EVAL-AD7147EBZ 查看數據表（PDF） - Analog Devices
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EVAL-AD7147EBZ
Analog Devices
EVAL-AD7147EBZ Datasheet PDF : 69 Pages
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CapTouch Programmable Controller for
Single-Electrode Capacitance Sensors
AD7147A
FEATURES
Programmable capacitance-to-digital converter (CDC)
Femtofarad (fF) resolution
13 capacitance sensor inputs
9 ms update rate, all 13 sensor inputs
No external RC components required
Automatic conversion sequencer
On-chip automatic calibration logic
Automatic compensation for environmental changes
Automatic adaptive threshold and sensitivity levels
Register map is compatible with the AD714x
On-chip RAM to store calibration data
Serial peripheral interface (SPI) (AD7147A)
I2C-compatible serial interface (AD7147A-1)
Separate VDRIVE level for serial interface
Interrupt output and general-purpose input/output (GPIO)
25-ball, 2.3 mm × 2.1 mm WLCSP
2.6 V to 3.6 V supply voltage
Low operating current
Full power mode: 1 mA
Low power mode: 28.96 μA
APPLICATIONS
Cell phones
Personal music and multimedia players
Smart handheld devices
Television, A/V, and remote controls
Gaming consoles
Digital still cameras
GENERAL DESCRIPTION
The AD7147A CapTouch™ controller is designed for use with
capacitance sensors implementing functions such as buttons,
scroll bars, and wheels. The sensors need only one PCB layer,
enabling ultrathin applications.
The AD7147A is an integrated CDC with on-chip environmen-
tal calibration. The CDC has 13 inputs channeled through a
switch matrix to a 16-bit, 250 kHz sigma-delta (Σ-Δ) converter.
The CDC is capable of sensing changes in the capacitance of the
external sensors and uses this information to register a sensor
activation. By programming the registers, the user has full control
over the CDC setup.
High resolution sensors require minor software to run on the
host processor and may require two PCB layers.
CIN0 D3
CIN1 A3
CIN2 B3
CIN3 A4
CIN4 C3
CIN5 A5
CIN6 B4
CIN7 B5
CIN8 C4
CIN9 C5
CIN10 D4
CIN11 D5
CIN12 E5
FUNCTIONAL BLOCK DIAGRAM
ACSHIELD VCC GND
E4
D2
E2
BIAS
E3
POWER-ON
RESET LOGIC
EXCITATION
SOURCE
AD7147A
CALIBRATION
RAM
16-BIT
Σ-Δ
CDC
CALIBRATION
ENGINE
CONTROL
AND DATA
REGISTERS
VDRIVE C2
SERIAL INTERFACE
AND CONTROL LOGIC
INTERRUPT
AND GPIO
LOGIC
B2 TP
A2 GPIO
E1
D1
C1
B1
A1
SDO SDI SCLK CS
INT
(SDA) (ADD0)
(ADD1)
NOTES
1. PIN NAMES IN PARENTHESES ARE FOR THE AD7147A-1.
Figure 1.
The AD7147A is designed for single electrode capacitance
sensors (grounded sensors). There is an active shield output to
minimize noise pickup in the sensor.
The AD7147A has on-chip calibration logic to compensate for
changes in the ambient environment. The calibration sequence
is performed automatically and at continuous intervals as long
as the sensors are not touched. This ensures that there are no
false or nonregistering touches on the external sensors due to a
changing environment.
The AD7147A has an SPI-compatible serial interface, and the
AD7147A-1 has an I2C®-compatible serial interface. Both parts
have an interrupt output, as well as a GPIO. There is a VDRIVE pin
to set the voltage level for the serial interface independent of VCC.
The AD7147A is available in a 25-ball, 2.3 mm × 2.1 mm
WLCSP and operates from a 2.6 V to 3.6 V supply. The operating
current consumption in low power mode is typically 28.96 μA
for 13 sensors.
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.
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