Question 7.11: A multiplexer is part of a 12-bit, 10-volt system. The CMOSF...

Analogue Electronic Circuits and Systems

A multiplexer is part of a 12-bit, 10-volt system. The CMOSFET switches have leakage currents of 45 nA and ‘on’ resistances of $450 \Omega$ . The multiplexer output capacitance is 44 pF. All inputs are scanned sequentially, (i) Calculate the number of input channels that the multiplexer has if the maximum static error is one-eighth of a least significant-bit ( $\frac{1}{8}$ LSB). (ii) Find the maximum sampling rate per channel for a dynamic error equal to the static error. In addition to the settling time, a further $0.05 \mu sec$ must be allowed to avoid momentary shorting between input channels.

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