GS1672 Datasheet, PDF (29/116 Pages) Gennum Corporation – Integrated Cable Driver

Table 4-2: GS1672 Input Video Data Format Selections (Continued)
Input Data Format
Pin/Register Bit Settings
10-bit multiplexed
SD format
10-bit multiplexed
SD format
10-bit ASI input
SD format
20BIT
/10BIT
LOW
LOW
LOW
RATE
_SEL
HIGH
SMPTE
_BYPASS
HIGH
DVB_ASI
LOW
HIGH
LOW
LOW
HIGH
LOW
HIGH
DIN[9:0]
High Impedance
High Impedance
High Impedance
The GS1672 is a high performance SD/HD-capable transmitter. In order to optimize the
output jitter performance across all operating conditions, input levels and overshoot at
the parallel video data inputs of the device need to be controlled. In order to do this,
source series termination resistors should be used to match the impedance of the PCB
data trace line. IBIS models can be used to simulate the board effects and then optimize
the output drive strength and the termination resistors to allow for the best transition
(one that produces minimal overshoot). If this is not viable, Gennum recommends
matching the source series resistance to the trace impedance, and then adjusting the
output drive strength to the minimum value that will give zero errors.
The above also applies to the PCLK input line. HVF and the Audio inputs should also be
well terminated, however due to the lower data rates and transition density it is not as
critical.
4.2.1 Parallel Input in SMPTE Mode
When the device is operating in SMPTE mode (SMPTE_BYPASS = HIGH), data must be
presented to the input bus in either multiplexed or demultiplexed form, depending on
the setting of the 20BIT/10BIT pin.
When operating in 20-bit mode (20BIT/10BIT = HIGH), the input data format must be
word aligned, demultiplexed Luma and Chroma data (SD or HD).
When operating in 10-bit mode (20BIT/10BIT = LOW), the input data format must be
multiplexed Luma (Y) and Chroma (C) data (SD, HD). C words precede Y words. In this
mode, the data must be presented on the DIN[19:10] pins. The DIN[9:0] inputs are
ignored.
4.2.1.1 Input Data Format in SDTI Mode
SDTI and HD-SDTI are a sub-set of SDI and HD-SDI formats. They may contain SDTI data
on any line in the frame. Those lines which contain SDTI or HD-SDTI data are identified
with an SDTI or HD-SDTI header packet in the HANC space.
DIN[19:10]
Luma/Chroma
DATA
DVB-ASI data
GS1672 HD/SD-SDI Serializer with Complete SMPTE
Audio & Video Support
Data Sheet
53623 - 6
July 2011
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