SBOS552A March   2011  – May 2026 OPA361-Q1

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Description
  4. 3Pin Configuration
  5. 4Specifications
    1. 4.1 Absolute Maximum Ratings
    2. 4.2 Electrical Characteristics: VS = +2.5V to +3.3V
    3. 4.3 Typical Characteristics: VS = 2.8V
  6. 5Application and Implementation
    1. 5.1 Application Information
      1. 5.1.1 Operating Voltage
      2. 5.1.2 Input Voltage
      3. 5.1.3 Input Overvoltage Protection
      4. 5.1.4 Enable/Shutdown
      5. 5.1.5 Internal 2-Pole Filter
        1. 5.1.5.1 Video Performance
      6. 5.1.6 Internal Level Shift
        1. 5.1.6.1 Output Swing Capability
        2. 5.1.6.2 TV-Detect Function
  7. 6Device and Documentation Support
    1. 6.1 Receiving Notification of Documentation Updates
    2. 6.2 Support Resources
    3. 6.3 Trademarks
    4. 6.4 Electrostatic Discharge Caution
    5. 6.5 Glossary
  8. 7Revision History
  9. 8Mechanical, Packaging, and Orderable Information

5.1.5 Internal 2-Pole Filter

The OPA361-Q1 filter is a Sallen-Key topology with a 9MHz cutoff frequency. Figure 5-2 shows a detailed drawing of the filter components. This filter allows video signals to pass without any visible distortion, as shown in Figure 5-3 through Figure 5-6. The video encoder embedded in the OMAP242x processor typically samples at 54MHz. At this frequency, the attenuation is typically 23dB, which effectively attenuates the sampling aliases.

The internal 500Ω resistor on the input to GND converts the output current of the OMAP2420 internal video DAC into a voltage. It is also part of the Sallen-Key filter. Using an external resistor to adjust the input voltage range will also alter the filter characteristics.

OPA361-Q1 Filter Structure of the OPA361-Q1Figure 5-2 Filter Structure of the OPA361-Q1