Negative rail LDO for precision analog and mixed-signal supplies
The MAX1735EUK50+T is a negative-output LDO from Analog Devices, delivering up to 200 mA from a single SOT-23-5 package. Its output can be set anywhere from -1.25 V down to -5.5 V via external resistors, or used as a fixed -5 V regulator with the internal trim. The 0.24 V maximum dropout at full load means it holds regulation even when the input rail sags close to the output voltage — useful for battery-powered or lightly regulated negative supplies.
The 60 dB PSRR at 100 Hz gives decent rejection of rectified mains ripple on the input, which matters when the regulator feeds an op-amp or ADC reference. At 85 µA quiescent current and 125 µA maximum supply current, the part keeps the overhead low — the efficiency penalty is small even at light loads. The enable pin lets you shut down the output entirely, pulling the supply current to near zero when the negative rail is not needed.
The SOT-23-5 footprint is a common, easy-to-source package; the part ships in tape-and-reel or cut-tape options.
Protection features and operating range
Built-in over-current, over-temperature, and short-circuit protection cover the common fault conditions on a negative rail — a short to ground or a load dump will trigger the limit without damaging the regulator.