SBOS394E November   2007  – July 2019 VCA824

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Differential Equalizer
      2.      Differential Equalization of an RC Load
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin 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 = ±5 V
    6. 7.6 Typical Characteristics: VS = ±5 V, AVMAX = 2 V/V
    7. 7.7 Typical Characteristics: VS = ±5 V, AVMAX = 10 V/V
    8. 7.8 Typical Characteristics: VS = ±5 V, AVMAX = 40 V/V
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
      1. 8.4.1 Maximum Gain Of Operation
      2. 8.4.2 Output Current And Voltage
      3. 8.4.3 Input Voltage Dynamic Range
      4. 8.4.4 Output Voltage Dynamic Range
      5. 8.4.5 Bandwidth
      6. 8.4.6 Offset Adjustment
      7. 8.4.7 Noise
      8. 8.4.8 Input and ESD Protection
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Difference Amplifier
      2. 9.1.2 Differential Equalizer
      3. 9.1.3 Differential Cable Equalizer
      4. 9.1.4 Voltage-Controlled Lowpass Filter [application sub]
      5. 9.1.5 Wideband Variable Gain Amplifier Operation
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Thermal Considerations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Demonstration Boards
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.1 Maximum Gain Of Operation

This section describes the use of the VCA824 in a fixed-gain application in which the VG control pin is set at
VG = 1 V. The tradeoffs described here are with bandwidth, gain, and output voltage range.

In the case of an application that does not make use of the VGAIN, but requires some other characteristic of the VCA824, the RG resistor must be set such that the maximum current flowing through the resistance IRG is less than ±2.6 mA typical, or 5.2 mAPP as defined in Electrical Characteristics: VS = ±5 V, and must follow Equation 1.

Equation 1. VCA824 q_irg_vout_bos343.gif

As Equation 1 illustrates, once the output dynamic range and maximum gain are defined, the gain resistor is set. This gain setting in turn affects the bandwidth, because in order to achieve the gain (and with a set gain element), the feedback element of the output stage amplifier is set as well. Keeping in mind that the output amplifier of the VCA824 is a current-feedback amplifier, the larger the feedback element, the lower the bandwidth because the feedback resistor is the compensation element.

Limiting the discussion to the input voltage only and ignoring the output voltage and gain, Equation 2 illustrates the tradeoff between the input voltage and the current flowing through the gain resistor.