Texas Instruments LM2831XMFX/NOPB

Overview

LM2831XMFX/NOPB from Texas Instruments is a high-frequency, current-mode PWM step-down DC-DC regulator IC in a 5-pin SOT-23 package, delivering up to 1.5-A output current with 0.6-V internal reference, 1.6-MHz fixed switching frequency, and 130-mΩ integrated PMOS switch. It operates from 3 V to 5.5 V input and regulates output voltages from 0.6 V to 4.5 V, commonly used in USB-powered devices and HDD core power supplies.

For engineers reviewing the LM2831XMFX/NOPB datasheet, LM2831XMFX/NOPB pinout, LM2831XMFX/NOPB application, or LM2831XMFX/NOPB equivalent, key selection considerations include its 1.6-MHz switching frequency enabling ultra-compact filter design, internal soft-start limiting inrush current, thermal shutdown at 165°C, and enable-controlled ultra-low 30-nA shutdown quiescent current.

Technical Context

The LM2831XMFX/NOPB implements constant-frequency current-mode control with an internal 0.6-V ±2% voltage reference and pulse-by-pulse current limiting. Its 130-mΩ PMOS switch supports 1.5-A continuous load with on-times as low as 30 ns, enabling stable regulation down to 0.6 V across the full 3–5.5 V input range.

It integrates undervoltage lockout (UVLO) with 2.73-V turn-on threshold and 430-mV hysteresis, output overvoltage protection triggered at 15% above VREF, and internal compensation for single-loop stability-requiring only five external components for full operation.

Key Specifications

Pinout & Package

LM2831XMFX/NOPB uses the 5-pin SOT-23 (DBV) package (1.60 mm × 2.90 mm), optimized for space-constrained applications. Thermal performance is characterized by R_θJA = 163.4°C/W on a standard 4-layer board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with TPS62231DRVR and MP1472GJ-Z, the LM2831XMFX/NOPB uniquely combines 0.6-V reference, integrated soft-start, output overvoltage protection, and 30-nA shutdown in a 5-pin SOT-23-making it optimal for cost-sensitive, space-constrained USB and consumer storage applications requiring robust fault handling.

Availability

LM2831XMFX/NOPB is available at Aetrix Electronics and suitable for USB powered devices, HDD core power supplies, and set-top box power rails requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LM2831XMFX/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 headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and digital signal processing technologies since 1930.

The LM2831XMFX/NOPB belongs to TI's high-frequency DC-DC regulator product line, engineered specifically for compact, efficient point-of-load conversion in portable and USB-powered electronics where board space and standby power are critical.

FAQ

What is the switching frequency of the LM2831XMFX/NOPB?

The LM2831XMFX/NOPB has a fixed switching frequency of 1.6 MHz, as indicated by the "X" suffix in its part number. This frequency is internally set and does not require external timing components. It enables the use of small surface-mount inductors (e.g., 3.3 µH) and ceramic capacitors while maintaining high efficiency-up to 94% at 1.5 A and 3.3 V output.

Does the LM2831XMFX/NOPB require external compensation components?

No, the LM2831XMFX/NOPB features internal compensation and is designed for stable operation with only five external components: input capacitor, output capacitor, inductor, catch diode, and feedback resistors. Its current-mode architecture eliminates the need for external compensation networks, simplifying layout and reducing BOM count compared to voltage-mode regulators.

What protection features does the LM2831XMFX/NOPB include?

The LM2831XMFX/NOPB integrates multiple protection functions: thermal shutdown (activates at 165°C junction temperature), output overvoltage protection (triggers when FB exceeds 0.69 V), undervoltage lockout with 430-mV hysteresis (2.73-V turn-on, 2.3-V turn-off), and cycle-by-cycle current limiting (typical 2.5-A switch limit). These features ensure robust operation in unattended or thermally constrained environments.

Can the LM2831XMFX/NOPB regulate output voltages below 1.0 V?

Yes, the LM2831XMFX/NOPB supports output voltages as low as 0.6 V due to its precise 0.6-V ±2% internal reference. For example, a 0.6-V output is achieved with R1 = 0 Ω and R2 = 10 kΩ; a 0.8-V output uses R1 = 3.32 kΩ and R2 = 10 kΩ. The 30-ns minimum on-time and current-mode control maintain regulation stability even at these low voltages across the full 3–5.5 V input range.

What is the recommended input capacitor for the LM2831XMFX/NOPB?

Texas Instruments recommends a minimum 22-µF X5R or X7R multilayer ceramic capacitor (MLCC) placed as close as possible to the VIN and GND pins. This value ensures low impedance at 1.6 MHz, minimizes input voltage droop during switching transients, and handles RMS currents up to ~0.7 A. A 0805 or 1206 case size with low ESL is preferred; leaded or high-ESL capacitors are discouraged due to degraded high-frequency performance.