• Visit our detailed system design support and FAQ page.
• View our Touch Control Demo.
• AD7142 web seminar: Design and Develop Innovative and Robust Touch Sensor Interfaces Using Capacitive-to-Digital Converters.

The AD7142 and AD7142-1 are integrated capacitance-to-digital converters (CDCs) with on-chip environmental calibration for use in systems requiring a novel user input method. The AD7142 and AD7142-1 can interface to external capacitance sensors implementing functions such as capacitive buttons, scroll bars, or wheels.

The CDC has 14 inputs channeled through a switch matrix to a 16-bit, 250 kHz sigma-delta (∑-Δ) capacitance-to-digital converter. The CDC is capable of sensing changes in the capacitance of the external sensors and uses this information to register a sensor activation. The external sensors can be arranged as a series of buttons, as a scroll bar or wheel, or as a combination of sensor types. 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.

The AD7142 and AD7142-1 have on-chip calibration logic to account for changes in the ambient environment. The calibration sequence is performed automatically and at continuous intervals, when 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 AD7142 has an SPI-compatible serial interface, and the AD7142-1 has an I²C-compatible serial interface. Both parts have an interrupt output, as well as a general-purpose input/ output (GPIO).

The AD7142 and AD7142-1 are available in a 32-lead, 5 mm × 5 mm LFCSP_VQ and operate from a 2.6 V to 3.6 V supply. The operating current consumption is less than 1 mA, falling to 50 μA in low power mode (conversion interval of 400 ms).

Applications

• Personal music and multimedia players
• Cell phones
• Digital still cameras
• Smart hand-held devices
• Television, A/V, and remote controls
• Gaming consoles

Data Sheet, Rev. A, 1/07

Part#	Resolution (Bits)	T-Put Rate	# Chan	Supply V	Pwr Diss (max)	Input Base C (pF Max)	Cin Range (pF)	Pkg Type	Price* (1000-4999)	Product Description	Interface
AD7142	16	27.8SPS	14	Single(+2.6 to +3.6), Single(+2.7), Single(+3), Single(+3.3)	3.6mW	20	±2	CSP	$1.35	CAPTouch (TM) Programmable Controller for 2-Electrode Capacitance Sensor with SPI or I2C Interface	I²C/Ser 2-Wire, Ser, SPI
AD7143	16	43.5SPS	8	Single(+2.6 to +3.6)	3.6mW	20	±2	CSP	$1.24	CAPTouch (TM) Programmable Controller for 2-Electrode Capacitance Sensor with I2C Interface	I²C/Ser 2-Wire, Ser
AD7147	16	111SPS	13	Single(+3), Single(+3.3)	3.6mW	20	±8	CSP	$1.30	CAPTouch (TM) Programmable Controller w/ SPI or I2C Interface for Single-Electrode Cap Sensors	I²C/Ser 2-Wire, Ser, SPI
AD7150	12	100SPS	2	Single(+2.7 to +3.6)	0.43mW	10	±4	SOP	$1.35	Ultra-Lo Pwr, 2-Ch Capacitance Converter for Proximity Sensing Applications	I²C/Ser 2-Wire, Ser
AD7151	12	100SPS	1	Single(+2.7 to +3.6)	0.3mW	10	±4	SOP	$1.35	Ultra-Low Power, 1-Ch, Capacitance Converter for Proximity Sensing Applications	I²C/Ser 2-Wire, Ser
AD7745	24	90SPS	1	Single(+2.7 to +5.25)	4.25mW	17	±4	SOP	$4.60	24-Bit, Cap-to-Dig Conv. w/ 1 SE/Diff Capacitive Input Ch for Interface to Dual Electrode Cap Sensor	I²C/Ser 2-Wire, Ser
AD7746	24	90SPS	2	Single(+2.7 to +5.25)	4.25mW	17	±4	SOP	$4.95	24-bit, Cap-to-Dig Conv. w/ 2 SE/Diff Capacitive Input Ch for interface to Dual Electrode Cap Sensor	I²C/Ser 2-Wire
AD7747	24	45.5SPS	1	Single(+2.7 to +5.25)	4.25mW	17	±8	SOP	$4.60	24-bit, Cap-to-Dig Conv w/1 SE/Diff Capacitive Input Ch for interface to Single Electrode Cap Sensor	I²C/Ser 2-Wire, Ser

* The pricing listed here is provided only for budgetary purposes as recommended list price in U.S. Dollars in the United States ex factor per unit for the stated volume. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
** Pricing is currently unavailable. Click on the product number to see the Product Page for additional information.

The model number is a specific version of a generic that can be purchased or sampled.

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• Pre-Release: The model has not been released to general production, but samples may be available.
• Production: The model is currently being produced, and generally available for purchase and sampling.
• Last Time Buy: The model has been scheduled for obsolescence, but may still be purchased for a limited time.
• Obsolete: The specific part is obsolete and no longer available. Other models listed in the table may still be available (if they have a status that is not obsolete).

The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

For detailed drawings and chemical composition please consult our  Package Site

Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

This is the acceptable operating range of the device. The various ranges specified are as follows:

• Commercial: 0 to +70 degrees Celsius
• Military : -55 to +125 degrees Celsius
• Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
• Automotive: -40 to +125 degrees Celsius

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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