STMicroelectronics LD1117V18

Overview

LD1117V18 from STMicroelectronics is a fixed-output 1.8 V low-dropout linear voltage regulator delivering up to 800 mA output current with 1.0 V typical dropout at 100 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz-used in powering microcontroller core logic, FPGA I/O banks, and industrial sensor signal chains.

For engineers reviewing the LD1117V18 datasheet, LD1117V18 pinout, LD1117V18 application, or LD1117V18 equivalent, this page provides verified package mapping (SOT-223/DPAK/TO-220/SO-8), thermal resistance data (R_thJA = 110 °C/W for SOT-223), load regulation (≤10 mV), and confirmed alternatives with documented output voltage and dropout differences.

Technical Context

The LD1117V18 employs 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 ±1 % initial accuracy at 25 °C and maintain ≤0.5 % temperature stability across –40 to +125 °C.

Stability requires only a 10 µF output capacitor; no input capacitor is mandatory. The device integrates thermal shutdown and current limiting, with junction-to-case thermal resistance as low as 5 °C/W in TO-220 and 8 °C/W in DPAK packages-critical for sustained 800 mA operation under ambient temperatures up to 125 °C.

Key Specifications

Pinout & Package

LD1117V18 is available in SOT-223, DPAK (TO-252), TO-220, and SO-8 packages. The tab (exposed pad) is electrically connected to V_OUT in all variants, serving as both thermal path and output terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-1802E/MB and TLV70118DBVR, LD1117V18 delivers 3.2× higher output current and maintains tighter tolerance over full temperature range, making it the only option among the three qualified for industrial 800 mA loads with 1.8 V rail integrity.

Availability

LD1117V18 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitoring sensors, and consumer wearable displays requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LD1117V18 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The LD1117 series belongs to ST's general-purpose linear regulator product line, engineered for cost-sensitive, high-reliability applications demanding robust thermal performance and tight DC accuracy without complex external circuitry.

FAQ

What is the minimum input voltage required for LD1117V18 to regulate at full 800 mA?

The minimum input voltage is determined by dropout: at 800 mA, V_IN(min) = 1.8 V + V_d(max) = 1.8 V + 1.2 V = 3.0 V per datasheet Table 4. Operation below 3.0 V risks dropout and unregulated output. Input must also remain within absolute maximum rating of 15 V.

Can LD1117V18 be used with ceramic output capacitors?

Yes-ST specifies stability with ≥10 µF ceramic or tantalum capacitors. Unlike older LDOs, LD1117V18 does not require ESR-based damping; low-ESR ceramics are fully compatible and improve transient response without oscillation risk.

How does thermal performance differ between SOT-223 and DPAK packages?

DPAK offers R_thJA = 100 °C/W vs. SOT-223's 110 °C/W, and lower R_thJC = 8 °C/W vs. 15 °C/W-enabling ~15 % higher continuous power dissipation at same ambient. DPAK's larger pad area improves solder thermal transfer to PCB copper planes.

Is LD1117V18 pin-compatible with the adjustable LD1117 variant?

No-the adjustable LD1117 uses a 3-pin configuration (IN, OUT, ADJ), while LD1117V18 is 3-pin (IN, OUT, GND). Pin functions differ: ADJ pin on adjustable version replaces GND on fixed versions; direct substitution would short GND and cause failure.