component

LP2985

Public Made by Adom

by adom

TI 150 mA low-noise LDO, SOT-23-5. Fixed 3.3 V, enable, bypass pin for low noise. For RF/analog. Datasheet-verified.

componentvoltage-regulatorldolow-noise3v3sot-23-5texas-instruments
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Contents

README

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LP2985

Texas Instruments · 150 mA low-noise LDO · SOT-23-5

A 150 mA low-dropout regulator tuned for low output noise, in SOT-23-5. A bypass pin takes a small capacitor that filters the internal reference, dropping output noise to levels that suit RF, ADC references, PLLs, and sensor front ends where a plain LDO would inject too much hash. It has a logic enable (ON/OFF) for power sequencing and shutdown, good line and load regulation, and needs only small ceramic capacitors. This page is the fixed 3.3 V version; the family covers 1.8 to 5 V. Input up to 16 V.

Pinout

Pin Name Type Function
1 VIN power_in Input supply pin. Range 2.5V to 16V (new chip) or 2.2V to 16V (legacy). Requires a 1µF or larger input capacitor from this pin to ground.
2 GND power_in Ground reference for the regulator. Carries the quiescent (GND pin) current, up to about 890µA at 150mA load.
3 ON/OFF input Active-high enable input for the LDO. Drive high (≥1.6V) to enable the regulator, low (≤0.15V) to place the device in shutdown. Tie to VIN if unused; do not leave floating. Withstands up to 16V (legacy) or 18V (new chip).
4 BYPASS passive Reference-voltage bypass pin used to lower output noise. Connect an external capacitor (typically 10nF) from BYPASS to GND to achieve the specified 30µVRMS noise performance and improve PSRR.
5 VOUT power_out Regulated output of the LDO, delivering up to 150mA at the factory-fixed output voltage (1.2V-5.0V in 100mV steps for new chip). Requires an output capacitor of at least 2.2µF (new chip) or 1µF effective, with ESR ≤1Ω for stability.

Key specifications

Parameter Value
Type Low-noise LDO regulator
Output current 150 mA
Output voltage 3.3 V (fixed, this variant)
Noise low (bypass-pin filtered)
Enable ON/OFF logic pin
Dropout ~280 mV at 150 mA
Input voltage up to 16 V
Package SOT-23-5

Ordering variants

Same part, different packaging or reel option.

  • LP2985AIM5-3.3 (SOT-23-5)
  • LP2985IM5X-3.3 (SOT-23-5, tape & reel)

CAD (KiCad official)

  • Symbol: Regulator_Linear:LP2985-3.3
  • Footprint: Package_TO_SOT_SMD:SOT-23-5
  • 3D model: SOT-23-5 (KiCad packages3D)
  • 3D model files: lp2985-etched.step / lp2985-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lp2985.step / lp2985.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (43 pp, sha256 bd79c7c5719a63c1, 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