Dual-rail LDO for noise-sensitive supplies
The LP3996SD-3308/NOPB: With two independent LDOs in a single 10-WSON (3x3 mm) package, it saves board area compared to two separate regulators while keeping the output noise low enough for analog and RF front-ends that share a board with digital logic.
PSRR is listed at 58 dB to 45 dB across 1 kHz to 20 kHz on one channel, and 70 dB to 60 dB across the same band on the other — the higher-figure channel rejects switching ripple from a DC-DC converter upstream by a factor of roughly 3000 at 1 kHz, dropping to 1000 at 20 kHz. Maximum dropout is 0.22 V at 150 mA and 0.55 V at 300 mA — the headroom between the input rail and the regulated output must stay above these figures across load and temperature, or the output falls out of regulation.
Package, thermal pad, and board integration
Control features include an Enable pin per channel (independent power-down) and a Power-On Reset output that can sequence downstream loads — both are active-high and referenced to the input voltage. Protection is built in: over-temperature shutdown and short-circuit current limiting. No external clamp diode needed for the output — the internal current limit handles a hard short to ground until the thermal cycle trips.
Sourcing and compliance
Fully ROHS3 compliant — the /NOPB suffix indicates lead-free (Pb-free) termination finish and exemption-free RoHS compliance per EU directive 2011/65/EU.