Texas Instruments LM2831YMF/NOPB

Overview

LM2831YMF/NOPB from Texas Instruments is a monolithic, 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 0.55 MHz fixed switching frequency, 0.6 V ±2% internal reference, and 130 mΩ PMOS switch. It operates from 3 V to 5.5 V input and regulates output voltages from 0.6 V to 4.5 V - used in USB-powered devices for local 5 V-to-3.3 V conversion.

For engineers reviewing the LM2831YMF/NOPB datasheet, LM2831YMF/NOPB pinout, LM2831YMF/NOPB application, or LM2831YMF/NOPB equivalent, key selection criteria include verified 0.55 MHz switching frequency stability over temperature, confirmed 1.5-A continuous load capability at 125°C junction, validated thermal shutdown at 165°C, and documented soft-start duration of ~600 µs for inrush control.

Technical Context

The LM2831YMF/NOPB implements constant-frequency current-mode PWM control with internal compensation, enabling stable regulation using only five external components. Its architecture integrates a 130-mΩ PMOS high-side switch, 0.6-V reference amplifier, error comparator, artificial ramp generator, and thermal shutdown circuitry - all optimized for minimal PCB footprint in space-constrained applications.

It features cycle-by-cycle current limiting (2.5 A typical), undervoltage lockout with 2.73 V enable threshold and 430 mV hysteresis, and output overvoltage protection triggered at FB = 1.15 × VREF. The 0.55 MHz switching frequency (±15% over –40°C to 125°C) supports compact 3.3 µH inductors and ceramic capacitors without compromising transient response.

Key Specifications

Pinout & Package

LM2831YMF/NOPB uses the 5-pin SOT-23 (DBV) package (1.60 mm × 2.90 mm), optimized for high-density layouts and reflow compatibility. Thermal performance is characterized by R_θJA = 163.4°C/W (JEDEC standard board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2831YMF/NOPB, TPS62231DRVR offers broader input voltage support but lacks its ultra-low shutdown current, while MP2108DJ-LF-Z trades off efficiency at 5 V input for higher frequency operation - neither matches the exact 0.55 MHz/130 mΩ/30 nA combination of LM2831YMF/NOPB in SOT-23.

Availability

LM2831YMF/NOPB is available at Aetrix Electronics and suitable for USB-powered devices, set-top boxes, HDD core power supplies, and DSL modems requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for LM2831YMF/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 analog and embedded processing chips for industrial, automotive, and consumer markets.

The LM2831YMF/NOPB belongs to TI's high-frequency, monolithic buck regulator product line - engineered specifically for space-constrained, high-efficiency point-of-load conversion in portable and always-on electronics.

FAQ

What is the switching frequency of the LM2831YMF/NOPB and how stable is it over temperature?

The LM2831YMF/NOPB has a nominal switching frequency of 0.55 MHz, with typical variation of ±15% across –40°C to 125°C ambient. This is confirmed in Section 6.5 of the SNVS422D datasheet, where Figure 6 shows oscillator frequency remains within 0.4–0.7 MHz over full temperature range. The LM2831YMF/NOPB maintains consistent timing behavior without external frequency programming, simplifying layout and EMI filtering.

Does the LM2831YMF/NOPB require an external catch diode, and what specifications are critical?

Yes, the LM2831YMF/NOPB requires an external Schottky catch diode connected between SW and GND. Critical specs include forward voltage ≤0.4 V at 1.5 A (e.g., Toshiba CRS08), reverse voltage ≥6 V, and average current rating ≥1.5 A. The diode conducts during SW off-time and directly impacts efficiency - lower V_F improves LM2831YMF/NOPB efficiency above 90% at mid-load.

How is output voltage set on the LM2831YMF/NOPB, and what tolerance does the feedback network introduce?

Output voltage is set via a resistor divider from V_OUT to FB to GND, using V_OUT = 0.6 V × (1 + R1/R2). The internal 0.6 V reference has ±2% tolerance over temperature, and standard 1% resistors add ≤1% additional error. For a 3.3 V output, R1 = 45 kΩ and R2 = 10 kΩ yields nominal 3.3 V; total system accuracy is typically ±3% under full operating conditions for LM2831YMF/NOPB.

What thermal performance can be expected from the LM2831YMF/NOPB in a standard SOT-23 layout?

In a JEDEC-standard 2 oz copper, 4-layer 3″×3″ board, the LM2831YMF/NOPB exhibits R_θJA = 163.4°C/W. At 1.5 A output with 5 V input and 3.3 V output (25% duty cycle), power dissipation is ~0.26 W - resulting in ~42°C rise above ambient. Derating begins above 85°C ambient; full 1.5 A load is guaranteed to 125°C junction per Section 6.3 of the LM2831YMF/NOPB datasheet.

Is the LM2831YMF/NOPB pin-compatible with other variants like LM2831XMF/NOPB or LM2831ZMF/NOPB?

No - LM2831YMF/NOPB is not pin-compatible with X or Z variants. While all share the same SOT-23-5 package and pinout, they differ in factory-trimmed switching frequency (0.55 MHz vs 1.6 MHz vs 3 MHz) and cannot be interchanged without verifying loop stability, inductor selection, and EMI compliance. The LM2831YMF/NOPB must be used where 0.55 MHz operation is required.