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STMicroelectronics LD1117D18 — Analog & Data Acquisition

ST LD1117D18 LDO Regulator, 1.8V Fixed, 800mA, 8-SOIC

MPNLD1117D18
Obsolete

STMicroelectronics LD1117D18, positive fixed LDO regulator, 1.8V output, 800mA, 75dB PSRR at 120Hz, dropout 1.2V max at 800mA, 8-SOIC package, 0°C to 125°C.

STMicroelectronics LD1117D18 datasheet (PDF)
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

LD1117D18 specifications
ParameterValue
Output typeFixed
MountingSurface Mount
Voltage - input15V
Voltage dropout1.2V @ 800mA
Voltage - output (Min (Fixed))1.8V
Output current800mA
Current - quiescent10 mA
Operating temperature0°C ~ 125°C
PSRR75dB (120Hz)
PackageTube
Case8-SOIC (0.154\", 3.90mm Width)
Protection featuresOver Current, Over Temperature
Number of regulators1
Output configurationPositive

Product details

Fixed 1.8 V rail, 800 mA capacity

The STMicroelectronics LD1117D18 is a single-output positive fixed LDO regulator delivering a regulated 1.8 V output at up to 800 mA.

Maximum dropout voltage is 1.2 V at the full 800 mA load, so the input rail must stay above 3.0 V to maintain regulation.

Protection and quiescent draw

Built-in over-current and over-temperature protection cover the usual fault conditions.

For new designs or BOM sustainment, a pin-compatible fixed 1.8 V LDO in the same 8-SOIC footprint from the LD1117 family is the natural cross-reference — confirm the dropout and current rating match the application.

Frequently asked questions

Is the LD1117D18 obsolete?

Yes, STMicroelectronics lists the LD1117D18 as obsolete.

What is the LD1117D18's PSRR?

The LD1117D18 provides 75 dB of power-supply rejection at 120 Hz, which is the typical line-frequency ripple frequency. This makes it suitable for noise-sensitive analog loads powered from a rectified AC source.

Can the LD1117D18 be used for a 3.3 V output?

No — the LD1117D18 is a fixed 1.8 V output regulator. For a 3.3 V rail, you would need the fixed 3.3 V variant in the same LD1117 family (e.g., LD1117D33) or an adjustable version with external resistors.