OPA361AIDCKT Datasheet, PDF (7/17 Pages) Texas Instruments – 3V VIDEO AMPLIFIER with Internal Gain and Filter in SC70

OPA361
www.ti.com
APPLICATIONS INFORMATION
The OPA361 video amplifier has been optimized to fit
seamlessly with Texas Instruments’ OMAP242x
Multimedia processor. The following features have been
integrated to provide excellent video performance.
D Internal gain setting resistors (G = 5.2V/V) reduce
the number of external components needed in the
video circuit.
D Integration of the 500Ω video encoder load resistor
and 4kΩ R_SET resistor used by the OMAP242x
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.
D TV-detection support in connection with an
OMAP242x multimedia processor. This feature
SBOS334A − SEPTEMBER 2005 − REVISED JANUARY 2006
helps to automate start/stop operation of the TV-out
function and minimizes power consumption.
D A 2-pole filter is incorporated for DAC signal
reconstruction.
D The OPA361 employs an internal level shift circuit
that avoids sync pulse clipping and allows
DC-coupled output.
D A shutdown feature reduces quiescent current to
less than 1.5µA—crucial for portable applications
Although OPA361 is optimized for the OMAP242x
processor, it is also suitable to interface with any digital
media processor that outputs a video signal on the order
of 0.4V_PP to 0.5V_PP.
Figure 1 shows a typical application drawing with the
OMAP242x processor and the TWL92230 Energy
Management Chip.
TWL92230
1.8V DAC 0.5V V_REF
OMAP2420
OPA361
Video
DAC
+In
500Ω
Regulator V_AUX
V+ 2.8V
2−Pole
Filter
10mV
R_SET
TV Detect
GPIO⁽³⁾
Enable
TV Detect
GPIO
4kΩ
Shutdown
Control
G = 5.2V/V
(see note 1)
GND
100kΩ⁽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 an interrupt.
1.8V
Out ^75Ω
Pull−Up
10kΩ
+
75Ω
Figure 1. Typical Application using the OMAP242x and the TWL92230
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