Texas Instruments LMS8117ADT-ADJ/NOPB

Overview

LMS8117ADT-ADJ/NOPB from Texas Instruments is an adjustable low-dropout linear regulator delivering up to 1 A output current with a typical dropout voltage of 1.25 V at full load, ±1% output voltage accuracy over temperature, and operation across 0°C to 125°C. It supports programmable output voltages from 1.25 V to 13.8 V using two external resistors and is commonly used as a post-regulator for DC-DC converters in industrial and embedded power systems.

For engineers reviewing the LMS8117ADT-ADJ/NOPB datasheet, LMS8117ADT-ADJ/NOPB pinout, LMS8117ADT-ADJ/NOPB application, or LMS8117ADT-ADJ/NOPB equivalent, key selection criteria include dropout performance at 1 A, thermal shutdown behavior, ADJUST pin current (60 µA typ), minimum 10-µF tantalum output capacitance requirement, and SOT-223 package thermal resistance (61.4°C/W).

Technical Context

The LMS8117ADT-ADJ/NOPB implements a Zener-trimmed band-gap reference to achieve ±1% output voltage accuracy and uses internal current limiting plus thermal shutdown for fault protection. Its ADJUST pin enables precise voltage programming via resistor divider feedback while maintaining stable regulation under varying line (0.2% max) and load (0.4% max) conditions.

Unlike fixed-output variants, the LMS8117ADT-ADJ/NOPB requires external R1/R2 resistors to set VOUT = 1.25 V × (1 + R2/R1), with ADJUST pin current (60–120 µA) contributing negligible error. The device operates with input voltages up to 15 V and maintains regulation down to VIN – VOUT ≥ 1.25 V across its full temperature range.

Key Specifications

Pinout & Package

SOT-223 (DCY) package: 3-pin surface-mount with exposed thermal pad (Pin 4 = OUTPUT tab). Body size 3.50 mm × 6.50 mm. Requires minimum 10-µF tantalum output capacitor for stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable LDO regulator applications.

Compared with LM1117DTX-ADJ/NOPB and TLV1117-ADJ, the LMS8117ADT-ADJ/NOPB provides superior output accuracy (±1% vs ±2%), guaranteed 1 A delivery across 0°C–125°C, and robust thermal shutdown-making it optimal for industrial and automotive-adjacent embedded power rails where reliability and precision are non-negotiable.

Availability

LMS8117ADT-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial sensor nodes, battery-powered instrumentation, FPGA I/O banks, and programmable logic supplies requiring stable component supply and long-term production continuity.

Supply support for LMS8117ADT-ADJ/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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability linear regulators and power solutions.

The LMS8117A product line was designed specifically for high-accuracy, high-current local regulation in space-constrained industrial and embedded systems-emphasizing thermal robustness, wide output adjustability, and compatibility with standard tantalum capacitors.

FAQ

What is the minimum output capacitance required for stable operation of the LMS8117ADT-ADJ/NOPB?

The LMS8117ADT-ADJ/NOPB requires a minimum 10-µF tantalum capacitor at the output to ensure loop stability and adequate transient response. This value is specified in the TI datasheet and applies regardless of output voltage setting. Using ceramic capacitors below 10 µF or with ESR outside 0.5–5 Ω may cause oscillation or poor load step recovery. The LMS8117ADT-ADJ/NOPB datasheet explicitly validates stability with 10-µF tantalum, making it the baseline design choice.

Can the LMS8117ADT-ADJ/NOPB be used as a precision current regulator?

Yes, the LMS8117ADT-ADJ/NOPB can function as a precision current regulator by connecting a single resistor between the ADJUST and OUTPUT pins. The current is set to 1.25 V / R, leveraging the internal 1.25-V reference. This mode is documented in Section 7.3.2 of the TI datasheet. For example, a 125-Ω resistor delivers 10 mA with ±1% accuracy. The LMS8117ADT-ADJ/NOPB maintains this regulation across temperature and input variations, provided the resistor power rating exceeds (1.25 V)²/R.

What is the maximum input voltage rating for the LMS8117ADT-ADJ/NOPB?

The absolute maximum input voltage for the LMS8117ADT-ADJ/NOPB is 20 V, as stated in Section 6.1 of the TI datasheet. However, the recommended operating condition limits input voltage to 15 V for reliable long-term operation. Exceeding 15 V increases thermal stress and reduces lifetime, especially at high output currents. The LMS8117ADT-ADJ/NOPB must maintain VIN – VOUT ≥ 1.25 V to remain in regulation; thus, 20 V input is only safe when VOUT is set ≥18.75 V and thermal limits are strictly observed.

Does the LMS8117ADT-ADJ/NOPB have built-in reverse polarity protection?

No, the LMS8117ADT-ADJ/NOPB does not include reverse polarity protection. Applying negative voltage to the INPUT pin relative to GND/ADJUST can damage the internal circuitry. The datasheet specifies absolute maximum ratings only for positive input voltage (0 to 20 V). External protection-such as a series Schottky diode or PMOS FET-must be added if reverse input is possible. This absence is consistent across the LMS8117A family and is explicitly omitted from all protection feature descriptions in the LMS8117ADT-ADJ/NOPB datasheet.

How does the ADJUST pin current affect output voltage accuracy in the LMS8117ADT-ADJ/NOPB?

The ADJUST pin current (60–120 µA) introduces a small error in the output voltage equation VOUT = 1.25 V × (1 + R2/R1) + (IADJ × R2). For typical R2 values (e.g., 1 kΩ), this adds ≤0.12 V error-negligible when R2 is kept ≤124 Ω per TI's design guidance. The LMS8117ADT-ADJ/NOPB datasheet confirms IADJ is stable and low-drift, so the error remains predictable and correctable via resistor trimming. At 1 A load, this effect is dwarfed by load regulation (0.4% max), making it a second-order consideration in most LMS8117ADT-ADJ/NOPB designs.