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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LD1117AV33

Name: LD1117AV33
Brand: STMicroelectronics
SKU: LD1117AV33
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD1117AV33

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: TO-220-3

Datasheet:: LD1117AV33.pdf

Description:: IC REG LINEAR 3.3V 1A TO220AB

Quantity:: RFQ Add To RFQ list

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Inventory:1,972

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Product details

Overview

LD1117AV33 from STMicroelectronics is a fixed-output 3.3 V low-dropout linear voltage regulator delivering up to 1 A output current with 1.15 V typical dropout at full load, ±2% output voltage tolerance at 25 °C, and 80 dB supply voltage rejection at 120 Hz - used for post-regulation in microcontroller power supplies and FPGA core voltage stabilization.

For engineers reviewing the LD1117AV33 datasheet, LD1117AV33 pinout, LD1117AV33 application, or LD1117AV33 equivalent, key selection criteria include dropout voltage at 1 A, thermal resistance (R_thJA = 50 °C/W in TO-220), quiescent current (5 mA typ.), stability with 10 µF output capacitor, and compatibility with 0–125 °C junction temperature operation.

Technical Context

The LD1117AV33 employs an NPN pass transistor architecture enabling low dropout while maintaining internal current and thermal limiting. Its reference voltage is trimmed to achieve ±2% output accuracy at 25 °C and ±4% over full temperature range (0–125 °C).

It operates with input voltages from 4.75 V to 10 V for 3.3 V output, requires only a 10 µF ceramic or electrolytic output capacitor for stability, and delivers 100 µV RMS output noise (10 Hz–10 kHz) with 60–75 dB supply ripple rejection under specified test conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	3.3 V nominal, ±2% tolerance at 25 °C - ensures reliable logic-level compliance for 3.3 V digital ICs.
Dropout Voltage	1.15 V typ. @ I_OUT = 1 A - enables regulation from 4.45 V input, supporting wide-input legacy rails.
Max Output Current	1000 mA - sufficient for powering single-core MCUs, sensors, and interface ICs without external heat sinking in TO-220.
Quiescent Current	5 mA typ. @ 25 °C - minimizes no-load power loss in battery-backed or always-on systems.
Supply Rejection	75 dB typ. @ 120 Hz - suppresses switching regulator ripple when used as post-regulator.
Thermal Resistance	R_thJA = 50 °C/W (TO-220) - allows ~12 W max power dissipation with adequate heatsinking.
Stability Capacitor	10 µF min. output capacitance - compatible with low-ESR tantalum or aluminum electrolytic, easing BOM sourcing.

Pinout & Package

LD1117AV33 is supplied in TO-220 package (SG variant), with exposed tab electrically connected to V_OUT for thermal conduction and electrical reference. The case serves as the output terminal and must be isolated from chassis ground unless V_OUT is referenced to system ground.

Pin/Terminal	Circuit Role	Design Meaning
1: INPUT	Voltage input node	Accepts 4.75–10 V DC; requires local 10 µF bypass capacitor to reduce high-frequency impedance.
2: OUTPUT	Regulated output node	Delivers stable 3.3 V; tab is internally bonded to this pin - critical for thermal path and grounding strategy.
3: GND	Ground reference	Low-impedance return for load current and internal bias; must be routed with minimal inductance to avoid instability.

Key Features

Feature	Design Value
Low dropout	1.15 V @ 1 A enables use with 5 V input rails where headroom is constrained.
Internal protection	Integrated current limit and thermal shutdown prevent damage during overload or ambient overheating.
Tight output tolerance	±2% at 25 °C ensures direct compatibility with 3.3 V I/O standards without external trimming.
High PSRR	75 dB at 120 Hz suppresses ripple from upstream DC/DC converters in mixed-signal systems.
Minimal external components	Only one 10 µF output capacitor required - reduces PCB area and bill-of-materials cost.

Applications

Industrial PLC I/O Module

Automotive Body Control Unit

Use Scenario: Powering isolated CAN transceivers and analog sensor signal conditioners in DIN-rail mounted controllers.

IC Role / Device Role / Timing Role: Primary 3.3 V LDO supplying MCU peripherals and level-shifting interfaces.

Use Value: 1.15 V dropout allows operation from 5 V backplane rail even under brownout; ±2% tolerance maintains ADC reference integrity.

Use Scenario: Regulating 3.3 V for microcontroller core and LIN transceiver in door module electronics.

IC Role / Device Role / Timing Role: Post-regulator downstream of automotive-grade buck converter to clean switching noise.

Use Value: 75 dB PSRR attenuates 120 Hz ripple from alternator-fed 5 V rail, preventing communication errors on LIN bus.

Medical Patient Monitor Front-End

Networking Switch Management Controller

Use Scenario: Supplying low-noise 3.3 V to ECG front-end amplifiers and SAR ADCs in portable monitors.

