GX9533_09 Datasheet, PDF (9/15 Pages) Gennum Corporation – Serial Digital 8x9 Crosspoint

3. Detailed Description
3.1 Differential Inputs
The inputs to the GX9533 will accept both SMPTE 259M as well as PECL input levels. The
fully differential data path provides low jitter data rates of up to 700Mb/s.
The main inputs (IN0..7) and expansion inputs (EXP0..7) are normally connected to a
biased differential data source. The GX9533 inputs are not self biased, so unused inputs
should be connected as shown in Figure 3-1 or Figure 3-2.
V_CC
IN_x
GX9533
IN_x
1k
Figure 3-1: Preferred Termination Of Unused Inputs
V_CC
IN_X
GX9533
NC
IN_X
Figure 3-2: Alternate Termination of Unused Inputs
Terminating the inputs as shown in Figure 3-1 will provide the highest noise immunity,
since there is no possibility of noise coupling into the unconnected input pin.
3.2 I/O Address Selection
The GX9533 has a versatile LOAD/CONFIGURE architecture which simplifies IN/OUT
switch configuration.
An output is normally connected to an input by a two stage process:
3.2.1 Stage One: Loading the Configuration Into Latches
1. The output address is selected on the OA pins as shown in Table 3-1.
2. The input address is selected on the IA pins as shown in Table 3-2.
3. A LOAD pulse then transfers the output and input addresses into the GX9533 LOAD
latch.
The above three steps can be repeated up to eight times in order to configure the latch
for all eight outputs.
GX9533 Serial Digital 8x9 Crosspoint
Data Sheet
8494 - 4
November 2009
9 of 15
Proprietary & Confidential