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Texas Instruments LM2931S-5.0/NOPB — Analog & Data Acquisition

LM2931S-5.0/NOPB LDO Regulator, 5V Fixed, 100mA, TO-263-3

MPNLM2931S-5.0/NOPB
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Texas Instruments LM2931S-5.0/NOPB, positive fixed-output LDO regulator, 5V, 100mA, 0.3V dropout at full load, 55dB PSRR at 120Hz, -40°C to 85°C, DDPAK/TO-263-3 surface-mount package.

$2.6600Ref. price · indicative, final on quote
Texas Instruments LM2931S-5.0/NOPB datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

LM2931S-5.0/NOPB specifications
ParameterValue
Output typeFixed
MountingSurface Mount
Voltage - input26V
Voltage dropout0.3V @ 100mA
Voltage - output (Min (Fixed))5V
Output current100mA
Current - supply15 mA
Current - quiescent1 mA
Operating temperature-40°C~85°C
PSRR55dB (120Hz)
PackageTube
CaseTO-263-4, D²Pak (3 Leads + Tab), TO-263AA
Protection featuresOver Temperature, Reverse Polarity, Short Circuit
Number of regulators1
Output configurationPositive

Product details

5 V fixed output, 100 mA — the always-on rail regulator

It is built for always-on or sensor supply rails in automotive and industrial systems where the input bus can swing up to 26 V — direct connection to a 24 V battery or a 12 V rail without a pre-regulator is within spec. The 55 dB PSRR at 120 Hz is the headline spec for this class: it attenuates the 100/120 Hz ripple from a rectified AC or a switching pre-regulator, keeping the output clean for analog or microcontroller supply.

Dropout and headroom — 0.3 V at full load

Maximum dropout is 0.3 V at 100 mA output. That means the input must stay above 5.3 V to maintain regulation — a 12 V battery at 11 V during cranking still holds margin. Below that threshold the output tracks the input minus dropout, and the PSRR drops off. Quiescent current is 1 mA typical, rising to 15 mA maximum under fault or heavy load. For a battery-backed always-on rail, the 1 mA Iq is the standing draw that must be included in the sleep-mode budget.

Protection set — over-temp, reverse polarity, short circuit

The LM2931S-5.0/NOPB integrates over-temperature shutdown, reverse polarity protection, and short-circuit current limiting. In an automotive environment where a load-dump transient or a miswired battery connection is a real event, these protections prevent the regulator from failing open or shorting the input rail.

D²Pak — thermal pad required

Frequently asked questions

Is LM2931S-5.0/NOPB a direct replacement for LM2931S-5.0?

The LM2931S-5.0/NOPB is the lead-free / RoHS-compliant version of the original LM2931S-5.0. The electrical specs — 5 V fixed output, 100 mA, 0.3 V dropout, 55 dB PSRR — are identical. The /NOPB suffix indicates no lead (Pb) in the package finish. It is a drop-in replacement on the same PCB footprint.

What is the typical application for LM2931S-5.0/NOPB in automotive designs?

It is used as a post-battery or post-switcher LDO for always-on 5 V rails — supplying microcontrollers, CAN transceivers, or sensor modules that need a clean, regulated 5 V from a 12 V or 24 V bus. The 26 V input max and reverse-polarity protection make it suitable for direct battery connection in cabin or chassis-domain electronics.