AME5250 Datasheet, PDF (1/21 Pages) Analog Microelectronics – 1A, 1.5MHz Synchronous Step-Down Converter

AME
AME5250
n General Description
The AME5250 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. Capable of delivering 1A output cur-
rent over a wide input voltage range from 2.5V to 5.5V,
the AME5250 is ideally suited for single Li-Ion battery
powered applications. 100% duty cycle provides low
dropout operation, extending battery life in portable sys-
tems. Under light load conditions, the AME5250 oper-
ates in a power saving mode that consumes just around
20µA of supply current, maximizing battery life in por-
table applications.
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 AME5250 is available
in small DFN-6D & QFN-16C packages.
Other features include soft start, lower internal refer-
ence voltage with 2% accuracy, over temperature protec-
tion, and over current protection.
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
V_IN
C_IN
4.7µF
CER
2.2µH
IN
SW
AME5250
EN
OUT
GND
VOUT
C_OUT
10µF
CER
Fixed Output Voltage
Figure 1. High Efficiency Step-Down Converter
n Features
l High Efficiency: Up to 95%
l Very Low 20µA Quiescent Current
l High efficiency in light load condition
l 2.5V to 5.5V Input Range
l Adjustable Output From 0.6V to V_IN
l 1.0V, 1.2V, 1.5V, 1.6V, 1.8V, 2.5V and
3.3V Fixed/Adjustable Output Voltage
l 1A Output Current
l Low Dropout Operation: 100% Duty Cycle
l No Schottky Diode Required
l 1.5MHz Constant Frequency PWM Operation
l Small DFN-6D & QFN-16C Packages
l All AME’ s Lead Free Product Meet RoHS
Standard
Rev.B.04
VIN
2.5V to 5.5V
IN
2.2µH
SW
CIN
4.7µF
CER
AME5250
C_FWD
EN
FB
GND
V_OUT
1.8V
R1 _1000mA
150K
C_OUT
10µF
R2 ^CER
75K
V_OUT=V_FB (R1+R2)/R2
Adjustable Output Voltage
Figure 2. 1.8V at 1000mA Step-Down Requlator
C_FWD: 22pF~220pF
1