G5728B Datasheet, PDF (1/2 Pages) Global Mixed-mode Technology Inc – 1.4MHz 1A Synchronous Step-Down Regulator

Global Mixed-mode Technology
G5728B
1.4MHz 1A Synchronous Step-Down Regulator
Features
„ High Efficiency: Up to 93%
„ Low Quiescent Current: Only 50µA During Op-
eration
„ Internal Soft Start Function
„ 1A Output Current
„ 2.5V to 6V Input Voltage Range
„ 1.4MHz Switching Frequency
„ No Schottky Diode Required
„ 100% Duty Cycle in Dropout Operation
„ 0.6V Reference Allows Low Output Voltages
„ <1µA Shutdown Current
„ Current Mode Operation for Excellent Line and
Load Transient Response
„ Over Temperature Protected
„ RoHS Compliant
General Description
The G5728B is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, cur-
rent mode architecture. Supply current during opera-
tion is only 50µA and drops to <1µA in shutdown. The
2.5V to 6V input voltage range makes the G5728B
ideally suited for single Li-Ion battery-powered applica-
tions. 100% duty cycle provides low dropout operation,
extending battery run time in portable systems.
Switching frequency is internally set at 1.4MHz, allow-
ing the use of small surface mount inductors and ca-
pacitors. The internal synchronous switch increase
efficiency and eliminates the need for an external
Schottky diode. Built-in soft start function eliminates
in-rush current that could damage the system.
Applications
„ Cellular Telephones
„ Personal Information Appliances
„ Microprocessors and DSP Core Supplies
„ Wireless and DSL Modems
„ Digital Still and Video Cameras
„ MP3 Players
„ Portable Instruments
Ordering Information
ORDER
NUMBER
MARKING
OUTPUT
VOLTAGE (V)
G5728BT11U
578Bx
Adjustable
G5728BTO1U
578Bx
Adjustable
G5728B-12TO1U
578Dx
1.2
G5728BU51D
578B
Note: T1: SOT-23-5 TO:TSOT-23-5 U5:WDFN2X2-6
1: Bonding Code
U&D: Tape & Reel
Adjustable
TEMP.
RANGE
-40°C~ +85°C
-40°C~ +85°C
-40°C~ +85°C
-40°C~ +85°C
PACKAGE
(Green)
SOT-23-5
TSOT-23-5
TSOT-23-5
WDFN2X2-6
Pin Configuration
Typical Application Circuit
EN 1
GND 2
G5728B
5 VFB _{VFB 1}
GND 2
G5728B
7
GND
6 EN
5 LX
LX 3
4 VIN VIN 3
4 GND
SOT-23-5/TSOT-23-5
WDFN2X2-6
V_IN
4~6V
G5728B
4
VIN
3
LX
C_IN
2.2µF
CER
1
EN
R1
V_OUT = 0.6V × (1+ _R2 )
5
VFB
GND
2
2.2µH
C_FB (option)
R1
R2* 82k
18k
* R2≦20kΩ for stability consideration.
V_OUT
3.3V
300mA
C_OUT
10µF
CER
Ver: 0.7
Jul 12, 2013
TEL: [phone]
http://www.gmt.com.tw
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