AD5753 datasheet(52/72 Pages) AD

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AD5753

Data Sheet

Rev. 0 | Page 52 of 72

PROGRAMMING SEQUENCE TO ENABLE THE

OUTPUT

To write to and set up the AD5753 from a power-on or reset

condition, take the following steps:

Perform a hardware or software reset and wait 100 μs.

Perform a calibration memory refresh by writing 0xFCBA to

the key register. Wait a minimum of 500 μs before proceeding

to Step 3 to allow time for the internal calibrations to

complete. As an alternative to waiting 500 μs for the refresh

cycle to complete, poll the CAL_MEM_UNREFRESHED bit

in the DIGITAL_DIAG_RESULTS register until it is 0.

Write 1 to Bit D13 in the DIGITAL_DIAG_RESULTS register

to clear the RESET_OCCURRED flag.

If the CLKOUT signal is required, configure and enable

CLKOUT via the GP_CONFIG1 register. It is important to

configure this feature before enabling the dc-to-dc converter.

Write to the DCDC_CONFIG2 register to set the dc-to-dc

current limit and enable the negative dc-to-dc converter (if

using negative DPC). Wait 300 μs to allow the 3-wire interface

communication to complete. As an alternative to waiting

300 μs for the 3-wire interface communication to complete,

poll the BUSY_3WI bit in the DCDC_CONFIG2 register

until it is 0.

Write to the DCDC_CONFIG1 register to set up the dc-to-dc

converter mode, which enables the dc-to-dc converter. Wait

300 μs to allow the 3-wire interface communication to

complete. As an alternative to waiting 300 μs for the 3-wire

interface communication to complete, poll the BUSY_3WI bit

in the DCDC_CONFIG2 register until it is 0.

Write to the DAC_CONFIG register to set the INT_EN bit,

which powers up the DAC and internal amplifiers without

enabling the channel output, and configure the output range,

internal or external RSET, and slew rate. Keep the OUT_EN

bit disabled at this point. Wait for a minimum of 500 μs

before proceeding to Step 8 to allow the internal

calibrations to complete. As an alternative to waiting 500 μs

for the internal calibrations to complete, poll the CAL_

MEM_UNREFRESHED bit in the DIGITAL_DIAG_

RESULTS register until it reads 0.

Write a zero-scale DAC code to the DAC_INPUT register.

If a bipolar range is selected in Step 7, then a DAC code

that represents a 0 mA/0 V output must be written to the

DAC_INPUT register. It is important that this step be

completed even if the contents of the DAC_INPUT register

are not changing.

If the LDAC functionality is being used, perform either a

software or hardware LDAC command.

10. Rewrite the same word, used in Step 7, to the DAC_CONFIG

of 1.25 ms to pass between Step 6 and Step 9, which is the

time from when the dc-to-dc is enabled to when the VIOUT

output is enabled.

11. Write the required DAC code to the DAC_INPUT register.

Figure 92 shows an example of a change to the programming

sequence.

Changing and Reprogramming the Range

After the output is enabled, take the following steps to change

the output range:

Write to the DAC_INPUT register. Set the output to 0 mA

or 0 V.

Write to the DAC_CONFIG register. Disable the output

(OUT_EN = 0) and set the new output range. Keep the

INT_EN bit set. Wait 500 μs minimum before proceeding

to Step 3 to allow time for internal calibrations to complete.

Write Code 0x0000 or the case of bipolar ranges, write

Code 0x8000 to the DAC_INPUT register. It is important

that this step be completed even if the contents of the DAC_

INPUT register do not change.

Reload the DAC_CONFIG register word from Step 2 and set

the OUT_EN bit to 1 to enable the output.

Write the required DAC code to the DAC_INPUT register.

AD5753 Datasheet(PDF) 52 Page - Analog Devices

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