| Electronics > Beginners |
| question about resistor across power pins |
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| sanman:
hello! I'm working on a board that contains a TI SN74VC8T245. This device uses a VCC-A and VCC-B at pins 1 and 24 respectively. The manufacturer has bodged a resistor between the two pins, connecting at the bypass capacitors for each pin. I was just curious why this was being done. Any insight? Thanks for the help! |
| cur8xgo:
--- Quote from: sanman on June 14, 2019, 01:58:56 pm ---hello! I'm working on a board that contains a TI SN74VC8T245. This device uses a VCC-A and VCC-B at pins 1 and 24 respectively. The manufacturer has bodged a resistor between the two pins, connecting at the bypass capacitors for each pin. I was just curious why this was being done. Any insight? Thanks for the help! --- End quote --- Just guessing here: -That resistor net effect is to keep the two Vcc's near each other -So if one goes down, the other goes down, if one comes up, the other comes up -Sort of synchronizing things Otherwise, one Vcc might be up a long time (relatively speaking) before the other, with undesirable results. Also notice the "keep ~OE high until vcca and vccb are up"...similar reasoning |
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