST730ABD ST730ABD-TR
ST730AC ST730ACN ST730ACD ST730ACD-TR
2/9
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 a capacitor that does not
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
exceed 47nF
protections.
feedback loop. Connect to OUT with 330pF capacitor
5V 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
ST730A
3/9
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