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STMicroelectronics LD1117ADT33TR
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- Part No.:
- LD1117ADT33TR
- Manufacturer:
- STMicroelectronics
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
LD1117ADT33TR.pdf
- Description:
- IC REG LINEAR 3.3V 1A DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:21,720
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Product details
Overview
LD1117ADT33TR from STMicroelectronics is a fixed-output 3.3 V low-dropout linear voltage regulator delivering up to 1 A output current in DPAK (TO-252) package, featuring 1.15 V typical dropout at 1 A, ±2% output voltage tolerance at 25 °C, and 80 dB supply voltage rejection at 120 Hz - used for post-regulation of 5 V rails in embedded microcontroller power supplies.
For engineers reviewing the LD1117ADT33TR datasheet, LD1117ADT33TR pinout, LD1117ADT33TR application, or LD1117ADT33TR equivalent, this page delivers verified electrical specs, thermal performance data, real-world use cases, and validated alternative parts with documented functional trade-offs.
Technical Context
The LD1117ADT33TR uses an NPN pass transistor architecture enabling low dropout while maintaining stability with only a 10 µF output capacitor. Its internal reference is trimmed to 3.3 V ±2% at 25 °C and maintains ±0.5% temperature stability across 0–125 °C junction range.
Thermal protection includes internal current limiting and thermal shutdown, with junction-to-ambient thermal resistance of 100 °C/W in DPAK. Quiescent current remains stable at 5 mA typ. across input voltages up to 10 V, supporting low-power standby operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±2% at 25 °C; ensures reliable 3.3 V logic rail for ARM Cortex-M microcontrollers without external feedback. |
| Dropout Voltage | 1.15 V typ. @ 1 A, 25 °C; enables regulation from 4.45 V input - critical for battery-powered 5 V systems with voltage sag. |
| Max Output Current | 1 A continuous; sufficient to power SoC + peripheral ICs on compact industrial control boards. |
| Supply Voltage Rejection | 80 dB typ. @ 120 Hz; suppresses ripple from upstream switching converters feeding the LDO. |
| Quiescent Current | 5 mA typ. @ 25 °C; minimizes no-load power loss in always-on subsystems like RTC or wake-up circuitry. |
| Operating Temperature | 0 °C to 125 °C junction; supports deployment in enclosed industrial enclosures without forced cooling. |
| Stability Capacitor | 10 µF ceramic or electrolytic; eliminates need for specialized low-ESR capacitors, reducing BOM cost and footprint. |
Pinout & Package
DPAK (TO-252) package with exposed thermal pad connected to VOUT; optimized for PCB heat spreading via copper pour under the tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Input) | VIN | Main DC input connection; requires local 10 µF bypass capacitor within 5 mm of pin to ensure stability. |
| 2 (Tab) | VOUT | Exposed thermal pad electrically tied to output; must be soldered to ≥2 cm² copper area for thermal performance. |
| 3 (Output) | VOUT | Regulated 3.3 V output; connects directly to load and output capacitor; Kelvin sensing not required. |
| 4 (GND) | GND | Ground return path; routed separately from high-current VIN/VOUT traces to avoid noise coupling into regulation loop. |
Key Features
| Feature | Design Value |
|---|---|
| Low dropout operation | 1.15 V @ 1 A enables use with 4.45 V minimum input - extends runtime in single-cell LiFePO₄ or degraded 5 V SMPS rails. |
| Internal thermal shutdown | Activates at ~160 °C junction temperature; prevents permanent damage during sustained overload or poor heatsinking. |
| Tight output tolerance | ±2% at 25 °C and ±0.5% over temperature ensures compatibility with 3.3 V I/O standards (e.g., SPI, UART, USB PHY). |
| High PSRR | 80 dB @ 120 Hz rejects switching noise from upstream DC/DC converters, eliminating need for additional LC filtering. |
| Minimal external components | Only input/output capacitors required - no feedback resistors or compensation networks needed for fixed-voltage operation. |
Applications
| Industrial PLC I/O Module | Medical Sensor Node |
|---|---|
|
Use Scenario: Powering isolated analog front-end and RS-485 transceiver from a shared 5 V bus in DIN-rail mounted PLC modules. IC Role / Device Role / Timing Role: Primary 3.3 V LDO supplying ADC reference, op-amps, and digital interface ICs. Use Value: 1.15 V dropout allows stable 3.3 V output even when 5 V bus sags to 4.45 V during motor startup surges. |
Use Scenario: Regulating power for ultra-low-noise biosignal amplifiers and BLE radio in portable ECG patch. IC Role / Device Role / Timing Role: Clean 3.3 V supply for precision analog signal chain and wireless MCU core. Use Value: 100 µV RMS output noise (10 Hz–10 kHz) and 80 dB PSRR prevent switching artifacts from corrupting µV-level ECG signals. |
| Automotive Body Control Unit | POS Terminal Mainboard |
|
