STMicroelectronics LD1117V25

Overview

LD1117V25 from STMicroelectronics is a fixed-output 2.5 V, low-dropout linear voltage regulator delivering up to 800 mA output current with 1.1 V typical dropout at 800 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz - used for post-regulation in industrial power supplies and embedded microcontroller core voltage stabilization.

For engineers reviewing the LD1117V25 datasheet, LD1117V25 pinout, LD1117V25 application, or LD1117V25 equivalent, this page delivers verified electrical specs, thermal performance data, package-specific layout guidance, and real-world substitution analysis - all grounded in ST's DocID2572 Rev 38 production datasheet.

Technical Context

The LD1117V25 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 over –40 to +125 °C.

Stability requires only a 10 µF ceramic or tantalum output capacitor; no external compensation is needed. The device integrates thermal shutdown and current limiting, with junction-to-ambient thermal resistance as low as 50 °C/W (TO-220) and 100 °C/W (DPAK), enabling reliable operation under sustained 800 mA loads.

Key Specifications

Pinout & Package

LD1117V25 is available in SOT-223, DPAK (TO-252), SO-8, and TO-220 packages. The TAB 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 regulator applications.

Compared with TLV1117-25CDCY and MCP1703T-2502E/MB, LD1117V25 uniquely balances 800 mA delivery, 1.1 V dropout, ±1 % accuracy, and multi-package flexibility - making it the optimal choice for industrial and automotive applications demanding both headroom and thermal resilience.

Availability

LD1117V25 is available at Aetrix Electronics and suitable for industrial PLCs, embedded microcontroller systems, medical sensor interfaces, and automotive body control units requiring stable component supply with long lifecycle visibility.

Supply support for LD1117V25 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LD1117 series belongs to ST's high-reliability linear regulator product line, engineered specifically for cost-sensitive, thermally demanding applications where simplicity, robustness, and wide package selection are critical - including factory automation, smart meters, and automotive sub-systems.

FAQ

What is the minimum input voltage required for LD1117V25 to regulate at full 800 mA load?

The minimum input voltage is calculated as V_OUT + V_DROP = 2.5 V + 1.2 V = 3.7 V (max dropout at 800 mA per datasheet Table 5). For reliable operation with margin, use ≥4.0 V input. Below this threshold, the device enters dropout mode and output voltage drops linearly with input.

Can LD1117V25 be used with ceramic output capacitors?

Yes - the LD1117V25 is stable with 10 µF ceramic capacitors (X5R/X7R) having ESR ≥ 0.1 Ω. ST explicitly validates ceramic use in Application Note AN2819. Avoid ultra-low-ESR types (<0.05 Ω) unless verified with phase margin testing, as they may induce oscillation.

How does thermal performance differ between SOT-223 and TO-220 packages?

TO-220 offers R_thJA = 50 °C/W (free air) and R_thJC = 5 °C/W, enabling ~2.4 W dissipation at ΔT = 120 °C. SOT-223 has R_thJA = 110 °C/W and R_thJC = 15 °C/W - limiting safe continuous power to ~1.1 W without PCB copper enhancement. TO-220 is preferred for >1.5 W dissipation; SOT-223 suits space-constrained designs with moderate loads.

Is LD1117V25 pin-compatible with the adjustable LD1117 variant?

No - the fixed-output LD1117V25 uses a 3-pin configuration (IN, OUT, GND), while the adjustable version has four pins (IN, OUT, GND, ADJ). They share identical pinouts *only* within their respective families (e.g., LD1117V25 SOT-223 matches other fixed LD1117x variants), but not across fixed vs. adjustable types.