CDK8307 Cadeka Microcircuits LLC., CDK8307 Datasheet - Page 24

• Manufacturer Part Number: CDK8307
• Description: 12/13-bit, 20/40/50/65/80msps, Eight Channel, Ultra Low Power Adc With Lvds
• Manufacturer: Cadeka Microcircuits LLC.

PRELIMINARY Data Sheet
Table 16. Register Values with Corresponding Change in Full-Scale Range
Table 17. Clock Frequency
To optimize startup time a register is provided where the input clock frequency can be set. Some internal circuitry has
startup times that are frequency independent. Default counter values are set to accommodate these startup times at
the maximum clock frequency. This will lead to increased startup times at low clock frequency. Setting the value of this
register to the nearest higher clock frequency will reduce the count values of the internal counters, to better fit the actual
startup time, such that the startup time will be reduced.
Table 18. Clock Frequency Settings
Table 19. Performance Control
There are two registers that impact performance and power dissipation.
The perfm_cntrl register adjusts the performance level of the ADC core. If full performance is required, the nominal
setting must be used. The lowest code can be used in situations where power dissipation is critical and performance is
less important. For most conditions the performance at the minimum setting will be similar to nominal setting. However,
only 10-bit performance can be expected at worst case conditions. The power dissipation savings shown in Table 20 are
only approximate numbers for the ADC current alone.
©2009 CADEKA Microcircuits LLC
clk_freq<1:0>
perfm_
cntrl<2:0>
ext_vcm_
bc<1:0>
Name
Name
clk_freq <1:0>
fs_cntrl <5:0>
111111
100001
100000
011111
000000
00
01
10
11
...
...
Input clock frequency
ADC performance control
VCM buffer driving strength
control
Description
Description
Full-Scale Range Adjustment
Clock Frequency (MHz)
65MHz
Nominal
Nominal
Default
Default
+9.7%
+0.3%
-0.3%
-10%
+0%
65
45
30
20
...
...
5
5
D
1
D
1
D
1
4
D
1
4
D
3
D
3
1
1
D
1
2
D
1
2
D
1
D
1
1
1
D
1
0
D
1
0
D
9
D
9
D
D
8
8
D
7
D
7
D
D
6
6
D
5
D
5
X X
D
4
D
4
D
D
3
3
D
2
D
2
X X X
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D
D
1
X X
1
D
0
D
0
Address
Address
In Hex
In Hex
56
50
24