Product Summary

The UC3844A control IC provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits of UC3844A include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFETs, is low in the off-state.

Parametrics

UC3844A absolute maximum ratings: (1)Supply Voltage (low impedance source): 30 V; (2)Supply Voltage (Ii < 30mA): Self Limiting; (3)Output Current: ±1 A; (4)Output Energy (capacitive load): 5 μJ; (5)Analog Inputs (pins 2, 3): – 0.3 to 5.5 V; (6)Error Amplifier Output Sink Current: 10 mA; (7)Power Dissipation at Tamb ≤ 25 ℃ (DIP-8): 1.25 W; (8)Power Dissipation at Tamb ≤ 25 ℃ (SO-8): 800 mW; (9)Storage Temperature Range: -65 to 150 ℃; (10)Junction Operating Temperature: -40 to 150 ℃; (11)Lead Temperature (soldering 10s): 300 ℃.

Features

UC3844A features: (1)trimmed oscillator discharge current; (2)current mode operation to 500kHz automatic feed forward compensation; (3)latching PWM for cycle-by-cycle current limiting; (4)internally trimmed reference with undervoltage lockout; (5)high current totem pole output undervoltage lockout with hysteresis; (6)low start-up current (< 0.5mA) double pulse suppression.

Diagrams

Image Part No Mfg Description Data Sheet Download Pricing
(USD)
Quantity
UC3844A
UC3844A

Other


Data Sheet

Negotiable 
UC3844AD
UC3844AD

Texas Instruments

Current Mode PWM Controllers Current Mode

Data Sheet

0-1: $0.85
1-25: $0.76
25-100: $0.67
100-250: $0.59
UC3844AD1
UC3844AD1

STMicroelectronics

Switching Converters, Regulators & Controllers RO 511-UC3844BD 9/04

Data Sheet

Negotiable 
UC3844AD8
UC3844AD8

Texas Instruments

Current Mode PWM Controllers Current Mode

Data Sheet

0-1: $0.85
1-25: $0.76
25-100: $0.67
100-250: $0.59
UC3844AD8G4
UC3844AD8G4

Texas Instruments

Current Mode PWM Controllers Current-Mode PWM Controller

Data Sheet

0-1: $0.85
1-25: $0.68
25-100: $0.62
100-250: $0.55
UC3844AD8TR
UC3844AD8TR

Texas Instruments

Current Mode PWM Controllers Current-Mode PWM Controller

Data Sheet

0-1730: $0.33
1730-2000: $0.31
2000-2500: $0.31
2500-5000: $0.30
UC3844AD8TRG4
UC3844AD8TRG4

Texas Instruments

Current Mode PWM Controllers Current-Mode PWM Controller

Data Sheet

0-1730: $0.33
1730-2000: $0.31
2000-2500: $0.31
2500-5000: $0.30
UC3844ADG4
UC3844ADG4

Texas Instruments

Current Mode PWM Controllers Current Mode

Data Sheet

0-1: $0.85
1-25: $0.68
25-100: $0.62
100-250: $0.55