Dual SP4T analog switch for precision signal routing
The Maxim Integrated MAX14778ETP+ is a dual SP4T (single-pole four-throw) analog switch, integrating two 4:1 multiplexer/demultiplexer circuits in a single 20-TQFN package. It routes up to four differential or single-ended signals per channel with a maximum on-resistance of 1.5 ohm, keeping insertion loss low in precision analog paths. The -3 dB bandwidth of 75 MHz supports video, RF, and high-speed data signals, while the -103 dB crosstalk at 100 kHz ensures minimal bleed between channels in multiplexed acquisition systems. Operating from a single 3 V to 5.5 V supply over -40°C to 85°C, it fits industrial sensor interfaces, data-acquisition front-ends, and ATE signal routing where signal integrity matters.
On-resistance and charge injection — what they mean for the BOM
The 1.5 ohm max on-resistance is the headline spec for this part. In a precision analog chain, every ohm of switch resistance adds a voltage divider with the source impedance and a thermal-noise floor.
Package and footprint — 20-TQFN with exposed pad
The 20-TQFN (5x5 mm) with exposed pad requires a thermal land on the PCB for adequate heat sinking. The exposed pad is electrically connected to the die substrate and should be tied to the most negative supply rail.
Lifecycle and sourcing
The MAX14778ETP+ carries an Active product status per the manufacturer, with ROHS3 compliance. No pin-compatible second source is listed in the manufacturer's cross-reference, so dual-sourcing would require a functional equivalent in a different footprint.