AME5258 Datasheet, PDF (1/17 Pages) AMETHERM Circuit Protection Thermistors – 1.5MHz, 600mA Synchronous Buck Converter

AME
AME5258
1.5MHz, 600mA
Synchronous Buck Converter
n General Description
The AME5258 is a high efficiency monolithic synchro-
nous buck regulator using a constant frequency, current
mode architecture. The device is available in an adjustable
version and fixed output voltages of 1.2V, 1.8V, 2.5V and
3.3V. Supply current with no load is 300µA and drops to
<1µA in shutdown. The 2.5V to 5.5V input voltage range
makes the AME5258 ideally suited for single Li-Ion bat-
tery-powered applications. 100% duty cycle provides low
dropout operation, extending battery life in portable sys-
tems. PWM pulse skipping mode operation provides very
low output ripple voltage for noise sensitive applications.
At very light load, the AME5258 will automatically skip
pulses in pulse skip mode operation to maintain output
regulation.
The AME5258 is simple to use. As with standard
LDO's,Input and output capacitor are required. The only
other element is a small, low cost, 2.2µH inductor.Low
output voltages are easily supported with the 0.6V feed-
back reference voltage. And 100% duty cycle when Vin
approaches Vout.
n Features
l High Efficiency: Up to 96%
l 600mA Output Current at V_IN=3V
l 2.5V to 5.5V Input Voltage Range
l 1.5MHz Constant Frequency Operation
l No Schottky Diode Required
l Low Dropout Operation: 100% Duty Cycle
l 0.6V Reference Allows Low Output
Voltages
l Shutdown Mode Draws<1µA Supply
Current
l Current Mode Operation for Excellent
Line and Load Transient Response
l Overtemperature Protection
l Internal Soft Start
l Space Saving 5-Pin SOT-25 Package
l Meet RoHS Standards
n Applications
l Cellular Phones
l Digital Cameras
l Portable Electronics
l USB Devices
l MP3 Players
l LDO Replacement
n Typical Application
VIN
C_IN
4.7µF
CER
Fixed Output Voltage
2.2µH
IN
SW
AME5258
EN
OUT
GND
VOUT
C_OUT
10µF
CER
Figure 1: High Efficiency Step-Down Conventer
Adjustable Output Voltage
V_IN = 2.5V to 5.5V
VIN
IN
2.2µH
SW
C_IN
4.7µF
CER
AME5258
22pF
EN
FB
GND
VOUT
1.8V
600mA
R1
887K _COUT
10µF
CER
R2
442K
V_OUT=V_FB (R1+R2)/R2
Figure 2: 1.8V at 600mA Step-Down Requlator
Rev.A.05
1