TL331/TL331B/TL391B/TL331B-Q1 Single Comparators Texas Instruments TL331/TL331B/TL391B/TL331B-Q1 Single Comparators provide outstanding value for cost-sensitive applications. Their features include lower offset voltage, higher supply voltage capability, lower supply current, and lower input bias current. The TL331/TL331B/TL391B/TL331B-Q1 also includes lower propagation delay, wider temperature range, and improved 2kV ESD performance with drop-in replacement convenience. The Texas Instruments TL331B is a drop-in improved replacement for both the TL331I and TL331K versions. The TL391B provides an alternate pinout of the TL331B to replace competitive devices.