Texas Instruments LM25575EVAL

Overview

LM25575EVAL from Texas Instruments is an evaluation board for the LM25575 42V, 1.5A step-down switching regulator, implementing emulated current-mode control to deliver a regulated 5V output across 7–42V input. It supports up to 1.5A continuous load, operates at 300kHz, and features over-current limiting (~2.1A), shutdown (SD) control, and SYNC pin for clock synchronization-used in industrial power supply validation and DC-DC converter design.

For engineers reviewing the LM25575EVAL datasheet, LM25575EVAL pinout, LM25575EVAL application, or LM25575EVAL equivalent, this board enables rapid functional verification of the LM25575 IC's regulation accuracy, efficiency, thermal behavior, and protection features under real-world line/load transients and synchronization scenarios.

Technical Context

The LM25575EVAL implements a non-isolated synchronous buck topology using the LM25575 IC, which integrates a high-side N-channel MOSFET and uses external low-side diode (CMSH3-60). Its 300kHz fixed-frequency operation balances efficiency and PCB footprint, with input filtering via 1µF/100V ceramic capacitors and output filtering using 10µF/16V and 120µF/6.3V bulk capacitance.

Board-level functions include programmable shutdown via open-drain SD pin, external clock synchronization through the SYNC terminal, and over-current protection triggered at ~2.1A. Thermal management relies on 2-oz copper layers and requires ≥200 LFM airflow during sustained full-load operation at high input voltage.

Key Specifications

Availability

LM25575EVAL is available at Aetrix Electronics and suitable for industrial power validation, DC-DC reference design development, and embedded system power architecture prototyping requiring stable component supply and documented TI-qualified performance data.

Supply support for LM25575EVAL 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, embedded processing, and power management technologies, with leadership in high-reliability power conversion solutions.

The LM25575EVAL belongs to TI's SIMPLE SWITCHER® evaluation platform family, designed specifically to accelerate design-in of robust, easy-to-use DC-DC regulators for harsh-input industrial and transportation applications.

FAQ

What is the primary function of the LM25575EVAL evaluation board?

The LM25575EVAL evaluation board is a fully assembled, tested platform that demonstrates the operation of the LM25575 42V, 1.5A step-down regulator IC. It delivers a regulated 5V output from 7–42V input and enables engineers to validate efficiency, transient response, protection features, and layout practices before custom design. The LM25575EVAL includes all necessary passives, thermal design, and test points per TI's AN-1578 reference.

Does the LM25575EVAL support synchronization with external clocks?

Yes, the LM25575EVAL exposes a SYNC pin that allows the LM25575 IC to synchronize its 300kHz switching frequency to an external clock source or to other LM25575EVAL boards. This capability reduces beat frequencies and EMI in multi-rail systems. The SYNC functionality is implemented per the LM25575 datasheet (SNVS479) and verified in the board schematic and layout.

What are the thermal requirements for continuous operation of the LM25575EVAL?

Continuous full-load operation of the LM25575EVAL at high input voltage (e.g., 42V) triggers internal thermal shutdown without forced airflow. TI specifies ≥200 LFM (linear feet per minute) airflow for sustained 1.5A output. The board uses 2-oz copper on FR4 but lacks onboard heatsinking; therefore, active cooling is mandatory during validation of worst-case thermal conditions. The LM25575EVAL thermal design assumes ambient ≤55°C with adequate ventilation.

How is over-current protection implemented on the LM25575EVAL?

The LM25575EVAL implements cycle-by-cycle current limiting via the LM25575 IC's internal sense amplifier and comparator, triggering at approximately 2.1A. During overload, the output current folds back and the IC enters hiccup mode after thermal stress accumulates. The board's BOM includes no external current-sense resistor - limiting is intrinsic to the LM25575. Users must monitor temperature and limit overload duration, as specified in the LM25575EVAL user guide (SNVA216B).

Can the LM25575EVAL be used to evaluate different output voltages?

No - the LM25575EVAL is factory-configured for a fixed 5V output using a specific resistor divider (R3 = 21kΩ, R4 = 49.9kΩ) that sets the FB pin voltage to 1.22V. To evaluate alternate output voltages, users must replace these resistors per the LM25575 datasheet's feedback network equation. The board does not include jumpers or DIP switches for output voltage selection; rework is required for non-5V testing.