SNOSC72F June 2012  – February 2015 LMH6881


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1Absolute Maximum Ratings
    2. 6.2ESD Ratings
    3. 6.3Recommended Operating Conditions
    4. 6.4Thermal Information
    5. 6.5Electrical Characteristics
    6. 6.6Typical Characteristics
      1. 6.6.1Single-Ended Input
  7. Detailed Description
    1. 7.1Overview
    2. 7.2Functional Block Diagram
    3. 7.3Feature Description
    4. 7.4Device Functional Modes
    5. 7.5Programming
      1. 7.5.1Digital Control of the Gain and Power-Down Pins
        1. Interface
        2. Serial Interface
  8. Application and Implementation
    1. 8.1Application Information
      1. 8.1.1Input Characteristics
      2. 8.1.2Output Characteristics
      3. 8.1.3Interfacing to an ADC
        1. Noise Filter
        2. Coupling to ADC
        3. Coupling to ADC
      4. 8.1.4Figure of Merit: Dynamic Range Figure
    2. 8.2Typical Applications
      1. 8.2.1LMH6881 Typical Application
        1. Requirements
        2. Design Procedure
        3. Curves
      2. 8.2.2LMH6881 Used as Twisted-Pair Cable Driver
        1. Requirements
        2. Design Procedure
        3. Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1Layout Guidelines
      1. 10.1.1Uncontrolled Impedance Traces
    2. 10.2Layout Example
    3. 10.3Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1Documentation Support
      1. 11.1.1Related Documentation
    2. 11.2Trademarks
    3. 11.3Electrostatic Discharge Caution
    4. 11.4Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Orderable Information

1 Features

  • Small Signal Bandwidth: 2400 MHz
  • OIP3 at 100 MHz: 44 dBm
  • HD3 at 100 MHz: −100 dBc
  • Noise Figure: 9.7 dB
  • Voltage Gain Range: 26 dB to 6 dB
  • Voltage Gain Step Size: 0.25 dB
  • Input Impedance: 100 Ω
  • Parallel and Serial Gain Control
  • Power Down Capability

2 Applications

  • Oscilloscope Front End
  • Spectrum Analyzer Gain Block
  • Differential ADC Driver
  • Differential Cable Driver
  • IF/RF and Baseband Gain Blocks
  • Medical Imaging

OIP3 vs Voltage Gain


3 Description

The LMH6881 is a high-speed, high-performance, programmable differential amplifier. With a bandwidth of 2.4 GHz and high linearity of 44 dBm OIP3, the LMH6881 is suitable for a wide variety of signal conditioning applications.

The LMH6881 programmable differential amplifier combines the best of both fully differential amplifiers and variable-gain amplifiers. The device offers superior noise and distortion performance over the entire gain range without external resistors, enabling the use of just one device and one design for multiple applications requiring different gain settings.

The LMH6881 is an easy-to-use amplifier that can replace both fully differential, fixed-gain amplifiers as well as variable-gain amplifiers. The LMH6881 requires no external gain-setting components and supports gain settings from 6 dB to 26 dB with small, accurate 0.25-dB gain steps. With an input impedance of 100 Ω, the LMH6881 is easy to drive from a variety of sources such as mixers or filters. The LMH6881 also supports 50-Ω single-ended signal sources and supports both DC- and AC-coupled applications.

Parallel gain control allows the LMH6881 to be soldered down in a fixed-gain so that no control circuit is required. If dynamic-gain control is desired, the LMH6881 can be changed with SPI™ serial commands or with the parallel pins.

The LMH6881 is fabricated in TI’s CBiCMOS8 proprietary complementary silicon germanium process and is available in a space-saving, thermally enhanced 24-pin lead quad WQFN package. The same amplifier is offered in a dual package as the LMH6882.

Device Information(1)

LMH6881WQFN (24)4.00 mm × 4.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.