AD7156

Rev. 0 | Page 7 of 28

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

SDA

10

SCL

9

OUT2

8

OUT1

7

EXC1

6

AD7156

TOP VIEW

(Not to Scale)

NOTES

1. THE EXPOSED PAD MUST BE CONNECTED TO

GND OR IT MUST BE ISOLATED (FLOATING).

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

GND

Ground Pin.

2

VDD

Power Supply Voltage. This pin should be decoupled to GND using a low impedance capacitor, such as a

0.1 μF X7R multilayer ceramic capacitor.

3

CIN2

CDC Capacitive Input Channel 2. The measured capacitance (sensor) is connected between the EXC2 pin and

the CIN2 pin. If not used, this pin can be left open circuit or be connected to GND. When a conversion is

performed on Channel 2, the CIN2 pin is internally connected to a high impedance input of the Σ-Δ

modulator. When a conversion is performed on the other channel or in idle mode

or power-down mode,

the CIN2 pin is internally disconnected and left floating by the part.

4

CIN1

CDC Capacitive Input Channel 1. The measured capacitance (sensor) is connected between the EXC1 pin and

the CIN1 pin. If not used, this pin can be left open circuit or be connected to GND. When a conversion is

performed on Channel 1, the CIN1 pin is internally connected to a high impedance input of the Σ-Δ

modulator. When a conversion is performed on the other channel or in idle mode

or power-down mode,

the CIN1 pin is internally disconnected and left floating by the part.

5

EXC2

CDC Excitation Output Channel 2. The measured capacitance is connected between the EXC2 pin and the

CIN2 pin. If not used, this pin should be left as an open circuit. When a conversion is performed on Channel 2,

the EXC2 pin is internally connected to the output of the excitation signal driver. When a conversion is per-

formed on the other channel or in idle mode or power-

down mode, the EXC2 pin is internally connected

to GND.

6

EXC1

CDC Excitation Output Channel 1. The measured capacitance is connected between the EXC1 pin and the

CIN1 pin. If not used, this pin should be left as an open circuit. When a conversion is performed on Channel 1,

the EXC1 pin is internally connected to the output of the excitation signal driver. When a conversion is per-

formed on the other channel or in idle mode or power-

down mode, the EXC1 pin is internally connected

to GND.

7

OUT1

Logic Output Channel 1. A high level on this output indicates proximity detected on CIN1.

8

OUT2

Logic Output Channel 2. A high level on this output indicates proximity detected on CIN2.

9

SCL

Serial Interface Clock Input. This pin connects to the master clock line and requires a pull-up resistor if not

provided elsewhere in the system.

10

SDA

Serial Interface Bidirectional Data. This pin connects to the master data line and requires a pull-up resistor if

not provided elsewhere in the system.