AD7764 View Datasheet(PDF) - Analog Devices

Part Name

Description

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AD7764

24-Bit, 312 kSPS, 109 dB Σ-Δ ADC with On-Chip Buffers and Serial Interface

Analog Devices 

USING THE AD7764

Step1 through Step 5 detail the sequence for powering up and

using the AD7764.

1. Apply power to the device.

2. Start the clock oscillator, applying MCLK.

3. Take RESET low for a minimum of one MCLK cycle.

4. Wait a minimum of two MCLK cycles after RESET has

been released.

5. If multiple parts are being synchronized, a SYNC pulse

must be applied to the parts. Otherwise, no SYNC pulse is

required.

When applying the SYNC pulse

• The application of a SYNC pulse to the device must

not coincide with a write to the device.

• Ensure that the SYNC pulse is taken low for a

minimum of 2.5 ICLK cycles.

AD7764

Data can then be read from the device using the default gain

and overrange threshold values. The conversion data read is not

valid, however, until the settling time of the filter has elapsed.

Once this has occurred, the FILTER-SETTLE status bit is set

indicating that the data is valid.

Values for gain and overrange thresholds can be written to or

read from the respective registers at this stage.

BIAS RESISTOR SELECTION

The AD7764 requires a resistor to be connected between the

RBIAS and AGND pins. The resistor value should be selected to

give a current of 25 μA through the resistor to ground. For a

4.096 V reference voltage, the correct resistor value is 160 kΩ.

Rev. 0 | Page 27 of 32

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