Texas Instruments LMH6401IRMZR

Overview

LMH6401IRMZR from Texas Instruments is a DC–4.5 GHz fully-differential digital variable-gain amplifier (DVGA) with 1-dB gain steps across –6 dB to 26 dB range, 4.5 GHz small-signal bandwidth at 26 dB gain, and differential 100 Ω input impedance. It serves as an ultra-wideband ADC driver in RF sampling receivers requiring precise common-mode alignment via VOCM control.

For engineers reviewing the LMH6401IRMZR datasheet, LMH6401IRMZR pinout, LMH6401IRMZR application, or LMH6401IRMZR equivalent, key selection criteria include its 8-dB noise figure at 1 GHz, –63-dBc HD2/HD3 at 1 GHz (2 V_PPD), 43 dBm OIP3 at 200 MHz, SPI-controlled gain programming, and UQFN-16 package compatibility with high-density RF layouts.

Technical Context

The LMH6401IRMZR integrates a high-linearity BiCMOS transconductance stage with digitally controlled attenuation and on-chip SPI interface logic. Its fully-differential architecture supports both single-supply (5.0 V) and split-supply (±2.5 V) operation, enabling dc- or ac-coupled ADC interfacing while maintaining >38 dB CMRR up to 1 GHz.

Gain is set via 5-bit SPI register (32 steps), with <1 ns gain-step transition time and <70 ns power-down turn-on delay. The VOCM pin provides direct control of output common-mode voltage (±0.5 V range), critical for matching ADC input requirements without external level-shifting circuitry.

Key Specifications

Pinout & Package

LMH6401IRMZR uses a 3.00 mm × 3.00 mm UQFN-16 package with wettable flanks and exposed thermal pad. Pin 1 is SDI (SPI data in); pins 5 & 16 are VS−; pins 8 & 13 are VS+; pins 9 & 12 are GND; pin 7 is VOCM (output common-mode control).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digitally controlled RF amplifier applications.

Compared with LMH6517RTVT and LMH6881IRHA, the LMH6401IRMZR uniquely combines 4.5 GHz bandwidth, VOCM-controlled differential output, and 8 dB noise figure-making it the only option for direct RF sampling ADC drivers requiring simultaneous wideband linearity, precision common-mode alignment, and low-noise performance.

Availability

LMH6401IRMZR is available at Aetrix Electronics and suitable for RF sampling receivers, ultra-wideband ADC drivers, and defense radar front-ends requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for LMH6401IRMZR 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 and embedded processing technologies, with decades of expertise in high-speed amplifier design and RF signal chain solutions.

The LMH6401IRMZR belongs to TI's high-performance RF DVGA product line, engineered specifically for direct-conversion and RF-sampling architectures in 5G infrastructure, defense electronics, and high-end test equipment.

FAQ

What is the maximum operating frequency of the LMH6401IRMZR?

The LMH6401IRMZR achieves a 4.5 GHz small-signal –3 dB bandwidth at 26 dB gain, verified per TI SBOS730A datasheet Figure 1. This enables use in RF sampling applications up to 2.25 GHz Nyquist zone. Large-signal bandwidth remains 4.5 GHz at 2 V_PPD, confirming sustained high-frequency linearity under real-world drive conditions. The LMH6401IRMZR maintains usable gain beyond 4 GHz, with measured voltage gain still >20 dB at 5 GHz.

Does the LMH6401IRMZR support single-supply operation?

Yes, the LMH6401IRMZR supports true single-supply operation from 4.0 V to 5.25 V, with VS+ connected to positive rail and VS− tied to ground. Internal biasing allows differential input/output operation without external level shifters. The LMH6401IRMZR also supports split-supply configurations (e.g., ±2.5 V), and the VOCM pin enables output common-mode adjustment across both topologies.

How does the VOCM pin function on the LMH6401IRMZR?

The VOCM pin on the LMH6401IRMZR directly controls the output common-mode voltage with 1 V/V gain and ±0.5 V input range. When driven to 0 V, output common-mode settles near mid-supply (e.g., 2.5 V on 5 V supply). This eliminates external resistor networks needed to align with ADC input common-mode specifications. The LMH6401IRMZR maintains >160 MHz bandwidth on VOCM, ensuring fast settling during gain transitions.

What is the power-down behavior of the LMH6401IRMZR?

Asserting PD = HIGH disables the LMH6401IRMZR amplifier core, reducing quiescent current from 69 mA to 7 mA typical. Turn-on delay is 70 ns to 90% of final output, and turn-off delay is 10 ns to 10% of original output. The SPI interface remains active during power-down, allowing register state retention. The LMH6401IRMZR also supports software-controlled power-down via SPI command, providing dual-control flexibility.

Can the LMH6401IRMZR drive a 100 Ω differential ADC input?

Yes, the LMH6401IRMZR is optimized to drive 200 Ω differential loads (e.g., TI ADS54J60), but its 20 Ω differential output impedance allows direct interface to 100 Ω ADC inputs with minimal mismatch. Measured output balance error is ≤ –47 dB at 1 GHz, and SDD22 shows >20 dB return loss up to 2 GHz. For best performance into 100 Ω, the LMH6401IRMZR's gain accuracy and harmonic distortion remain within datasheet limits without external termination.