Quad JFET op-amp for precision analog front-ends
The AD8643ARZ-REEL7 from Analog Devices is a quad-channel JFET-input operational amplifier in a 14-SOIC package. It combines a 3.5 MHz gain-bandwidth product with a 3V/µs slew rate, rail-to-rail output swing, and an input bias current of 0.25 pA. The device operates from a single 5 V supply up to 26 V dual supplies, and is rated over the -40°C to 125°C temperature range. This makes it a fit for precision signal conditioning in industrial sensor interfaces, data acquisition systems, and multichannel ADC driver stages where low input leakage and wide temperature tolerance are required.
0.25 pA input bias — what it means for your front-end
The 0.25 pA typical input bias current is the standout parameter here. For a photodiode amplifier or a high-impedance sensor bridge, that leakage floor determines the minimum detectable signal. A CMOS-input op-amp might claim similar bias, but the JFET architecture also keeps voltage noise low at higher source impedances. The 70 µV input offset voltage is respectable for a general-purpose precision part — not the sub-10 µV class of auto-zero amplifiers, but well within what a 12-bit or 14-bit ADC driver needs after a gain stage.
Rail-to-rail output and supply range
The rail-to-rail output swings close to the supply rails. Supply range spans 5 V minimum to 26 V maximum. Each channel sources or sinks 12 mA.
Active production — no last-time-buy scramble
The AD8643ARZ-REEL7 carries an Active product status with ROHS3 compliance.
Package and footprint for the layout
The part comes in a 14-SOIC package with a 3.90 mm body width (0.154"). Cut Tape quantities are also available for prototyping. Surface-mount only — no through-hole variant exists. The 14-SOIC footprint is standard, so existing land patterns for quad op-amps in this package work without modification.