LD1117ADT33TR - 3.3V Fixed 800mA LDO Regulator | STMicroelectronics
MPN: LD1117ADT33TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.29 | $29.00 |
| 500 | $0.24 | $120.00 |
| 1,000 | $0.19 | $190.00 |
Drop-in alternatives for LD1117ADT33TR — 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:
LD1117ADT33TR
✅ Drop-In✓ 99,999 In Stock
$0.19 / Unit
View Datasheet →AMS1117-3.3
✅ Drop-In📋 Reference alternative (not in catalog)
AP1117-33
✅ Drop-In📋 Reference alternative (not in catalog)
LD1117ADT33TR Maximum Ratings & Electrical Characteristics
| Output Type | Fixed |
| Output Voltage | 3.3 V |
| Maximum Output Current | 800 mA |
| Input Voltage Range | 4.75 V to 15 V |
| Dropout Voltage | 1.1 V (typical at 800 mA) |
| Quiescent Current | 5 mA |
| Line Regulation | 0.2% (typical) |
| Load Regulation | 0.4% (typical) |
| Thermal Resistance (junction-to-ambient) | 50 °C/W |
| Operating Temperature Range | -40°C to +125°C |
| Package | DPAK (TO-252) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
LD1117ADT33TR Pin Configuration
| Pin 1 | GND — Ground |
| Pin 2 | VOUT — Regulated 3.3V output |
| Pin 3 | VIN — Input voltage (4.75V to 15V) |
| Pin Tab | VOUT — Exposed pad connected to VOUT |
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
LD1117ADT33TR is suitable for 6 applications: Microcontroller Power Supply, FPGA Core Voltage, Sensor Interface, Set-Top Box, Router and Networking Equipment, Industrial Control.
Microcontroller Power Supply
The LD1117ADT33TR provides a stable 3.3V rail for microcontrollers, ensuring reliable operation. Its 800mA output current is sufficient for most MCUs and peripheral circuits. The low dropout voltage allows operation from 5V rails with minimal power loss. The fixed output simplifies design, and the thermal shutdown protects the MCU from overheating. In a typical application, the LDO is placed between the 5V supply and the MCU's VDD pin, with a 10µF capacitor on the output for stability. The low quiescent current of 5mA is acceptable for non-battery-powered systems. Compared to switching regulators, the LDO provides a cleaner output with no switching noise, which is critical for analog peripherals. However, power dissipation is higher; for a 5V-to-3.3V conversion at 500mA, power dissipation is 0.85W, requiring adequate PCB copper for heat sinking.
Recommended
FPGA Core Voltage
The LD1117ADT33TR can power the core logic of small FPGAs that require 3.3V. Its 800mA output current is suitable for low-power FPGAs like the ICE40 series. The low dropout voltage ensures regulation even with a 5V input. The thermal shutdown protects the FPGA from thermal damage. In a typical design, the LDO is placed close to the FPGA's VCCINT pins, with multiple decoupling capacitors. The fixed 3.3V output eliminates the need for external resistors. The LDO's fast transient response helps maintain stable voltage during FPGA switching activity. However, for larger FPGAs with higher current demands, a switching regulator may be more efficient. The LD1117ADT33TR is best for small, low-power FPGAs in cost-sensitive applications.
Recommended
Sensor Interface
The LD1117ADT33TR provides a clean 3.3V supply for sensors and analog front-ends. Its low noise and stable output are essential for accurate sensor readings. The 800mA output current can power multiple sensors. The thermal shutdown protects the sensors from over-temperature. In a typical application, the LDO is used to power a temperature sensor and an ADC, with a 10µF capacitor on the output. The fixed 3.3V output simplifies the design. The LDO's line regulation of 0.2% ensures stable output even with input voltage variations. Compared to switching regulators, the LDO eliminates switching noise that could corrupt sensor measurements. However, the LDO's quiescent current of 5mA may be a concern for battery-powered sensor nodes, where a low-quiescent LDO would be preferred.
Recommended
Set-Top Box
The LD1117ADT33TR is used in set-top boxes to provide a stable 3.3V rail for the main processor and tuner. Its 800mA output current is sufficient for these components. The low dropout voltage allows operation from a 5V rail. The thermal shutdown protects the device in case of overload. In a typical set-top box, the LDO is placed on the main board, with a heat sink or copper area for dissipation. The fixed 3.3V output simplifies the power supply design. The LDO's low noise is important for the tuner's RF performance. Compared to switching regulators, the LDO provides a cleaner output, but at the cost of efficiency. For a 12V-to-3.3V conversion at 500mA, power dissipation is 4.35W, requiring a heatsink. The LD1117ADT33TR is a cost-effective solution for set-top boxes.