Use Scenario: Post-regulating switched 5 V supply for microcontroller, CAN transceiver, and EEPROM in BCM. IC Role / Device Role / Timing Role: Secondary LDO providing fault-tolerant 3.3 V domain independent of main SMPS behavior. Use Value: Internal current limit and thermal shutdown protect against short-circuited downstream loads without external circuitry. |
Use Scenario: Supplying 3.3 V to payment processor, display driver, and secure element in retail POS terminal. IC Role / Device Role / Timing Role: High-reliability fixed-output regulator for mission-critical transaction processing logic. Use Value: ±2% output tolerance over 0–125 °C ensures consistent timing margins for high-speed serial interfaces (e.g., SDIO, USB 2.0). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV1117-33CDR | Lower quiescent current (4 mA typ.), but higher dropout (1.2 V @ 1 A) and narrower input range (up to 15 V vs. 10 V max for LD1117A). | Preferred in battery-powered devices where standby current dominates lifetime; less suitable for high-temperature industrial environments due to lower thermal robustness. | Select TLV1117-33CDR when optimizing for <10 µA shutdown current or requiring wider VIN range beyond 10 V. |
| AP1117D33G-13 | Same 3.3 V output and DPAK package, but ±4% tolerance over full temperature range and 1.3 V dropout @ 1 A. | Acceptable for non-critical digital logic rails where cost sensitivity outweighs tight regulation needs. | Choose AP1117D33G-13 only for cost-driven consumer applications where ±4% output tolerance is acceptable. |
Compared with TLV1117-33CDR and AP1117D33G-13, the LD1117ADT33TR offers superior thermal resilience (125 °C operation), tighter initial tolerance (±2%), and lower dropout - making it optimal for industrial and medical designs demanding long-term regulation accuracy under thermal stress.
Availability
LD1117ADT33TR is available at Aetrix Electronics and suitable for industrial automation controllers, portable medical diagnostics, point-of-sale terminals, and automotive body electronics requiring stable component supply with full traceability and lifecycle continuity.
Supply support for LD1117ADT33TR 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 high-reliability linear regulator product line, engineered specifically for space-constrained industrial and medical applications needing robust thermal performance and tight DC accuracy without complex external compensation.
FAQ
What is the maximum input voltage for LD1117ADT33TR?
The absolute maximum DC input voltage is 15 V per datasheet Table 2, but the recommended operating input voltage is ≤10 V for reliable long-term performance at full load and elevated temperature. Exceeding 10 V increases power dissipation and thermal stress, especially above 85 °C ambient.
Can LD1117ADT33TR be used with ceramic output capacitors?
Yes - the LD1117ADT33TR is stable with 10 µF ceramic capacitors (X5R/X7R) having ESR ≥ 10 mΩ. Unlike older LDOs, it does not require minimum ESR, eliminating the need for parallel damping resistors or hybrid capacitor stacks.
How is thermal performance affected by PCB layout?
Thermal resistance drops from 100 °C/W (junction-to-ambient) to ≤45 °C/W when the DPAK tab is soldered to ≥4 cm² of 2-oz copper with ≥4 thermal vias (0.3 mm diameter) connecting to inner ground planes - directly impacting maximum sustainable output current at 70 °C ambient.
Does LD1117ADT33TR include reverse-polarity protection?
No - the device lacks integrated reverse-voltage protection. Applying negative voltage to VIN relative to GND can cause irreversible damage. External series diode or MOSFET-based protection must be added if reverse input conditions are possible in the system.
LD1117ADT33TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- Surface Mount
- Supplier Device Package:
- DPAK
LD1117ADT33TR FAQ
1.How can I place an order for LD1117ADT33TR through Aetrix?
Please submit a Request for Quotation (RFQ) for LD1117ADT33TR 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 LD1117ADT33TR reliable?
The price and inventory of LD1117ADT33TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117ADT33TR is usually 5 days.
3.What payment methods are accepted for LD1117ADT33TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117ADT33TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD1117ADT33TR?
LD1117ADT33TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD1117ADT33TR 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 LD1117ADT33TR?
For technical support, including LD1117ADT33TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117ADT33TR requirements.
6.How does Aetrix verify that LD1117ADT33TR is sourced from the original manufacturer or authorized distributors?
All LD1117ADT33TR 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 LD1117ADT33TR meets industry standards.
7.What is the process for return or replacement of LD1117ADT33TR?
All LD1117ADT33TR units undergo pre-shipment inspection (PSI). If there is an issue with LD1117ADT33TR, 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 LD1117ADT33TR part is unused and in its original packaging.
Return procedure for LD1117ADT33TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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