LT6205
Linear Technology
LT6205 (single)
Design DocumentAnalog
Video Signal Distribution Using Low Supply Voltage Amplifiers
Design Note 327 discusses using low-voltage video amplifiers (3.3V and 5V) for signal distribution in DC-coupled and AC-coupled configurations with clamping techniques.
Overview
This design note addresses the challenges of distributing composite video signals (NTSC/PAL) using low supply voltage rails, such as 3.3V and 5V. It explains the requirements for driving series-terminated 75Ω cables, which necessitates 2V P-P output into 150Ω loads. The document details the headroom constraints of traditional op amps and introduces a family of Linear Technology video amplifiers (LT6205, LT6206, LT6207, LT6550, LT6551) with low output saturation characteristics. It provides a technical analysis of signal wander in AC-coupled designs and demonstrates a clamping scheme using the LT6205 and BAT54 diode to minimize black-level shift, allowing for reliable operation on a 3.3V supply.
Use Cases
- Low-voltage video signal distribution
- Battery-powered video equipment
- Video driver integration with low-voltage logic rails
- AC-coupled video signal clamping
- NTSC and PAL broadcast-grade video circuits
Topics
video amplifiers
low voltage
3.3V
5V
AC-coupled video
DC-coupled video
clamping circuit
composite video
NTSC
PAL
LT6205
LT6206
Referenced Parts
LT6206
Linear Technology
LT6206 (dual)
LT6207
Linear Technology
LT6207 (quad)
LT6550
Linear Technology
LT6550 (triple, fixed gain of 2)
LT6551
Linear Technology
LT6551 (quad, fixed gain of 2)
BAT54
Various
BAT54
| LT6205 | Linear Technology | LT6205 (single) |
| LT6206 | Linear Technology | LT6206 (dual) |
| LT6207 | Linear Technology | LT6207 (quad) |
| LT6550 | Linear Technology | LT6550 (triple, fixed gain of 2) |
| LT6551 | Linear Technology | LT6551 (quad, fixed gain of 2) |
| BAT54 | Various | BAT54 |