TMUX1308: 8KHz Clock Multiplexer

Hi JH,

The TMUX1308 is suitable for a 8KHz clock signal. The TMUX1308 has a bandwidth of 500MHz, if the VDD is between 1.8V and 5V, with the signal range being within the range 0V to VDD.

As for a 16 channel part the CD74HC4067 is our lower voltage 16:1 channel multiplexer, and it has the same voltage range as the TMUX1308, but with a lower bandwidth of 89MHz, which should still be sufficient for a 8KHz clock.  However, there is a larger Ron for this device, if your load is high impedance, and not drawing a lot of current, the higher on resistance is usually negligible.

Best,

Parker Dodson

Hi JH,

The Additive Jitter caused by the Mux is a result of variations in the propagation delay of the mux. We don't spec this for our Multiplexers/Switches because the prop delay of our switches is typically small compared to the clock frequencies put through them. 

The TMUX1308 has the largest prop delay at Vdd = 1.8V, with a typical value being 15ns and the max value being 30ns. However raising supply voltage and decreasing load capacitance (it is 50pF in this above example) will also decrease the range of possible propagation delay values, also minimimizing additive jitter.

The CD74HC4067 is an older part, and has a worse performance on propagation delay, with a max of 110ns at VDD = 2V, but a lower load capacitance (this example uses a 50pF load capacitor) and a higher supply voltage can decrease the range of transition times. 

The TMUX1308 will add less jitter because of the lower range of possible propagation times. With a clock signal of 8KHz, the amount of jitter added from these switchs, (realistic worst case ~10ns of nanoseconds depending on the part used) you are looking at very little impact to the overall clock signal. 

Best,

Parker Dodson