se98a NXP Semiconductors, se98a Datasheet - Page 10

• Manufacturer Part Number: se98a
• Description: Ddr Memory Module Temp Sensor, 1.7 V To 3.6 V
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SE98A_1
Product data sheet
7.4.1 What temperature is read when conversion is in progress
7.4 Conversion rate
7.5 Power-up default condition
The conversion time is the amount of time required for the ADC to complete a temperature
measurement for the local temperature sensor. The conversion rate is the inverse of the
conversion period which describes the number of cycles the temperature measurement
completes in one second—the faster the conversion rate, the faster the temperature
reading is updated. The SE98A’s conversion rate is at least 8 Hz or 125 ms.
The SE98A has been designed to ensure a valid temperature is always available. When a
read to the temperature register is initiated through the SMBus, the device checks to see if
the temperature conversion process (Analog-to-Digital conversion) is complete and a new
temperature is available:
It is possible that while the SMBus Master is reading the temperature register, a new
temperature conversion completes. However, this will not affect the data (MSB or LSB)
that is being shifted out. On the next read of the temperature register the new temperature
value will be shifted out.
After power-on, the SE98A is initialized to the following default condition:
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– Competitor devices: If the EVENT output is not cleared before or when the
– Work-around: Always clear the EVENT output before temperature exceeds the
– SE98B will keep EVENT asserted after the temperature drops below the critical
If the temperature conversion process is complete, then the new temperature value is
sent out on the SMBus.
If the temperature conversion process in not complete, then the previous temperature
value is sent out on the SMBus.
Starts monitoring local sensor
EVENT register is cleared—EVENT output is pulled HIGH by external pull-ups
EVENT hysteresis is defaulted to 0 C
Command pointer is defaulted to ‘00h’
Critical Temp, Alarm Temperature Upper and Lower Boundary Trip register are
defaulted to 0 C
Capability register is defaulted to ‘0037h’ for the B-grade and VHV capability
Operational mode: comparator
SMBus register is defaulted to ‘00h’
temperature is in the critical temperature threshold, EVENT will remain asserted
after the temperature drops below the critical temperature until a Clear EVENT
command.
critical temperature.
temperature until a Clear EVENT command de-asserts EVENT.
Rev. 01 — 5 March 2009
DDR memory module temp sensor, 1.7 V to 3.6 V
© NXP B.V. 2009. All rights reserved.
SE98A
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