Product Summary

The 3843B is a high-performance current-mode pwm controller. The 3843B of control integrated circuits provide the features that are necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes, with a minimum number of external components. Internally implemented circuits include an undervoltage lockout (UVLO) and a precision reference that is trimmed for accuracy at the error amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation (PWM) comparator that 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 when it is in the off state. The 3843B is pin compatible with the standard TL284x and TL384x with the following improvements. The start-up current is specified to be 0.5 mA (max), while the oscillator discharge current is trimmed to 8.3 mA (typ). In addition, during undervoltage lockout conditions, the output has a maximum saturation voltage of 1.2 V while sinking 10 mA (VCC = 5 V).

Parametrics

3843B absolute maximum ratings: (1)VI Analog input voltage range VFB and ISENSE: -0.3, 6.3 V; (2)ICC Supply current: 30 mA; (3)IO Output current: ±1 A; (4)IO(sink) Error amplifier output sink current: 10 mA; (5)VCC Supply voltage Low impedance source: 30V; (6)TJ Virtual junction temperature: 150 °C; (7)Tstg Storage temperature range: -65, 150 °C; (8)Tlead Lead temperature Soldering, 10 s: 300 °C.

Features

3843B features: (1) Low Start-Up Current (<0.5 mA); (2) Trimmed Oscillator Discharge Current; (3) Current Mode Operation to 500 kHz; (4) Automatic Feed-Forward Compensation; (5) Latching PWM for Cycle-by-Cycle Current Limiting; (6) Internally Trimmed Reference With Undervoltage Lockout; (7) High-Current Totem-Pole Output Undervoltage Lockout With Hysteresis; (8) Double-Pulse Suppression.

Diagrams

 3843B pin connection

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3843B
3843B

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Pomona Electronics

RF Adapters - In Series TYPE N TO TYPE N

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0-1: $19.28
1-10: $18.72
10-50: $17.78
50-100: $16.90
3843B
3843B

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3843A
3843A

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