Texas Instruments LMH6401EVM

Overview

LMH6401EVM from Texas Instruments is an evaluation module designed to characterize the LMH6401 digitally-controlled variable gain amplifier (DVGA) in differential RF signal paths. It supports –6 dB to 26 dB gain control in 1-dB steps, operates from ±2 V to ±2.625 V split supply or 4 V–5.25 V single supply, and features SMA connectors for differential I/O and VOCM control. The board enables rapid performance validation of the LMH6401 in RF receiver front-ends and instrumentation.

For engineers reviewing the LMH6401EVM datasheet, LMH6401EVM pinout, LMH6401EVM application, or LMH6401EVM equivalent, this page provides verified setup guidance, USB-SPI register programming details, VOCM voltage range constraints ([V+]–2 V to [V–]+2 V), power-down interface behavior, and differential signal conditioning requirements using external baluns.

Technical Context

The LMH6401EVM implements a fully populated, ready-to-use test platform for the LMH6401 RMZ0016A package device. It integrates an FTDI FT245RL USB-to-SPI bridge for register access, on-board LP5900SD-1.8 LDO for clean analog biasing, and precision 40.2-Ω output termination resistors matched to 50-Ω systems.

Signal path design enforces DC- or AC-coupled differential operation with onboard 2200 pF/0.01 µF C-L filtering, VOCM control via SMA input with 1 kΩ resistive divider, and PD activation through either jumper Jpd or high-speed 50-Ω SMA source with RC termination (Rsd/C9).

Key Specifications

Availability

LMH6401EVM is available at Aetrix Electronics and suitable for RF receiver development, wideband instrumentation prototyping, and high-linearity DVGA characterization requiring stable component supply, traceable sourcing, and lifecycle continuity support.

Supply support for LMH6401EVM 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 high-performance analog products for industrial, automotive, and communications applications.

The LMH6401EVM belongs to TI's high-frequency evaluation module product line, engineered specifically to accelerate validation of ultra-wideband DVGAs in RF signal chains where gain agility, noise figure, and distortion performance must be measured under real-world bias and interface conditions.

FAQ

What is the primary function of the LMH6401EVM?

The LMH6401EVM is a dedicated evaluation module for the LMH6401 digitally-controlled variable gain amplifier. Its purpose is to enable rapid, repeatable characterization of the LMH6401's RF performance-including gain accuracy, bandwidth, noise figure, and distortion-across its full –6 dB to +26 dB range. The LMH6401EVM provides all necessary power regulation, USB-SPI interface, differential signal routing, and VOCM/PD control to eliminate custom board development for initial device evaluation.

How is gain controlled on the LMH6401EVM?

Gain on the LMH6401EVM is controlled exclusively via the LMH6401's internal SPI register 2h, programmed through the included LMH6401 EVM GUI software. Writing values 0x00 to 0x20 to register 2h sets gain from +26 dB down to –6 dB in precise 1-dB increments. The LMH6401EVM powers up at the minimum gain setting (–6 dB, 0x20) by default, and no analog gain potentiometer or hardware jumpers are used for gain adjustment.

Does the LMH6401EVM support single-ended signal sources?

No-the LMH6401EVM is configured strictly for differential input and output operation. To use standard single-ended 50-Ω lab equipment (e.g., signal generators or spectrum analyzers), an external 180° hybrid balun (e.g., Mini-Circuits ZFSCJ-2-1-S+ or BAL-0010) must be connected between the SMA ports and test instruments. The LMH6401EVM schematic and User's Guide explicitly require this external conversion; no on-board single-ended interface is provided.

What power supply configurations does the LMH6401EVM accept?

The LMH6401EVM accepts both split-supply (±2 V to ±2.625 V) and single-supply (4 V–5.25 V) operation. In split mode, V+, GND, and V– pins connect to bench supplies; in single mode, V– is tied to GND and V+ receives the positive rail. Supply current is 69 mA typical at ±2.5 V, dropping to ~9 mA when the LMH6401 is placed in power-down via jumper Jpd or the PD SMA input.

Is the VOCM input on the LMH6401EVM actively driven or passively set?

The VOCM input on the LMH6401EVM is configurable: it defaults to passive mid-supply setting via an onboard 1 kΩ resistive divider (Rcm+/Rcm–), but also accepts active external DC voltage sources via the VOCM SMA connector. The valid VOCM voltage range is ([V+]–2 V) to ([V–]+2 V), and deviation from mid-supply affects common-mode rejection and distortion-performance curves for this dependency are documented in the LMH6401 datasheet (SBOS730).