SBOS407D December   2007  – May 2016 VCA821

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 = ±5 V
    6. 7.6  Typical Characteristics: VS = ±5 V, DC Parameters
    7. 7.7  Typical Characteristics: VS = ±5 V, DC and Power-Supply Parameters
    8. 7.8  Typical Characteristics: VS = ±5 V, AVMAX = 6 dB
    9. 7.9  Typical Characteristics: VS = ±5 V, AVMAX = 20 dB
    10. 7.10 Typical Characteristics: VS = ±5 V, AVMAX = 32 dB
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Feature Description
    3. 9.3 Device Functional Modes
      1. 9.3.1 Maximum Gain of Operation
      2. 9.3.2 Output Current and Voltage
      3. 9.3.3 Input Voltage Dynamic Range
      4. 9.3.4 Output Voltage Dynamic Range
      5. 9.3.5 Bandwidth
      6. 9.3.6 Offset Adjustment
      7. 9.3.7 Noise
        1. 9.3.7.1 Input and ESD Protection
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Design-In Tools
        1. 10.1.1.1 Demonstration Boards
        2. 10.1.1.2 Macromodels and Applications Support
        3. 10.1.1.3 Operating Suggestions
        4. 10.1.1.4 Package Considerations
    2. 10.2 Typical Applications
      1. 10.2.1 Wideband Variable-Gain Amplifier Operation Application
        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 Difference Amplifier Application
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
        3. 10.2.2.3 Application Curve
      3. 10.2.3 Differential Equalizer Application
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
        3. 10.2.3.3 Application Curve
      4. 10.2.4 Differential Cable Equalizer Application
        1. 10.2.4.1 Design Requirements
        2. 10.2.4.2 Detailed Design Procedure
        3. 10.2.4.3 Application Curve
      5. 10.2.5 AGC Loop Application
        1. 10.2.5.1 Design Requirements
        2. 10.2.5.2 Detailed Design Procedure
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • 710-MHz Small-Signal Bandwidth
    (G = +2 V/V)
  • 320 MHz, 4 VPP Bandwidth (G = +10 V/V)
  • 0.1-dB Gain Flatness to 135 MHz
  • 2500 V/μs Slew Rate
  • > 40-dB Gain Adjust Range
  • High Gain Accuracy: 20 dB ±0.3 dB
  • High Output Current: ±90 mA

2 Applications

  • AGC Receivers With RSSI
  • Differential Line Receivers
  • Pulse Amplitude Compensation
  • Variable Attenuators
  • Voltage-Tunable Active Filters

3 Description

The VCA821 device is a DC-coupled, wideband, linear in dB, continuously variable, voltage-controlled gain amplifier. It provides a differential input to single-ended conversion with a high-impedance gain control input used to vary the gain down 40 dB from the nominal maximum gain set by the gain resistor (RG) and feedback resistor (RF).

The VCA821 device internal architecture consists of two input buffers and an output current feedback amplifier stage integrated with a multiplier core to provide a complete variable gain amplifier (VGA) system that does not require external buffering. The maximum gain is set externally with two resistors, providing flexibility in designs. The maximum gain is intended to be set between 6 dB and 32 dB. Operating from ±5-V supplies, the gain control voltage for the VCA821 device adjusts the gain linearly in dB as the control voltage varies from 0V to +2 V. For example, set at a maximum gain of 20 dB, the VCA821 device provides 20 dB, at VG = +2 V, to less than –20 dB at VG = 0 V. The VCA821 device offers excellent gain linearity. For a 20-dB maximum gain, and a gain-control input voltage varying between +1 V and +2 V, the gain does not deviate by more than ±0.3 dB (maximum at +25°C).

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
VCA821 SOIC (14) 8.65 mm × 3.91 mm
VSSOP (10) 3.00 mm × 3.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Differential Equalizer

VCA821 front_cir_bos407.gif

Differential Equalization of an RC Load

VCA821 front_graph_bos407.gif