TDA6920 Datasheet, PDF (7/20 Pages) Siemens Semiconductor Group – 7 x 5 Video Matrix Switch

TDA 6920
2
Functional Description
The main function of the IC is to switch 7 input video sources to 5 outputs.
Each output can be switched to only one input.
It is possible to have the same input connected to several outputs.
3 of the inputs can be used as non-clamping-input, switching is controlled by bus.
The clamping function of the other 4 inputs can be overriden by external resistor divider.
The other 4 inputs can be switched to non-clamping mode with external R/C network.
All switching possibilities are controlled by the I²C Bus.
All outputs can be switched to low impedance off condition by the I²C Bus.
Driving 75 Ω load requires external transistors for best performance.
The recommended coupling capacitor at each input is 47 nF.
Each clamping input requires a 75 Ω (max. 500 Ω) termination resistor.
Operation without or with a termination resistor greater than 500 Ω causes malfunction
of the new high performance clamping circuit.
Unused inputs should be directly grounded.
6 × 8 bits are necessary to determine one complete configuration change.
(1 addressbyte, 5 databytes)
Minimum configuration change for 1 output needs 2 × 8 bit (1 addressbyte, 1 databyte).
Power on reset state: all 5 outputs switched to input 1, all inputs clamped, Y+C off.
q Address Selection (fast I²C Bus)
1st byte of transmisson (8 bit)
Hex
Binary
MSB
LSB
96
1001
0110
94
1001
0100
Address Pin
V_CC (min. 3 V)
GND
Semiconductor Group
7