AME5253A Datasheet, PDF (1/18 Pages) Analog Microelectronics – 1A, 1.5MHz Synchronous Step-Down Converter

AME
AME5253A
n General Description
The AME5253A is a high efficiency monolithic syn-
chronous buck regulator using a constant frequency, cur-
rent mode architecture. Capable of delivering 1A output
current over a wide input voltage range from 2.5V to 5.5V.
Supply current with no load is 400µA and drops to<1µA
in shutdown. The 2.5V to 5.5V input Voltage range makes
the AME5253A ideally suited for single Li-Ion battery-
powered applications. 100% duty cycle provides low drop-
out operation, extending battery life in portable systems.
PWM pulse skipping mode operation provides very low
output ripple voltage for noise sensitive applications. At
very light load, the AME5253A will automatically skip
pulses in pulse skip mode operation to maintain output
regulation.
The internal synchronous switch increases efficiency
and eliminates the need for an external Schottky diode.
Low output voltages are easily supported with the 0.6V
feedback reference voltage. The AME5253A is available
in SOT-25 packages.
Other features include soft start, lower internal refer-
ence voltage with 2% accuracy, over temperature protec-
tion, and over current protection.
n Features
l High Efficiency: Up to 95%
l Shutdown Mode Draws < 1µA Supply Current
l 2.5V to 5.5V Input Range
l Adjustable Output From 0.6V to V_IN
l 1A Output Current
l Low Dropout Operation: 100% Duty Cycle
l No Schottky Diode Required
l 1.5MHz Constant Frequency PWM Operation
l SOT-25 Packages
l All AME’ s Lead Free Product Meet RoHS
Standard
1A, 1.5MHz Synchronous
Step-Down Converter
n Applications
l Cellular Telephones
l Personal Information Appliances
l Wireless and DSL Modems
l MP3 Players
l Portable Instruments
n Typical Application
VIN= 2.5V to 5.5V
VIN
IN
2.2µH
SW
C_IN
4.7µF
CER
AME5253A
C_FWD
EN _GND FB
VOUT
1.8V
R1 ^1000mA
150K
C_OUT
10µF
R2 ^CER
75K
V_OUT=V_FB (R1+R2)/R2
Figure 1: 1.8V at 1000mA Step-Down Requlator
C_FWD: 22pF~220pF
Rev.A.03
1