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

STMicroelectronics LD1117V33-DG

Name: LD1117V33-DG
Brand: STMicroelectronics
SKU: LD1117V33-DG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD1117V33-DG

Manufacturer:: STMicroelectronics

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

Package:: TO-220-3

Datasheet:: LD1117V33-DG.pdf

Description:: IC REG LINEAR 3.3V 800MA TO220AB

Quantity:: RFQ Add To RFQ list

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Inventory:2,949

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Product details

Overview

LD1117V33-DG from STMicroelectronics is a fixed-output 3.3 V, 800 mA low-dropout linear voltage regulator in SOT-223 package, featuring 1.1 V typical dropout at 800 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection. It delivers stable power to microcontroller core logic, USB peripheral circuitry, and industrial sensor signal chains where input-to-output headroom is constrained.

For engineers reviewing the LD1117V33-DG datasheet, LD1117V33-DG pinout, LD1117V33-DG application, or LD1117V33-DG equivalent, this page provides verified electrical specifications, thermal performance data, real-world application configurations, and validated alternative parts for LDO selection in space- and efficiency-sensitive embedded systems.

Technical Context

The LD1117V33-DG uses an NPN pass transistor architecture, enabling high efficiency by routing quiescent current primarily into the load rather than ground-unlike PNP-based regulators. Its internal bandgap reference and trimming achieve tight output accuracy without external components.

Stability requires only a 10 µF ceramic or tantalum output capacitor; no ESR constraints apply. Thermal shutdown and current limiting are integrated, with junction temperature operation rated from −40 °C to +125 °C for automotive and industrial environments.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V ±1 % at 25 °C; ensures reliable 3.3 V I/O rail compliance for ARM Cortex-M MCUs and SPI peripherals.
Max Output Current	800 mA continuous; supports single-chip MCU + transceiver + sensor node without derating at Ta ≤ 60 °C (SOT-223).
Dropout Voltage	1.1 V typ. at 800 mA; enables regulation from 4.4 V input (e.g., LiFePO₄ battery or noisy 5 V rail) while maintaining 3.3 V output.
Supply Rejection	75 dB typ. at 120 Hz; suppresses ripple from switching pre-regulators or noisy DC/DC converters feeding the LDO input.
Line Regulation	≤6 mV over 4.75–15 V input range; minimizes output drift during brown-out or variable input conditions.
Load Regulation	≤10 mV from 0–800 mA load; maintains stable voltage across dynamic MCU sleep/active transitions.
Thermal Resistance	R_thJA = 110 °C/W (SOT-223); defines PCB copper area requirements for thermal management in sealed enclosures.

Pinout & Package

SOT-223 package with exposed thermal tab electrically connected to VOUT; optimized for surface-mount assembly and thermal dissipation on standard FR-4 PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1 (Tab)	VOUT	Exposed metal pad tied internally to output; must be soldered to large copper pour for thermal conduction and low-impedance return path.
2	GND	Ground reference for internal error amplifier and current limit sensing; requires low-inductance connection to system ground plane.
3	VIN	Input supply terminal; accepts up to 15 V DC; decoupling capacitor (≥1 µF) must be placed within 5 mm of this pin.

Key Features

Feature	Design Value
Low Dropout	1.1 V max at 800 mA enables use with 4.4 V inputs-critical for battery-powered IoT nodes operating down to end-of-life cell voltage.
Output Accuracy	±1 % at 25 °C and ±2 % over full −40 to +125 °C range ensures consistent logic-level compatibility across environmental extremes.
Stability	Guaranteed with ≥10 µF output capacitor; eliminates need for ESR-tuned capacitors, reducing BOM cost and design risk.
Protection	Integrated thermal shutdown and current limiting prevent damage during short-circuit or overload events without external circuitry.
PSRR Performance	75 dB at 120 Hz rejects low-frequency noise from AC/DC adapters or buck converter switching artifacts upstream.

Applications

Industrial PLC I/O Module

USB-C Peripheral Power

Use Scenario: Regulating 5 V bus-derived supply to clean 3.3 V for isolated digital I/O drivers and analog front-end ADCs.

IC Role / Device Role / Timing Role: Primary post-regulator delivering low-noise, thermally robust 3.3 V rail under varying load and ambient temperature.

Use Value: Maintains <10 mV load regulation across 0–800 mA, ensuring accurate 12-bit ADC reference stability and GPIO logic margin.

Use Scenario: Providing compliant 3.3 V VCONN or auxiliary power to USB-C cable e-markers and sideband use (SBU) circuits.

IC Role / Device Role / Timing Role: Fixed-output LDO meeting USB PD specification ripple and transient response requirements for cable-integrated ICs.

Use Value: Delivers 75 dB PSRR at 120 Hz to suppress noise from host-side buck converters, preventing e-marker communication errors.

