AD7147 Analog Devices User's Manual and Specifications
Summary
The AD7147 is a high-resolution Capacitance-to-Digital Converter (CDC) designed for sensing changes in capacitance using up to 13 inputs. Featuring automatic on-chip calibration and low power consumption, it provides highly accurate touch and environmental detection vital for smart devices, mobile applications, and embedded controls. This manual guides engineers through the full technical specifications, operational modes (SPI/I²C), functional block diagram, and advanced setup required for seamless integration into demanding electronics designs.
Page 1 Text Content
Cap Touch Programmable Controller for Single-Electrode Capacitance Sensors
AD7147 FEATURES FUNCTIONAL BLOCK DIAGRAM
ACSHIELD VCC GND BIAS
Programmable capacitance-to-digital converter (CDC) Femtofarad resolution
13 capacitance sensor inputs POWER-ON
19CIN0 RESET LOGIC
9 ms update rate, all 13 sensor inputs
20CIN1
No external RC components required
21CIN2
EXCITATION
Automatic conversion sequencer
SOURCE
22CIN3
On-chip automatic calibration logic
23CIN4
Automatic compensation for environmental changes
24CIN5
CALIBRATION
Automatic adaptive threshold and sensitivity levels AD7147/
1CIN6 AD7147-1
Register map is compatible with the AD7142
2CIN7
On-chip RAM to store calibration data
3CIN8 16-BIT
SPI-compatible (serial-peripheral-interface-compatible) CALIBRATION
ENGINE
4CIN9 CDC
serial interface (AD7147)
5CIN10
I2C-compatible serial interface (AD7147-1)
6CIN11 CONTROL
Separate VDRIVE level for serial interface
AND DATA
7CIN12 REGISTERS
Interrupt output and general-purpose input/output (GPIO) 24-lead, 4 mm × 4 mm LFCSP 2.6 V to 3.3 V supply voltage
Low operating current INTERRUPT
SERIAL INTERFACE
VDRIVE AND GPIO GPIO
AND CONTROL LOGIC
Full power mode: 1 m A LOGIC
SW IT Low power mode: 21.5 μA TR IX
www.BDTIC.com/ADI
APPLICATIONS SDO/ SDI/ SCLK CS/ INT SDA ADD0 ADD1
Cell phones Figure 1. Personal music and multimedia players Smart handheld devices
Television, A/V, and remote controls The AD7147 is designed for single electrode capacitance Gaming consoles sensors (grounded sensors). There is an active shield output to Digital still cameras minimize noise pickup in the sensor. The AD7147 has on-chip calibration logic to compensate for
GENERAL DESCRIPTION
changes in the ambient environment. The calibration sequence
The AD7147 Cap Touch™ controller is designed for use with
is performed automatically and at continuous intervals as long
capacitance sensors implementing functions such as buttons,
as the sensors are not touched. This ensures that there are no
scroll bars, and wheels. The sensors need only one PCB layer,
false or nonregistering touches on the external sensors due to
enabling ultrathin applications.
a changing environment.
The AD7147 is an integrated CDC with on-chip environmental
The AD7147 has an SPI-compatible serial interface, and the
calibration. The CDC has 13 inputs channeled through a switch
AD7147-1 has an I2C®-compatible serial interface. Both parts have
matrix to a 16-bit, 250 k Hz sigma-delta (∑-Δ) converter. The CDC
an interrupt output, as well as a GPIO. There is a VDRIVE pin to set
is capable of sensing changes in the capacitance of the external
the voltage level for the serial interface independent of VCC.
sensors and uses this information to register a sensor activation.
The AD7147 is available in a 24-lead, 4 mm × 4 mm LFCSP and
By programming the registers, the user has full control over the
operates from a 2.6 V to 3.6 V supply. The operating current con-
CDC setup.
sumption in low power mode is typically 26 μA for 13 sensors.
High resolution sensors require minor software to run on the host processor.
Rev. A 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
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2007–2008 Analog Devices, Inc. All rights reserved.
Page Summary Contents For AD7147 Analog Devices User's Manual and Specifications
Manual Details
| Brand | Analog Devices |
|---|---|
| Pages | 72 |
| File Size | 1.30 MB |
| Published | May 14, 2026 |
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Frequently Asked Questions
How does the chip compensate for environmental changes?
It uses on-chip calibration logic that automatically performs adjustments to compensate for ambient environment changes continuously.
What is the low power consumption rate for operation?
The operating current in low power mode is typically 21.5 μA (or 26 μA if all 13 sensors are used).
How many capacitive inputs does the AD7147 support?
It has 13 capacitance sensor inputs, suitable for functions like buttons and scroll bars.