Active production, 5.5 Ohm SPDT switch for RF and analog signal routing
The MAX4730ELT+T is an active-production SPDT analog switch from Analog Devices, specified with a maximum on-resistance of 5.5 Ohm and a -3dB bandwidth of 300 MHz. This combination makes it suitable for routing RF and high-speed analog signals up to the VHF band without significant insertion loss.
Crosstalk is specified at -67 dB at 1 MHz. This means that with a 1 MHz signal on one channel, less than 0.05% of that signal amplitude couples into the other channel. For a 10-bit ADC front-end, this level of isolation keeps adjacent-channel bleed well below the quantization noise floor. Charge injection is rated at 3 pC typical. When the switch turns off, this small charge packet dumps onto the load capacitance. In a sample-and-hold circuit with a 10 pF hold capacitor, 3 pC produces a 300 mV glitch — enough to matter in a precision acquisition path. The 6.5 pF off-channel capacitance (CS(off), CD(off)) also contributes to the settling time when switching between channels.
The part comes in a 6-WFDFN package (supplier device package 6-µDFN, 1.5 mm x 1.0 mm body). Supplied in Tape & Reel (TR) or Cut Tape (CT) options. The reel quantity is standard for this package size; store the reels in a dry cabinet if the MSL label indicates moisture sensitivity, though the small body size limits moisture absorption compared to larger packages.
Switching speed and channel matching
Maximum turn-on time is 45 ns, turn-off time is 26 ns. These switching edges set the maximum data rate through the switch — for a 50% duty-cycle signal, the switch can toggle at roughly 11 MHz before the on-time compresses below the datasheet minimum. Channel-to-channel on-resistance matching is 50 mOhm max, which keeps the gain error between two signal paths below 1% when driving a matched load. Off-state leakage current is 2 nA max at 25°C. In a high-impedance node (e.g., a 1 MOhm ADC input), 2 nA leakage produces a 2 mV offset error — negligible for 12-bit systems but worth budgeting for 16-bit or higher precision chains.