OPA362 Datasheet, PDF (12/18 Pages) Texas Instruments – 3V VIDEO AMPLIFIER with Internal Gain and Filter in SC70

OPA362
SBOS480 – SEPTEMBER 2009 ........................................................................................................................................................................................ www.ti.com
TWL92230
1.8V DAC 0.5V V_REF
Regulator V_AUX
OMAP3430
Video
DAC
OPA362
10mV
+In
Two-Pole
872W
Filter
V+ 2.5V or 2.8V
1.8V
Out ^75W
Pull-up
10kW
+
75W
R_SET
3750W
G = 5.2V/V
TV Detect
GPIO⁽³⁾
Enable
TV Detect
GPIO
Shutdown
Control
(See note 1)
GND _100kW(2)
(1) Closed when enabled during normal operation; open when shut down.
(2) Protects GPIO against overvoltage conditions during active video transmission.
(3) GPIO must be able to generate interrupt.
Figure 27. Using TV-Detect Signal to Disable/Enable the OPA362
Disabling the OPA362 also disconnects the internal
feedback resistor path to GND, and therefore there is
no current flowing from the logic supply through the
pull-up resistor to GND if no video load is connected;
this architecture helps to conserve battery life. The
typical leakage when the output is pulled high and
OPA362 is disabled is approximately 300pA.
The following functionality can be achieved by
implementing TV-detection:
• Automatic video start by polling the video line
periodically.
• Automatic video stop if the TV (or other
equipment) is disconnected.
Proper implementation allows to significantly simplify
the user interface. For more information, see
Application Report SBOA109, OPA361 and TV
Detection, available for download at www.ti.com.
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