Quad SPST-NC switch with 85Ω on-resistance
The DG444DJ+ is a quad SPST-NC (normally-closed) analog switch from Analog Devices, packaged in a 16-pin DIP (0.300", 7.62mm) through-hole package. Each of the four switches presents a maximum on-resistance of 85Ω, with channel-to-channel matching held to 4Ω max — tight enough that gain errors in a multiplexed signal chain stay within a few millivolts across channels. The normally-closed topology means the switch conducts when the control voltage is low — a useful fail-safe in applications where the signal path should remain connected if the logic supply drops or the controller resets.
Supply flexibility and signal integrity
The part runs from either a single supply (10 V to 30 V) or dual supplies (±4.5 V to ±20 V), making it adaptable to both single-rail systems and bipolar analog front-ends. The wide supply range covers common industrial rails like ±12 V, ±15 V, and 24 V single-ended without needing a separate regulator. Switching speed is 250 ns on, 140 ns off (max) — fast enough for audio muting, sample-and-hold front-ends, or relay-replacement in low-speed data acquisition. Crosstalk between channels is -100 dB at 1 MHz, so a 10 Vpp signal on one channel couples less than 100 µV into an adjacent channel — adequate for 16-bit systems at moderate frequencies. Charge injection is 5 pC typical, which translates to a voltage glitch of about 1.25 mV into a 4 pF load capacitance — low enough that downstream sample-and-hold circuits or precision integrators see minimal pedestal error. Off-state leakage is 500 pA max, and off-capacitance is 4 pF per channel — both figures keep the signal path high-impedance when the switch is open, preserving accuracy in high-source-impedance applications like photodiode amplifiers or pH probe interfaces.
Through-hole DIP for prototyping and legacy designs
Housed in a 16-pin PDIP (0.300" body width), the DG444DJ+ is a through-hole part — the same footprint used by the original DG444 series. It is a natural fit for breadboarding, socketed test fixtures, or legacy board spins that already carry the DIP footprint.