AD7719 Ver la hoja de datos (PDF) - Analog Devices

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AD7719

Low Voltage, Low Power, Factory-Calibrated 16-/24-Bit Dual Σ-Δ ADC

Analog Devices 

AD7719

The serial interface can be reset by exercising the RESET input

on the part. It can also be reset by writing a series of 1s on the

DIN input. If a logic 1 is written to the AD7719 DIN line for at

least 32 serial clock cycles, the serial interface is reset. This ensures

that in 3-wire systems, if the interface gets lost, either via a software

error or by some glitch in the system, it can be reset back to a

known state. This state returns the interface to where the AD7719

is expecting a write operation to its Communications register. This

operation resets the contents of all registers to their power-on

reset values.

Some microprocessor or microcontroller serial interfaces have a

single serial data line. In this case, it is possible to connect the

AD7719’s DATA OUT and DATA IN lines together and connect

them to the single data line of the processor. A 10 kΩ pull-up

resistor should be used on this single data line. In this case, if the

interface gets lost, because the read and write operations share

the same line, the procedure to reset it to a known state is

somewhat different than previously described. It requires a read

operation of 24 serial clocks followed by a write operation where

a logic 1 is written for at least 32 serial clock cycles to ensure

that the serial interface is back in a known state.

PIN CONFIGURATION

IOUT1 1

28 XTAL1

IOUT2 2

27 XTAL2

AVDD 3

AGND 4

26 DVDD

25 DGND

REFIN1(–)

REFIN1(+)

AIN1

5 AD7719 24 DIN

6 TOP VIEW 23 DOUT

7 (Not to Scale) 22 RDY

AIN2 8

21 CS

AIN3 9

20 SCLK

AIN4 10

19 RESET

AIN5 11

18 P1/SW1

AIN6 12

17 PWRGND

REFIN2 13

16 P2/SW2

P4 14

15 P3

Pin No. Mnemonic

1

IOUT1

2

IOUT2

3

AVDD

4

AGND

5

REFIN1(–)

6

REFIN1(+)

7

AIN1

8

AIN2

9

AIN3

10

AIN4

11

AIN5

12

AIN6

13

REFIN2

14

P4

15

P3

REV. A

PIN FUNCTION DESCRIPTIONS

Function

Output for Internal 200 µA Excitation Current Source. Current source IEXC1 and/or IEXC2 can be

switched to this output.

Output for Internal 200 µA Excitation Current Source. Current source IEXC1 and/or IEXC2 can be

switched to this output.

Analog Supply Voltage.

Analog Ground.

Negative Reference Input for Main ADC Channel. This reference input can lie anywhere between AGND

and AVDD – 1 V.

Positive Reference Input for Main ADC Channel. REFIN1(+) can lie anywhere between AVDD and

AGND + 1 V. The nominal reference voltage (REFIN1(+) – REFIN1(–)) is 2.5 V, but the part is functional

with a reference range from 1 V to AVDD.

Analog Input. AIN1 is dedicated to the main channel.

Analog Input. AIN2 is dedicated to the main channel.

Analog Input. AIN3 can be multiplexed to either the main or auxiliary channel.

Analog Input. AIN4 can be multiplexed to either the main or auxiliary channel.

Analog Input. AIN5 is dedicated to the auxiliary channel and is referenced to AIN6 or AGND.

Analog Input. AIN6 is dedicated to the auxiliary channel. It forms a differential input pair with AIN5 in

fully differential input mode or is referenced to AGND in pseudodifferential mode.

Single-Ended Reference Input for Auxiliary Channel. The nominal input reference is 2.5 V. The auxiliary

channel will function with an input reference range from 1 V to AVDD.

General-Purpose I/O Bit. The input and output voltage levels are referenced to AVDD and AGND.

General-Purpose I/O Bit. The input and output voltage levels are referenced to AVDD and AGND.

–9–

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