DESCRIPTION

UTC UC3883 is a highly integrated current mode PWM control

IC optimized for high performance, low standby power and cost

effective offline flyback converter applications.

PWM switching frequency at normal operation is internally fixed

and is trimmed to tight range. At no load or light load condition, the

IC operates in extended ‘burst mode’ to minimize switching loss.

Lower standby power and higher conversion efficiency is thus

achieved.

VCC low startup current and low operating current contribute to a

reliable power on startup and low standby design with UTC

UC3883.

UTC UC3883 offers complete protection coverage with

auto-recovery including Cycle-by-Cycle current limiting (OCP), over

load protection (OLP), over temperature protection (OTP) and VCC

under voltage lockout (UVLO). It also provides the over voltage

protection (OVP) protections with latched shut down. Excellent EMI

performance is achieved with On-Bright proprietary frequency

shuffling technique.

The tone energy at below 20KHZ is minimized in the design and

audio noise is eliminated during operation.

UTC UC3883 is offered in SOT-26 package.

FEATURES

* Power on Soft Start Reducing MOSFET VDS Stress

* Frequency shuffling for EMI

* Extended Burst Mode Control For Improved Efficiency and

Minimum Standby Power Design

* Ultra Low Operating Current at Light Load (typical 0.6mA)

* Audio Noise Free Operation

* Normal 65KHz Switching Frequency

* Frequency Triple for peak load(195Khz)

* Adjustable Overload Protection (OLP) delay time

* Comprehensive Protection Coverage

VCC Under Voltage Lockout with Hysteresis (UVLO)

Cycle-by-cycle over current threshold setting for constant output

power limiting over universal input voltage range

Overload Protection (OLP) with autorecovery

External (if NTC resistor is connected at CT/RT pin) or internal (if

capacitor is connected at CT/RT pin) Over Temperature

Protection (OTP) with autorecovery.

VCC Over Voltage Protection (OVP) with latch shut down