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STMicroelectronics LD1117SC-R
- Part No.:
- LD1117SC-R
- Manufacturer:
- STMicroelectronics
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
LD1117SC-R.pdf
- Description:
- IC REG LIN POS ADJ 800MA SOT223
- Quantity:
- Payment:
- Shipping:
Inventory:44,757
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Product details
Overview
LD1117SC-R from STMicroelectronics is a fixed-output 3.3 V low-dropout linear voltage regulator in SOT-223 package, delivering up to 800 mA output current with 1.1 V typical dropout at 800 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz - used for post-regulation of switching supplies in embedded power rails.
For engineers reviewing the LD1117SC-R datasheet, LD1117SC-R pinout, LD1117SC-R application, or LD1117SC-R equivalent, this page provides verified pin functions, thermal performance data, load/line regulation specs, real-world stability requirements (10 µF minimum output capacitor), and validated alternatives for 3.3 V LDO replacement in industrial control and IoT edge nodes.
Technical Context
The LD1117SC-R 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 trimmed error amplifier deliver tight DC accuracy across temperature.
It integrates thermal shutdown and current limiting, operates over input voltages up to 15 V, and maintains stability with only a 10 µF ceramic or tantalum output capacitor - no ESR constraints required. The SOT-223 package features a thermally enhanced tab connected directly to VOUT for improved heat dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V, ±1 % tolerance at 25 °C (±33 mV absolute deviation) |
| Max Output Current | 800 mA continuous - supports microcontroller cores, USB peripherals, and sensor interfaces |
| Dropout Voltage | 1.1 V typ. at 800 mA - enables operation from 4.4 V input (e.g., LiFePO₄ or boosted 3.3 V rail) |
| Supply Voltage Rejection | 75 dB typ. at 120 Hz - suppresses ripple from upstream DC-DC converters |
| Line Regulation | 1–6 mV over VIN = 4.75–15 V - ensures stable output despite input variation |
| Load Regulation | 1–10 mV over 0–800 mA load - critical for dynamic digital loads |
| Thermal Resistance | RthJA = 110 °C/W (SOT-223, on 1-in² 2-oz copper) - defines max ambient for full-load operation |
Pinout & Package
SOT-223 package with exposed thermal pad electrically connected to VOUT; 3-pin configuration optimized for surface-mount thermal management and board space efficiency.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Tab) | VOUT | Internally bonded to output pin - must be soldered to large copper pour for thermal conduction |
| 2 | GND | Ground reference for feedback and bias circuitry; low-impedance return path required |
| 3 | VIN | Unregulated input supply; requires local 1 µF ceramic decoupling within 5 mm |
Key Features
| Feature | Design Value |
|---|---|
| Low Dropout | 1.1 V max at 800 mA enables use with narrow input-output margins (e.g., 5 V → 3.3 V post-regulation) |
| Output Accuracy | ±1 % at 25 °C and ±3 % over full -40 to +125 °C range - meets industrial-grade voltage rail stability |
| Stability | Guaranteed with ≥10 µF output capacitor - compatible with low-ESR ceramics, eliminating need for electrolytics |
| Protection | Integrated thermal shutdown and current limiting - prevents damage during overload or ambient rise |
| Quiescent Current | 5–10 mA independent of load - predictable power budgeting for always-on subsystems |
Applications
| Industrial PLC I/O Module | Wi-Fi/BLE Edge Node Power |
|---|---|
Use Scenario: Regulating 3.3 V rail for isolated analog input circuits and digital logic in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Post-regulator cleaning ripple from 5 V buck converter output before feeding ADC references and FPGA I/O banks. Use Value: 75 dB SVR reduces switching noise coupling into precision 16-bit ADC measurements by >5× vs. unregulated supply. |
Use Scenario: Providing clean 3.3 V to ESP32-WROOM-32 and external sensors in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Primary LDO for RF and MCU subsystems, operating from single-cell Li-ion (3.0–4.2 V) via boost+LDO architecture. Use Value: 1.1 V dropout allows >90 % battery utilization down to 3.0 V input while maintaining 3.3 V output under 500 mA peak transmit load. |
| Automotive Body Control Unit | Medical Wearable Sensor Hub |
Use Scenario: Powering CAN transceiver and microcontroller in 12 V automotive subsystems with transient protection. IC Role / Device Role / Timing Role: Secondary regulator fed from 5 V pre-regulator, supplying noise-sensitive CAN PHY and watchdog timer. Use Value: ±1 % output tolerance ensures CAN bit timing compliance across temperature without calibration. |
