AD7607
DIGITAL FILTER
The AD7607 contains an optional first-order digital sinc filter that
should be used in applications where slower throughput rates are
used and digital filtering is required. The oversampling ratio of
the digital filter is controlled using the oversampling pins, OS[2:0]
(see Table 9). OS 2 is the MSB control bit, and OS 0 is the LSB
control bit. Table 9 lists the oversampling bit decoding to select the
Table 9. Oversample Bit Decoding
OS[2:0]
000
001
010
011
100
101
110
111
Oversampling Ratio
No oversampling
2
4
8
16
32
64
Invalid
3 dB BW, 5 V Range (kHz)
15
15
13.7
10.3
6
3
1.5
Data Sheet
different oversample rates. The OS pins are latched on the falling
edge of BUSY. This sets the oversampling rate for the next
conversion (see Figure 43).
Selection of the oversampling mode has the effect of adding
a digital filter function after the ADC. The different oversampling
rates and the CONVST x sampling frequency produce different
digital filter frequency profiles.
3 dB BW, 10 V Range (kHz)
22
22
18.5
11.9
6
3
1.5
Maximum Throughput,
CONVST Frequency (kHz)
200
100
50
25
12.5
6.25
3.125
CONVST A
AND
CONVST B
BUSY
OS x
OVERSAMPLE RATE
LATCHED FOR CONVERSION N + 1
CONVERSION N
CONVERSION N + 1
tOS_SETUP
tOS_HOLD
Figure 43. OS x Pin Timing
Rev. B | Page 26 of 32