Re: [time-nuts] 50 ohm drivers

2018-03-04 Thread Bob kb8tq
Hi We have gone over CMOS 50 ohm line driving a bunch of times. Check the archives for all of the various opinions. A quick summary: If you are driving CMOS, the output swing does not have to hit 99% of the supply. You can do a pretty good job with gates in parallel and no source termination.

Re: [time-nuts] 50 ohm drivers

2018-03-03 Thread Gerhard Hoffmann
Am 04.03.2018 um 03:17 schrieb David C. Partridge: Brice said: . Some fast CMOS devices (esp clock drivers) have an output R close to 50 ohms as they are intended to drive 50 ohm source terminated transmission lines. Any in particular that you'd recommend? I need to drive a 50ohm line

Re: [time-nuts] 50 ohm drivers

2018-03-03 Thread Bruce Griffiths
These devices are only suitable for driving source terminated 50 ohm transmission lines not a 50 ohm load to ground (or even 1/2Vcc) to produce CMOS levels at the load. If you are driving a low pass filter or similar intending to produce a sinewave output then its somewhat easier. Even

[time-nuts] 50 ohm drivers

2018-03-03 Thread David C. Partridge
Brice said: >. Some fast CMOS devices (esp clock drivers) have an output R close to 50 ohms as they are intended to drive 50 ohm source terminated transmission lines. Any in particular that you'd recommend? I need to drive a 50ohm line and a single gate inverter doesn't have the grunt to do so