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LP2951 Micropower LDO

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by Ray

100 mA micropower adjustable low-dropout regulator with error flag and shutdown.

regulatorldomicropoweradjustableshutdowntisoic-8
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LP2951

Texas Instruments · Linear Regulator (LDO) · SOIC-8

The LP2951 is a 100 mA micropower low-dropout regulator with low quiescent current (75 uA typ). It offers an adjustable or fixed output, a shutdown input, and a power-good error flag that signals when the output falls out of regulation, making it well suited to battery-powered and always-on designs.

Pinout

Pin Name Type Function
1 OUTPUT power_out Regulated output supply, up to 100mA. Requires a ceramic capacitor to GND for stability (COUT 1µF to 100µF, ESR 0 to 2Ω on the new chip). Place the output cap as close to the pin as possible.
2 SENSE input Kelvin sense of the output voltage. Tie to OUTPUT (with FEEDBACK tied to VTAP) for the fixed-output configuration. Leave floating when using the adjustable-output configuration.
3 SHUTDOWN input Active-high shutdown input. Drive high (>~1.5V) to disable the regulator; drive low (VSHUTDOWN ≤ 0.7V) to enable normal operation. Absolute max 42V (new chip) / 35V (legacy).
4 GND power_in Device ground reference for the regulator, error comparator, and internal bandgap.
5 ERROR output Active-low open-drain error flag. Asserts (pulls low) when VOUT drops more than ~6% below its nominal value, indicating an out-of-regulation or under-voltage condition. Requires an external pull-up; useful for power-sequencing multiple rails.
6 VTAP input Tap of the internal fixed-voltage resistor divider. Connect to FEEDBACK for the fixed 3.3V/5V output option. Leave floating when using the device in adjustable-output mode.
7 FEEDBACK input Error-amplifier feedback input (regulates to VREF ≈ 1.235V). Connect to VTAP (with OUTPUT tied to SENSE) for fixed output; connect to the mid-point of an external R1/R2 divider for adjustable output (VOUT = VREF × (1 + R1/R2), VREF to 29V). Divider current should be ≥12µA or add a feed-forward cap for stability.
8 INPUT power_in Unregulated supply input, 2V to 30V operating (absolute max 42V new chip / 35V legacy). Bypass with at least a 1µF capacitor to GND close to the pin.

Key specifications

Parameter Value
Type Micropower adjustable LDO
Output current 100 mA
Quiescent current 75 uA typ
Dropout voltage 380 mV at 100 mA
Output Adjustable (1.24 V ref) or fixed 3.0/3.3/5 V
Features Shutdown, error flag
Supply voltage Up to 30 V
Operating temperature -40 C to 125 C

Ordering variants

Same part, different packaging or reel option.

  • LP2951D
  • LP2951DRG

CAD (KiCad official)

  • Symbol: lp2951.kicad_sym
  • Footprint: lp2951.kicad_mod
  • 3D model: SOIC-8 body from KiCad Package_SO/SOIC-8_3.9x4.9mm_P1.27mm.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (49 pp, sha256 4a441bb26d2b5975, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF