Product Summary

The UC3843 is a high performance current mode PWM controller. The UC3843 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 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 of the UC3843 suitable for driving N-Channel MOSFETs, is low in the off-state.

Parametrics

UC3843 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 μJ; (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 ≤ 25℃ (DIP-8): 1.25 W; (8)Ptot Power Dissipation at Tamb ≤ 25℃ (SO-8): 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

UC3843 features: (1)trimmed oscillator discharge current; (2)current mode operation to 500khz automatic feed forward; (3)compensation; (4)latching pwm for cycle-by-cycle current limiting; (5)internally trimmed reference with undervoltage lockout; (6)high current totem pole output undervoltage lockout with; (7)hysteresis; (8)low start-up current (＜0.5mA) double pulse suppression.

Diagrams

UC3843 block diagram

Image Part No Mfg Description Data Sheet Download Pricing
(USD)		 Quantity
UC3843
UC3843
Other

Data Sheet
Negotiable 
UC3843A
UC3843A
Other

Data Sheet
Negotiable 
UC3843AD
UC3843AD
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
UC3843AD2R2
UC3843AD2R2
ON Semiconductor
Other Power Management 52kHz 1A Current PWM
Data Sheet
Negotiable 
UC3843AD8
UC3843AD8
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
UC3843AD8G4
UC3843AD8G4
Texas Instruments
Current Mode PWM Controllers Current-Mode PWM Controller
Data Sheet
0-1: $0.85
1-25: $0.76
25-100: $0.67
100-250: $0.59
UC3843ADG4
UC3843ADG4
Texas Instruments
Current Mode PWM Controllers Current-Mode PWM Controller
Data Sheet
0-1: $0.85
1-25: $0.76
25-100: $0.67
100-250: $0.59
UC3843ADM
UC3843ADM

IC REG CTRLR BST FLYBK ISO 8SOIC
Data Sheet
0-1: $1.40
1-10: $1.26
10-100: $1.01
100-250: $0.90
250-500: $0.79
500-1000: $0.65
1000-2500: $0.61
2500-5000: $0.59
5000-10000: $0.56