Texas Instruments LM1117LD-1.8/NOPB

Overview

LM1117LD-1.8/NOPB from Texas Instruments is a fixed-output, 1.8 V, 800 mA low-dropout linear regulator in SOT-223 package. It delivers ±1% output voltage accuracy over 0°C to +125°C, features thermal shutdown and current limiting, and maintains regulation with only 1.2 V dropout at full load - ideal for powering FPGA I/O banks and low-voltage microcontroller cores.

For engineers reviewing the LM1117LD-1.8/NOPB datasheet, LM1117LD-1.8/NOPB pinout, LM1117LD-1.8/NOPB application, or LM1117LD-1.8/NOPB equivalent, key selection criteria include guaranteed 1.8 V output tolerance (±1%), minimum 3.2 V input requirement, 10 µF tantalum output capacitor dependency, and SOT-223 thermal resistance of 61.6°C/W.

Technical Context

The LM1117LD-1.8/NOPB uses a Zener-trimmed bandgap reference to achieve ±1% initial output accuracy and integrates internal current limiting and thermal protection circuitry. Its architecture eliminates need for external protection diodes under normal operation, though an external VIN-to-VOUT diode is recommended when using ≥1000 µF output capacitance.

Unlike adjustable variants, the LM1117LD-1.8/NOPB embeds R1/R2 feedback resistors internally - eliminating external component count while retaining tight line regulation (≤6 mV over 3.2–10 V input) and load regulation (≤10 mV over 0–800 mA). Dropout voltage rises predictably with load: 1.2 V at 800 mA, 1.15 V at 500 mA, and 1.1 V at 100 mA.

Key Specifications

Pinout & Package

SOT-223 (DCY) package: 6.50 mm × 3.50 mm body, 4-pin configuration with exposed thermal pad (pin 4 = VOUT/TAB). Pin 1 = ADJ/GND (grounded for fixed-output version), Pin 2 = VOUT, Pin 3 = VIN, Pin 4 = VOUT/TAB (electrically tied to Pin 2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV76118 and TLV1117-18, the LM1117LD-1.8/NOPB provides superior thermal robustness in SOT-223 (61.6°C/W vs. 104.3°C/W for TLV1117 WSON) and proven field reliability in industrial motor drives - making it preferred where long-term stability under 125°C junction conditions is critical.

Availability

LM1117LD-1.8/NOPB is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, ultrasound scanners, servo drive control modules, and AC drive power stage modules requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LM1117LD-1.8/NOPB 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 company specializing in analog and embedded processing technologies, with leadership in power management ICs since the 1980s.

The LM1117 product line was designed for cost-sensitive, high-reliability linear regulation in industrial, medical, and computing applications - emphasizing thermal robustness, ±1% accuracy without trimming, and simplified external component requirements.

FAQ

What is the minimum input voltage required for stable operation of the LM1117LD-1.8/NOPB?

The LM1117LD-1.8/NOPB requires a minimum input voltage of 3.2 V to maintain regulation across its full 0–800 mA load range and 0°C to +125°C temperature span. This accounts for the 1.2 V maximum dropout voltage at 800 mA and ensures the device remains in linear regulation even under worst-case thermal and load conditions. Input voltages below 3.2 V risk output collapse during peak current demand.

Does the LM1117LD-1.8/NOPB require an external capacitor on the ADJ pin?

No - the LM1117LD-1.8/NOPB is a fixed-output variant with internal feedback resistors; the ADJ pin is internally grounded and has no external connection. Unlike the adjustable LM1117-ADJ, this part does not use the ADJ pin for voltage setting, so no bypass capacitor is needed or recommended. The ADJ/GND pin (Pin 1) must be connected directly to system ground.

Can the LM1117LD-1.8/NOPB be used with ceramic output capacitors?

The LM1117LD-1.8/NOPB is optimized for 10 µF tantalum capacitors with 0.3–22 Ω ESR. While some ceramic capacitors may work, their near-zero ESR can cause instability and oscillation. If ceramic output capacitance is required, a series resistor (typically 0.5–2 Ω) must be added to emulate minimum ESR - or consider the TLV76118, which is explicitly designed for ceramic-capacitor stability.

What thermal derating applies to the LM1117LD-1.8/NOPB in SOT-223 package?

With RθJA = 61.6°C/W and TJ(max) = 150°C, the LM1117LD-1.8/NOPB must be thermally managed to avoid exceeding junction temperature. At 25°C ambient, maximum continuous power dissipation is 2.03 W - corresponding to ~1.69 A at 1.2 V dropout. For 800 mA load, maximum allowable ambient temperature is 111°C with standard PCB copper; above that, forced air or heatsink is required. Derating curves are provided in Section 7.4 of the SNOS412Q datasheet.

Is the LM1117LD-1.8/NOPB pin-compatible with other LM1117 fixed-output variants?

Yes - all LM1117 fixed-output versions (1.8 V, 2.5 V, 3.3 V, 5.0 V) share identical SOT-223 pinout, thermal pad layout, and electrical interface. The LM1117LD-1.8/NOPB can be substituted for LM1117LD-33/NOPB or LM1117LD-25/NOPB on the same PCB footprint, provided input voltage and load requirements align with the new output voltage's dropout and regulation specifications.