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STMicroelectronics LD1117S18CTR — Power Management (PMIC / Gate Driver)

LD1117S18CTR – STMicro 1.8V Fixed 800mA LDO, SOT-223, Active

MPNLD1117S18CTR
Active

STMicroelectronics LD1117S18CTR, a positive fixed-output LDO regulator, 1.8V at 800mA, SOT-223 surface-mount package, 75dB PSRR at 120Hz.

$0.7800Ref. price · indicative, final on quote
STMicroelectronics LD1117S18CTR datasheet (PDF)
PackagingTO-261-4, TO-261AA
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

LD1117S18CTR specifications
ParameterValue
Output typeFixed
MountingSurface Mount
Voltage - input15V
Voltage dropout1.3V @ 800mA
Voltage - output (Min (Fixed))1.8V
Output current800mA
Current - quiescent10 mA
Operating temperature-40°C~125°C
PSRR75dB (120Hz)
PackageTape & Reel (TR); Cut Tape (CT)
CaseTO-261-4, TO-261AA
Protection featuresOver Current, Over Temperature
Number of regulators1
Output configurationPositive

Product details

What this 1.8V 800mA LDO delivers on the board

The LD1117S18CTR is a single-output, positive fixed LDO from STMicroelectronics, delivering 1.8V at up to 800mA continuous output current. Maximum dropout is 1.3V at full load, so the input rail must stay above 3.1V to maintain regulation.

Dropout, quiescent current, and protection

Over-current and over-temperature protection are built in, so the regulator folds back safely under a short or thermal runaway. Input voltage range extends to 15V max, giving headroom for 5V or 12V intermediate rails.

Frequently asked questions

What is the LD1117S18CTR's PSRR and why does it matter?

PSRR is 75dB at 120Hz. That figure tells you how well the regulator rejects ripple from a full-wave rectified mains supply — critical for keeping noise off a 1.8V analog rail or a sensitive digital core.

Is the LD1117S18CTR pin-compatible with other LD1117 variants?

The LD1117 family shares the same pinout and SOT-223 footprint across fixed and adjustable output voltage options. A 1.8V fixed version like this one can be swapped with a 3.3V or adjustable sibling on the same board layout, provided the output voltage matches the rail requirement.