LD1117S33TR device package

LD1117S33TR schematic symbol

Almost all modern digital electronic devices require low level DC voltages for their operation. This low DC voltage allows these electronics systems to be battery-powered, portable, lightweight and safe. The typical power supply voltage range for such devices is 3.3V to 5V. Many digital electronic devices require AC mains power supply for charging or direct powering up. In such cases rectifier circuits are required to convert the AC power to DC power. These rectifier circuits use diodes, capacitors and voltage regulators to provide low level DC voltage to the electronic components. When a diode bridge converts the AC voltage to DC voltage, the output voltage contains high ripple content which degrades power quality. Capacitors along with voltage regulators are used in such circuits to remove the ripple and provide a stable DC voltage to the electronic load such as microprocessors or LCDs.

Table of Contents

What is LD1117S33TR？

The LD1117S33TR is a low voltage drop regulator manufactured by ST Microelectronics. This regulator is capable of providing a maximum current of 1300mA to the load. The output voltage of the regulator is 3.3VDC. This regulator has a compact size with excellent thermal characteristics. The built in NPN pass transistor ensures high efficiency. Other than 1 or 2 capacitors, the device does not need any other external components. The device is packaged in an SOT-223 compact package.

Pin Configuration

The pin configuration of the LD1117S33TR linear voltage regulator is given in the table below:

Pin name	Pin description
Common	Ground pin
Input	Supply input
Output	Voltage output

Features

3 terminal device
Stable 3.3V DC output
1V low drop voltage
Output current up to 800mA
Availability of adjustable version
Supply voltage rejection of 75dB
Positive output configuration
Over current protection
Over heat protection
NPN pass transistor

Applications

The applications of LD1117S33TR voltage regulator are provided as following:

Voltage regulation in handheld devices
Computer and server power supplies
Power supplies in telecommunication equipment
Power supplies in digital and embedded systems

Specifications

The major technical specifications of the LD1117S33TR are provided as following:

Terminals: 3
Max DC input voltage: 15V
Max power dissipation: 12W
Max operating junction temperature: 125^OC
Output voltage: 3.3V
Max output current: 1.3A
Typical line regulation: 1mV
Typical load regulation: 1mV
Supply voltage rejection: 75dB
Package: SOT-223

Alternatives

PAM3110ABA330R, AME8810AEGTZ, SC1202CST-3.3;

How LD1117S33TR work?

The LD1117S33TR is a general-purpose low-drop voltage regulator which is widely used in power supply circuits. One of the most common LD1117 based circuit is the full wave diode rectifier power supply. In this power supply, the first stage is a power transformer which steps down 220/120VAC to 3.3VAC. The 2^nd circuit stage is the diode rectifier which converts the 3.3VAC to 3.3VDC. The 3^rd stage in the circuit is the LD1117 regulator which removes the ripple from the converted DC voltage and provides a stable DC voltage at the output.

The application circuit of such a power supply is given in the figure below:

LD1117S33TR application circuit

LD1117S33TR Related Products Prices

Parts	Mfr.	Description	Stock	Prices
LD1117S33TR	STMicroelectronics	IC REG LDO 3.3V 0.8A SOT223	314150	$0.111 Lowest
LD1117S33CTR	STMicroelectronics	IC REG LDO 3.3V 0.8A SOT223	289282	$0.114 Lowest
LD1117AV33	STMicroelectronics	IC REG LDO 3.3V 1A TO220AB	18500	$0.175 Lowest