LD1117ADT18TR - 1.8V Fixed 800mA LDO Regulator | STMicroelectronics
MPN: LD1117ADT18TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.3 | $30.00 |
| 500 | $0.25 | $125.00 |
| 1,000 | $0.2 | $200.00 |
Drop-in alternatives for LD1117ADT18TR — 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:
LD1117ADT18TR
✅ Drop-In✓ 99,999 In Stock
$0.2 / Unit
View Datasheet →LD1117DT18TR
✅ Drop-In📋 Reference alternative (not in catalog)
NCP1117ST18T3G
✅ Drop-In📋 Reference alternative (not in catalog)
AP1117-18
✅ Drop-In📋 Reference alternative (not in catalog)
LD1117ADT18TR Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage | 1.8 V |
| Maximum Output Current | 800 mA |
| Input Voltage Range | Up to 15 V |
| Dropout Voltage | 1.1 V at 800 mA |
| Line Regulation | 0.2% (typical) |
| Load Regulation | 0.4% (typical) |
| Quiescent Current | 5 mA (typical) |
| Output Noise | [DATA_NEEDED: Output Noise] |
| PSRR | [DATA_NEEDED: PSRR] |
| Operating Temperature Range | -40°C to +125°C |
| Package | DPAK (TO-252) |
| Mounting Type | Surface Mount |
| Thermal Resistance (Junction-to-Ambient) | 100 °C/W |
| RoHS Status | Compliant |
LD1117ADT18TR Pin Configuration
| Pin 1 | GND — Ground |
| Pin 2 | VOUT — Regulated 1.8V output |
| Pin 3 | VIN — Input supply voltage |
| Pin 4 | TAB — Exposed pad, connected to GND |
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
LD1117ADT18TR is suitable for 6 applications: Microcontroller Power Supply, FPGA Core Supply, Battery-Powered Devices, Industrial Control Systems, Audio Equipment, Networking Equipment.
Microcontroller Power Supply
The LD1117ADT18TR provides a stable 1.8V rail for microcontrollers that operate at 1.8V logic levels. Its low dropout voltage ensures efficient operation from a 3.3V or 3.6V battery, and its 800mA output current can handle the peak current demands of the MCU and its peripherals. The low output noise and good line/load regulation ensure reliable operation of the MCU's internal analog peripherals, such as ADCs and comparators. In a typical application, the regulator is placed between the battery and the MCU's VDD pin, with a 10µF output capacitor to maintain stability. The thermal shutdown protection prevents damage during short circuits or excessive load.
Recommended
FPGA Core Supply
FPGAs often require a separate 1.8V core supply for their internal logic. The LD1117ADT18TR can deliver up to 800mA, which is sufficient for small to medium FPGAs. Its low dropout voltage allows it to operate from a 2.5V or 3.3V rail, and its low noise output is critical for maintaining signal integrity in high-speed designs. The DPAK package with exposed pad provides good thermal dissipation, essential for continuous operation. In a typical FPGA design, the regulator is placed close to the FPGA's core voltage pins, with multiple decoupling capacitors to minimize voltage ripple. The enable pin (if available) can be used for power sequencing, ensuring the core voltage ramps up before I/O voltage.
Recommended
Battery-Powered Devices
The LD1117ADT18TR is ideal for battery-powered devices such as portable electronics, wireless sensors, and wearables. Its low dropout voltage of 1.1V allows the regulator to operate even when the battery voltage drops close to the output voltage, maximizing battery life. The quiescent current of 5mA is relatively low, but for ultra-low-power applications, a regulator with lower quiescent current may be preferred. The device's thermal shutdown and current limiting protect the battery and the load from faults. In a typical battery-powered design, the regulator is connected directly to the battery, with a 1µF input capacitor and a 10µF output capacitor. The low noise output ensures clean power for sensitive analog circuits.
Recommended
Industrial Control Systems
In industrial control systems, the LD1117ADT18TR provides a reliable 1.8V supply for sensors, actuators, and control logic. Its wide operating temperature range of -40°C to +125°C makes it suitable for harsh environments. The device's robust protection features, including current limiting and thermal shutdown, ensure reliable operation in the presence of voltage transients and overloads. The DPAK package is easy to solder and provides good thermal performance, even in high-vibration environments. In a typical industrial application, the regulator is used to power a microcontroller or FPGA that controls motors, valves, or other actuators. The low dropout voltage allows it to operate from a 24V bus with a pre-regulator, or directly from a 3.3V rail.
Recommended
Audio Equipment
The LD1117ADT18TR can be used in audio equipment to provide a clean 1.8V supply for audio codecs, DACs, and op-amps. Its low output noise and high PSRR (if specified) help minimize hum and noise in the audio signal path. The low dropout voltage ensures stable operation even when the input voltage is close to the output, which is common in battery-powered audio devices. In a typical audio application, the regulator is placed between the battery and the audio codec's analog supply pin, with a 10µF output capacitor and a 0.1µF bypass capacitor for high-frequency noise. The thermal shutdown protection prevents damage during prolonged high-volume operation.
Recommended
Networking Equipment
In networking equipment such as routers and switches, the LD1117ADT18TR provides a stable 1.8V supply for PHY chips, switch ICs, and other digital components. Its low dropout voltage allows it to operate from a 3.3V rail, and its 800mA output current can handle the power requirements of multiple ICs. The device's low noise output is important for maintaining signal integrity in high-speed Ethernet interfaces. The DPAK package is suitable for compact PCB designs, and the thermal pad helps dissipate heat generated by continuous operation. In a typical networking application, the regulator is used to power the PHY's digital core, with proper decoupling to minimize voltage ripple.
Recommended
Recommended Products Summary
Engineering reference data for LD1117ADT18TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LD1117DT18TR | NCP1117ST18T3G | AP1117-18 |
|---|---|---|---|---|
| Package | DPAK (TO-252) | DPAK (TO-252) | DPAK (TO-252) | DPAK (TO-252) |
| Brand | STMicroelectronics | STMicroelectronics | onsemi | Diodes Incorporated |
| Output Voltage | 1.8V | 1.8V | 1.8V | 1.8V |
| Maximum Output Current | 800mA | 800mA | 1A | 1A |
| Dropout Voltage | 1.1V | 1.2V | 1.1V | 1.1V |
| Input Voltage Range | Up to 15V | Up to 15V | Up to 20V | Up to 18V |
| Quiescent Current | 5mA | 5mA | 5mA | 5mA |
| Operating Temperature Range | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C |
Key Differentiators
- Lower dropout voltage than non-A version (vs LD1117DT18TR)
- Same package and pinout as onsemi NCP1117 (vs NCP1117ST18T3G)
- Lower quiescent current than AP1117 (vs AP1117-18)
Design Notes
Place the input and output capacitors as close to the respective pins as possible. Use a 10µF output capacitor and a 1µF input capacitor, both with low ESR. The thermal pad (TAB) should be connected to a large copper area on the PCB to enhance heat dissipation. For best performance, use a ground plane and keep the trace lengths short.
The LD1117ADT18TR in DPAK package has a junction-to-ambient thermal resistance of 100°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 88°C above ambient. Ensure adequate copper area or a heatsink to keep the junction temperature below 125°C.
Do not exceed the maximum input voltage of 15V. Ensure the output capacitor is at least 10µF to maintain stability. Avoid using high-ESR capacitors, as they can cause oscillation. Also, be aware that the dropout voltage increases with temperature, so provide sufficient headroom in high-temperature environments.
Compliance Information
RoHS compliant per STMicroelectronics. Not AEC-Q100 qualified. Lead-free finish.
