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

STMicroelectronics LD1117V33C-DG

Name: LD1117V33C-DG
Brand: STMicroelectronics
SKU: LD1117V33C-DG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD1117V33C-DG

Manufacturer:: STMicroelectronics

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

Package:: TO-220-3

Datasheet:: LD1117V33C-DG.pdf

Description:: IC REG LINEAR 3.3V 800MA TO220

Quantity:: RFQ Add To RFQ list

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Inventory:2,537

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Product details

Overview

LD1117V33C-DG from STMicroelectronics is a fixed-output 3.3 V, 800 mA low-dropout linear voltage regulator in SOT-223 package, featuring 1 V typical dropout at 100 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz - used for post-regulation of 5 V rails in industrial microcontroller power supplies.

For engineers reviewing the LD1117V33C-DG datasheet, LD1117V33C-DG pinout, LD1117V33C-DG application, or LD1117V33C-DG equivalent, key selection criteria include dropout performance under 800 mA load, thermal resistance (R_thJA = 110 °C/W), output voltage stability across -40 to +125 °C, and compatibility with standard 10 µF ceramic output capacitors.

Technical Context

The LD1117V33C-DG employs an NPN pass transistor architecture, enabling high efficiency by routing quiescent current primarily into the load rather than ground. Its internal bandgap reference and trimming circuitry achieve tight ±1 % output accuracy at 25 °C and maintain ≤0.5 % temperature stability over full operating range.

Designed for stable operation with only a 10 µF minimum output capacitor, it integrates thermal shutdown and current limiting. The C-grade version supports extended junction temperature operation from -40 to +125 °C, distinguishing it from standard versions rated 0 to +125 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V, ±1 % tolerance at 25 °C ensures reliable logic-level compliance for 3.3 V MCU cores and peripherals.
Max Output Current	800 mA continuous - sufficient to power ARM Cortex-M microcontrollers with peripherals active.
Dropout Voltage	1.0 V typ. at 100 mA; 1.1 V max at 800 mA - enables regulation from 4.75 V input, supporting USB-powered or battery-backed systems.
Supply Voltage Rejection	75 dB typ. at 120 Hz - suppresses ripple from upstream switching converters in mixed-signal designs.
Operating Temperature	-40 to +125 °C junction range - qualified for industrial and automotive under-hood auxiliary power rails.
Thermal Resistance	R_thJA = 110 °C/W (SOT-223) - requires minimal PCB copper area for thermal management at full load.
Output Noise	100 µV RMS (10 Hz–10 kHz) - suitable for analog sensor front-ends and ADC reference supplies.

Pinout & Package

LD1117V33C-DG is housed in a 3-pin SOT-223 surface-mount package with exposed thermal pad connected internally to V_OUT. The package supports high-power dissipation in compact layouts and is compatible with standard reflow profiles.

Pin/Terminal	Circuit Role	Design Meaning
1 (Tab)	V_OUT	Exposed metal tab electrically tied to output pin - must be soldered to large PCB copper pour for thermal conduction.
2	GND	Ground reference for internal error amplifier and current limit circuitry; requires low-impedance connection to system ground plane.
3	V_IN	Unregulated input supply; must be ≥4.3 V to sustain 3.3 V output at 800 mA due to dropout margin.

Key Features

Feature	Design Value
Low Dropout	1.0 V typical at 100 mA enables use with 5 V sources where headroom is constrained.
Output Accuracy	±1 % at 25 °C and ≤1 % over full temperature range ensures consistent logic interface levels.
Stability	Guaranteed stable with ≥10 µF ceramic output capacitor - eliminates need for tantalum or electrolytic types.
Protection	Integrated thermal shutdown and current limiting prevent damage during overload or ambient temperature rise.
Quiescent Current	5–10 mA independent of load - predictable bias consumption for power budgeting in always-on subsystems.

Applications

Industrial PLC I/O Modules

Automotive Body Control Units

Use Scenario: Powering isolated CAN transceivers and digital I/O drivers in DIN-rail mounted programmable logic controllers.

IC Role / Device Role / Timing Role: Post-regulator converting 5 V backplane supply to clean 3.3 V for microcontroller and level-shifting circuitry.

Use Value: 75 dB SVR suppresses noise from shared 5 V switcher, preventing communication errors on 1 Mbps CAN FD buses.

Use Scenario: Supplying 3.3 V to door module MCUs and LIN transceivers in 12 V vehicle electrical systems.

IC Role / Device Role / Timing Role: Local LDO providing fault-tolerant 3.3 V rail independent of main DC/DC converter transients.

Use Value: -40 to +125 °C operation and thermal shutdown ensure reliability during engine compartment temperature cycling.

