[time-nuts] 50 ohm Driver
Tom Van Baak
tvb at LeapSecond.com
Wed Mar 4 13:20:45 EST 2015
Martyn -- the 74AC spec allows Vcc to go up to 6.0 VDC (absolute max is 7.0 VDC) so that might help you meet your 4.5 VDC goal, especially if this is for play and not a product. Pick the resistors and use more than 3 gates if necessary. Note the peak current spec is 50 mA per gate. Not sure what the combined gate current limit is; there is a package thermal limit. You also have to decide if you want some level of short-circuit protection or if you can always assume 50R termination.
John -- have you tried long duration output shorts on the TADD-2? I figured that was also a reason for each gate having its own resistor.
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