IC Role / Device Role / Timing Role: Low-noise analog domain regulator with dedicated output capacitor filtering.

Use Value: 100 µV RMS output noise (10 Hz–10 kHz) avoids introducing measurable artifacts into biopotential signals.

Use Scenario: Providing stable 3.3 V to ARM-based management SoC and EEPROM in enterprise Ethernet switches.

IC Role / Device Role / Timing Role: Secondary regulator ensuring voltage integrity during hot-swap events and transient load steps.

Use Value: Internal thermal limit prevents latch-up during sustained 1 A loads caused by firmware update activity.

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM1117MP-3.3/NOPB	Higher dropout (1.2 V min. @ 1 A), wider initial tolerance (±3%), R_thJA = 65 °C/W (SOT-223)	Limited to lower ambient temperatures or reduced load currents without heatsink	Prefer when SOT-223 footprint is mandatory and thermal margin >15 °C exists.
TLV1117-33CDCYR	Lower quiescent current (4 mA typ.), tighter line/load regulation (1 mV), but lower max current (800 mA)	Not suitable for sustained 1 A loads; better for low-power always-on subsystems	Choose when system idle current dominates and peak load ≤800 mA.

Compared with LM1117MP-3.3/NOPB, LD1117AV33 offers lower dropout and superior thermal performance in TO-220; versus TLV1117-33CDCYR, it trades higher IQ for guaranteed 1 A delivery and ruggedized industrial temperature range.

Availability

LD1117AV33 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical monitoring equipment requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LD1117AV33 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LD1117A series belongs to ST's standard linear regulator product line, engineered for cost-sensitive, high-reliability applications demanding robust thermal behavior, tight DC accuracy, and minimal external component count.

FAQ

What is the minimum input voltage required for LD1117AV33 to maintain regulation at 1 A load?

The minimum input voltage is calculated as V_OUT + V_DROP = 3.3 V + 1.30 V (max dropout @ 1 A) = 4.60 V. ST specifies 4.75 V as the guaranteed minimum operating input voltage across temperature and process variation, ensuring regulation under worst-case conditions including 125 °C junction temperature and ±4% output tolerance.

Can LD1117AV33 be used with ceramic output capacitors?

Yes - the LD1117AV33 is stable with ceramic capacitors ≥10 µF, provided they meet the manufacturer's ESR specification (0.3 Ω typical). ST confirms stability with X5R/X7R dielectrics; however, DC bias derating must be considered - a 22 µF 6.3 V X5R capacitor typically delivers ~12–15 µF effective capacitance at 3.3 V bias, satisfying the minimum requirement.

How does the TO-220 package's thermal performance compare to SOT-223 for LD1117AV33?

In TO-220, R_thJA = 50 °C/W enables ~12 W power dissipation with standard heatsinking; in SOT-223, R_thJA = 110 °C/W limits continuous 1 A operation to <5 W without forced air. For ambient temperatures above 60 °C or unheatsinked designs, TO-220 provides ≥2.2× greater thermal margin, making it preferred for industrial environments.

Is LD1117AV33 qualified for automotive applications?

No - LD1117AV33 is not AEC-Q100 qualified and is not recommended for automotive powertrain or safety-critical domains. ST explicitly states in its datasheet disclaimer that LD1117A products are not designed or authorized for automotive or safety-critical applications. For automotive use, ST recommends the AEC-Q100 qualified LDOs such as the LD3985 or TCR3UG series.

LD1117AV33 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 15V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 1.3V @ 1A

Current - Output:: 1A

Current - Quiescent (Iq):: 10 mA

Current - Supply (Max):: -

PSRR:: 75dB (120Hz)

Control Features:: -

Protection Features:: Over Current, Over Temperature

Operating Temperature:: 0°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

LD1117AV33 FAQ

1.How can I place an order for LD1117AV33 through Aetrix?

Please submit a Request for Quotation (RFQ) for LD1117AV33 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LD1117AV33 reliable?

The price and inventory of LD1117AV33 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117AV33 is usually 5 days.

3.What payment methods are accepted for LD1117AV33?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117AV33 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD1117AV33?

LD1117AV33 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD1117AV33 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LD1117AV33?

For technical support, including LD1117AV33 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117AV33 requirements.

6.How does Aetrix verify that LD1117AV33 is sourced from the original manufacturer or authorized distributors?

All LD1117AV33 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LD1117AV33 meets industry standards.

7.What is the process for return or replacement of LD1117AV33?

All LD1117AV33 units undergo pre-shipment inspection (PSI). If there is an issue with LD1117AV33, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LD1117AV33 part is unused and in its original packaging.

Return procedure for LD1117AV33:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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