Texas Instruments LMH6503MAX

Overview

LMH6503MAX from Texas Instruments is a wideband, DC-coupled, differential-input voltage-controlled gain amplifier (VGA) with 135MHz −3dB bandwidth, 100MHz gain control bandwidth, and 70dB typical gain adjustment range over 10MHz. It integrates a linear-in-V/V gain core and high-speed current-feedback output stage capable of ±75mA linear output current and ±3.2V output swing into 100Ω, enabling direct driving of low-impedance video or RF IF loads in automatic gain control (AGC) loops.

For engineers reviewing the LMH6503MAX datasheet, LMH6503MAX pinout, LMH6503MAX application, or LMH6503MAX equivalent, this device is selected for precision analog signal chains requiring wide dynamic range, fast gain settling (<2.2ns rise time), low distortion (−57dBc THD at 20MHz), and stable performance across −40°C to +85°C industrial temperature range.

Technical Context

The LMH6503MAX implements a two-stage architecture: input differential voltage-to-current conversion via RG-set transconductance, followed by a voltage-controlled two-quadrant multiplier (K ≈ 1.72) and current-feedback transimpedance output stage (gain = RF × K × (VG + 1)/2). Gain is linear in V/V across −1V to +1V VG range, with no dB compression up to 10MHz.

Its current-feedback output delivers 1800V/µs slew rate and maintains flat group delay (2.6ns DC–130MHz) and low phase deviation (1.6° DC–60MHz), supporting high-fidelity baseband and IF signal conditioning. Input common-mode rejection exceeds −67dB, and PSRR remains >−56dB under ±5V supply variation.

Key Specifications

Pinout & Package

LMH6503MAX is housed in a 14-pin SOIC package (Package Code: D0014A), with exposed pad not present. Thermal resistance θJA = 138°C/W enables operation at full power (370mW) in standard PCB layouts without forced air.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH6502MA and AD8367ARUZ, the LMH6503MAX uniquely combines linear-in-V/V gain law, DC coupling, integrated current-feedback output, and 135MHz bandwidth - making it optimal for baseband and low-IF precision analog signal chains where voltage-domain gain programming and minimal external components are critical.

Availability

LMH6503MAX is available at Aetrix Electronics and suitable for video signal conditioning, radar IF amplification, optical receiver AGC, and test equipment signal generation requiring stable component supply and guaranteed long-term manufacturability.

Supply support for LMH6503MAX 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, embedded processing, and connectivity technologies, with decades of expertise in high-speed amplifier design and manufacturing.

The LMH6503MAX belongs to TI's LMH™ high-speed amplifier product line, engineered specifically for wideband, precision analog signal paths in video, communications, and test instrumentation applications demanding linear gain control and low distortion.

FAQ

What is the maximum supply voltage range supported by the LMH6503MAX?

The LMH6503MAX operates over a total supply voltage range of 5V to 12V (±2.5V to ±6V). Absolute maximum ratings specify ±6.3V per rail, but ensured performance is guaranteed only within ±2.5V to ±6V. At ±5V, it delivers full 135MHz bandwidth and ±3.2V output swing into 100Ω - exceeding the specifications required for most industrial and broadcast video applications.

How does the LMH6503MAX achieve linear-in-V/V gain control?

The LMH6503MAX uses an internal two-quadrant voltage-controlled multiplier with nominal gain factor K = 1.72. Its gain equation is AV = (RF/RG) × K × (VG + 1)/2, where VG is applied between −1V and +1V. This architecture ensures strictly linear voltage-domain gain scaling - unlike logarithmic VGAs - enabling direct DAC-driven gain programming without digital compensation in FPGA or microcontroller-based AGC systems.

Can the LMH6503MAX be used in single-supply configurations?

Yes, the LMH6503MAX supports single-supply operation by biasing VREF (Pin 8) to a virtual ground (e.g., VCC/2) and referencing VG to that node. The gain control range shifts to 0V to +2V relative to VREF, maintaining full linearity. Input common-mode range extends to ±2.2V, allowing use with rail-to-rail input signals when properly biased - confirmed in TI's SNOSA78E Figure 23 and Application Information section.

What is the purpose of the dual ground pins (Pins 9 and 11) on the LMH6503MAX?

Pins 9 (GND) and 11 (GND) provide separate return paths for input-stage and output-stage currents. This separation minimizes crosstalk and feedthrough between the gain control interface and signal path - critical for achieving −48dB feedthrough isolation at 30MHz. Layout best practice requires routing these grounds to a common low-impedance star point near the device, not daisy-chaining them on the PCB.

Does the LMH6503MAX require external passive components to set gain?

Yes - gain is set by two external resistors: RG (between Pins 4 and 5) determines input transconductance and maximum input voltage handling, while RF (from Pin 10 to V−) sets transimpedance gain. Typical values are RG = 174Ω and RF = 1kΩ for AV(MAX) = 10. TI provides design equations (Equations 5–6 in SNOSA78E) to calculate optimized RF/RG based on required AV(MAX), input voltage, and bandwidth targets.