Texas Instruments LM3668SD-3034EV/NOPB

Overview

LM3668SD-3034EV/NOPB from Texas Instruments is an evaluation board for the LM3668 synchronous buck-boost DC-DC converter, configured to deliver 3.3 V output at up to 1 A load current with 2.5 V–5.5 V input range, supporting automatic and forced PWM modes via MODE/SYNC pin, and voltage selection (2.8 V/3.3 V) via VSEL pin - used in portable power rail validation for mobile baseband processors.

For engineers reviewing the LM3668SD-3034EV/NOPB datasheet, LM3668SD-3034EV/NOPB pinout, LM3668SD-3034EV/NOPB application, or LM3668SD-3034EV/NOPB equivalent, this page provides verified board-level specifications, thermal layout guidance, jumper-configurable operating modes, and TI-validated component bill-of-materials for rapid feasibility testing of dual-output buck-boost power architectures.

Technical Context

The LM3668SD-3034EV/NOPB implements a four-switch synchronous buck-boost topology with integrated PFET/NFET power stages (SW1, SW2), enabling seamless transition between step-down and step-up operation across its 2.5 V–5.5 V input range. It supports dual fixed-output configurations (2.8 V/3.3 V) selected by logic level on VSEL and operates in either automatic mode (MODE/SYNC = LOW) or forced PWM mode (MODE/SYNC = HIGH).

Feedback is closed via FB pin connected to VOUT through an RC network, while EN enables/disables regulation and PVIN/PGND handle high-current power paths. The board uses a WSON-12 package with exposed DAP thermally tied to SGND, and separates PGND and SGND on inner layers to minimize noise coupling in mixed-signal environments.

Key Specifications

Availability

LM3668SD-3034EV/NOPB is available at Aetrix Electronics and suitable for portable electronics development, battery-powered instrumentation, and embedded system power architecture validation requiring stable component supply and TI-validated reference design fidelity.

Supply support for LM3668SD-3034EV/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, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The LM3668 product line targets space-constrained portable devices needing efficient, low-noise dual-voltage power conversion - specifically designed for baseband processor core and I/O rail generation in smartphones and wearables.

FAQ

What is the default output voltage setting on the LM3668SD-3034EV/NOPB?

The LM3668SD-3034EV/NOPB is factory-configured for 3.3 V output. To change to 2.8 V, the VSEL pin must be pulled low using the onboard jumper per Section 7 of AN-1623. This configuration directly sets the feedback divider ratio inside the LM3668 IC, and the board's resistor network is calibrated for these two precise output levels only.

Can the LM3668SD-3034EV/NOPB operate in forced PWM mode?

Yes, the LM3668SD-3034EV/NOPB supports forced PWM mode by setting the MODE/SYNC pin high, as documented in the Pin Descriptions section. In this mode, the converter maintains constant switching frequency (1.6–2.7 MHz when synchronized externally), eliminating PFM frequency variation and improving EMI predictability - critical for noise-sensitive RF sections powered from the same source.

What is the purpose of the DAP pad on the LM3668SD-3034EV/NOPB board?

The DAP (Die Attach Pad) on the LM3668SD-3034EV/NOPB is thermally connected to the IC's substrate and must be soldered to SGND on the PCB per TI layout guidelines. It enhances thermal performance by conducting heat from the die to the ground plane but is not intended as the primary current return path - PGND remains the dedicated high-current ground node.

Does the LM3668SD-3034EV/NOPB include input overvoltage protection?

No, the LM3668SD-3034EV/NOPB does not incorporate input overvoltage protection circuitry. The LM3668 IC itself has no built-in OVP function, and the evaluation board relies on external front-end protection (e.g., TVS diode or dedicated OVP IC) if required by the end application - consistent with TI's stated use case for R&D validation rather than production deployment.

How is ground separation implemented on the LM3668SD-3034EV/NOPB?

The LM3668SD-3034EV/NOPB uses a four-layer stackup with PGND assigned to inner layer 1 and SGND to inner layer 2, physically separated except at a single "star GND" point near the device's PGND pin. This layout minimizes noise coupling between high-current switching paths (PGND) and sensitive analog/feedback nodes (SGND), as specified in Section 8 of AN-1623.