Product Summary

The UC3842B is a control IC. The UC3842B 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 include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lock out featuring start-upcurrent less than 0.5mA, a precision reference trimmed for accuracy at the error ampinput, logicto insure latched operation, a PWM comparator which also provides current limit control, and a totempole output stage designed to source or sink high peakcurrent.The UC3842B outputstage, suitable for driving N-Channel MOSFETs, is low in the off state.

Parametrics

UC3842B absolute maximum ratings: (1)Vi, Supply Voltage (low impedance source): 30 V; (2)Vi, Supply Voltage (Ii < 30mA): Self Limiting; (3)IO, Output Current: ±1 A; (4)EO, Output Energy (capacitive load): 5 mJ; (5)Analog Inputs (pins 2, 3): – 0.3 to 5.5 V; (6)Error Amplifier Output Sink Current: 10 mA; (7)Ptot, Power Dissipation at Tamb 3 25 ℃ (Minidip): 1.25 W; (8)Ptot, Power Dissipation at Tamb 3 25 ℃ (SO8): 800 mW; (9)Tstg, Storage Temperature Range: – 65 to 150 ℃; (10)TJ, Junction Operating Temperature: – 40 to 150 ℃; (11)TL, Lead Temperature (soldering 10s): 300 ℃.

Features

UC3842B features: (1)trimmed oscillator for precise fre-quency control oscillator frequency guaranteed at 250kHz; (2)current mode operation to 500kHz; (3)automatic feed forward compensation latching pwm for cycle-by-cycle current limiting; (4)internally trimmed reference with undervoltage lockout; (5)high current totempoleoutput undervoltage lockout with hysteresis low start up and operating current.

Diagrams

UC3842B block diagram

Image Part No Mfg Description Data Sheet Download Pricing
(USD)
Quantity
UC3842BD
UC3842BD

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM

Data Sheet

Negotiable 
UC3842BD1013TR
UC3842BD1013TR

STMicroelectronics

Current Mode PWM Controllers 0.5mA Current Mode

Data Sheet

0-1: $0.34
1-10: $0.30
10-100: $0.26
100-250: $0.24
UC3842BD1G
UC3842BD1G

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM w/96% Duty Cycle Max

Data Sheet

0-1: $0.37
1-25: $0.32
25-100: $0.23
100-500: $0.20
UC3842BD1R2
UC3842BD1R2

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM

Data Sheet

Negotiable 
UC3842BD1R2G
UC3842BD1R2G

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM w/96% Duty Cycle Max

Data Sheet

0-1: $0.37
1-25: $0.32
25-100: $0.23
100-500: $0.20
UC3842BDG
UC3842BDG

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM w/96% Duty Cycle Max

Data Sheet

0-1: $0.37
1-25: $0.32
25-100: $0.23
100-500: $0.20
UC3842BDR2
UC3842BDR2

ON Semiconductor

Current Mode PWM Controllers 52kHz 1A Current PWM

Data Sheet

Negotiable 
UC3842BN
UC3842BN

STMicroelectronics

Current Mode PWM Controllers 0.5mA Current Mode

Data Sheet

0-1: $0.28
1-10: $0.28
10-100: $0.26
100-250: $0.25