AIC2351的特性及應用

Low-Noise Synchronous PWM/PFM Step-Down DC/DC Converter

FEATURES
2.5V to 5.5V Input Voltage Range
600mA Guaranteed Output Current
95% Efficiency
No Schottky Diode Required
30?A Low Quiescent Current
100% Duty Cycle in Low Dropout Operation
1.5MHz Fixed-Frequency PWM Operation
Accurate Reference 0.6V Provides Low Output Voltages
Small 5-Pin SOT23 Package

APPLICATIONS
Cellular Phones
CPU I/O Supplies
Cordless Phones
Notebook Chipset Supplies
PDAs and Handy-Terminals
Battery-Operated Devices (1 Li-Ion or 3 NiMH/ NiCd).

DESCRIPTION
The AIC2351 is a low-noise, pulse-width-modulated (PWM), DC-DC step-down converter. The device is available in an adjustable version and fixed output voltages of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. AIC2351 is capable of delivering continuous 600mA output current over a wide input voltage range from 2.5V to 5.5V. However, it can provide higher peak current. For example, over 1A peak current in the condition of 5V input and 1.2V output. See Fig.12 for detail.

The device features an internal synchronous rectifier for high efficiency; it requires no external Schottky diode. Internally fixed-frequency 1.5MHz operation provides easy post-filtering and allows the use of small inductors and capacitors. The AIC2351 is ideally suited for Li-Ion battery applications. PWM/PFM mode extends battery life by switching to a pulse-frequency-modulated mode during light loads. Shutdown mode places the device in standby, reducing quiescent supply current to under 0.1?A.

Other features of the AIC2351 include high efficiency, low dropout voltage, and an accurate reference 0.6V provides low output voltages. It is available in a space-saving 5-pin SOT23 package.

?AIC2351 datasheet,pdf