Datasheet

ADT7320 Data Sheet
Rev. 0 | Page 10 of 24
DIN
DATA
SCLK
DOUT
CS
WAIT 240ms MINIMUM
FOR CONVERSION TO FINISH
09012-300
0x08 0x20
Figure 12. Typical SPI One-Shot Write to Configuration Register Followed by a Read from the Temperature Value Register
TEMPERATURE
149°C
148°C
147°C
146°C
145°C
144°C
143°C
142°C
141°C
140°C
CT PIN
POLARITY = ACTIVE LOW
CT PIN
POLARITY = ACTIVE HIGH
T
CRIT
T
CRIT
– T
HYST
TIME
*THERE IS A 240ms DELAY BETWEEN WRITING TO THE CONFIGURATION REGISTER TO START
A STANDARD ONE-SHOT CONVERSION AND THE CT PIN GOING ACTIVE. THIS IS DUE TO THE
CONVERSION TIME. THE DELAY IS 60ms IN THE CASE OF A ONE-SHOT CONVERSION.
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
WRITE TO
BIT 5 AND BIT 6 OF
CONFIGURATION
REGISTER.*
0
9012-013
Figure 13. One-Shot CT Pin
ONE-SHOT MODE
When one-shot mode is enabled, the ADT7320 immediately
completes a conversion and then goes into shutdown mode. The
one-shot mode is useful when one of the circuit design priorities is
to reduce power consumption.
To enable one-shot mode, set Bits [6:5] of the configuration
register (Register Address 0x01) to 01.
After writing to the operation mode bits, wait for at least 240 ms
before reading back the temperature from the temperature value
register. This delay ensures that the ADT7320 has adequate time
to power up and complete a conversion.
To obtain an updated temperature conversion, reset Bits[6:5] of the
configuration register (Register Address 0x01) to 01.
CT and INT Operation in One-Shot Mode
See Figure 13 for more information on one-shot CT pin
operation for T
CRIT
overtemperature events when one of the
limits is exceeded. Note that in interrupt mode, a read from
any register resets the INT and CT pins.
For the INT pin in comparator mode, if the temperature drops
below the T
HIGH
− T
HYST
value or goes above the T
LOW
+ T
HYST
value,
a write to the operation mode bits (Bit 5 and Bit 6 of the
configuration register, Register Address 0x01) resets the INT pin.
For the CT pin in comparator mode, if the temperature drops
below the T
CRIT
− T
HYST
value, a write to the operation mode bits
(Bit 5 and Bit 6 of the configuration register, Register Address 0x01)
resets the CT pin (see Figure 13).
When using one-shot mode, ensure that the refresh rate is
appropriate to the application being used.