LD1117-3.3 — Datasheet Summary, Specs & Alternatives

01 — Overview

This datasheet covers the UTC LD1117/A, a low-dropout positive voltage regulator family including fixed and adjustable versions like the 3.3V and 5.0V variants. It serves as the primary technical reference for designers needing efficient linear regulation up to 1A output current. Key parameters include a maximum output current of 800mA to 1A depending on the series, built-in current limit protection, over-temperature safety features, and low dropout voltage suitable for SCSI-2 termination applications.

02 — Key specifications

Datasheet parameters

Parameter	Min	Typ	Max	Conditions
quiescent current	—	5 mA	10 mA	VIN≤10V
output voltage	1.18 V	1.2 V	1.22 V	VIN = 3.2V, IOUT = 10mA, TJ = 25°C
output current	—	800 mA	—
supply voltage range	—	—	18 V
operating temperature	-20 °C	—	125 °C
standby current	—	5 mA	—
psrr	60 dB	75 dB	—	IOUT = 40mA, f = 120Hz, TJ = 25°C, VIN = 4.2V, VRIPPLE = 1VPP
dropout voltage	—	1 V	1.1 V	IOUT = 100mA
output noise voltage	—	100 µV	—	B = 10Hz to 10KHz, TJ = 25°C
output count	—	1	—

03 — Alternatives

Closest matches to LD1117-3.3

AZ1117C-3.3 2.8× higher output voltage, 1.2× higher output current, 1.2× lower quiescent current

L78M05ABV 4.2× higher output voltage, 2.5× lower output noise voltage, 2.0× higher dropout voltage

AZ1117D-3.3TRE1 2.8× higher output voltage, 1.2× higher output current, 1.2× lower operating temperature

L78L05ABD13TR 8.0× lower output current, 4.2× higher output voltage, 2.5× lower output noise voltage

AMS1117 1.9× lower supply voltage range, 1.2× higher output current, 1.2× lower operating temperature

AP2112-1.2 4.2× lower supply voltage range, 2.3× lower operating temperature, 2.0× lower output noise voltage

TLV758P 4.8× lower supply voltage range, 2.5× higher output voltage, 1.9× lower output noise voltage

AP2127K-3.3TRG1 2.8× lower supply voltage range, 2.8× higher output voltage, 2.3× lower operating temperature

04 — FAQ

Frequently asked questions

What is the dropout voltage of the LD1117-3.3 at IOUT = 100mA?

The dropout voltage is 1 V at IOUT = 100mA.

What is the maximum operating temperature for the LD1117-3.3?

The maximum operating temperature is 125 °C.

What is the output count for the LD1117-3.3?

The output count is 1.

What is the output current of the LD1117-3.3?

The output current is 800 mA.

What is the output noise voltage of the LD1117-3.3?

The output noise voltage is 100 µV when measured from 10Hz to 10KHz at a junction temperature of 25°C.

What is the output voltage of the LD1117-3.3 when VIN = 3.2V, IOUT = 10mA, and TJ = 25°C?

The output voltage is 1.2 V.

What is the Power Supply Rejection Ratio (PSRR) of the LD1117-3.3?

The PSRR is 75 dB at IOUT = 40mA, f = 120Hz, TJ = 25°C, VIN = 4.2V, and VRIPPLE = 1VPP.

What is the quiescent current when VIN≤10V?

The quiescent current is 5 mA.