Skip to main content
Log in
STMicroelectronics LD1117ASTR — Power Management (PMIC / Gate Driver)

LD1117ASTR – STMicroelectronics Adjustable LDO, 1 A, SOT-223

MPNLD1117ASTR
Active

STMicroelectronics LD1117ASTR, adjustable positive LDO, 1 A output, 80 dB PSRR at 120 Hz, 1.3 V max dropout at 1 A, SOT-223 package, active production.

$0.8600Ref. price · indicative, final on quote
STMicroelectronics LD1117ASTR datasheet (PDF)
PackagingTO-261-4, TO-261AA
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

LD1117ASTR specifications
ParameterValue
Output typeAdjustable
MountingSurface Mount
Voltage - input15V
Voltage dropout1.3V @ 1A
Voltage - output15V
Voltage - output (Min (Fixed))1.25V
Output current1A
Current - quiescent5 mA
Operating temperature0°C ~ 125°C
PSRR80dB (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 adjustable LDO does and who specifies it

The LD1117ASTR is an adjustable positive linear regulator from STMicroelectronics, delivering up to 1 A output current from a 15 V max input rail. The 1.3 V max dropout at 1 A sets the headroom requirement: the input must stay at least 1.3 V above the programmed output at full load, or the regulator drops out of regulation.

Dropout and quiescent current — sizing the supply rail

The 5 mA quiescent current is the current the regulator draws from the input regardless of load — it adds to the input-side budget and matters for battery-powered designs where every milliamp counts. Compared to the STMicroelectronics LDFPVR, which offers a PSRR of 62 dB to 55 dB across 120 Hz to 100 kHz, the LD1117ASTR's 80 dB at 120 Hz gives it a clear advantage for 50/60 Hz ripple rejection, though the LDFPVR adds Enable and Power Good control features not present here.

Active production and compliance posture

Protection features and package fit

Built-in over-current and over-temperature protection guard the regulator against output shorts and thermal runaway — the device shuts down rather than exceeding its safe operating area. The SOT-223 package footprint is common and well-documented; the centre tab is the output pin and carries the heat to the PCB copper.

Frequently asked questions

What are the alternatives to LD1117ASTR?

Within STMicroelectronics, the LDFPVR is a functional alternative with a lower PSRR (62 dB to 55 dB across 120 Hz to 100 kHz) but adds Enable and Power Good control features. The LD39020DTPU33R is a fixed-output 3.3 V, 200 mA LDO with a higher PSRR bandwidth but lower current capability.

Does LD1117ASTR have overcurrent protection?

Yes, the LD1117ASTR includes both over-current and over-temperature protection. The regulator limits output current and shuts down if the junction temperature exceeds the safe limit.

Is LD1117ASTR compatible with SOT223-3?

The LD1117ASTR uses the SOT-223 package (ST's supplier device package designation), which is the same footprint as the industry-standard SOT-223-3. The pinout is: pin 1 (adjust), pin 2 (output/tab), pin 3 (input), pin 4 (ground). Confirm the pin assignment against your PCB layout before committing.