AD5593R Datasheet, PDF (21/34 Pages) Analog Devices – Control and monitoring

AD5593R
GPIO SECTION
Each of the eight I/Ox pins can be configured as a general-
purpose digital input or output pin by programming the GPIO
control register. When an I/Ox pin is configured as an output,
the pin can be set high or low by programming the GPIO write
data register. Logic levels for general-purpose outputs are relative
to VDD and GND. When an I/Ox pin is configured as an input, its
status can be determined by reading the GPIO read configuration
register. When an I/Ox pin is set as an output, it is possible to
read its status by also setting it as an input pin. When reading
the status of the I/Ox pins set as inputs the status of an I/Ox pin
set as both and input and output pin is also returned.
INTERNAL REFERENCE
The AD5593R contains an on-chip 2.5 V reference. The
reference is powered down by default and is enabled by setting
Bit D9 in the power-down/reference control register to 1. When
the on-chip reference is powered up, the reference voltage
appears on the VREF pin and may be used as a reference source
for other components. When the internal reference is used, it is
recommended to decouple VREF to GND using a 100 nF
capacitor. It is recommended that the internal reference be
buffered before using it elsewhere in the system. When the
reference is powered down, an external reference must be
connected to VREF. Suitable external reference sources for the
AD5593R include the AD780, AD1582, ADR431, REF193, and
ADR391.
RESET FUNCTION
The AD5593R has an asynchronous RESET pin. For normal
operation, RESET is tied high. A falling edge on RESET resets
all registers to their default values and reconfigures the I/O pins
to their default values (85 kΩ pull-down resistor to GND). The
reset function takes 250 μs maximum; do not write new data to
Data Sheet
the AD5593R during this time. The AD5593R has a software
reset that performs the same function as the RESET pin. The
reset function is activated by writing 0x0F to the pointer byte
and 0x0D and 0xAC to the most significant and least significant
bytes, respectively.
TEMPERATURE INDICATOR
The AD5593R contains an integrated temperature indicator that
can be read to provide an estimation of the die temperature.
This can be used in fault detection where a sudden rise in die
temperature may indicate a fault condition, such as a shorted
output. Temperature readback is enabled by setting Bit D8 in
the ADC sequence register. The temperature result is then
added to the ADC sequence. The temperature result has an
address of 0b1000 and care must be taken that this result is not
confused with the readback from DAC0. The temperature
conversion takes 5 μs with the ADC buffer enabled and 20 μs
when the buffer is disabled. Calculate the temperature using the
following formulae:
For ADC gain = 1,
Temperature (°C) = 25 + ^{ADC Code  820}
2.654
For ADC gain = 2,
Temperature (°C) = 25 + ^{ADC Code  410}
2.654
The range of codes returned by the ADC when reading from
the temperature indicator is approximately 645 to 1035,
corresponding to a temperature between −40°C to +105°C. The
accuracy of the temperature indicator is typically 3°C when
averaged over five samples.
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