The Current Mode Pwm Controller UC3845B is a high performance fixed frequency current mode controller. This current mode PWM is specifically designed for Off-Line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components. This PWM controller features an oscillator, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET.
Also included are protective features consisting of input and reference under-voltage lockouts each with hysteresis, cycle-by-cycle current limiting, a latch for single pulse metering, and a flip-flop which blanks the output of every other oscillator cycle, allowing output deadtimes to be programmed from 50% to 70%.
Features Of High-Performance Current Mode PWM Controller UC3845B:
Trimmed oscillator for precise frequency control.
Oscillator frequency guaranteed at 250 kHz.
Current mode operation to 500 kHz output switching frequency.
Output deadtime adjustable from 50% to 70%.
Automatic feed-forward compensation.
Latching PWM for cycle-by-cycle current limiting.
Internally trimmed reference with undervoltage lockout.
High current totem pole output.
Under-voltage lockout with hysteresis.
Low startup and operating current.
Specifications Of Best 8 Pins PWM Controller IC UC3845B:
Supply Voltage (low impedance source): 30V
Supply Voltage (Ii < 30mA): Self Limiting
Output Current: ±1A
Output Energy (capacitive load): 5µJ
Analog Inputs (pins 2, 3): – 0.3 to 5.5V
Error Amplifier Output Sink Current: 10mA
Power Dissipation at Tamb: ≤ 25°C (Mini dip) 1.25W
Power Dissipation at Tamb: ≤ 25°C (SO8) 800mW
Storage Temperature Range: – 65 to 150°C
Operating Temperature: – 40 to 150°C
Temperature (soldering 10s): 300°C
Package Includes:
1 x Current Mode PWM Controller UC3845B
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