Micropower dual op-amp for low-frequency signal chains
The rail-to-rail output stage swings within millivolts of each supply rail, and the 0.002 pA input bias current lets it interface directly with high-impedance sources such as photodiode transimpedance stages, piezoelectric sensors, and electrochemical cell amplifiers without an external buffer. Supply range spans 4.5 V to 15.5 V, covering single 5 V and dual ±5 V rails as well as 12 V industrial supplies. The 8-DIP through-hole package (0.300" body, 7.62 mm pitch) is socket-friendly for prototyping and field-service replacement.
Slew rate and bandwidth — sizing for the signal
At 0.02 V/µs the LMC6042AIN is intentionally slow — that is the trade-off for the micropower supply current. For a 100 mV peak-to-peak output swing the amplifier can slew through the full transition in about 5 µs, which limits the useful small-signal bandwidth to roughly 3 kHz for a sine wave. This makes the part a natural fit for DC measurement, thermocouple conditioning, strain-gauge amplification, and low-frequency filter stages where the signal bandwidth stays below a few kilohertz. If the application needs to pass audio or switch faster than a few microseconds, a general-purpose op-amp with a 1 MHz to 10 MHz GBW and a 1 V/µs to 5 V/µs slew rate would be the correct class — but it would draw 10× to 50× the supply current.
Input bias current — direct sensor connection
The 0.002 pA (2 fA) typical input bias is among the lowest available in a dual CMOS op-amp. In a photodiode transimpedance amplifier with a 10 MΩ feedback resistor, that bias contributes just 20 nV of offset error — negligible compared to the 1 mV input offset voltage. For a pH probe or a high-impedance bridge, the bias current does not load the source, preserving accuracy. The CMOS input stage also keeps the input common-mode range within 0.3 V of the negative rail, so single-supply ground-referenced signals are handled without a negative rail.
Temperature grade and environment
The 8-PDIP package is not rated for high-vibration or sealed-environment applications where a surface-mount SOIC or TSSOP would be preferred, but it is well suited for benchtop instrumentation, lab equipment, and field-repairable control boards where socketed replacement is a design goal.
Output drive and rail-to-rail swing
The rail-to-rail output stage pulls within about 50 mV of the positive rail and within 10 mV of the negative rail at light loads, so the full supply range is usable for ADC drive or comparator thresholds. At 40 mA the output swing degrades — expect about 1.5 V from each rail — but for driving a 2 kΩ load the rail margin stays under 100 mV.
Lifecycle and sourcing
The part is RoHS non-compliant (lead-bearing), which limits its use in new EU RoHS-regulated designs but makes it a direct drop-in for legacy boards that require the tin-lead finish for solder-joint reliability or existing regulatory approvals.