Global Mixed-mode Technology Inc.
G5503
300KHz, 3A Buck Converter
Features
Voltage Mode Asynchronous PWM Control
3.3V, 5V and Adjustable Output Version
Operation Voltage can be up to 20V
Adjustable Version Output Voltage Range, 0.8V
to 16V±2%
300KHz Fixed Frequency Internal Oscillator
Built-in Switching Transistor on Chip
3A Output Load Current
Thermal Shutdown and Current Limit Protec-
tion
ON/OFF Shutdown Control
Iq of Low Power Standby Mode 1µA
Available in SOP-8 Packages
The G5503 is a voltage-mode buck PWM converter
capable of driving up to 3A loads over a wide input
supply range. High efficiency is obtained through the
use of a low R
DS(ON)
P-channel power switch. The in-
ternal compensation makes feedback control have
excellent line and load regulation characteristics with-
out external designs.
It uses a fixed switching frequency of 300KHz. The
output voltage is 3.3V, 5V and an user-programmable
version via an external resistive voltage divider. The
built-in soft-start can reduce inrush current on the input
source at turn on.
The device also has built-in current-limit, thermal
shutdown, under-voltage lockout and an ON/OFF
logic-control that can power down the regulator to a
shutdown mode. When current limit function occurred
and V
FB
is down to 0.3V below, the device changes
switching frequency to 120KHz to protect IC from
damage.
G5503 is available in SOP-8 package.
Applications
Simple high-efficiency step-down regulator
On-card switching regulators
Positive to negative converter
General Description
Ordering Information
ORDER
NUMBER
G5503-ADJP11U
G5503-33P11U
G5503-50P11U
Note: P1: SOP-8
1: Bonding Code
U: Tape & Reel
MARKING
5503A
5503B
5503C
VOLTAGE
Adjustable
3.3V
5.0V
TEMP.
RANGE
-40°C~85°C
-40°C~85°C
-40°C~85°C
PACKAGE
(Pb free)
SOP-8
SOP-8
SOP-8
Pin Configuration
Typical Application Circuit
G5503
FB
EN
NC
IN
1
2
3
4
8
7
6
5
NC
GND
LX
NC
V
OUT
= 0.8
x
(
1 +
R1
R2
G5503
V
IN
6V~18V
470µF
1µF
EN
GND
FB
IN
LX
33µH
D1
SCD36 R1/31.25K 220µF
1µF
*
V
OUT
3.3V/2A
R2/10K
SOP-8
)
*
optional
Ver: 0.1
May 02, 2008
TEL: 886-3-5788833
http://www.gmt.com.tw
1
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