AD7147ACPZ-1REEL Analog Devices Inc, AD7147ACPZ-1REEL Datasheet - Page 32

• Manufacturer Part Number: AD7147ACPZ-1REEL
• Description: IC,Converter, Other/Special/Miscellaneous,LLCC,24PIN
• Manufacturer: Analog Devices Inc
• Series: CapTouch™r
• Type: Capacitive Sensor Controllerr

Specifications of AD7147ACPZ-1REEL

• 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
• 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

AD7147
OUTPUTS
AC
The AD7147 measures capacitance between CINx and ground.
Any capacitance to ground on the signal path between the CINx
pins and the sensor is included in the AD7147 conversion result.
To eliminate stray capacitance to ground, the AC
be used to shield the connection between the sensor and CINx,
as shown in Figure 47. The plane around the sensors should also
be connected to AC
The AC
excitation signal on CINx. Therefore, there is no ac current
between CINx and AC
pins does not affect the CINx charge transfer.
Using AC
means that the AD7147 can be placed up to 10 cm away from
the sensors. This allows the AD7147 to be placed on a separate
PCB than that of the sensors if the connections between the
sensors and the CINx inputs are correctly shielded using
AC
GENERAL-PURPOSE INPUT/OUTPUT (GPIO)
The AD7147 has one GPIO pin. It can be configured as an input or
an output. The GPIO_SETUP Bits[13:12] in the interrupt enable
register determine how the GPIO pin is configured.
Table 16. GPIO_SETUP Bits
GPIO_SETUP
00
01
10
11
SHIELD
SHIELD
SHIELD
.
SHIELD
OUTPUT
output is the same signal waveform as the
eliminates capacitance-to-ground pickup, which
SHIELD
SHIELD
.
Figure 47. AC
GPIO Configuration
GPIO disabled
Input
Output low
Output high
, and any capacitance between these
SHIELD
CIN0
CIN1
CIN2
CIN3
SHIELD
AC
SHIELD
signal should
AD7147
GND
Rev. B | Page 32 of 72
When the GPIO is configured as an output, the voltage level on
the pin is set to either a low level or a high level, as defined by
the GPIO_SETUP bits (see Table 16).
The GPIO_INPUT_CONFIG bits in the interrupt enable
register determine the response of the AD7147 to a signal on
the GPIO pin when the GPIO is configured as an input. The
GPIO can be configured as either active high or active low, as
well as either edge triggered or level triggered (see Table 17).
Table 17. GPIO_INPUT_CONFIG Bits
GPIO_INPUT_CONFIG
00
01
10
11
When GPIO is configured as an input, it triggers the interrupt
output on the AD7147. Table 15 lists the interrupt output
behavior for each of the GPIO configuration setups.
USING THE GPIO TO TURN ON/OFF AN LED
The GPIO on the AD7147 can be used to turn on and off an
LED by setting the GPIO as either output high or low. Setting
the GPIO output high turns on the LED; setting the GPIO
output low turns off the LED. The GPIO pin connects to a
transistor that provides the drive current for the LED. Suitable
transistors include the KTC3875 from Korea Electronics Co.,
Ltd. (KEC).
Figure 48. Controlling an LED Using the GPIO
AD7147
GPIO
GPIO Configuration
Triggered on negative level (active low)
Triggered on positive edge (active high)
Triggered on negative edge (active low)
Triggered on positive level (active high)
OR SIMILAR
KTC3875
V
CC