Texas Instruments LM2831YMF

Overview

LM2831YMF from Texas Instruments is a monolithic, current-mode PWM step-down DC-DC regulator in SOT23-5 package, delivering 1.5A output with internal 130 mΩ PMOS switch, fixed 550 kHz switching frequency, 0.6V ±2% reference voltage, and input range 3.0–5.5V. It serves as a compact core power supply for USB-powered devices and set-top boxes.

For engineers reviewing the LM2831YMF datasheet, LM2831YMF pinout, LM2831YMF application, or LM2831YMF equivalent, key selection criteria include its 550 kHz fixed-frequency operation, SOT23-5 thermal performance (θ_JA = 118°C/W), 30 nA shutdown current, internal soft-start, and compatibility with ceramic output capacitors for low-noise local regulation.

Technical Context

The LM2831YMF employs constant-frequency current-mode PWM control with internal compensation, enabling stable regulation across load and line variations without external loop components. Its 550 kHz switching frequency-specific to the Y variant-supports use of standard 4.7 µH inductors and 22 µF ceramic capacitors while maintaining fast transient response.

Operation relies on cycle-by-cycle current limiting (typ. 2.5A), thermal shutdown at 165°C, undervoltage lockout (UVLO rising threshold 2.90V), and output overvoltage protection triggered at FB = 1.15 × V_FB. The internal 0.6V reference feeds an error amplifier that adjusts duty cycle to regulate output from 0.6V to 4.5V via external resistor divider.

Key Specifications

Pinout & Package

SOT23-5 package (NSC drawing MF05A, top mark SKZB), thermally enhanced with exposed pad not present in this variant; requires minimal PCB area (2.9 mm × 1.6 mm) and supports reflow soldering per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62231DRYT and MP2108DQ-LF-Z, the LM2831YMF offers optimal thermal balance for 1.5A loads at 550 kHz in SOT23-5, with integrated soft-start, robust UVLO, and proven 88%+ efficiency at 3.3V/1.25A - making it ideal for thermally constrained USB and STB designs where layout simplicity is critical.

Availability

LM2831YMF is available at Aetrix Electronics and suitable for USB-powered devices, set-top boxes, and HDD core power applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM2831YMF 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-efficiency DC-DC conversion.

The LM2831 family was designed specifically for space-constrained, high-current local regulation in consumer and computing applications - emphasizing minimal external components, fixed-frequency predictability, and robust protection features without sacrificing efficiency.

FAQ

What is the switching frequency of the LM2831YMF?

The LM2831YMF has a fixed internal switching frequency of 550 kHz, as designated by the "Y" suffix in its part number. This frequency is factory-trimmed and does not require external components for setting. It enables use of standard 4.7 µH inductors and maintains high efficiency across the 3.0–5.5V input range while avoiding audible noise in sensitive applications. The LM2831YMF datasheet confirms this value applies over the full –40°C to +125°C junction temperature range.

Does the LM2831YMF require external compensation components?

No, the LM2831YMF uses internal compensation and does not require external compensation components. Its current-mode control architecture and factory-tuned loop response eliminate the need for external RC networks or type-II/type-III compensators. This simplifies design and improves consistency across manufacturing lots. All stability-critical elements - including error amplifier, PWM comparator, and slope compensation - are integrated, as verified in the LM2831YMF typical application circuits and block diagram.

What is the maximum output current capability of the LM2831YMF?

The LM2831YMF delivers up to 1.5A continuous output current under recommended operating conditions (T_J ≤ 125°C, proper PCB layout, adequate copper area). Its internal 130 mΩ PMOS switch and thermal shutdown at 165°C enable this rating in the SOT23-5 package. Peak current limit is typically 2.5A, but sustained operation above 1.5A requires careful thermal design due to θ_JA = 118°C/W. The LM2831YMF datasheet specifies 1.5A as the guaranteed continuous output current across –40°C to +125°C.

Can the LM2831YMF operate from a 3.3V input supply?

Yes, the LM2831YMF supports input voltages from 3.0V to 5.5V, so it operates reliably from a 3.3V source. At 3.3V input, it can regulate down to 0.6V output with appropriate duty cycle (e.g., ~18% for 0.6V), and maintains >85% efficiency at 1.2V/1.0A per typical performance curves. Undervoltage lockout releases at 2.90V (rising), ensuring stable startup. The LM2831YMF electrical characteristics table explicitly lists VIN = 3.3V test conditions for parameters including current limit and quiescent current.

What protection features are built into the LM2831YMF?

The LM2831YMF integrates pulse-by-pulse current limiting (typ. 2.5A), thermal shutdown at 165°C, output overvoltage protection (triggered at FB = 1.15 × 0.6V), and undervoltage lockout with 430 mV hysteresis. These functions operate autonomously without external components. The current limit prevents switch damage during short-circuit events; thermal shutdown disables switching until junction temperature falls to ~150°C; OVP clamps output during feedback disconnection; and UVLO ensures clean startup. All protections are confirmed in the LM2831YMF datasheet's Applications Information section.