MK14 SN74S571 PROM Power reduction test
I got some tiny P-channel MOSFETs for a different project, so I thought I might have a go at the power reduction idea mentioned in the Micky thread.
I just wired the FET to apply 5v to the PROM when /OE ( pin 13 ) was low. The FET gate was wired directly to the /OE pin.
Results were quite promising. The current consumption of the MK14 dropped from 470mA to 380mA. The current into a single PROM normally was 85mA, so this idea has reduced that by half.
There is plenty room for improvement.
The way the FET, ( an AO3401 ) is wired is far from optimum. The FET has a huge input capacitance, nearly 700pF. The gate in IC17 can easily drive the FET 'on', but takes ages to turn it 'off'. I tried a few pullup resistor ideas to improve switching times, but in reality I don't think a FET is the way to go.
Definately an idea with legs.
Cheers,
Buzby
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