Quad op-amp in a through-hole legacy footprint
The Texas Instruments LM324AN/PB is a LinCMOS™ general-purpose quad operational amplifier in a 14-pin DIP package (14-PDIP). It integrates four independent op-amp channels into one through-hole package, each rated for 40 mA output drive and drawing 1.5 mA total supply current. With a 1 MHz gain-bandwidth product and 3 V to 32 V supply range, this part covers the standard signal-conditioning sweet spot — sensor buffering, active filters below 100 kHz, and DC-level shifting in commercial-temperature equipment.
The 1 MHz gain-bandwidth product sets a practical closed-loop bandwidth of 100 kHz at a gain of 10. Above that, phase margin erodes and the part cannot maintain linear operation. For audio-band filtering below 20 kHz or DC instrumentation loops, this is ample; for video or high-speed ADC drive, it is not. Input offset voltage is 2 mV typical, input bias current 45 nA — adequate for single-supply 5 V or 12 V circuits where the signal is several hundred millivolts or more. For microvolt-level precision, a zero-drift amplifier would be the better call.
Texas Instruments no longer manufactures this specific variant. Available inventory is limited to surplus and broker-channel stock. The 14-PDIP package and through-hole format mean this part is most often sought for repair, legacy board support, or one-off builds where a drop-in replacement is required.