OPA362 Datasheet, PDF (8/18 Pages) Texas Instruments – 3V VIDEO AMPLIFIER with Internal Gain and Filter in SC70

OPA362
SBOS480 – SEPTEMBER 2009 ........................................................................................................................................................................................ www.ti.com
APPLICATION INFORMATION
The OPA362 video amplifier has been optimized to fit
seamlessly with Texas Instruments’ OMAP343x
multimedia processor. The following features have
been integrated to provide excellent video
performance:
• Internal gain setting resistors (G = 5.2V/V) reduce
the number of external components needed in the
video circuit.
• Integration of the 872Ω video encoder load
resistor and 3750Ω R_SET resistor used by the
OMAP343x helps minimize the number of external
components and also ensures excellent ratio and
temperature tracking. This feature helps to keep
the overall gain accurate and stable over
temperature.
• TV-detection support in connection with an
OMAP343x multimedia processor. This feature
helps to automate start/stop operation of the
TV-out function and minimizes power
consumption.
• A two-pole filter is incorporated for DAC signal
reconstruction.
• The OPA362 employs an internal level shift circuit
that avoids sync pulse clipping and allows
dc-coupled output.
• A shutdown feature reduces quiescent current to
less than 1.5μA—crucial for portable applications.
Although the OPA362 is optimized for the OMAP343x
processor, it is also well-suited to interface with any
digital media processor that outputs a video signal on
the order of 0.4V_PP to 0.5V_PP.
Figure 18 shows a typical application drawing with
the OMAP343x processor and the TWL92230 Energy
Management Chip.
TWL92230
1.8V DAC 0.5V V_REF
OMAP3430
OPA362
Video
DAC
+In
872W
Regulator V_AUX
V+ 2.8V
10mV
Two-Pole
Filter
R_SET
TV Detect
(3)
GPIO
Enable
TV Detect
GPIO
3750W
Shutdown
Control
G = 5.2V/V
(See note 1)
GND
(2)
100kW
1.8V
(4)
Out ^75W
Pull-up
10kW
+
75W
(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 an interrupt.
(4) External 75Ω resistor is necessary when driving 75Ω terminated loads.
Figure 18. Typical Application Using the OMAP343x and the TWL92230
8
Submit Documentation Feedback
Product Folder Link(s): OPA362
Copyright © 2009, Texas Instruments Incorporated