AD7147ACPZ-1500RL7 Analog Devices Inc, AD7147ACPZ-1500RL7 Datasheet - Page 21

• Manufacturer Part Number: AD7147ACPZ-1500RL7
• Description: IC, CDC, 16BIT, 111SPS, LFCSP-24
• Manufacturer: Analog Devices Inc
• Series: CapTouch™r
• Type: Capacitive Sensor Controllerr

Specifications of AD7147ACPZ-1500RL7

• Resolution (bits): 16bit
• Input Channel Type: Single Ended
• Data Interface: Serial, SPI
• Supply Voltage Range - Digital: 1.65V To 3.6V
• Supply Current: 900µA
• Digital Ic Case Style: CSP
• No. Of Pins: 24
• 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
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-AD7147EBZ - BOARD EVAL FOR AD7147ACPZEVAL-AD7147-1EBZ - BOARD EVAL FOR AD7147ACPZ-1
• Sampling Rate (per Second): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: AD7147ACPZ-1500RL7TR

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