Texas Instruments LM3100EVAL

Overview

LM3100EVAL from Texas Instruments is a demonstration board for the LM3100 synchronous buck regulator IC, designed to deliver 3.3 V at up to 1.5 A from an 8–36 V input. It implements Constant ON-Time (COT) control, integrates dual 40 V N-Channel MOSFETs, and operates at 250 kHz with ceramic output capacitors in an HTSSOP-20 footprint.

For engineers reviewing the LM3100EVAL datasheet, LM3100EVAL pinout, LM3100EVAL application, or LM3100EVAL equivalent, this board serves as a validated reference design for evaluating efficiency, transient response, soft-start behavior, short-circuit protection, and thermal performance of the LM3100 in industrial power supply applications.

Technical Context

The LM3100EVAL implements a fixed-output 3.3 V buck converter using TI's LM3100 controller IC, which embeds high-side and low-side synchronous MOSFETs. Its COT regulation eliminates loop compensation and enables fast load transients without ESR-dependent stability.

Key design elements include a 100 kΩ ON-time setting resistor (R1), 15 µH power inductor (L1), dual 22 µF X5R output capacitors (C10/C11), and 0.68 µF VCC bypass capacitor (C8). Input filtering uses two 10 µF Y5V MLCCs (C1/C2), and the board supports shutdown via JP1.

Key Specifications

Availability

LM3100EVAL is available at Aetrix Electronics and suitable for industrial power conversion, embedded system prototyping, and DC/DC regulator validation requiring stable component supply and documented reference performance.

Supply support for LM3100EVAL 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, specializing in analog, embedded processing, and power management technologies with over 90 years of innovation in electronics.

The LM3100EVAL belongs to TI's Power Management Demonstration Board family, developed to accelerate evaluation and adoption of their integrated synchronous buck regulators in cost-sensitive, space-constrained industrial and automotive power designs.

FAQ

What is the primary function of the LM3100EVAL?

The LM3100EVAL is a Texas Instruments demonstration board that implements a complete 3.3 V, 1.5 A synchronous buck regulator using the LM3100 IC. It provides a ready-to-test platform for validating efficiency, transient response, thermal behavior, and protection features-including under-voltage lockout, thermal shutdown, and short-circuit current limiting-without requiring custom PCB development. The LM3100EVAL enables rapid characterization of the LM3100 in real-world conditions.

Does the LM3100EVAL support adjustable output voltage?

No, the LM3100EVAL is configured for a fixed 3.3 V output using a precision feedback divider (R3 = 6.81 kΩ, R4 = 2.21 kΩ). While the underlying LM3100 IC supports adjustable outputs via external resistors, this board's layout and BOM are optimized for 3.3 V operation only. Modifying the feedback network requires rework and recalculating compensation-free COT timing; such changes are not validated for the LM3100EVAL design.

What input voltage range does the LM3100EVAL accept?

The LM3100EVAL accepts a DC input voltage from 8 V to 36 V, as verified in its AN-1443 reference design documentation and performance testing. This range accommodates nominal 12 V and 24 V industrial systems, including automotive battery-supplied applications with load-dump tolerance. Operation outside this range may trigger UVLO or exceed internal MOSFET voltage ratings in the LM3100EVAL's implemented circuit.

How is shutdown controlled on the LM3100EVAL?

Shutdown on the LM3100EVAL is controlled via jumper JP1: leaving it open enables normal operation, while shorting it pulls the SD pin low to disable the LM3100 IC. This hardware-based shutdown signal directly gates the internal gate drivers and halts switching, reducing quiescent current to <100 µA. The LM3100EVAL does not implement software-controlled or logic-level enable sequencing-the JP1 method is the sole supported shutdown interface.

Can the LM3100EVAL be used with non-ceramic output capacitors?

The LM3100EVAL is specifically optimized for ceramic output capacitors (two 22 µF X5R MLCCs), as confirmed in its schematic, layout guide, and ripple performance data. Using electrolytic or tantalum capacitors would degrade high-frequency transient response, increase output ripple beyond the specified 50 mV_P-P, and risk instability due to the LM3100's COT architecture-which does not rely on ESR for control loop damping. The LM3100EVAL's performance claims assume ceramic capacitance per its documented BOM.