THS7319_14 Datasheet, PDF (16/34 Pages) Texas Instruments – 3-Channel, Very Low Power Video Amplifiers with EDTV Filters and 6-dB Gain

THS7319
SBOS468A – JUNE 2009 – REVISED JULY 2009.............................................................................................................................................................. www.ti.com
APPLICATION INFORMATION
The THS7319 is targeted for triple-channel video
output applications that require three
enhanced-definition (ED) video and/or RGB video
output buffers. The THS7319 also supports standard
definition (SD) video for oversampled systems with
DAC sampling frequency of 54-MHz or greater.
Although the THS7319 can be used for numerous
other applications, the needs and requirements of the
video signal are the most important design
parameters. Built on the revolutionary,
complementary Silicon Germanium (SiGe) BiCom3X
process, the THS7319 incorporates many features
not typically found in integrated video parts while
consuming very low power. The THS7319 includes
the following features:
• Single-supply 2.6-V to 5-V operation with low total
quiescent current of 3.4 mA at 3.3 V and 3.7 mA
at 5 V
• Enable mode for shutting down the THS7319
amplifiers to save system power in
power-sensitive applications
• DC input configuration with internal 150-mV dc
level shifting to prevent sync crushing and
saturation effects
• Third-order 20-MHz (–3-dB) low-pass filter for
DAC reconstruction or ADC image rejection ideal
for:
– NTSC/PAL 480p/576p Y’P’_BP’_R or G’B’R’
(R’G’B’) signals
– NTSC/PAL/SECAM composite video (CVBS),
S-Video Y’/C’, 480i/576i Y’P’_BP’_R, and G’B’R’
(R’G’B’) signals for oversampled systems
• Internally-fixed gain of 2-V/V (+6 dB) amplifiers
that allows for dc-coupling or traditional
ac-coupling
• Flow-through configuration using an ultra-small
MicrostarCSP package
OPERATING VOLTAGE
The THS7319 is designed to operate from 2.6 V to
5 V over a –40°C to +85°C temperature range. The
impact on performance over the entire temperature
range is negligible as a result of the implementation
of thin film resistors and high-quality, low-temperature
coefficient capacitors. The design of the THS7319
allows operation down to 2.5 V, but it is
recommended to use at least a 2.7 V supply to
ensure that no issues arise with headroom or clipping
with 100% color-saturated CVBS signals. If only 75%
color saturated CVBS is supported, then the output
voltage requirements are reduced to 2 V_PP on the
output, allowing a 2.6-V supply to be used without
issues.
A 0.1-µF capacitor should be placed as close as
possible to the power-supply pins to avoid potential
ringing or oscillation. Additionally, a large capacitor
(such as 22 µF to 100 µF) should be placed on the
power-supply line to minimize interference with
50-/60-Hz line frequencies.
INPUT VOLTAGE
The THS7319 input range allows for an input signal
range from –0.06 V to approximately (V_S+ – 1.5 V).
However, because of the internal fixed gain of 2 V/V
(+6 dB) and the internal output level shift of 150 mV
(typical), the output is generally the limiting factor for
the allowable linear input range. For example, with a
5-V supply, the linear input range is from –0.06 V to
3.5 V. However, because of the gain and level shift,
the linear output range limits the allowable linear
input range to approximately –0.06 V to 2.3 V.
INPUT OVERVOLTAGE PROTECTION
The THS7319 is built using a very high-speed,
complementary, bipolar, and CMOS process. The
internal junction breakdown voltages are relatively
low for these very small geometry devices. These
breakdowns are reflected in the Absolute Maximum
Ratings table. All input and output device pins are
protected with internal ESD protection diodes to the
power supplies, as shown in Figure 49.
These diodes provide moderate protection to input
overdrive voltages above and below the supplies as
well. The protection diodes can typically support
30 mA of continuous current when overdriven.
+V_S
External
Input/Output
Pin
Internal
Circuitry
Figure 49. Internal ESD Protection
16
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