UC3550

DESCRIPTION

The UTC UC3550 series is a compact, high efficiency, step-up

DC/DC controllers includes an error amplifier, oscillator, PWM

comparator, skip cycle comparator, voltage reference, soft-start, and

high speed lower ON-resistance driver for driving external power

devices (NMOS or NPN) ,Additionally, a CE (chip enable) function that

reduces power consumption during shut-down mode.

That typically operated from a single-or dual-cell battery packs. It

have a driver pin ,ext pin, for connecting to an external

transistor(NMOS or NPN). a lower ON-resistance external transistor

can obtain larger output current. With only external components, this

series allow a simple means to accommodate high output current

applications.

The UTC UC3550 series goes automatically into skip switching

cycles under light load condition to maintain high efficiency.

FEATURES

* Input Voltage Range：0.9~8V

* Output Voltage Range：1.8~6V Programmable in 0.1V with High

Accuracy ± 2.5%

* High Efficiency 88% (Typ.)

* Low Start-up Voltage of 0.9V Typical at I OUT = 1.0mA

* Oscillator Frequency: 300kHz.(±20%)

* Chip Enable Pin with Pull-up Current Source

* High Output Current up to 1000mA (V IN = 2.0V, V OUT =3.3V)

规格书UC3550