ADT7420 Analog Devices, ADT7420 Datasheet - Page 14

• Manufacturer Part Number: ADT7420
• Description: 16-Bit Digital I2C Temperature Sensor
• Manufacturer: Analog Devices

ADT7420
STATUS REGISTER
This 8-bit read-only register reflects the status of the overtempera-
ture and undertemperature interrupts that can cause the CT and
INT pins to go active. It also reflects the status of a temperature
conversion operation. The interrupt flags in this register are
reset by a read operation to the status register and/or when
the temperature value returns within the temperature limits,
including hysterisis. The RDY bit is reset after a read from the
Table 10. Status Register (Register Address 0x02)
Bit
[0:3]
4
5
6
7
Table 11. Configuration Register (Register Address 0x03)
Bit
[0:1]
2
3
4
[5:6]
7
Default
Value
00
0
0
0
00
0
Default
Value
0000
0
0
0
1
Type
R/W
R/W
R/W
R/W
R/W
R/W
Type
R
R
R
R
R
Name
Fault queue
CT pin polarity
INT pin polarity
INT/CT mode
Operation mode
Resolution
Name
Unused
T
T
T
RDY
LOW
HIGH
CRIT
Description
Reads back 0.
This bit is set to 1 when the temperature goes below the T
when the status register is read and/or when the temperature measured goes back above the limit
set in the setpoint T
This bit is set to 1 when the temperature goes above the T
when the status register is read and/or when the temperature measured goes back below the limit
set in the setpoint T
This bit is set to 1 when the temperature goes above the T
when the status register is read and/or when the temperature measured goes back below the limit
set in the setpoint T
This bit goes low when the temperature conversion result is written into the temperature value
register. It is reset to 1 when the temperature value register is read. In one-shot and 1 SPS modes,
this bit is reset after a write to the one-shot bits.
Description
These two bits set the number of undertemperature/overtemperature faults that can occur before
setting the INT and CT pins. This helps to avoid false triggering due to temperature noise.
00 = 1 fault (default).
01 = 2 faults.
10 = 3 faults.
11 = 4 faults.
This bit selects the output polarity of the CT pin.
0 = active low.
1 = active high.
This bit selects the output polarity of the INT pin.
0 = active low.
1 = active high.
This bit selects between comparator mode and interrupt mode.
0 = interrupt mode
1 = comparator mode
These two bits set the operational mode for the ADT7420.
00 = continuous conversion (default). When one conversion is finished, the ADT7420 starts
another.
01 = one shot. Conversion time is typically 240 ms.
10 = 1 SPS mode. Conversion time is typically 60 ms. This operational mode reduces the average
current consumption.
11 = shutdown. All circuitry except interface circuitry is powered down.
This bit sets up the resolution of the ADC when converting.
0 = 13-bit resolution. Sign bit + 12 bits gives a temperature resolution of 0.0625°C.
1 = 16-bit resolution. Sign bit + 15 bits gives a temperature resolution of 0.0078°C.
Rev. PrA | Page 14 of 4
LOW
HIGH
CRIT
− T
+ T
− T
HYST
HYST
HYST
registers.
registers.
registers.
temperature value register. In one-shot and 1 SPS modes, the
RDY bit is reset after a write to the operation mode bits.
CONFIGURATION REGISTER
This 8-bit read/write register stores various configuration modes
for the ADT7420, including shutdown, overtemperature and
undertemperature interrupts, one-shot, continuous conversion,
interrupt pins polarity, and overtemperature fault queues.
Preliminary Technical Data
LOW
HIGH
CRIT
temperature limit. This bit clears to 0
temperature limit. The bit clears to 0
temperature limit. The bit clears to 0
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