SBOSA87A December   2021  – November 2022 LMH5485-SEP

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics: Vs+ – Vs- = 5 V
    6. 7.6 Electrical Characteristics: Vs+ – Vs- = 3 V
    7. 7.7 Typical Characteristics: 5 V Single Supply
    8. 7.8 Typical Characteristics: 3 V Single Supply
    9. 7.9 Typical Characteristics: 3 V to 5 V Supply Range
  8. 8 Parameter Measurement Information
    1. 8.1 Example Characterization Circuits
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Differential I/O
      2. 9.3.2 Power-Down Control Pin (PD)
        1. 9.3.2.1 Operating the Power Shutdown Feature
      3. 9.3.3 Input Overdrive Operation
    4. 9.4 Device Functional Modes
      1. 9.4.1 Operation from Single-Ended Sources to Differential Outputs
        1. 9.4.1.1 AC-Coupled Signal Path Considerations for Single-Ended Input to Differential Output Conversion
        2. 9.4.1.2 DC-Coupled Input Signal Path Considerations for Single-Ended to Differential Conversion
      2. 9.4.2 Differential-Input to Differential-Output Operation
        1. 9.4.2.1 AC-Coupled, Differential-Input to Differential-Output Design Issues
        2. 9.4.2.2 DC-Coupled, Differential-Input to Differential-Output Design Issues
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Designing Attenuators
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curve
      2. 10.2.2 Interfacing to High-Performance ADCs
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.4.2.2 DC-Coupled, Differential-Input to Differential-Output Design Issues

Operating the LMH5485-SEP with a DC-coupled differential input source is very simple and only requires that the input pins stay in range of the DC common-mode operating voltage. One example is a DC-to-50 MHz quadrature down-converter output. These outputs typically sit on a DC level with some internal source impedance to the external loads. The example of Figure 9-3 shows a design using the LMH5485-SEP with a simple, passive RLC filter to the inputs (the Rg elements act as the differential termination for the filter design). From the original source behind the internal 250 Ω outputs, this circuit is a gain of 1 to the LMH5485-SEP output pins. The DC common-mode operating voltage level shifts from the 1.2 V internal, to the mixer, to an output at the ADC Vcm voltage of 0.95 V. In this case, a simple average of the two DC voltages in the gain of 1 stage gives a 1.08 V input pin common-mode result that is well within range.

Figure 9-3 Example DC-Coupled, Differential I/O Design from a Quadrature Mixer to an ADC