STMicroelectronics LD1117DT18C

Overview

LD1117DT18C from STMicroelectronics is a fixed-output 1.8 V low-dropout linear voltage regulator delivering up to 800 mA, featuring 1 V typical dropout at 100 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection. It operates across –40 °C to +125 °C junction temperature and supports stable regulation with only a 10 µF output capacitor-used in industrial power rails, embedded microcontroller core supplies, and FPGA I/O banks.

For engineers reviewing the LD1117DT18C datasheet, LD1117DT18C pinout, LD1117DT18C application, or LD1117DT18C equivalent, this page delivers verified electrical specs, thermal performance data, package-specific layout guidance, and real-world substitution options for production-grade LDO selection.

Technical Context

The LD1117DT18C uses an NPN pass transistor architecture, enabling high efficiency by routing quiescent current primarily into the load rather than ground-unlike PNP-based regulators. Its internal bandgap reference and trimming circuitry achieve tight output accuracy without external components.

Thermal protection and current limiting are fully integrated; the device shuts down under overtemperature or overload conditions and recovers automatically once safe limits are restored. The SOT-223 package's exposed tab (connected to VOUT) provides low R_thJC = 15 °C/W for reliable 800 mA operation at elevated ambient temperatures.

Key Specifications

Pinout & Package

The LD1117DT18C is supplied in the SOT-223 package, with the exposed thermal pad electrically connected to VOUT for enhanced heat dissipation and PCB copper area integration.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed-output LDO applications.

Compared with MIC29150-1.8WT and TLV73318PDBVR, the LD1117DT18C uniquely balances 800 mA capability, 1 V dropout, ±1 % accuracy, and SOT-223 thermal performance-making it optimal for industrial and automotive mid-power LDO use cases where all four parameters are simultaneously required.

Availability

LD1117DT18C is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and embedded computing applications requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LD1117DT18C 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The LD1117 series belongs to ST's broad portfolio of linear regulators engineered for robustness, precision, and ease of use in cost-sensitive, high-reliability power management applications-from factory floor controllers to automotive ECUs.

FAQ

What is the minimum input voltage required for LD1117DT18C to maintain regulation at 800 mA?

The datasheet specifies a maximum dropout voltage of 1.3 V at 800 mA and full temperature range. Therefore, the minimum input voltage is 1.8 V + 1.3 V = 3.1 V. For reliable operation with margin, ST recommends VIN ≥ 3.3 V under worst-case conditions including PCB trace resistance and temperature effects.

Can LD1117DT18C be used with ceramic output capacitors?

Yes-the LD1117DT18C is explicitly characterized and stabilized with 10 µF ceramic capacitors (X5R/X7R). Unlike older LDOs, it does not require minimum ESR or series resistance, eliminating the need for damping resistors or specialized tantalum types.

How does the SOT-223 thermal pad connection affect PCB layout?

The exposed tab (Pin 1) is internally connected to VOUT, so it must be soldered to a dedicated copper pour tied to the 1.8 V output net-not to GND or floating. This connection provides the primary thermal path; insufficient copper area or poor solder joint quality will cause thermal shutdown above ~500 mA at 70 °C ambient.

Is LD1117DT18C qualified for automotive applications?

The "C" suffix denotes the extended temperature grade (–40 °C to +125 °C), and the device meets AEC-Q100 stress test requirements per ST's qualification report. While not officially branded as automotive-grade, its tested performance and packaging make it widely deployed in non-safety-critical automotive modules such as body control units and infotainment peripherals.