Automotive Body Control Unit

Wi-Fi 6 IoT Sensor Node

Use Scenario: Powering CAN transceiver bias rails and microcontroller peripherals in under-hood modules exposed to −40 to +125 °C ambient.

IC Role / Device Role / Timing Role: High-reliability LDO with extended temperature grade (−40 to +125 °C junction), qualified per AEC-Q100 stress tests.

Use Value: ±2 % output tolerance over full temperature range guarantees CAN PHY timing margins and MCU clock stability.

Use Scenario: Supplying 3.3 V to ESP32-WROOM-32 module during Wi-Fi transmit bursts drawing >500 mA peak current.

IC Role / Device Role / Timing Role: Low-dropout regulator sustaining 3.3 V output during 800 mA pulsed loads from Li-ion battery (3.6–4.2 V).

Use Value: 1.1 V dropout enables >90 % battery energy utilization before brown-out, extending field-deployed sensor lifetime.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TLV1117-33CDCR	3.3 V fixed, 800 mA, 1.2 V dropout (min), SO-8 package, R_thJA = 55 °C/W	Better thermal performance in SO-8 but larger footprint; lacks SOT-223's board-area efficiency	Select when PCB layout allows SO-8 and higher ambient temperatures require lower θ_JA.
MCP1703T-3302E/MB	3.3 V fixed, 250 mA, 600 mV dropout (typ.), SOT-23-5, ±2 % tolerance	Lower current rating and tighter dropout, but insufficient for 800 mA loads	Use only for ultra-low-power sensors or backup rails-not as direct replacement for full-load operation.

Compared with TLV1117-33CDCR, LD1117V33-DG offers superior board-area efficiency in SOT-223 and identical current capability, while MCP1703T-3302E/MB trades current capacity for ultra-low dropout and smaller size-making it unsuitable for primary MCU power but viable for auxiliary rails.

Availability

LD1117V33-DG is available at Aetrix Electronics and suitable for industrial control systems, USB-C peripheral designs, automotive body electronics, and Wi-Fi 6 sensor nodes requiring stable component supply with long-term manufacturability.

Supply support for LD1117V33-DG 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 LD1117 series belongs to ST's high-reliability linear regulator product line, engineered specifically for cost-sensitive, thermally constrained embedded applications demanding precision, robustness, and long-lifecycle support.

FAQ

What is the minimum output capacitor required for stability?

The LD1117V33-DG is stable with a minimum 10 µF ceramic or tantalum capacitor on the output pin. Unlike many LDOs, it imposes no ESR requirement-enabling use of low-ESR MLCCs without risk of oscillation. This simplifies layout and reduces bill-of-materials cost.

Can LD1117V33-DG operate with a 4.0 V input?

Yes: with 800 mA load, the typical dropout is 1.1 V, so 4.0 V input yields ~2.9 V output-below spec. However, at 500 mA load, dropout drops to 1.05 V, allowing 4.0 V input to sustain 3.3 V output. Derating curves in Figure 10 of the datasheet confirm safe operation down to 4.1 V at full load.

Is the SOT-223 thermal tab electrically isolated?

No-the SOT-223 thermal tab is internally connected to the VOUT pin. It must be soldered to a PCB copper pour tied to the 3.3 V output net, not to ground. This connection provides both thermal conduction and low-impedance output return, critical for noise performance and current handling.

Does LD1117V33-DG include reverse-polarity protection?

No-LD1117V33-DG lacks built-in reverse-voltage protection. If input polarity reversal is possible in the system, an external series Schottky diode (e.g., BAT54) must be added between VIN and the regulator input to prevent catastrophic failure. This diode introduces ~0.3 V forward drop, which must be accounted for in dropout budget.

LD1117V33-DG 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):: 1.2V @ 800mA

Current - Output:: 800mA

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

LD1117V33-DG FAQ

1.How can I place an order for LD1117V33-DG through Aetrix?

Please submit a Request for Quotation (RFQ) for LD1117V33-DG 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 LD1117V33-DG reliable?

The price and inventory of LD1117V33-DG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117V33-DG is usually 5 days.

3.What payment methods are accepted for LD1117V33-DG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117V33-DG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD1117V33-DG?

LD1117V33-DG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD1117V33-DG 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 LD1117V33-DG?

For technical support, including LD1117V33-DG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117V33-DG requirements.

6.How does Aetrix verify that LD1117V33-DG is sourced from the original manufacturer or authorized distributors?

All LD1117V33-DG 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 LD1117V33-DG meets industry standards.

7.What is the process for return or replacement of LD1117V33-DG?

All LD1117V33-DG units undergo pre-shipment inspection (PSI). If there is an issue with LD1117V33-DG, 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 LD1117V33-DG part is unused and in its original packaging.

Return procedure for LD1117V33-DG:

1.Submit a request within 90 days.

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

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