Charge pump for unipolar-to-bipolar or voltage doubling
The LM828M5X/NOPB is a Texas Instruments ratiometric charge pump that generates a fixed output of either -Vin or 2Vin from a 1.8 V to 5.5 V input rail, delivering up to 25 mA. No external inductor is needed — the 12 kHz switching frequency keeps radiated noise low enough for analog bias supplies in mixed-signal boards. The output configuration is selectable as positive or negative, making this part suitable for generating a negative rail from a positive supply or doubling a low-voltage battery rail. The ratiometric topology means the output voltage tracks the input ratio — -Vin or 2Vin — rather than regulating to a fixed absolute voltage.
Package and temperature grade for embedded designs
Housed in a 5-pin SOT-23-5 (SC-74A) package, the LM828M5X/NOPB occupies minimal board area — roughly 3 mm × 3 mm — and suits space-constrained portable or sensor-node PCBs. The surface-mount footprint is standard for the SOT-23 family, with a 0.95 mm pin pitch that routes easily on two-layer boards. Rated for -40°C to 85°C junction temperature, this part covers industrial ambient environments — outdoor telecom enclosures, motor-drive control boards, and battery-powered field instruments. The 25 mA output ceiling limits the load to op-amp rails, comparator bias, or low-power sensor supplies rather than main power buses.
Lifecycle and compliance status
The part is ROHS3 compliant, with no restricted-substance exemptions that would complicate EU or California market entry. Available in Tape & Reel (TR) for automated pick-and-place or Cut Tape (CT) for prototype builds. No synchronous rectifier is integrated — the charge pump uses diode-based switching, which is standard for this output current class.