EL2090
100MHz DC-Restored Video Amplifier
Not Recommended for New Designs.Contact our Technical Support Center at 1-888-INTERSIL.
Typical Diagram
Key Features
- Complete video level restoration system
- 0.01% differential gain and 0.02o differential phase accuracy at NTSC
- 100MHz bandwidth
- 0.1dB flatness to 20MHz
- Sample-and-hold has 15nA typical leakage and 1.5pC charge injection
- System can acquire DC correction level in 10µs, or 5 scan lines of 2µs each, to 1/2 IRE
- VS = ±5V to ±15V
- TTL/CMOS hold signal
Description
The EL2090 is the first complete DC-restored monolithic video amplifier sub-system. It contains a very high-quality video amplifier and a nulling sample-and-hold amplifier specifically designed to stabilize video performance. When the HOLD logic input is set to a logic 0 during a horizontal sync, the sample-and-hold amplifier may be used as a general-purpose op-amp to null the DC offset of the video amplifier. When the HOLD input goes to a logic 1 the sample-and-hold stores the correction voltage on the hold capacitor to maintain DC correction during the subsequent scan line.
The video amplifier is optimized for video characteristics, and performance at NTSC is nearly perfect. It is a current-feedback amplifier, so that -3dB bandwidth changes little at various closed-loop gains. The amplifier easily drives video signal levels into 75Ω loads. With 100MHz bandwidth, the EL2090 is also useful in HDTV applications.
The sample-and-hold is optimized for fast sync pulse response. The application circuit shown will restore the video DC level in five scan lines, even if the HOLD pulse is only 2µs long. The output impedance of the sample-and-hold is low and constant over frequency and load current so that the performance of the video amplifier is not compromised by connections to the DC restore circuitry.
The EL2090 is fabricated in Elantec's proprietary Complementary Bipolar process which produces NPN and PNP transistors with equivalent AC and DC performance. The EL2090 is specified for operation over the 0oC to 75oC temperature range.
Applications
- Input amplifiers in video equipment
- Restoration amplifiers in video mixers
