AD7156 Ultralow Power, 1.8 V, 3 mm × 3 mm, 2-Channel Capacitance Converter

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

Features and Benefits

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)

Analog to Digital Converters

Data Sheets

Document	note
AD7156: Ultralow Power, 1.8 V, 3 mm × 3 mm, 2-Channel Capacitance Converter Data Sheet (Rev. 0)	PDF 527 kB

Application Notes

Document	note
AN-1048: AD7150 On-Chip Noise Filter (Rev. 0)	PDF 92 kB

Frequently Asked Questions

Document	note

Order Information

Part Number	Package	Packing Qty	Temp Range	Price 100-499	Price 1000+	RoHS
AD7156BCPZ-REEL Production	10 ld LFCSP (3x3mm)	REEL 5000	-40 to 85C	0	1.25	Y
AD7156BCPZ-REEL7 Production	10 ld LFCSP (3x3mm)	REEL 1500	-40 to 85C	0	1.25	Y

Evaluation Boards

Part Number	Description	Price	RoHS
EVAL-AD7156EBZ	Evaluation Board	59	Y

Reference Materials

Technical Articles：MS-2210: Designing Power Supplies for High Speed ADC

AD7156: Ultralow Power, 1.8 V, 3 mm × 3 mm, 2-Channel Capacitance Converter Data Sheet (Rev. 0) ad7156

AN-1048: AD7150片内噪声滤波器 (Rev. 0) ad7150

AN-1048: AD7150 On-Chip Noise Filter (Rev. 0) ad7150

MS-2210：高速ADC的电源设计 ad9861