Recommended
Router and Networking Equipment
The LD1117ADT33TR provides a stable 3.3V supply for networking processors and PHY chips. Its 800mA output current is adequate for these components. The low dropout voltage allows operation from a 5V rail. The thermal shutdown protects the equipment from overheating. In a typical router, the LDO is used to power the main SoC and Ethernet PHY, with a 10µF capacitor on the output. The fixed 3.3V output simplifies the design. The LDO's low noise is important for the PHY's signal integrity. Compared to switching regulators, the LDO provides a cleaner output, but with lower efficiency. For a 5V-to-3.3V conversion at 500mA, power dissipation is 0.85W, which is manageable with proper PCB layout. The LD1117ADT33TR is a reliable choice for networking equipment.
Recommended
Industrial Control
The LD1117ADT33TR is used in industrial control systems to provide a stable 3.3V supply for PLCs and sensors. Its 800mA output current is sufficient for these applications. The wide input voltage range (up to 15V) allows operation from 24V industrial rails with a pre-regulator. The thermal shutdown protects the device in harsh environments. In a typical industrial application, the LDO is used to power a microcontroller and fieldbus interface, with a 10µF capacitor on the output. The fixed 3.3V output simplifies the design. The LDO's operating temperature range of -40°C to +125°C makes it suitable for industrial environments. Compared to switching regulators, the LDO provides a cleaner output, but with higher power dissipation. For a 24V-to-3.3V conversion at 500mA, power dissipation is 10.35W, requiring a heatsink or a pre-regulator. The LD1117ADT33TR is a robust choice for industrial control.
Recommended
Recommended Products Summary
Engineering reference data for LD1117ADT33TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LD1117DT33TR | AMS1117-3.3 | NCP1117ST33T3G | AP1117-33 |
|---|---|---|---|---|---|
| Package | DPAK (TO-252) | SOT-223 | DPAK (TO-252) | SOT-223 | DPAK (TO-252) |
| Brand | STMicroelectronics | STMicroelectronics | Advanced Monolithic Systems | onsemi | Diodes Incorporated |
| Output Voltage | 3.3V | 3.3V | 3.3V | 3.3V | 3.3V |
| Maximum Output Current | 800mA | 800mA | 1A | 1A | 1A |
| Input Voltage Range | 4.75V to 15V | 4.75V to 15V | 4.75V to 12V | 4.75V to 18V | 4.75V to 18V |
| Dropout Voltage | 1.1V typical | 1.1V typical | 1.1V typical | 1.1V typical | 1.1V typical |
| Quiescent Current | 5mA | 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 | -40°C to +125°C |
Key Differentiators
- Wide input voltage range up to 15V (vs AMS1117-3.3)
- Lower quiescent current than some alternatives (vs NCP1117ST33T3G)
- Proven STMicroelectronics quality (vs AP1117-33)
Design Notes
The LD1117ADT33TR has a junction-to-ambient thermal resistance of 50°C/W. At 5V input and 3.3V output with 800mA load, power dissipation is (5-3.3)*0.8 = 1.36W, causing a temperature rise of 68°C. Ensure adequate PCB copper area (at least 1 square inch) connected to the thermal pad to keep junction temperature below 125°C. For higher input voltages, consider a heatsink or a pre-regulator.
Place a 10µF ceramic capacitor on the output and a 10µF capacitor on the input, as close to the pins as possible. The output capacitor is required for stability. Use a 0.1µF capacitor in parallel for high-frequency decoupling. The thermal pad should be soldered to a large copper area for heat dissipation.
Do not exceed the maximum input voltage of 15V. Ensure the input voltage is at least 4.75V to maintain regulation. The LD1117ADT33TR is a fixed output device; do not attempt to adjust the output voltage. Use a proper heat sink for high power dissipation. Avoid reverse polarity on the input.
Compliance Information
RoHS compliant and lead-free per STMicroelectronics datasheet. Not AEC-Q100 qualified. Halogen-free status not specified in the provided data.