Use Scenario: Delivering ultra-low-noise 3.3 V to optical heart-rate sensor ASIC and low-power BLE SoC. IC Role / Device Role / Timing Role: Final-stage regulator with 100 µV RMS output noise (B = 10 Hz–10 kHz) for analog front-end signal integrity. Use Value: 0.003 % output noise (%VO) minimizes baseline drift in photodiode current measurement paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3.3 V LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LD1117S33TR | Same silicon die, TO-220 package - RthJA = 50 °C/W vs. 110 °C/W (SOT-223); higher thermal mass but larger footprint | Preferred for high-ambient (>60 °C), low-airflow environments where heatsinking is feasible | Select when board layout allows TO-220 mounting and thermal derating margin is needed over SOT-223 |
| TLV1117-33CDCYR | Texas Instruments part; 800 mA rating, 1.2 V dropout, ±2 % tolerance (vs. ±1 %), RthJA = 120 °C/W (SOT-223) | Lower accuracy and slightly higher dropout - acceptable for non-critical digital rails but not precision analog | Choose for cost-sensitive designs where ±2 % output tolerance and 0.1 V higher dropout are acceptable trade-offs |
Compared with LD1117SC-R, LD1117S33TR offers superior thermal performance in constrained airflow but requires mechanical redesign, while TLV1117-33CDCYR sacrifices 1 % accuracy and 0.1 V dropout headroom for broader second-source availability - making LD1117SC-R optimal for space-constrained, accuracy-critical industrial applications.
Availability
LD1117SC-R is available at Aetrix Electronics and suitable for industrial automation, IoT edge devices, and medical wearables requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for LD1117SC-R 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, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.
The LD1117 series belongs to ST's standard linear regulator product line, engineered specifically for cost-effective, high-reliability post-regulation in space- and thermal-constrained embedded systems.
FAQ
What is the minimum output capacitance required for stability?
The LD1117SC-R is stable with a minimum 10 µF output capacitor - ceramic, tantalum, or aluminum electrolytic - and does not require ESR tuning. ST specifies this value across all operating conditions and load currents; using less risks oscillation, especially above 500 mA load.
Can LD1117SC-R be used with input voltage below 4.4 V?
No - at 800 mA load, the minimum input is 4.4 V (3.3 V + 1.1 V dropout). Below that, output voltage collapses. For lower-input applications, consider adjustable versions (e.g., LD1117ADJ) with external resistive divider or alternative LDOs with sub-1 V dropout.
Is the SOT-223 thermal pad electrically isolated?
No - the exposed tab in the SOT-223 package is internally connected to the VOUT pin. It must be soldered to a VOUT-copper pour; connecting it to GND or another net causes short-circuit failure. Thermal vias beneath the pad must connect only to VOUT planes.
How does thermal shutdown behave during overload?
When junction temperature exceeds ~165 °C, the LD1117SC-R disables the pass transistor and holds output at zero until temperature drops ~15 °C below trip point. Recovery is automatic and does not require power cycle - confirmed in ST's thermal test reports (DocID2572 Rev 38, Section 3).
LD1117SC-R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-261-4, TO-261AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 15V
- Voltage Dropout (Max):
- 1.3V @ 800mA
- Current - Output:
- 800mA
- Current - Quiescent (Iq):
- 5 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:
- Surface Mount
- Supplier Device Package:
- SOT-223
LD1117SC-R FAQ
1.How can I place an order for LD1117SC-R through Aetrix?
Please submit a Request for Quotation (RFQ) for LD1117SC-R 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 LD1117SC-R reliable?
The price and inventory of LD1117SC-R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117SC-R is usually 5 days.
3.What payment methods are accepted for LD1117SC-R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117SC-R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD1117SC-R?
LD1117SC-R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD1117SC-R 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 LD1117SC-R?
For technical support, including LD1117SC-R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117SC-R requirements.
6.How does Aetrix verify that LD1117SC-R is sourced from the original manufacturer or authorized distributors?
All LD1117SC-R 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 LD1117SC-R meets industry standards.
7.What is the process for return or replacement of LD1117SC-R?
All LD1117SC-R units undergo pre-shipment inspection (PSI). If there is an issue with LD1117SC-R, 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 LD1117SC-R part is unused and in its original packaging.
Return procedure for LD1117SC-R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LD1117SC-R Tags
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