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STMicroelectronics LD1117ADT-TR
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- Part No.:
- LD1117ADT-TR
- Manufacturer:
- STMicroelectronics
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
LD1117ADT-TR.pdf
- Description:
- IC REG LINEAR POS ADJ 1A DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:5,997
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Product details
Overview
LD1117ADT-TR from STMicroelectronics is an adjustable low-dropout linear voltage regulator delivering up to 1 A output current with a 1.25 V internal reference voltage, 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 in post-regulation stages of power management subsystems for microcontrollers and analog sensors.
For engineers reviewing the LD1117ADT-TR datasheet, LD1117ADT-TR pinout, LD1117ADT-TR application, or LD1117ADT-TR equivalent, key selection criteria include dropout voltage under full load, thermal resistance (RthJA = 100 °C/W in DPAK), minimum required output capacitance (10 µF), and adjustment pin current (60–120 µA) for precision external feedback design.
Technical Context
The LD1117ADT-TR uses an NPN pass transistor architecture enabling low dropout while maintaining stability with only 10 µF output capacitance. Its internal 1.25 V reference is thermally stabilized with ±0.025 V variation over temperature and load.
It integrates thermal shutdown and current limiting, operates from 0 °C to 125 °C junction temperature, and supports input voltages up to 15 V DC. The adjustable version requires two external resistors (R1 = 120 Ω fixed, R2 variable) to set output voltage per VOUT = 1.25 V × (1 + R2/R1) + R2 × IADJ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | 1000 mA max - supports single-rail powering of MCU cores or analog front-ends without external boost circuitry. |
| Dropout voltage | 1.15 V typ. @ 1 A - enables regulation from 5 V input down to 3.3 V or 2.5 V outputs with margin. |
| Reference voltage | 1.25 V ±0.025 V - sets absolute accuracy baseline for externally programmed output voltages. |
| Supply voltage rejection | 80 dB typ. @ 120 Hz - suppresses ripple from upstream switching regulators in hybrid power architectures. |
| Quiescent current | 5 mA typ. @ 25 °C - minimizes no-load power loss in always-on subsystems like real-time clocks. |
| Thermal resistance | RthJA = 100 °C/W (DPAK) - defines maximum power dissipation (1.2 W) before thermal shutdown at 25 °C ambient. |
| Stability capacitor | 10 µF min. aluminum or tantalum - eliminates need for specialized low-ESR ceramics, reducing BOM cost and layout complexity. |
Pinout & Package
LD1117ADT-TR is supplied in DPAK (TO-252) package with exposed thermal pad connected to VOUT. The package provides 100 °C/W junction-to-ambient thermal resistance and supports surface-mount reflow assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: INPUT | Regulator input supply | Accepts 2.75–15 V DC; must be decoupled with ≥10 µF capacitor near pin to prevent oscillation. |
| 2: OUTPUT | Regulated output node | Connected internally to exposed thermal tab; serves as reference for ADJ pin and output filter capacitor anchor. |
| 3: ADJ | Feedback reference input | Sinks 60–120 µA; forms voltage divider with R1 (120 Ω) and R2 to program output from 1.25 V to >10 V. |
Key Features
| Feature | Design Value |
|---|---|
| Low dropout operation | 1.15 V @ 1 A enables efficient 3.3 V/2.5 V regulation from 5 V rails in space-constrained PCBs. |
| Internal thermal shutdown | Activates at ~165 °C junction temperature - prevents permanent damage during sustained overload or poor heatsinking. |
| Fixed 1.25 V reference | ±0.025 V tolerance over 0–125 °C ensures <±1% output error when using precision R1/R2 resistors. |
| High PSRR | 80 dB at 120 Hz rejects ripple from AC/DC adapters or buck converter switching noise. |
| Minimal external components | Only two resistors (R1 = 120 Ω, R2 programmable) and one 10 µF capacitor required for stable adjustable operation. |
Applications
| Industrial Sensor Node | USB-Powered Peripheral |
|---|---|
|
Use Scenario: Powering 3.3 V analog sensor ICs and 1.8 V ADCs from a noisy 5 V USB bus in factory-floor environmental monitors. IC Role / Device Role / Timing Role: Post-regulator providing clean, low-noise bias for precision signal conditioning circuits. Use Value: 100 µV RMS output noise and 80 dB PSRR ensure <1 LSB error in 12-bit ADC conversions despite USB bus ripple. |
Use Scenario: Generating 2.8 V for Bluetooth Low Energy SoCs from 5 V USB VBUS in portable medical wearables. IC Role / Device Role / Timing Role: Primary LDO supplying core logic and RF transceiver, synchronized to host USB enumeration timing. Use Value: 1.15 V dropout allows reliable 2.8 V output even as USB voltage sags to 4.75 V during high-current transfers. |
| Automotive Body Control Module | Programmable Logic Supply |
|
