SiGe rectifier diodes maintain effiency at high temperature

Nexperia has introduced 120V silicon germanium (SiGe) rectifier diodes “with reverse voltages that combine the high efficiency of their Schottky counterparts with the thermal stability of fast-recovery diodes”, according to the company. “Design engineers can rely on an extended safe-operating area with no thermal runaway up to 175°C.”

150V and 200V parts are in the pipeline.

The thermal run-away comparison is with Schottky diodes, whose reverse leakage climbs fast at high temperature – allowing thermal runaway if used improperly.

Taking the 2A rated PMEG120G20ELR as an example (see table), 120V reverse leakage is typically 300pA at 25°C (30nAmax) and 20μA at 150°C (200μAmax).

Low forward voltage and reverse recovery charge are also claimed. From the data sheet I get: typical figures of 770mV (25°C), 860mV (-40°C) or 620mV (125°C), then 5nC. From these, the conpany said: “The SiGe rectifiers have an advantage of 10-20 % lower conduction losses.”

They are AEC-Q101 qualified for automotive use.

The first four are in production:

There are too be followed by eight more devices rated at 150 or 200V – which are sampling now, according to Nexperia, although no data sheets appear to be available.

The CFP3 1.9 x 3.7mm) and CFP5 (2.7 x 5mm) packages have a solid copper clip to improve heat transfer – 18 and 12K/W junction to solder point respectively. “Simple pin-to-pin replacements of Schottky and fast recovery diodes are possible when switching to SiGe technology,” said Nexperia.

Particular application are expected at high temperature in automotive (engine control units or fuel injection) and LED lighting, as well as in comms infrastructure and server.

There is a Nexperia SiGe rectifier home page