Data Sheet

AD7887

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

CS

1

GND

3

SCLK

8

DOUT

7

DIN

6

AIN0

5

AD7887

TOP VIEW

(Not to Scale)

CS

1

GND

3

SCLK

8

DOUT

7

DIN

6

AIN0

5

AD7887

TOP VIEW

(Not to Scale)

Figure 3. SOIC_N Pin Configuration

Figure 4. MSOP Pin Configuration

Table 4. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

CS

Chip Select. Active low logic input. This input provides the dual function of initiating conversions on the AD7887

and also frames the serial data transfer. When the AD7887 operates in its default mode, the CS pin also acts as

the shutdown pin such that with the CS pin high, the AD7887 is in its power-down mode.

2

two-channel operation, this pin also provides the reference source for the part.

3

GND

Ground Pin. This pin is the ground reference point for all circuitry on the AD7887. In systems with separate AGND

and DGND planes, these planes should be tied together as close as possible to this GND pin. Where this is not

possible, this GND pin should connect to the AGND plane.

4

Analog Input 1/Voltage Reference Input. In single-channel mode, this pin becomes the reference input/output.

In this case, the user can either access the internal 2.5 V reference or overdrive the internal reference with the

channel mode, this pin provides the second analog input channel, AIN1. The input voltage range on AIN1 is

5

AIN0

6

DIN

Data In. Logic Input. Data to be written to the AD7887’s control register is provided on this input and clocked into

the register on the rising edge of SCLK (see the Control Register section). The AD7887 can be operated as a

single-channel, read-only ADC by tying the DIN line permanently to GND.

7

DOUT

Data Out. Logic output. The conversion result from the AD7887 is provided on this output as a serial data stream.

The bits are clocked out on the falling edge of the SCLK input. The data stream consists of four leading zeros

followed by the 12 bits of conversion data, which is provided MSB first.

8

SCLK

Serial Clock. Logic input. SCLK provides the serial clock for accessing data from the part and writing serial data to

the control register. This clock input is also used as the clock source for the AD7887’s conversion process.

Rev. E | Page 7 of 24