Active rectifier controller provides reverse protection for automotive designs

November 14, 2017 //By Nick Flaherty
Analog Devices has launched an active rectifier controller with reverse input protection to –40V. The 3V to 42V input voltage capability is aimed at automotive applications to regulate through cold-crank and stop-start scenarios with minimum input voltages as low as 3.0V and load dump transients up to 40V.

The LT8672 marks the move from branding as Linear Technology to 'Power by Linear'. 

It drives an external N-channel MOSFET, offering a 20mV drop, reducing power dissipation by 90% compared to a Schottky diode and so eliminating requirements for a costly heat sink. The ultrafast transient response enables it to meet stringent automotive applications requiring AC input ripple rectification up to 100kHz and the 20µA quiescent current while operating and 3.5µA in shutdown make it suitable  for always-on systems. The combination of the MSOP-10 package and external MOSFET ensures a compact footprint.

The combination of 3V minimum input capability and a 20mV drop eases the minimum input voltage requirement during cold-crank and stop-start, providing simpler and more efficient circuits. If the input power source fails or is shorted, a very fast turn-off minimises reverse current transients. Also, a power good pin signals when the external MOSFET is ready to take load current.

The LT8672EMS is packaged in an MSOP-10 package. An industrial temperature version, the LT8672IMS, is tested and guaranteed to operate from a –40°C to 125°C operating junction temperature. The LT8672HMS version is tested and guaranteed to operate from a –40°C to 150°C operating junction temperature and pricing starts at $2.25.

www.linear.com/product/LT8672