AD7156

PRODUCTION

Ultralow Power, 1.8 V, 3 mm × 3 mm, 2-Channel Capacitance Converter

Data Sheet (Rev. 0) Product Selection Table

Part Models: 2
1ku List Price: Starting From $1.66

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Overview

Ultralow power
Power supply voltage: 1.8 V to 3.6 V
Operation power supply current: 70 μA typical
Power-down current: 2 μA typical
Fast response time
Conversion time: 10 ms per channel
Wake-up time from serial interface: 300 μs
Adaptive environmental compensation
2 capacitance input channels
Sensor capacitance (C_SENS): 0 pF up to 13 pF
Sensitivity up to 3 fF

2 modes of operation
Standalone with fixed settings
Interfaced to a microcontroller for user-defined settings
2 detection output flags
2-wire serial interface (I²C-compatible)
Operating temperature: −40°C to +85°C
10-lead LFCSP package (3 mm × 3 mm × 0.8 mm)

The AD7156 delivers a complete signal processing solution for capacitive sensors, featuring an ultralow power converter with fast response time.

The AD7156 uses an Analog Devices, Inc., capacitance-to-digital converter (CDC) technology, which combines features important for interfacing to real sensors, such as high input sensitivity and high tolerance of both input parasitic ground capacitance and leakage current.

The integrated adaptive threshold algorithm compensates for any variations in the sensor capacitance due to environmental factors like humidity and temperature or due to changes in the dielectric material over time.

By default, the AD7156 operates in standalone mode using the fixed power-up settings and indicates detection on two digital outputs. Alternatively, the AD7156 can be interfaced to a micro-controller via the serial interface, the internal registers can be programmed with user-defined settings, and the data and status can be read from the part.

The AD7156 operates with a 1.8 V to 3.6 V power supply. It is specified over the temperature range of −40°C to +85°C.

Applications

Buttons and switches
Proximity sensing
Contactless switching
Position detection
Level detection
Portable products

Part Models: 2
1ku List Price: Starting From $1.66

Documentation

Frequently Asked Question 1

FAQ 03/20/2018

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
AD7156BCPZ-REEL	10-Lead LFCSP (3mm x 3mm)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7156BCPZ-REEL7	10-Lead LFCSP (3mm x 3mm)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

This is the most up-to-date revision of the Data Sheet.

Software Resources

Device Drivers 2

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Evaluation Kits

Study Watch 4.5 User Guide

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Features and Benefits

Device Configuration Block (DCB)
VSM Suite Library Configuration (LCFG)
Low Touch Feature

Product Details

This user guide explains the steps in connecting the ADI Study Watch 4.5 to a Microsoft Windows computer using a universal serial bus (USB) or Bluetooth low energy (BLE) for data streaming or logging, and analyzing the vital signs data using the Application Wavetool software.

ADI Vital Signs Monitoring Watch 4.5 is a product designed to showcase the capabilities of Analog Devices’ biomedical sensors and algorithms for vital sign monitoring.

The Study Watch 4.5 is a wearable, battery-powered device, which enables continuous monitoring and on-demand spot check measurement of photoplethysmography (PPG), electrocardiography (ECG, biopotential based), electrodermal activity (EDA, bioimpedance based), and skin temperature and motion/activity (based on a three-axis accelerometer). The raw sensor data can be parsed through the algorithms embedded within the watch to obtain real-time vital signs such as heart rate (HR), Oxygen saturation (SpO2), and respiration rate (RR).

Resources

EVAL-STUDYWATCH45Z User Guide: Study Watch 4.5 User Guide (Rev.0)
6/16/2025

Software

EVAL-STUDYWATCH45Z Application Wavetool
28.32 M

EVAL-STUDYWATCH45Z Android Application
32.98 M

EVAL-STUDYWATCH45Z Python SDK

AD7156 Evaluation Board

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Product Details

The EVAL-AD7156EBZ is a fully featured evaluation board for the AD7156. The evaluation board can be operated in complete standalone, battery-powered mode or connected to a PC via a standard USB interface. When operated with a PC, software is provided enabling the user to perform detailed analysis of the CDC's performance. This software includes the technical note describing the operation and set up of the evaluation board.

Resources

AD7150 IIO Capacitance to Digital Converter GitHub Linux Driver Source Code
11/9/2011

EVAL-AD7156EBZ: Evaluation Kit for AD7156 Ultralow Power Capacitance Converter
6/10/2009

Software

AD7156 Evaluation Software
290452 kB

Vital Signs Monitoring (VSM) Watch

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Features and Benefits

Vital signs monitoring platform
Wearable battery powered platform
Real-time live data view
Data storage to flash memory for offline analyses
Easy configuration

Product Details

The vital signs monitoring (VSM) watch, EVAL-HCRWATCH4Z, is a modular development, demonstration, and data collection platform for high performance vital signs monitoring applications based on Analog Devices, Inc., analog front ends (AFEs) and sensors.

The VSM watch is a wearable, battery-powered device that enables the continuous monitoring and on-demand spot check measurement of photoplethysmography (PPG), electrodermal activity (EDA, bioimpedance-based), skin temperature, electrocardiography (ECG, biopotential based), and motion/activity (based on a 3‑axis accelerometer).

The VSM watch allows synchronized, multiparameter data storage on internal memory for later data retrieval and offline analysis and/or live monitoring on a PC (Windows^® OS) or Android- or iOS-based device.