Texas Instruments REG1117FA-2.5/500

Overview

REG1117FA-2.5/500 from Texas Instruments is a 2.5V fixed-output, 1A low-dropout linear voltage regulator in DDPAK-3 (TO-263) package, featuring 1.3V max dropout at 1A, ±1% output tolerance over temperature, internal current limit, and thermal overload protection. It delivers stable core power for FPGA, PLD, and DSP supplies in space-constrained industrial and portable systems.

For engineers reviewing the REG1117FA-2.5/500 datasheet, REG1117FA-2.5/500 pinout, REG1117FA-2.5/500 application, or REG1117FA-2.5/500 equivalent, key selection criteria include dropout voltage at full load, thermal resistance with PCB copper area, output voltage accuracy across −40°C to +125°C, and compatibility with 10µF tantalum output capacitance.

Technical Context

The REG1117FA-2.5/500 uses an NPN pass transistor architecture enabling high efficiency and low dropout. Its laser-trimmed reference ensures 2.5V output accuracy without external adjustment, and the internal 1.25V bandgap reference supports tight line/load regulation.

Thermal shutdown activates at ~165°C junction temperature, while continuous operation is rated up to +125°C. The device requires no minimum load for regulation and maintains stability with ≥10µF tantalum or ≥50µF aluminum electrolytic output capacitors having ESR < 0.5Ω.

Key Specifications

Pinout & Package

REG1117FA-2.5/500 is housed in a 3-lead DDPAK-3 (TO-263) surface-mount package with the mounting tab electrically connected to VOUT. Thermal performance depends on soldering the tab to ≥1 in² of 1oz copper; increasing copper area reduces θ_JA from 65°C/W to as low as 27°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with TLV1117-2.5 and TPS7A4700RGWR, REG1117FA-2.5/500 offers higher current capability in a thermally optimized DDPAK package but lacks adjustability and ultra-low-noise performance - making it optimal for cost-sensitive, fixed 2.5V digital core supplies.

Availability

REG1117FA-2.5/500 is available at Aetrix Electronics and suitable for FPGA core voltage supply, battery-powered instrumentation, SCSI-2 active termination, and notebook PC battery management requiring stable component supply and long-term industrial lifecycle support.

Supply support for REG1117FA-2.5/500 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, serving industrial, automotive, and communications markets since 1930.

REG1117FA-2.5/500 belongs to TI's REG1117A family of low-dropout regulators designed for high-efficiency, space-constrained linear regulation in portable and industrial systems demanding precision and reliability.

FAQ

What is the maximum input voltage rating for REG1117FA-2.5/500?

The absolute maximum input voltage for REG1117FA-2.5/500 is +15V, per TI's SBVS001D datasheet Absolute Maximum Ratings table. Operation above this level risks permanent damage. For reliable 2.5V output at 1A, input should remain between 4.5V and 10V to maintain specified dropout and thermal performance - REG1117FA-2.5/500 is not intended for high-input-voltage applications like 24V industrial rails without pre-regulation.

Does REG1117FA-2.5/500 require an external capacitor, and what type is recommended?

Yes, REG1117FA-2.5/500 requires a minimum 10µF tantalum capacitor at the VOUT pin for stability and high-frequency load regulation, as specified in the Applications Information section. Aluminum electrolytic capacitors ≥50µF may also be used if ESR remains below 0.5Ω. Ceramic capacitors alone are not recommended due to insufficient ESR; REG1117FA-2.5/500 relies on controlled output impedance for phase margin.

What is the thermal resistance (θ_JA) of REG1117FA-2.5/500 under standard PCB conditions?

REG1117FA-2.5/500 has a junction-to-ambient thermal resistance (θ_JA) of 65°C/W with no heatsink, dropping to 27°C/W when mounted on a 4in² (≈25.8cm²) 1oz copper pad, per Figure 4 in the datasheet. This means at 1A load with 3.8V input (1.3V dropout → 1.3W dissipation), junction temperature rise is 84.5°C above ambient with no heatsink - confirming need for adequate copper area to stay within the +125°C max rating.

Is REG1117FA-2.5/500 pin-compatible with the SOT-223 version REG1117A-2.5?

No, REG1117FA-2.5/500 is not pin-compatible with REG1117A-2.5. REG1117FA-2.5/500 uses a 3-lead DDPAK-3 (TO-263) package with VIN, VOUT, and GND pins, while REG1117A-2.5 uses a 4-lead SOT-223 package (VIN, VOUT, GND, and tab/VOUT). Layout redesign and footprint change are required - REG1117FA-2.5/500 offers superior thermal performance but demands different PCB land pattern and assembly process.

What is the output voltage tolerance of REG1117FA-2.5/500 over temperature and load?

REG1117FA-2.5/500 guarantees ±1% output voltage tolerance - i.e., 2.45V to 2.55V - over the full operating junction temperature range (−40°C to +125°C) and load current range (0 to 1A), as confirmed in the Electrical Characteristics table for REG1117A-2.5. This specification holds with input voltage between 4.5V and 10V, ensuring robustness for mission-critical 2.5V digital supplies where voltage margin is tightly constrained.