ADT7517ARQ Analog Devices Inc, ADT7517ARQ Datasheet - Page 25

• Manufacturer Part Number: ADT7517ARQ
• Description: IC TEMP SNSR QUAD DAC 16-QSOP
• Manufacturer: Analog Devices Inc

Specifications of ADT7517ARQ

• Rohs Status: RoHS non-compliant
• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 120°C, External Sensor
• Output Type: I²C™, MICROWIRE™, QSPI™, SPI™
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 120°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP

FUNCTIONAL DESCRIPTION—MEASUREMENT
Temperature Sensor
The ADT7516/ADT7517/ADT7519 contain an ADC with
special input signal conditioning to enable operation with
external and on-chip diode temperature sensors. When the
ADT7516/ADT7517/ADT7519 operate in single-channel mode,
the ADC continually processes the measurement taken on one
channel only. This channel is preselected by Bits[C0:C2] in the
Control Configuration 2 register (Address 0x19). When in
round robin mode, the analog input multiplexer sequentially
selects the V
to measure its internal temperature, either the external tempera-
ture sensor or AIN1 and AIN2, AIN3, and then AIN4. These
signals are digitized by the ADC and the results are stored in
the various value registers.
The measured results from the temperature sensors are com-
pared with the internal and external T
These temperature limits are stored in on-chip registers. If the
temperature limits are not masked, any out-of-limit comparisons
generate flags that are stored in the Interrupt Status 1 register.
One or more out-of-limit results cause the INT/ INT output to
pull either high or low depending on the output polarity setting.
Theoretically, the temperature measuring circuit can measure
temperatures from −128°C to +127°C with a resolution of
0.25°C. However, temperatures outside T
guaranteed operating temperature range of the device.
Temperature measurement from −128°C to +127°C is possible
using an external sensor.
Temperature measurement is initiated by three methods. The
first method is applicable when the part is in single-channel
measurement mode. The temperature is measured 16 times and
internally averaged to reduce noise. In single-channel mode, the
part is continuously monitoring the selected channel, that is, as
soon as one measurement is taken another one is started on the
same channel. The total time to measure a temperature channel
with the ADC operating at slow speed is typically 11.4 ms
(712 μs × 16) for the internal temperature sensor and 24.22 ms
(1.51 ms × 16) for the external temperature sensor. The new
temperature value is stored in two 8-bit registers and is ready
for reading by the I
of disabling the averaging by setting Bit 5 in the Control
Configuration 2 register (Address 0x19). The ADT7516/
ADT7517/ADT7519 default on power-up is with averaging
enabled.
The second method is applicable when the part is in round
robin measurement mode. The part measures both the internal
and external temperature sensors as it cycles through all
possible measurement channels. The two temperature channels
are measured each time the part runs a round robin sequence.
In round robin mode, the part is continuously measuring all
channels.
DD
input channel, the on-chip temperature sensor
2
C or SPI interface. The user has the option
HIGH
A
and T
are outside the
LOW
limits.
Rev. B | Page 25 of 44
Temperature measurement is also initiated after every read or
write to the part when the part is in either single-channel
measurement mode or round robin measurement mode.
Once serial communication has started, any conversion in
progress stops and the ADC resets. Conversion restarts
immediately after the serial communication has finished. The
temperature measurement proceeds normally as described above.
V
The ADT7516/ADT7517/ADT7519 also have the ability to
monitor their own power supply. The part measures the voltage
on its V
stored in two 8-bit registers; the two LSBs are stored in register
Address 0x03 and the eight MSBs are stored in register
Address 0x06. This allows the option of doing just a 1-byte read
if 10-bit resolution is not important. The measured result is
compared with the V
not masked, any out-of-limit comparison generates a flag in the
Interrupt Status 2 register and one or more out-of-limit results
cause the INT/ INT output to pull either high or low, depending
on the output polarity setting.
Measuring the voltage on the V
a channel along with the internal, external, and AIN channels.
The user can select the V
measurement by setting Bit C4 = 1 and setting Bits[C0:C2] to all
0s in the Control Configuration 2 register.
When measuring the V
sourced from the internal reference. Table 8 shows the data
format. As the maximum measurable V
internal scaling is performed on the V
2.28 V internal reference value. Following is an example of how
the transfer function works:
DD
Monitoring
V
ADC Reference = 2.28 V
1 LSB = ADC Reference/2
Scale Factor = Full-Scale V
Conversion Result = V
DD
DD
= 5 V
= 2.28/1024
= 2.226 mV
= 7/2.28
= 3.07
= 5/(3.07 × 2.226 mV)
= 0x2DC
pin to a resolution of 10 bits. The resulting value is
ADT7516/ADT7517/ADT7519
HIGH
DD
DD
and V
value, the reference for the ADC is
DD
channel for single-channel
/(Scale Factor × LSB size)
10
DD
LOW
CC
/ADC Reference
pin is regarded as monitoring
limits. If the V
DD
DD
voltage to match the
voltage is 7 V,
DD
interrupt is