Texas Instruments LMH6504MAX/NOPB

Overview

LMH6504MAX/NOPB from Texas Instruments is a wideband, low-power, DC-coupled voltage-controlled variable gain amplifier (VGA) featuring 150 MHz −3 dB bandwidth, 80 dB gain adjustment range (<10 MHz), ±55 mV output offset voltage, and 1500 V/μs inverting slew rate. It integrates a transconductance input stage, linear-in-dB gain cell, and high-speed current-feedback output amplifier-designed for precision AGC loops in video imaging and RF signal conditioning.

For engineers reviewing the LMH6504MAX/NOPB datasheet, LMH6504MAX/NOPB pinout, LMH6504MAX/NOPB application, or LMH6504MAX/NOPB equivalent, key selection criteria include gain control linearity (±0.42 dB matching), feed-through rejection (−53 dB at 30 MHz), supply current (11 mA), output drive capability (±60 mA), and SOIC-8 thermal performance (θ_JA = 165°C/W).

Technical Context

The LMH6504MAX/NOPB implements a three-stage architecture: a transconductance input buffer (gain set by RG), a voltage-controlled multiplier core with hyperbolic tangent transfer function, and a current-feedback op amp output stage (gain set by RF). Its linear-in-dB gain control (VG = 0–2 V) enables stable closed-loop AGC operation without external log-domain circuitry.

Gain accuracy is maintained across temperature (−40°C to +85°C) via matched internal components, while high-impedance VG (25 MΩ) and VIN (7 MΩ) inputs minimize loading. The device supports both split-supply (±5 V) and single-supply configurations using a virtual ground reference on Pin 4 (GND).

Key Specifications

Pinout & Package

LMH6504MAX/NOPB is packaged in an 8-pin SOIC (Package Number D0008A), with exposed pad not present. Thermal resistance θ_JA = 165°C/W and θ_JC = 60°C/W support continuous operation at ambient temperatures up to +85°C under typical PCB layout conditions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar variable gain amplifier applications.

Compared with LMH6504MAX/NOPB, LMH6503MAX/NOPB offers superior linearity for digitally stepped gain but lacks AGC-optimized logarithmic control, while AD8370ACPZ-R7 provides wider bandwidth and digital configurability at the cost of analog interface simplicity and SOIC compatibility.

Availability

LMH6504MAX/NOPB is available at Aetrix Electronics and suitable for video imaging processing, automatic gain control, and variable attenuator applications requiring stable component supply, long-term obsolescence management, and traceable sourcing for medical and industrial OEM programs.

Supply support for LMH6504MAX/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 leader specializing in analog and embedded processing technologies, with decades of expertise in high-speed amplifiers and signal chain solutions.

The LMH6504MAX/NOPB belongs to TI's LMH™ wideband amplifier family, engineered specifically for precision analog gain control in video, communications, and test equipment where bandwidth, linearity, and low power must coexist.

FAQ

What is the maximum recommended supply voltage for LMH6504MAX/NOPB?

The absolute maximum supply voltage (V+ − V−) for LMH6504MAX/NOPB is 12.6 V, but the recommended operating range is ±3.5 V to ±6 V (7–12 V total). Operating at ±5 V ensures optimal distortion performance (THD = −45 dBc @ 20 MHz) and thermal stability within the SOIC package's 165°C/W θ_JA limit. Exceeding ±6 V risks exceeding junction temperature limits under load.

Does LMH6504MAX/NOPB support single-supply operation?

Yes, LMH6504MAX/NOPB supports single-supply operation by biasing Pin 4 (GND) to a stable virtual ground (e.g., V_CC/2) and referencing VG and input signals to that node. The device maintains full gain control linearity and output swing symmetry when configured this way, provided the virtual ground can source/sink RG current and VG remains 0–2 V relative to Pin 4.

What is the gain control bandwidth of LMH6504MAX/NOPB?

The gain control bandwidth of LMH6504MAX/NOPB is 150 MHz, measured as the −3 dB point of the VG-to-VOUT small-signal transfer function. This allows real-time gain modulation of RF and video signals up to 100 MHz without phase lag or amplitude droop, making it suitable for burst-mode and pulsed applications such as radar IF gain control.

How does LMH6504MAX/NOPB achieve linear-in-dB gain control?

LMH6504MAX/NOPB achieves linear-in-dB gain control through an internal hyperbolic tangent (tanh) multiplier core. Its gain follows A(V/V) = K × RF/RG × tanh[(N − VG)/V_C], yielding near-linear dB response over 80 dB. This eliminates external log-domain circuitry in AGC loops and ensures predictable loop dynamics without calibration.

Can LMH6504MAX/NOPB drive a 50 Ω load directly?

LMH6504MAX/NOPB can drive a 50 Ω load, but output voltage swing is reduced to ±1.7 V (vs. ±2.2 V at 100 Ω) and THD increases to −42 dBc @ 20 MHz. For optimal performance into 50 Ω, use a series 50 Ω termination at the output and match source impedance-this preserves bandwidth and minimizes reflections while maintaining specified distortion and slew rate.