SNOSC72F June   2012  – February 2015 LMH6881

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
      1. 6.6.1 Single-Ended Input
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 Digital Control of the Gain and Power-Down Pins
        1. 7.5.1.1 Parallel Interface
        2. 7.5.1.2 SPI-Compatible Serial Interface
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Input Characteristics
      2. 8.1.2 Output Characteristics
      3. 8.1.3 Interfacing to an ADC
        1. 8.1.3.1 ADC Noise Filter
        2. 8.1.3.2 AC Coupling to ADC
        3. 8.1.3.3 DC Coupling to ADC
      4. 8.1.4 Figure of Merit: Dynamic Range Figure
    2. 8.2 Typical Applications
      1. 8.2.1 LMH6881 Typical Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LMH6881 Used as Twisted-Pair Cable Driver
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Uncontrolled Impedance Traces
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, 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

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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)

PART NUMBER PACKAGE BODY SIZE (NOM)
LMH6881 WQFN (24) 4.00 mm × 4.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.