描述 Description

The LM74502, LM74502H is a controller which operates in conjunction with an external back-to-back connected N-channel MOSFETs to realize a low loss reverse polarity protection and load disconnect solution. The device can also be configured to drive high side MOSFET as a load switch with overvoltage protection . The wide supply input range of 3.2 V to 65 V allows control of many popular DC bus voltages such as 12-V, 24-V and 48-V input systems. The device can withstand and protect the loads from negative supply voltages down to –65 V. The LM74502, LM74502H does not have reverse current blocking and is suitable for input reverse polarity protection only.

The LM74502 controller provides a charge pump gate drive for an external N-channel MOSFET. With the enable pin low, the controller is off and draws approximately 1 μA of current, thus offering low system current when put into sleep mode. LM74502 and LM74502H offers programmable overvoltage and undervoltage protection which cuts off the load from the input source in case of these fault events. The devices are available in a 2.9 mm × 1.6 mm 8-pin DDF package and are specified over a –40°C to +125°C temperature range.

特性 Features

? 3.2-V to 65-V input range (3.9-V start-up)
? –65-V input reverse voltage rating
? Integrated charge pump to drive
? External back-to-back N-Channel MOSFETs
? External high side switch MOSFET
? External reverse polarity protection MOSFET

? Gate drive variants
? LM74502: 60-μA peak gate drive source capacity
? LM74502H: 11-mA peak gate drive source capacity

? 2.3-A peak gate sink current capacity
? Enable pin feature
? 45-μA typical operating quiescent current (EN/UVLO = High)
? 1-μA shutdown current (EN/UVLO = Low)
? Adjustable overvoltage and undervoltage protection
? –40°C to +125°C ambient operating temperature range
? Available in 8-pin SOT-23 package 2.90 mm × 1.60 mm