225 MHz SPDT switch with wide supply flexibility
The MAX4659EUA+T is a single-pole double-throw (SPDT) analog switch from Analog Devices, built for routing high-frequency analog signals up to 225 MHz (-3 dB bandwidth) with a maximum on-resistance of 25 Ohm. The 8-uMAX/uSOP package (3.00 mm width, 0.118" pitch) saves board area in dense mixed-signal designs where every mm² counts.
Crosstalk is rated at -76 dB at 1 MHz — this is the isolation between the two switch channels when one is active and the other is off. At 1 MHz, -76 dB means less than 0.016% of the signal on the active channel couples into the off channel, which is clean enough for 12-bit multiplexed data acquisition without extra shielding. Charge injection is 1.5 pC typical — this is the charge dumped onto the signal line when the switch turns off. For a 10 pF sampling capacitor, 1.5 pC creates a 150 mV glitch; the designer must budget this into the settling time or use a downstream sample-and-hold with enough acquisition window. Off-leakage current is 1 nA maximum at 25°C — negligible for most signal paths, but in a high-impedance front-end (e.g., 10 MOhm sensor), 1 nA creates a 10 mV offset error that may need calibration. Channel capacitance is 6 pF (source and drain off) — this loads the upstream driver and sets the RC roll-off with the source impedance. A 50 Ohm source sees a -3 dB corner at roughly 530 MHz, so the 225 MHz bandwidth is not capacitance-limited in a 50 Ohm system.
The wide single-supply range (9 V to 40 V) lets the switch run directly off a 12 V, 24 V, or 36 V industrial bus without a local regulator — a cost and board-space win in PLC I/O modules and sensor interfaces. Dual-supply operation (±4.5 V to ±20 V) supports bipolar analog signals up to ±20 V swing, common in audio, ATE, and precision measurement where the signal crosses ground. Channel-to-channel on-resistance matching is 400 mOhm maximum — important when the switch is used in a differential signal path (e.g., balanced audio or bridge sensor), because mismatched Ron creates a DC offset between the two legs.
RoHS3 compliant (2015/863/EU) with no exemptions — no red phosphorus, no lead in solder finish, no restricted phthalates. Suitable for EU-market equipment without a RoHS waiver. Supplied in Tape & Reel (TR) or Cut Tape (CT) — the reel format is standard for pick-and-place assembly; CT suits prototype or low-volume builds where a full reel is wasteful.