LM74700QDBVRQ1.pdf

Features for the LM74700-Q1

AEC-Q100 qualified with the following results

Device temperature grade 1: –40°C to +125°C ambient operating temperature range

Device HBM ESD classification level 2

Device CDM ESD classification level C4B

Functional Safety-Capable

Documentation available to aid functional safety system design

3.2-V to 65-V input range (3.9-V start up)

–65-V reverse voltage rating

Charge pump for external N-Channel MOSFET

20-mV ANODE to CATHODE forward voltage drop regulation

Enable pin feature

1-µA shutdown current (EN=Low)

80-µA operating quiescent current (EN=High)

2.3-A peak gate turnoff current

Fast response to reverse current blocking: < 0.75 µs

Meets automotive ISO7637 transient requirements with a suitable TVS Diode

Available in 6-pin and 8-pin SOT-23 Package 2.90 mm × 1.60 mm

Description for the LM74700-Q1

The LM74700-Q1 is an automotive AEC Q100 qualified ideal diode controller which operates in conjunction with an external N-channel MOSFET as an ideal diode rectifier for low loss reverse polarity protection with a 20-mV forward voltage drop. 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 automotive battery systems. The 3.2-V input voltage support is particularly well suited for severe cold crank requirements in automotive systems. The device can withstand and protect the loads from negative supply voltages down to –65 V.

The device controls the GATE of the MOSFET to regulate the forward voltage drop at 20 mV. The regulation scheme enables graceful turn off of the MOSFET during a reverse current event and ensures zero DC reverse current flow. Fast response (< 0.75 µs) to Reverse Current Blocking makes the device suitable for systems with output voltage holdup requirements during ISO7637 pulse testing as well as power fail and input micro-short conditions.

The LM74700-Q1 controller provides a charge pump gate drive for an external N-channel MOSFET. The high voltage rating of LM74700-Q1 helps to simplify the system designs for automotive ISO7637 protection. With the enable pin low, the controller is off and draws approximately 1 µA of current.