Description

The LT1242CS8 is an 8-pin, fixed frequency, current mode, pulse width modulator. It is an improved version of the industry standard UC1842 series, offering both improved speed and lower quiescent current. This model is optimized for off-line and DC/DC converter applications and features a temperature-compensated reference, high-gain error amplifier, current sensing comparator, and a high-current totem pole output stage designed for driving power MOSFETs. The start-up current has been reduced to less than 250µA.

Specifications and features

- Low Start-Up Current: < 250µA

- 50ns Current Sense Delay

- Current Mode Operation: Up to 500kHz

- Pin Compatible with UC1842 Series

- Undervoltage Lockout with Hysteresis

- No Cross-Conduction Current

- Trimmed Bandgap Reference

- 1A Totem Pole Output

- Trimmed Oscillator Frequency and Sink Current

- Active Pull-Down on Reference and Output During Undervoltage Lockout

- High Level Output Clamp: 18V

- Current Sense Leading Edge Blanking

Application Scenarios

- Off-Line Converters

- DC/DC Converters

Comparison

- Improved speed and lower quiescent current

- Optimized for off-line and DC/DC converter applications

- Features a temperature-compensated reference and high-gain error amplifier

- High-current totem pole output stage for driving power MOSFETs

- None mentioned