UC1844A-EP

Features:

 Controlled Baseline
    One Assembly/Test Site, One Fabrication Site
 Extended Temperature Performance of
    55°C to 125°C
 Enhanced Diminishing Manufacturing Sources (DMS) Support
 Enhanced Product Change Notification
 Qualification Pedigree†
Optimized for Off-line and DC to DC Converters
 Low Start Up Current (<0.5 mA)
 Trimmed Oscillator Discharge Current
 Automatic Feed Forward Compensation
 Pulse-by-Pulse Current Limiting
 Enhanced Load Response Characteristics
 Under-Voltage Lockout With Hysteresis
 Double Pulse Suppression
 High Current Totem Pole Output
 Internally Trimmed Bandgap Reference
 500 kHz Operation
 Low R_O Error Amp


Pinout




Specifications

VCC voltage (low impedance source) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . 30 V
VCC voltage (I_CC mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . self limiting
Output current, I_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . ±1 A
Output energy (capacitive load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 J
Analog Inputs (pins 3, 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.3 V to 6.3 V
Error Amp Output Sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA
Power Dissipation at T_A < +25C (D package) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . 1 W
Package thermal impedance, JA (see Note 1): D (8-pin) package . . . . . . . . . . . . . . . . . . . . 97°C/W
Storage temperature range, T_stg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65^oC to 150^oC
Lead temperature soldering 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . .. 260 ^oC


Description

The UC1842A/3A/4A/5A family of control ICs is a pin for pin compatible improved version of the UC3842/3/4/5 family. Providing the necessary features to control current mode switched mode power supplies, this family has the following improved features. Start up current is guaranteed to be less than 0.5 mA. Oscillator discharge is trimmed to 8.3 mA. During under voltage lockout, the output stage can sink at least 10 mA at less than 1.2 V for V_CC over 5 V.

The difference between members of this family are shown in the table below.