LD1117S25TR - 800mA Low Dropout Positive Regulator | STMicroelectronics
MPN: LD1117S25TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.35 | $0.35 |
| 10 | $0.3 | $3.00 |
| 100 | $0.25 | $25.00 |
| 500 | $0.2 | $100.00 |
| 1,000 | $0.18 | $180.00 |
Drop-in alternatives for LD1117S25TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LD1117S25TR
✅ Drop-In✓ 99,999 In Stock
$0.18 / Unit
View Datasheet →LD1117S33TR
✅ Drop-In✓ 99,999 In Stock
$0.2 / Unit
View Datasheet →LD1117S18TR
✅ Drop-In✓ 99,999 In Stock
$0.15 / Unit
View Datasheet →AMS1117-2.5
✅ Drop-In📋 Reference alternative (not in catalog)
NCP1117ST25T3G
✅ Drop-In📋 Reference alternative (not in catalog)
AP1117-2.5
✅ Drop-In📋 Reference alternative (not in catalog)
LD1117S25TR Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage | 2.5 V |
| Maximum Output Current | 800 mA |
| Input Voltage Range | Up to 15 V |
| Dropout Voltage | 1.1 V at 800 mA |
| Quiescent Current | 5 mA |
| Line Regulation | 0.2% (typical) |
| Load Regulation | 0.4% (typical) |
| Output Capacitor | 10 µF (minimum) |
| Operating Temperature Range | 0°C to +125°C |
| Package | SOT-223 |
| Mounting Type | Surface Mount |
| Thermal Resistance (θJA) | 50 °C/W |
| RoHS Status | Compliant |
| Lead-Free | Yes |
LD1117S25TR Pin Configuration
| Pin 1 | IN — Input voltage pin |
| Pin 2 | GND — Ground pin |
| Pin 3 | OUT — Regulated output voltage |
| Pin 4 | TAB — Thermal pad, connected to OUT |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
LD1117S25TR is suitable for 6 applications: Post-Regulation for Switching Power Supplies, Battery-Powered Equipment, Low-Voltage Logic Supplies, Consumer Electronics, Industrial Control Systems, Telecommunication Equipment.
Post-Regulation for Switching Power Supplies
The LD1117S25TR is used as a post-regulator to provide a clean 2.5V rail from a noisy switching converter output. Its low dropout voltage of 1.1V allows it to operate with minimal headroom, and its 800mA output current is sufficient for many digital loads. The device's internal current limiting and thermal shutdown protect the downstream circuitry from faults. In a typical application, the LD1117S25TR is placed after a buck converter, with a 10µF output capacitor to ensure stability. The low output noise and good line/load regulation make it suitable for powering sensitive analog and digital circuits.
Recommended
Battery-Powered Equipment
In battery-powered devices, the LD1117S25TR regulates a 2.5V rail from a battery voltage that may drop as low as 3.6V. Its low quiescent current of 5mA helps extend battery life, and the low dropout voltage ensures efficient operation even when the battery is nearly discharged. The SOT-223 package is compact, making it suitable for portable devices. The device's thermal shutdown prevents damage from excessive power dissipation, which is important in small enclosures. For a 3.7V Li-ion battery, the LD1117S25TR can provide a stable 2.5V output until the battery voltage falls below 3.6V.
Recommended
Low-Voltage Logic Supplies
The LD1117S25TR provides a stable 2.5V supply for low-voltage logic ICs, such as FPGAs, CPLDs, and memory devices. Its 800mA output current can power multiple logic devices, and the fixed 2.5V output eliminates the need for external resistor dividers. The device's fast transient response ensures stable operation during rapid load changes. In a typical application, the LD1117S25TR is connected to a 3.3V rail, and the output is decoupled with a 10µF capacitor. The low dropout voltage allows the regulator to maintain regulation even if the 3.3V rail dips slightly.
Recommended
Consumer Electronics
The LD1117S25TR is widely used in consumer electronics such as set-top boxes, routers, and gaming consoles to provide a clean 2.5V rail for various ICs. Its low cost and availability in the SOT-223 package make it a popular choice for high-volume production. The device's thermal shutdown and current limiting ensure reliable operation in consumer environments. In a typical application, the LD1117S25TR is powered from a 5V adapter, and the output is filtered with a 10µF capacitor. The low dropout voltage allows the regulator to operate efficiently even with a 5V input.
Recommended
Industrial Control Systems
In industrial control systems, the LD1117S25TR provides a stable 2.5V reference for analog-to-digital converters (ADCs), sensors, and microcontrollers. Its wide input voltage range up to 15V allows it to be powered from industrial 24V buses with a pre-regulator. The device's low output noise and good line regulation ensure accurate measurements. In a typical application, the LD1117S25TR is used to power an ADC reference, with a 10µF output capacitor and a 0.1µF bypass capacitor for noise reduction. The device's thermal shutdown protects it from overtemperature conditions in harsh industrial environments.
Recommended
Telecommunication Equipment
The LD1117S25TR is used in telecommunication equipment to provide a clean 2.5V rail for line drivers, transceivers, and digital signal processors. Its low dropout voltage and high output current make it suitable for powering multiple ICs. The device's low quiescent current is beneficial in always-on communication modules. In a typical application, the LD1117S25TR is powered from a 3.3V rail, and the output is decoupled with a 10µF capacitor. The device's thermal shutdown ensures reliable operation in equipment that may be exposed to high ambient temperatures.
Recommended
Recommended Products Summary
Engineering reference data for LD1117S25TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LD1117S33TR | AMS1117-2.5 | NCP1117ST25T3G |
|---|---|---|---|---|
| Package | SOT-223 | SOT-223 | SOT-223 | SOT-223 |
| Brand | STMicroelectronics | STMicroelectronics | Advanced Monolithic Systems | onsemi |
| Output Voltage | 2.5V | 3.3V | 2.5V | 2.5V |
| Maximum Output Current | 800mA | 800mA | 1A | 1A |
| Dropout Voltage | 1.1V at 800mA | 1.1V at 800mA | 1.1V at 1A | 1.1V at 1A |
| Quiescent Current | 5mA | 5mA | 5mA | 5mA |
| Input Voltage Range | Up to 15V | Up to 15V | Up to 15V | Up to 15V |
| Operating Temperature Range | 0°C to +125°C | 0°C to +125°C | 0°C to +125°C | 0°C to +125°C |
Key Differentiators
- Fixed 2.5V output with 800mA current capability (vs LD1117S33TR)
- Low dropout voltage of 1.1V at full load (vs AMS1117-2.5)
- SOT-223 package with thermal pad (vs NCP1117ST25T3G)
Design Notes
The SOT-223 package has a thermal resistance of approximately 50°C/W. At maximum output current of 800mA and a dropout voltage of 1.1V, the power dissipation is 0.88W, resulting in a temperature rise of 44°C above ambient. Ensure adequate copper area on the PCB to dissipate heat, especially in high-temperature environments.
Place the input and output capacitors as close to the LD1117S25TR pins as possible. A minimum output capacitor of 10µF is required for stability, and a 0.1µF ceramic capacitor should be placed in parallel for high-frequency noise bypass. The thermal pad (tab) should be connected to a large copper area to improve heat dissipation.
Do not exceed the maximum input voltage of 15V. Ensure the input voltage is at least 1.1V above the output voltage to maintain regulation. The output capacitor must be placed close to the output pin to avoid instability. Use a capacitor with low ESR, such as a tantalum or aluminum electrolytic capacitor, as specified in the datasheet.
Compliance Information
RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified. Lead-free and conflict minerals compliant.
