AD7888 Ver la hoja de datos (PDF) - Analog Devices

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componentes Descripción

Fabricante

AD7888

2.7 V to 5.25 V, Micropower, 8-Channel, 125 kSPS, 12-Bit ADC in 16-Lead TSSOP

Analog Devices 

PIN CONFIGURATIONS

SOIC AND TSSOP

CS 1

16 SCLK

REF IN/REF OUT 2

15 DOUT

VDD 3

14 DIN

AGND 4 AD7888 13 AGND

AIN1

5

TOP VIEW

(Not to Scale) 12

AIN8

AIN2 6

11 AIN7

AIN3 7

10 AIN6

AIN4 8

9 AIN5

AD7888

PIN FUNCTION DESCRIPTIONS

Pin

No. Mnemonic

1

CS

2

REF IN/REF OUT

3

VDD

4, 13 AGND

5–12 AIN1–AIN8

14 DIN

15 DOUT

16 SCLK

Function

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

the AD7888 and also frames the serial data transfer.

Reference Input/Output. The on-chip reference is available on this pin for use external to the AD7888.

Alternatively, the internal reference can be disabled and an external reference applied to this input.

The voltage range for the external reference is from 1.2 V to VDD.

Power Supply Input. The VDD range for the AD7888 is from 2.7 V to 5.25 V.

Analog Ground. Ground reference point for all circuitry on the AD7888. All analog input signals and

any external reference signals should be referred to this AGND voltage. Both of these pins should

connect to the AGND plane of a system.

Analog Input 1 through Analog Input 8. Eight single-ended analog input channels that are multiplexed

into the on-chip track/hold. The analog input channel to be converted is selected by using the ADD0

through ADD2 bits of the Control Register. The input range for all input channels is 0 to VREF. Any

unused input channels should be connected to AGND to avoid noise pickup.

Data In. Logic Input. Data to be written to the AD7888’s Control Register is provided on this input

and is clocked into the register on the rising edge of SCLK (see Control Register section).

Data Out. Logic Output. The conversion result from the AD7888 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.

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 AD7888’s

conversion process.

REV. C

–5–

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