THS7353 Datasheet, PDF (38/51 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
SLOS484 – NOVEMBER 2005
www.ti.com
Channel Register Bit Descriptions
Each bit of the subaddress (channel selection) control register as described above allows the user to individually
control the functionality of the THS7353. The benefit of this process allows the user to control the functionality of
each channel independent of the other channels. The bit description is decoded in Table 3.
BIT
(MSB)
7, 6
5
4,3
2, 1, 0
(LSB)
Table 3. THS7353 Channel Register Bit Decoder Table
FUNCTION
STC Low Pass Filter Selection
Input MUX Selection
Low-Pass Filter
Frequency Selection
Input Bias Mode Selection and
Disable Control
BIT
VALUE(S)
00
01
10
11
0
1
00
01
10
11
000
001
010
011
100
101
110
111
RESULT
500-kHz Filter – Useful for 9-MHz Video LPF
2.5-MHz Filter – Useful for 16-MHz Video LPF
5-MHz Filter – Useful for 35-MHz/Bypass Video LPF
5-MHz Filter – Useful for 35-MHz/Bypass Video LPF
Input A Select
Input B Select
9-MHz LPF – Useful for SDTV, S-Video, 480i/576i
16-MHz LPF – Useful for EDTV 480p/576p and VGA
35-MHz LPF – Useful for 720p, 1080i, and SVGA/XGA
Bypass LPF – Useful for 1080p and SXGA/UXGA
Disable Channel – Conserves Power
Channel On – Mute Function – No Output
Channel On – DC Bias Select
Channel On – DC Bias + 250 mV Offset Select
Channel On – AC Bias Select
Channel On – Sync Tip Clamp with low bias
Channel On – Sync Tip Clamp with mid bias
Channel On – Sync Tip Clamp with high bias
Bits 7 (MSB) and 6 – Controls the AC-Sync Tip Clamp Low Pass Filter function. If AC-STC mode is not used,
this function is ignored.
Bit 5 – Controls the input MUX of the THS7353.
Bits 4 and 3 – Controls the 5^th order Low Pass Filter –3 dB corner frequency or the bypass mode of operation.
Bits 2, 1, and 0 (LSB) – Selects the input biasing of the THS7353 and the power-savings function. When sync-tip
clamp is selected, the dc input sink bias current is also selectable.
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