3.3V fixed LDO for noise-sensitive rails
The LP5951MG-3.3/NOPB is a fixed-output low-dropout linear regulator from Texas Instruments, delivering 3.3V at up to 150mA from a single positive supply rail. Housed in the compact SC-70-5 (SOT-353) package, it targets space-constrained designs where board real estate is at a premium — think sensor modules, portable instruments, or wireless nodes.
PSRR is specified at 60dB at 100Hz, rolling off to 50dB at 10kHz. That means at 100Hz, the regulator attenuates input ripple by a factor of 1000; at 10kHz, by a factor of about 316. For an audio-codec or ADC supply, this keeps switching-noise feedthrough from upstream converters below the noise floor of the signal chain. Maximum dropout voltage is 0.35V at the full 150mA load. So if the input rail dips to 3.65V, the output still holds 3.3V within regulation — useful when the upstream rail is a battery near its end-of-discharge or a lightly loaded buck converter.
Industrial temp range and protection set
No derating needed for outdoor or under-hood environments that see 105°C ambient. On-chip protection includes over-current, over-temperature, and short-circuit shutdown. The thermal-shutdown threshold prevents die damage if the load exceeds the 150mA rating for extended periods — the regulator cycles on and off until the fault clears. An enable pin (active-high logic) allows the regulator to be shut down externally, dropping the supply current to near-zero for power-gating in multi-rail designs.
Package and board-fit for SC-70-5
The SC-70-5 (also known as SOT-353) has a 1.25mm × 2.0mm body with 0.65mm pin pitch. It's a surface-mount package suitable for reflow soldering, with the exposed die pad on the bottom — the thermal path goes through the PCB copper, not a separate tab. Available in Tape & Reel (TR) or Cut Tape (CT) options for volume assembly or prototype runs.
Compliance and lifecycle status
Listed as Active in production by Texas Instruments.