DS90UB914ATRHSTQ1 Datasheet, PDF (44/68 Pages) Texas Instruments – DS90UB913A-Q1/DS90UB914A-Q1 25 to100 MHz 10/12-Bit

DS90UB913A-Q1, DS90UB914A-Q1
SNLS443A – MAY 2013 – REVISED JUNE 2013
1.8V
10k
MODE
R_MODE
Deserializer
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Figure 29. Mode Pin Configuration on DS90UB914A-Q1 Deserializer
Table 8. DS90UB914A-Q1 Deserializer MODE Resistor Value
DS90UB914A-Q1 Deserializer MODE resistor Value
MODE Select
12-bit low frequency mode 25-50 MHz PCLK, 10/12-bits DATA+ 2 SYNC.
Note: No HS/VS restrictions (raw).
12-bit high frequency mode 25-75 MHz PCLK, 10/12-bits DATA+ 2 SYNC.
Note: No HS/VS restrictions (raw).
10-bit mode 25–100 MHz PCLK, 10-bits DATA+ 2 SYNC.
Note: HS/VS restricted to no more than one transition per 10 PCLK cycles.
R_MODE Resistor Value
0kΩ
3kΩ
11kΩ
Line Rate Calculations for the DS90UB913A/914A
The DS90UB913A-Q1 device divides the clock internally by divide-by-1 in the 12-bit low frequency mode, by
divide-by-2 in the 10-bit mode and by divide-by-1.5 in the 12-bit high frequency mode. Conversely, the
DS90UB914A-Q1 multiplies the recovered serial clock to generate the proper pixel clock output frequency. Thus
the maximum line rate in the three different modes remains 1.4Gbps. The following are the formulae used to
calculate the maximum line rate in the different modes:
• For the 12-bit low frequency mode, Line rate = f_PCLK*28; e.g. f_PCLK = 50MHz, line rate = 50*28 = 1.4Gbps
• For the 12-bit high frequency mode, Line rate = f_PCLK*(2/3)*28; e.g. f_PCLK = 75MHz, line rate = (75)*(2/3)*28 =
1.4Gbps
• For the 10-bit mode, Line rate = f_PCLK/2*28; e.g. f_PCLK = 100MHz, line rate = (100/2)*28 = 1.4Gbps
Deserializer Multiplexer Input
The DS90UB914A-Q1 offers a 2:1 multiplexer that can be used to select which camera is used as the input.
Figure 30 shows the operation of the 2:1 multiplexer in the Deserializer. The selection of the camera can be pin
controlled as well as register controlled. Both the Deserializer inputs cannot be enabled at the same time. If the
Serializer A is selected as the active Serializer, the back-channel for Deserializer A turns ON and vice versa. To
switch between the two cameras, first the Serializer B has to be selected using the SEL pin/register on the
Deserializer. After that the back channel driver for Deserializer B has to be enabled using the register in the
Deserializer.
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