The UC1637 is a pulse width modulator circuit intended to be used for a variety of PWM motor drive and amplifier applications requiring either uni-directional or bi-directional drive circuits. When used to replace conventional drivers, this circuit can increase efficiency and reduce component costs for many applications. All necessary circuitry is included to generate an analog error signal and modulate two bi-directional pulse train outputs in proportion to the error signal magnitude and polarity. This monolithic device contains a sawtooth oscillator, error amplifier, and two PWM comparators with ±100mA output stages as standard features. Protection circuitry includes under-voltage lockout, pulse-by-pulse current limiting, and a shutdown port with a 2.5V temperature compensated threshold. The UC1637 is characterized for operation over the full military temperature range of -55°C to +125°C, while the UC2637 and UC3637 are characterized for -25°C to +85°C and 0°C to +70°C, respectively.
The document describes the Unitrode UC1637, UC2637, and UC3637 as monolithic pulse width modulator circuits intended for uni-directional or bi-directional drive applications. These devices integrate a sawtooth oscillator, error amplifier, and PWM comparators with ±100mA output stages to increase efficiency and reduce component costs.
| Supply Voltage Range | ±2.5V to ±20V |
|---|---|
| Output Current (Source/Sink) | 100mA steady state, 500mA pulsed |
| Oscillator Initial Accuracy | ±5% (UC1637/2637), ±10% (UC3637) |
| Temperature Range (UC1637) | -55°C to +125°C |
The UC1637 operates from -55°C to +125°C, while the UC2637 and UC3637 operate from -25°C to +85°C and 0°C to +70°C respectively.
The shutdown port has a temperature compensated threshold of 2.5V.