• Product introduction

LT1243IS8

High speed current mode pulse width modulator

peculiarity

• Low start-up current:
• 50ns current sense delay
• Current mode operation: up to 500kHz
• The UC1842 series is pin compatible
• Hysteresis undervoltage lockout
• No cross-conducted current
• Trim the bandgap datum
• 1A totem pole output
• Trim the oscillator frequency and sink current
• Output active pull-down during reference and undervoltage lockout
• High output clamping: 18V
• Current sensing leading-edge blanking

description

® The LT 1241 family of devices are 8-pin, fixed frequency, current mode, pulse-width modulators. They have improved plug-in compatibility with industry-standard versions of the UC1842 series. These devices feature improved speed and lower quiescent current. The LT1241 family is optimized for off-wire and DC/DC converter applications. They contain a temperature-compensated reference, a high gain error amplifier, a current sense comparator, and a high current totem pole output stage, ideal for driving power MOSFETs. Start-up, which has now been reduced to less than 250μA. Cross-conduction current spikes in the output phase have been eliminated, enabling 500kHz in practice. Some new features have been included. Cutting-edge blanking has been added to current sense comparators. The car has two frequencies of oscillation circuit and sinking current, these parameters are tightly specified. The output stage is clamped to a maximum of 18V and is on. Output and reference outputs are actively pulled low during undervoltage lockout