AD7873

Rev. D | Page 7 of 28

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

AD7873

TOP VIEW

(Not to Scale)

1

2

3

4

12

11

10

9

16 15 14 13

56

7

8

PIN 1

INDICATOR

AUX

PENIRQ

Y+

X+

DCLK

Figure 3. LFCSP Pin Configuration

1

2

3

4

5

6

7

10

8

9

11

12

13

14

15

16

AD7873

TOP VIEW

(Not to Scale)

X+

Y+

X–

Y–

GND

AUX

DCLK

CS

DIN

BUSY

DOUT

PENIRQ

Figure 4.QSOP/TSSOP Pin Configuration

Table 4. Pin Function Descriptions

Mnemonic

Function

together.

X+

X+ Position Input. ADC Input Channel 1.

Y+

Y+ Position Input. ADC Input Channel 2.

X–

X– Position Input.

Y–

Y– Position Input. ADC Input Channel 3.

GND

Analog Ground. Ground reference point for all circuitry on the AD7873. All analog input signals and any external reference

signals should be referred to this GND voltage.

Battery Monitor Input. ADC Input Channel 4.

AUX

Auxiliary Input. ADC Input Channel 5.

Reference Output for the AD7873. Alternatively an external reference can be applied to this input. The voltage range for the

available on this pin for use external to the device. The reference output must be buffered before it is applied elsewhere in a

system. A 0.1 µF capacitor is recommended between this pin and GND to reduce system noise effects.

PENIRQ

Pen Interrupt. CMOS logic open drain output (requires 10 kΩ to 100 kΩ pull-up resistor externally).

DOUT

Data Out. Logic Output. The conversion result from the AD7873 is provided on this output as a serial data stream. The bits are

clocked out on the falling edge of the DCLK input. This output is high impedance when CS is high.

BUSY

BUSY Output. Logic Output. This output is high impedance when CS is high.

DIN

Data In. Logic Input. Data to be written to the AD7873 control register is provided on this input and is clocked into the

register on the rising edge of DCLK (see the Control Register section).

CS

Chip Select Input. Active Low Logic Input. This input provides the dual function of initiating conversions on the AD7873 and

enabling the serial input/output register.

DCLK

External Clock Input. Logic Input. DCLK provides the serial clock for accessing data from the part. This clock input is also used

as the clock source for the AD7873 conversion process.