Use Scenario: Providing 5 V auxiliary rail for LIN transceivers and EEPROMs in non-safety-critical vehicle body electronics. IC Role / Device Role / Timing Role: Secondary regulator fed from main 12 V DC-DC converter, operating within automotive ambient range (−40 °C to +125 °C). Use Value: Guaranteed operation to 125 °C junction temperature and internal current limit protect against shorted LIN bus faults. |
Use Scenario: Configurable 1.2–5.0 V supply for FPGA I/O banks or CPLD configuration voltage in test equipment. IC Role / Device Role / Timing Role: Adjustable voltage source enabling single-board support of multiple logic families (LVCMOS, SSTL, HSTL). Use Value: External resistor programming allows precise voltage setting without firmware or digital interface overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM1117DTX-ADJ/NOPB | Higher quiescent current (10 mA typ.), lower PSRR (70 dB), RthJA = 120 °C/W (SOT-223) | Limited to ≤800 mA continuous output in same thermal environment due to higher thermal resistance | Preferred where TI's qualification pedigree or existing SOT-223 footprint reuse is prioritized over efficiency. |
| MCP1703T-3302E/MB | Fixed 3.3 V output only; no adjustable version; 250 mA max output; 6 µA quiescent current | Not suitable for programmable voltage requirements; targets ultra-low-power always-on monitoring nodes | Select only when fixed 3.3 V and nanoamp quiescent current outweigh need for adjustability and 1 A capability. |
Compared with LM1117DTX-ADJ/NOPB, LD1117ADT-TR delivers 200 mA more output current and 10 dB higher PSRR in the same DPAK footprint; versus MCP1703T-3302E/MB, it trades ultra-low IQ for full adjustability and industrial-grade current capacity.
Availability
LD1117ADT-TR is available at Aetrix Electronics and suitable for industrial sensor nodes, USB-powered peripherals, automotive body control modules, and programmable logic supplies requiring stable component supply across multi-year production cycles.
Supply support for LD1117ADT-TR 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 performance and minimal external components in industrial and embedded systems.
FAQ
What is the minimum output capacitance required for stability with LD1117ADT-TR?
The LD1117ADT-TR requires a minimum 10 µF output capacitor-aluminum, tantalum, or polymer-with ESR between 0.1 Ω and 10 Ω. Ceramic capacitors alone are not recommended unless paralleled with a 1–2 Ω damping resistor or ≥1 Ω ESR polymer variant to avoid instability.
Can LD1117ADT-TR be used in parallel to increase output current?
No-LD1117ADT-TR lacks built-in current-sharing features. Parallel operation causes unequal current distribution due to output voltage tolerance (±2%) and thermal drift, risking thermal runaway in one device. Use a single higher-current regulator or discrete current-balancing circuitry instead.
What is the purpose of the ADJ pin current specification (60–120 µA)?
The ADJ pin draws 60–120 µA to bias the internal reference amplifier. This current flows through the R2 resistor in the feedback divider, introducing a small offset error in VOUT; for 1% accuracy, R2 should be ≤5 kΩ to limit this error to <60 mV.
Does LD1117ADT-TR support reverse-voltage protection?
No-the device has no intrinsic reverse-battery or reverse-polarity protection. Applying reverse voltage (>−0.3 V on INPUT relative to OUTPUT) can damage the internal pass transistor. An external series Schottky diode (e.g., 1N5819) is required for reverse-input protection.
LD1117ADT-TR 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:
- Adjustable
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 15V
- Voltage Dropout (Max):
- 1.3V @ 1A
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 5 mA
- Current - Supply (Max):
- -
- PSRR:
- 80dB (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
LD1117ADT-TR FAQ
1.How can I place an order for LD1117ADT-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for LD1117ADT-TR 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 LD1117ADT-TR reliable?
The price and inventory of LD1117ADT-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD1117ADT-TR is usually 5 days.
3.What payment methods are accepted for LD1117ADT-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD1117ADT-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LD1117ADT-TR?
LD1117ADT-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LD1117ADT-TR 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 LD1117ADT-TR?
For technical support, including LD1117ADT-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD1117ADT-TR requirements.
6.How does Aetrix verify that LD1117ADT-TR is sourced from the original manufacturer or authorized distributors?
All LD1117ADT-TR 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 LD1117ADT-TR meets industry standards.
7.What is the process for return or replacement of LD1117ADT-TR?
All LD1117ADT-TR units undergo pre-shipment inspection (PSI). If there is an issue with LD1117ADT-TR, 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 LD1117ADT-TR part is unused and in its original packaging.
Return procedure for LD1117ADT-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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