AD5522JSVD AD [Analog Devices], AD5522JSVD Datasheet - Page 42

• Manufacturer Part Number: AD5522JSVD
• Description: Quad Parametric Measurement Unit With Integrated 16-Bit Level Setting DACs
• Manufacturer: AD [Analog Devices]

AD5522
SETTING UP THE DEVICE ON POWER ON
On power on, default conditions are recalled from the power on
reset register ensuring each PMU and DAC channel is powered
up to a known condition. To operate the device, the user must:
1)
2)
3)
4)
Configure the device by writing to the System Control
register to set up different functions as required.
Calibrate out errors and load required calibration values to
(Gain) m and (Offset) c registers, and load codes to each
DAC input register (x1). Once x1 values are loaded to the
individual DACs, the calibration engine calculates the
appropriate x2 value and stores it ready for the PMU
address to call it.
Load the required PMU channel with the required force
mode, current range etc. Loading the PMU channel
configures the switches around the Force Amplifier,
Measure function, clamps and comparators and also acts as
a load signal for the DACs, loading the DAC register with
the appropriate stored x2 value.
As the voltage and current ranges have individual DAC
registers associated with them, each PMU register mode of
operation calls a particular x2 register. Hence, only updates
(changes to x1 register) to DACs associated with the
selected mode of operation are reflected to the output of
the PMU. If there is a change to the x1 value associated
with a different PMU mode of operation, then this x1 value
and it’s m and c coefficients are used to calculate a
corresponding x2 value which is stored in the correct x2
register, but it does not get loaded to the DAC.
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CHANGING MODES
There are different ways of handling a mode change:
1)
2)
or
1)
2)
3)
4)
Load any DAC x1 values that are required to change.
Remember that x1 registers are available per voltage and
current range (for Force Amplifier and Comparator
DACs), so you can preload these and may not need to
make changes. The calibration engine will calculate the x2
values and store them.
new switch conditions in the PMU circuitry and load the
DAC register with the stored x2 data.
makes the amplifier high impedance.
Remember that x1 registers are available per voltage and
current range, so you can preload these and may not need
to make changes.
outputs are automatically updated (FIN, CLL, CLH DACs).
For example, when selecting Hi-Z V (Voltage), the FIN
Voltage x2 result is loaded, offset and gain corrected,
cached and loaded to the FIN DAC. When forcing a
voltage, current clamps are engaged, so the CLL I (Current)
register can be loaded, gain and offset corrected and loaded
to the DAC register. Similarly, for the CLH I register.
load the new switch conditions in the PMU circuitry. As
the DAC outputs are already loaded, transients when
changing current or voltage mode will be minimized.
Now change into the new PMU mode. This will load the
Use the Hi-Z V or Hi-Z I mode in the PMU register, this
Now load any DAC x1 values that need to be loaded.
When the Hi-Z (V or I) modes are used, the relevant DAC
Now change into the new PMU mode (FI/FV). This will
Preliminary Technical Data