Texas Instruments LMH6503MTX

Overview

LMH6503MTX 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 control interface (−1V to +1V), high-speed current-feedback output stage, and delivers ±75mA linear output current into 100Ω loads - enabling direct drive of ADC inputs, RF IF stages, and video signal chains.

For engineers reviewing the LMH6503MTX datasheet, LMH6503MTX pinout, LMH6503MTX application, or LMH6503MTX equivalent, this device is selected for precision analog signal conditioning where wide dynamic range, low distortion (−57dBc THD at 20MHz), and stable gain linearity across temperature (±0.7dB gain matching) are required in instrumentation, automatic gain control loops, and programmable filter front-ends.

Technical Context

The LMH6503MTX implements a two-stage architecture: first, differential input voltage is converted to current via precision input buffers and a gain-setting resistor (RG); second, that current is scaled by a voltage-controlled multiplier (K ≈ 1.72) and converted to output voltage via a current-feedback op amp with transimpedance gain set by RF. Gain is linear in V/V across the full −1V to +1V VG range.

Its design supports both differential and single-ended operation, features high input impedance (750kΩ) and low input noise (6.6nV/√Hz), and maintains ±0.2dB gain flatness up to 20MHz at AV(MAX)=10. Output offset voltage remains under ±350mV across the full VG range and temperature (−40°C to +85°C).

Key Specifications

Pinout & Package

LMH6503MTX is packaged in a 14-pin TSSOP (PW0014A), optimized for high-density PCB layouts and thermal performance (θJA = 160°C/W). Pin functions are validated per TI SNOSA78E Rev. April 2013.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-controlled gain amplifier applications.

Compared with LMH6503MTX, LMH6502MA/NOPB trades V/V linearity for dB linearity and bandwidth, while AD8367ARUZ offers higher RF bandwidth but sacrifices DC coupling and differential input capability - making LMH6503MTX uniquely suited for precision analog signal chains requiring both wide dynamic range and baseband integrity.

Availability

LMH6503MTX is available at Aetrix Electronics and suitable for video signal conditioning, RF/IF automatic gain control, and high-speed data acquisition front-ends requiring stable component supply, guaranteed long-term availability, and full traceability.

Supply support for LMH6503MTX 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-performance amplifier design.

The LMH6503MTX belongs to TI's LMH™ high-speed amplifier product line, engineered specifically for wideband, precision analog signal conditioning in test & measurement, communications infrastructure, and medical imaging systems.

FAQ

What is the recommended supply voltage range for stable operation of the LMH6503MTX?

The LMH6503MTX operates reliably across ±2.5V to ±6V total supply range (i.e., 5V to 12V between V+ and V−), with tested performance specified from ±5V. At ±2.5V, supply current drops to ~20mA and AV(MAX) reduces to ~6V/V, but gain linearity and bandwidth remain intact. Operation outside this range risks exceeding absolute maximum ratings and invalidating electrical specifications.

How does the LMH6503MTX achieve linear-in-V/V gain control, and what is the exact relationship between VG and gain?

The LMH6503MTX uses an internal two-quadrant multiplier where gain scales linearly as AV = (RF/RG) × K × (VG + 1)/2, with K ≈ 1.72. For −1V < VG < +1V, gain varies from zero (VG = −1V) to AV(MAX) (VG = +1V) in strict proportion - e.g., VG = 0V yields exactly 50% of AV(MAX). This eliminates log-conversion circuitry and ensures predictable, monotonic gain vs. control voltage.

Can the LMH6503MTX be used in single-supply configurations, and how is the input/output biased?

Yes - the LMH6503MTX supports single-supply operation using its internal VREF pin (Pin 9), which provides a stable mid-rail voltage. Input common-mode is set by biasing +VIN/−VIN to VREF, and output is centered at VREF. The gain control range remains −1V to +1V relative to VREF, enabling full 0–100% gain sweep without external level-shifting circuitry.

What are the key layout considerations to maintain 135MHz bandwidth and low distortion in LMH6503MTX circuits?

Maintain short, matched-length traces for +VIN/−VIN; place 0.1µF ceramic + 4.7µF bulk capacitors within 5mm of Pins 1 and 13; isolate analog ground (Pin 11) from digital/power planes; route VG away from noisy signals; and use controlled-impedance 50Ω routing for VOUT if driving long traces or cables. Avoid vias in high-speed paths to prevent parasitic inductance.

Does the LMH6503MTX require external gain-setting resistors, and how do RF and RG affect performance?

Yes - RF and RG are mandatory external components. RG sets input current (IRG = VIN_DIFF / RG) and influences bandwidth (higher RG lowers BW); RF sets transimpedance gain (VOUT = IRG × K × (VG+1)/2 × RF) and affects stability (lower RF improves phase margin). Typical values are RG = 174Ω and RF = 1kΩ for AV(MAX) = 10 and 135MHz BW, per TI SNOSA78E.