THS7353_15 Datasheet, PDF (20/57 Pages) Texas Instruments – 3-Channel Low Power Video Buffer with I2C Control, Selectable Filters, External Gain Control, 2:1 Input MUX, and Selectable Input Modes

THS7353
SLOS484B – NOVEMBER 2005 – REVISED AUGUST 2012
APPLICATION INFORMATION
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The THS7353 is targeted for video output buffer applications. Although it can be used for numerous other
applications, the needs and requirements of the video signal are the most important design parameters of the
THS7353. Built on the complimentary silicon germanium (SiGe) BiCom-3 process, the THS7353 incorporates
many features not typically found in integrated video parts while consuming low power. Each channel
configuration is completely independent of the other channels. This allows for configurations for each channel to
be dictated by the end user and not device. This results in a highly flexible system for most video systems. The
THS7353 contains the following features:
• I²C Interface for easy interfacing to the system with up to 4 addresses.
• Single-supply 2.7-V to 5-V operation with low quiescent current of 16.2-mA with 3.3-V supply and 18.75-mA
with 5-V supply.
• 2:1 input MUX.
• Input configuration accepting dc, dc + 250 mV shift, ac bias, or ac sync-tip clamp selection.
• Selectable 5^th order, low-pass filter for ADC anti-aliasing image rejection or DAC reconstruction:
– 9-MHz for SDTV NTSC and 480i, PAL/SECAM and 576i, S-Video, and G'B'R' (R'G'B') signals.
– 16-MHz for EDTV 480p and 576p Y'P'_BP'_R signals, G'B'R', and VGA signals.
– 35-MHz for HDTV 720p and 1080i Y’P’_BP’_R signals, G'B'R', and SVGA/XGA signals.
– Bypass mode for passing HDTV 1080p Y’P’_BP’_R, G'B'R', and SXGA/UXGA signals.
• Externally configured gain setting allowing from 0-dB buffering up to 14-dB gain allowing for system loss
compensation, high-frequency cable loss compensation, or SinX/X DAC compensation.
• Output can be used with dc coupling or ac coupling.
• Disable mode which reduces quiescent current to as low as 0.1-μA or a mute function that keeps the
THS7353 powered on, but does not allow a signal to pass through.
• Signal flow-through configuration using a 20-pin TSSOP package that complies with the latest lead-free
(RoHS compatible) and green manufacturing requirements.
OPERATING VOLTAGE
The THS7353 is designed to operate from 2.7 V to 5 V over a -40°C to 85°C temperature range. The impact on
performance over the entire temperature range is negligible due to the implementation of thin film resistors and
low-temperature coefficient capacitors.
The power supply pins should have a 0.1-μF to 0.01-μF capacitor placed as close as possible to these pins.
Failure to do so may result in the THS7353 outputs ringing or oscillating. Additionally, a large capacitor, such as
22μF to 100 μF, should be placed on the power supply line to minimize issues with 50/60 Hz line frequencies.
INPUT VOLTAGE
The THS7353 input range allows for an input signal range from Ground to (V_S+ – 1.4 V). But, if the gain is
configured to be greater than 0 dB, the output voltage swing range is generally the limiting factor for the
allowable linear input range. For example, with a 5-V supply and a gain set to 6 dB, the linear input range is from
GND to 3.6 V. But due to the gain, the linear output range limits the allowable linear input range to be from GND
to a maximum of 2.5 V.
The THS7353 operates down to 2.7-V. But, due to the input voltage range limitation, the signal may clip. For
example, with ac-bias selected, the bias point is about 1 V with 3.3-V supply. Under certain video signal
conditions, the signal may clip with this mode due strictly to the input voltage range.
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