800 mOhm on-resistance and 130 MHz bandwidth — the signal-path limits
The MAX4736EGC+ is a dual SPDT analog switch from Analog Devices with a maximum on-resistance of 800 mOhm. This low Rds(on) keeps insertion loss below 0.1 dB when driving a 50-ohm load at 10 MHz, and the 130 MHz -3 dB bandwidth means the switch passes the fundamental and second harmonic of a 65 MHz IF signal without measurable roll-off.
Crosstalk and charge injection — the analog-domain specs that matter
Channel-to-channel crosstalk is -78 dB at 1 MHz. In a multiplexed data-acquisition system switching between two sensor channels, a 1 Vpp signal on the active channel couples less than 125 µV into the inactive channel — below the LSB of a 12-bit ADC with a 2.5 V reference. Charge injection is 60 pC typical. When the switch toggles, the injected charge into a 10 nF hold capacitor produces a voltage glitch of 6 mV — the capacitor settles to within 0.1 % of final value in under 1 µs, fast enough for a 100 kSPS sample-and-hold front-end. Maximum leakage current is 1 nA in the off state.
Switching speed and channel matching — timing closure for multiplexed buses
Turn-on time is 25 ns max, turn-off 20 ns max. The switch toggles faster than a 10 MHz clock period, so a multiplexed ADC front-end can switch channels between conversions without inserting wait states. Channel-to-channel on-resistance matching is 100 mOhm max. In a differential signal path where the two SPDT halves carry the positive and negative legs, the 100 mOhm mismatch contributes less than 0.02 dB of gain error at 10 MHz — negligible for a 12-bit system.
Package and thermal — the 12-QFN exposed pad
The MAX4736EGC+ is supplied in a 12-VFQFN exposed pad package measuring 3x3 mm (supplier device package 12-QFN).