High Efficiency 8A Synchronous Buck Converter

G5312
Global Mixed-mode Technology
High Efficiency 8A Synchronous Buck Converter
Features
General Description
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G5312 is a 8A, synchronous DC/DC buck converter
with integrated 20mΩ N-channel high-side MOSFET
and 20mΩ N-channel low-side MOSFET. It uses constant on-time control scheme to handle wide input/output voltage ratios with ease and provides 100ns
“instant-on” response to load transients while maintaining a relatively constant switching frequency. The
G5312 achieves high efficiency at a reduced cost by
eliminating the current-sense resistor found in traditional current-mode PWMs. Single-stage buck conversion allows these devices to directly step down
high-voltage batteries for the highest possible efficiency. The built-in 5V LDO supports 20mA for internal
circuits. The G5312 is intended for the main power
supply of LCD TV, Notebook Computer, or other
low-voltage supplies as low as 0.75V. The G5312 is
available in QFN4X4-28 package.
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Ultra-High Efficiency
Integrated 20mΩ at Vcc=5V N-Channel MOSFET
for Low Side
Integrated 20mΩ at Vcc=5V N-Channel
MOSFET for High Side
No Current-Sense Resistor (Lossless ILIMIT)
Quasi-PWM with 100ns Load-Step Response
1% VOUT Accuracy Over Line and Load
Programmable Switching Frequency
Adjustable Output Range from 0.75V
4.5V to 28V Adapter or Battery Input Range
Integrated Boost Switch
OVP & UVP
Over Temperature Protection (non-latch)
3.3ms Soft-Start
Power-Good Indicator
Fixed 5V, 20mA Linear Regulator
Applications
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LCD Monitor/LCD TV
Notebook Computers
„ I/O Supply
„ Chipset/RAM Supply as Low as 0.75V
„ Networking Power Supply
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Ordering Information
ORDER
NUMBER
MARKING
TEMP.
RANGE
PACKAGE
(Green)
G5312QN1U
5312
-40°C to +85°C
QFN4X4-28
G5312QN2U
5312
-40°C to +85°C
QFN4X4-28
Note:QN: QFN4X4-28
1 & 2: Leadframe Code
U : Tape & Reel
TON
EN
BST
NC
23
22
21
25
24
VCC
OUT
26
PGOOD
21
FB
22
28
BST
NC
23
27
TON
EN
24
VCC
OUT
25
FB
27
26
PGOOD
28
Pin Configuration
ILIM
1
20
V+
ILIM
1
20
V+
AGND
2
19
V+
AGND
2
19
V+
V5V
3
18
V+
V5V
3
18
V+
PGND
4
17
V+
PGND
4
17
V+
LX
5
16
PGND
15
16
PGND
PGND
15
PGND
12
PGND
13
11
PGND
14
10
LX
PGND
9
LX
PGND
8
14
LX
13
8
PGND
LX
LX
PGND
7
12
6
LX
LX
PGND
LX
7
11
6
LX
PGND
LX
9
5
10
LX
V+
AGND
LX
V+
LX
AGND
G5312QN2U QFN4X4-28
G5312QN1U QFN4X4-28
Note: Recommend connecting the Thermal Pad to the Ground for excellent power dissipation.
TEL: 886-3-5788833
http://www.gmt.com.tw
Ver: 1.1
Oct 21, 2013
1