AD7147PACPZ-1RL Analog Devices Inc, AD7147PACPZ-1RL Datasheet - Page 21

• Manufacturer Part Number: AD7147PACPZ-1RL
• Description: CAPACITANCE TO DIGITAL CONVERTER
• Manufacturer: Analog Devices Inc
• Series: CapTouch™r
• Type: Capacitive Sensor Controllerr

Specifications of AD7147PACPZ-1RL

• Resolution (bits): 16 b
• Data Interface: I²C, Serial
• Voltage Supply Source: Single Supply
• Voltage - Supply: 2.6 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-LFCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sampling Rate (per Second): -
• Lead Free Status / Rohs Status: Compliant

FF_SKIP_CNT
The proximity detection fast FIFO is used by the on-chip logic
to determine if proximity is detected. The fast FIFO expects to
receive samples from the converter at a set rate. FF_SKIP_CNT
is used to normalize the frequency of the samples going into the
FIFO, regardless of how many conversion stages are in a sequence.
In Register 0x002, Bits[3:0] are the fast filter skip control,
FF_SKIP_CNT. This value determines which CDC samples
are not used (skipped) by the proximity detection fast FIFO.
Table 13. FF_SKIP_CNT Settings
FF_SKIP
_CNT
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Decimation = 64
0.768 × (SEQUENCE_STAGE_NUM + 1) ms
1.536 × (SEQUENCE_STAGE_NUM + 1) ms
2.3 × (SEQUENCE_STAGE_NUM + 1) ms
3.072 × (SEQUENCE_STAGE_NUM + 1) ms
3.84 × (SEQUENCE_STAGE_NUM + 1) ms
4.6 × (SEQUENCE_STAGE_NUM + 1) ms
5.376 × (SEQUENCE_STAGE_NUM + 1) ms
6.144 × (SEQUENCE_STAGE_NUM + 1) ms
6.912 × (SEQUENCE_STAGE_NUM + 1) ms
7.68 × (SEQUENCE_STAGE_NUM + 1) ms
8.448 × (SEQUENCE_STAGE_NUM + 1) ms
9.216 × (SEQUENCE_STAGE_NUM + 1) ms
9.984 × (SEQUENCE_STAGE_NUM + 1) ms
10.752 × (SEQUENCE_STAGE_NUM + 1) ms
11.52 × (SEQUENCE_STAGE_NUM + 1) ms
12.288 × (SEQUENCE_STAGE_NUM + 1) ms
Decimation = 128
1.536 × (SEQUENCE_STAGE_NUM + 1) ms
3.072 × (SEQUENCE_STAGE_NUM + 1) ms
4.608 × (SEQUENCE_STAGE_NUM + 1) ms
6.144 × (SEQUENCE_STAGE_NUM + 1) ms
7.68 × (SEQUENCE_STAGE_NUM + 1) ms
9.216 × (SEQUENCE_STAGE_NUM + 1) ms
10.752 × (SEQUENCE_STAGE_NUM + 1) ms
12.288 × (SEQUENCE_STAGE_NUM + 1) ms
13.824 × (SEQUENCE_STAGE_NUM + 1) ms
15.36 × (SEQUENCE_STAGE_NUM + 1) ms
16.896 × (SEQUENCE_STAGE_NUM + 1) ms
18.432 × (SEQUENCE_STAGE_NUM + 1) ms
19.968 × (SEQUENCE_STAGE_NUM + 1) ms
21.504 × (SEQUENCE_STAGE_NUM + 1) ms
23.04 × (SEQUENCE_STAGE_NUM + 1) ms
24.576 × (SEQUENCE_STAGE_NUM + 1) ms
Rev. B | Page 21 of 72
FAST FIFO Update Rate
Determining the FF_SKIP_CNT value is required only once
during the initial setup of the capacitance sensor interface.
Table 13 shows how FF_SKIP_CNT controls the update rate of
the fast FIFO. The recommended value for the setting when
using all 12 conversion stages on the AD7147 is 0000, or no
samples skipped.
Decimation = 256
3.072 × (SEQUENCE_STAGE_NUM + 1) ms
6.144 × (SEQUENCE_STAGE_NUM + 1) ms
9.216 × (SEQUENCE_STAGE_NUM + 1) ms
12.288 × (SEQUENCE_STAGE_NUM + 1) ms
15.36 × (SEQUENCE_STAGE_NUM + 1) ms
18.432 × (SEQUENCE_STAGE_NUM + 1) ms
21.504 × (SEQUENCE_STAGE_NUM + 1) ms
24.576 × (SEQUENCE_STAGE_NUM + 1) ms
27.648 × (SEQUENCE_STAGE_NUM + 1) ms
30.72 × (SEQUENCE_STAGE_NUM + 1) ms
33.792 × (SEQUENCE_STAGE_NUM + 1) ms
36.864 × (SEQUENCE_STAGE_NUM + 1) ms
39.936 × (SEQUENCE_STAGE_NUM + 1) ms
43.008 × (SEQUENCE_STAGE_NUM + 1) ms
46.08 × (SEQUENCE_STAGE_NUM + 1) ms
49.152 × (SEQUENCE_STAGE_NUM + 1) ms
AD7147