Medical Patient Monitoring Sensors

Smart Energy Metering Units

Use Scenario: Biasing precision analog front-ends (AFE) for ECG and SpO₂ signal conditioning circuits.

IC Role / Device Role / Timing Role: Low-noise 3.3 V source for ADC reference and op-amp rails in battery-operated portable devices.

Use Value: 100 µV RMS output noise avoids degradation of 16-bit ADC effective resolution in sub-µV signal paths.

Use Scenario: Regulating power for metrology SoCs and real-time clocks in ANSI C12.20-compliant electricity meters.

IC Role / Device Role / Timing Role: Primary 3.3 V supply for metering ICs requiring long-term voltage stability and low drift.

Use Value: 0.3 % long-term stability after 1000 hrs at 125 °C ensures calibration integrity over 10+ year field lifetime.

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
TLV1117-33CDCYR	Lower 800 mA rating but tighter 2 % tolerance over temperature; R_thJA = 120 °C/W (SOT-223).	Optimized for cost-sensitive consumer electronics; lacks extended temperature qualification (-40 to +125 °C).	Select when budget constraints outweigh industrial temp grade requirements and thermal margin is available.
MCP1703T-3302E/MB	Higher 6 V max input; 1.2 V dropout at 250 mA; R_thJA = 130 °C/W (SOT-23-5); no thermal pad.	Targeted at space-constrained IoT nodes; limited to 250 mA output, unsuitable for high-current MCU loads.	Choose only for ultra-low-power, low-current applications where board area is critical and 800 mA capability is unnecessary.

Compared with TLV1117-33CDCYR and MCP1703T-3302E/MB, LD1117V33C-DG delivers superior thermal performance (110 °C/W), guaranteed industrial temperature support, and higher sustained current - making it the preferred choice for embedded control systems demanding robustness and longevity.

Availability

LD1117V33C-DG is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical sensor subsystems requiring stable component supply with long lifecycle visibility.

Supply support for LD1117V33C-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 specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and embedded markets.

LD1117V33C-DG belongs to ST's legacy LDO regulator family designed for cost-effective, thermally robust local regulation in space- and reliability-constrained applications.

FAQ

What is the minimum input voltage required for LD1117V33C-DG to maintain regulation at 800 mA?

The maximum dropout voltage is 1.3 V at 800 mA and full temperature range. To guarantee 3.3 V output, input must be ≥4.6 V. At room temperature, 4.4 V suffices per typical 1.1 V dropout - but design margin requires 4.6 V minimum for worst-case conditions.

Can LD1117V33C-DG operate without an input bypass capacitor?

No. An input capacitor (≥1 µF ceramic) is mandatory to prevent oscillation and improve transient response. The datasheet specifies 10 µF output capacitance for stability, and omission of input capacitance risks instability under fast load steps or high-source-impedance inputs.

Is the SOT-223 thermal pad of LD1117V33C-DG electrically connected to V_OUT?

Yes. Per Figure 2 and note in the Pin Configuration section, the exposed tab is internally connected to the V_OUT pin. It must be soldered to a dedicated PCB copper pour tied to the 3.3 V net to ensure both thermal conduction and electrical continuity.

Does LD1117V33C-DG require a minimum load current to maintain regulation?

Yes. The datasheet specifies IO(min) = 2–5 mA at VIN = 15 V. A 1 kΩ pull-down resistor from V_OUT to GND (3.3 mA) satisfies this requirement and prevents output voltage rise during light-load or no-load conditions.

LD1117V33C-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):: 1.3V @ 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:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

LD1117V33C-DG FAQ

1.How can I place an order for LD1117V33C-DG through Aetrix?

Please submit a Request for Quotation (RFQ) for LD1117V33C-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 LD1117V33C-DG reliable?

The price and inventory of LD1117V33C-DG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117V33C-DG is usually 5 days.

3.What payment methods are accepted for LD1117V33C-DG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117V33C-DG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD1117V33C-DG?

LD1117V33C-DG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD1117V33C-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 LD1117V33C-DG?

For technical support, including LD1117V33C-DG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117V33C-DG requirements.

6.How does Aetrix verify that LD1117V33C-DG is sourced from the original manufacturer or authorized distributors?

All LD1117V33C-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 LD1117V33C-DG meets industry standards.

7.What is the process for return or replacement of LD1117V33C-DG?

All LD1117V33C-DG units undergo pre-shipment inspection (PSI). If there is an issue with LD1117V33C-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 LD1117V33C-DG part is unused and in its original packaging.

Return procedure for LD1117V33C-DG:

1.Submit a request within 90 days.

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

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