OPA361-Q1 Datasheet, PDF (11/18 Pages) Texas Instruments – 3V Video Amplifier with Internal Gain and Filter in SC70

www.ti.com
∆: 305mV
@: 3.00mV
OPA361-Q1
SBOS552 – MARCH 2011
Figure 7. No Clipping of the Sync Pulse
TV-Detect Function
The TV-detection feature of the OPA361-Q1 works in conjunction with the OMAP242x (or other processors) to
detect if a television is connected to the video output of the device. In order to detect a TV load, the OPA361-Q1
is briefly turned off, ideally during the first vertical sync pulse. For the detection, a simple pull-up resistor to the
processor logic supply is used on the output of the OPA361-Q1. The voltage level is pulled LOW if the TV (or
other video equipment) is connected, or HIGH if nothing is connected. A GPIO in the processor can be used to
read this logic level and decide if a video load is connected. Figure 8 shows a scope plot with the TV
disconnected and Figure 9 shows a scope plot with the TV connected; the upper line in both figures is the
disable pulse. Figure 10 shows a circuit drawing using the TV-detect signal to disable or enable the OPA361-Q1.
OPA361 Disable Pulse
OPA361 Ouput
Pulled HIGH;
No Video Load
Connected
∆: 1.84V
@: 1.84V
Equilization Pulses
1st Vertical Sync Pulse
Vertical Sync Pulses
Figure 8. Output of OPA361-Q1 Pulled Up To 1.8V During Disable: TV Disconnected
Copyright © 2011, Texas Instruments Incorporated
Product Folder Link(s) :OPA361-Q1
Submit Documentation Feedback
11