The ADM1051/ADM1051A are dual, precision, voltage regulator controllers intended for power rail generation and active bus termination on personal computer motherboards. They contain a precision 1.2 V bandgap reference and two channels consisting of control amplifiers driving external power devices. Each channel has a shutdown input to turn off amplifier output and Hiccup Mode protection circuitry for the external power device. The shutdown input on the 1.5 V channel can also be used with the TYPEDET signal on a PC motherboard to select the output voltage. The ADM1051/ADM1051A operate from a 12 V supply, which gives sufficient headroom for the amplifiers to drive external N-channel MOSFETs, operating as source-followers, as the external series pass devices. This has the advantage that Nchannel devices are cheaper than P-channel devices of similar performance, and the circuit is easier to stabilize than one using P-channel devices in a common-source configuration.