NCT1008CMN3R2G ON Semiconductor, NCT1008CMN3R2G Datasheet - Page 11

• Manufacturer Part Number: NCT1008CMN3R2G
• Description: IC TEMP MONITOR 2CH DGTL 8-DFN
• Manufacturer: ON Semiconductor

Specifications of NCT1008CMN3R2G

• Function: Temp Monitoring System (Sensor)
• Topology: ADC (Sigma Delta), Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: 0°C ~ 127°C, -64°C ~ 191°C
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 2.8 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-VFDFN Exposed Pad
• Full Temp Accuracy: +/- 1 C
• Digital Output - Bus Interface: 2 Wire, SMBus, I2C
• Digital Output - Number Of Bits: 8 bit
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2.8 V
• Description/function: Temperature Monitor with Series Resistance Cancellation
• Supply Current: 240 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Offset Register
temperature measurement by clock noise or when the
thermal diode is located away from the hot spot. To achieve
the specified accuracy on this channel, these offsets must be
removed.
value in Register 0x11 (high byte) and Register 0x12 (low
byte, left justified). Only the upper two bits of Register 0x12
are used. The MSB of Register 0x11 is the sign bit. The
minimum, programmable offset is −128°C, and the
maximum is +127.75°C. The value in the offset register is
added to, or subtracted from, the measured value of the
remote temperature.
and has no effect unless the user writes a different value to it.
Table 5. Status Register Bit Assignments
1. These flags stay high until the status register is read or they
Offset errors can be introduced into the remote
The offset value is stored as a 10−bit, twos complement
The offset register powers up with a default value of 0°C
Bit
7
6
5
4
3
2
1
0
are reset by POR unless Pin 6 is configured as THERM2.
Then, only Bit 2 remains high until the status register is read
or is reset by POR.
(Note 1)
(Note 1)
(Note 1)
(Note 1)
(Note 1)
RTHRM
LTHRM
RHIGH
LHIGH
RLOW
LLOW
OPEN
Name
BUSY
1 when ADC is converting
1 when local high temperature limit is
tripped
1 when local low temperature limit is
tripped
1 when remote high temperature limit is
tripped
1 when remote low temperature limit is
tripped
1 when remote sensor is an open circuit
1 when remote THERM limit is tripped
1 when local THERM limit is tripped
Function
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11
One−Shot Register
comparison cycle when the NCT1008 is in standby mode,
after which the device returns to standby. Writing to the
one−shot register address (0x0F) causes the NCT1008 to
perform a conversion and comparison on both the internal
and the external temperature channels. This is not a data
register as such, and it is the write operation to Address 0x0F
that causes the one−shot conversion. The data written to this
address is irrelevant and is not stored.
Consecutive ALERT Register
out−of−limit measurements must occur before an ALERT is
generated. The default value is that one out−of−limit
measurement generates an ALERT. The maximum value
that can be chosen is 4. The purpose of this register is to
allow the user to perform some filtering of the output. This
is particularly useful at the fastest three conversion rates,
where no averaging takes place. This register is at Address
0x22.
Table 6. Sample Offset Register Codes
Table 7. Consecutive ALERT Register Codes
NOTE:
The one−shot register is used to initiate a conversion and
The value written to this register determines how many
Register Value
Offset Value
+127.75°C
yxxx 000x
yxxx 001x
yxxx 011x
yxxx 111x
−0.25°C
+0.25°C
−128°C
−4°C
−1°C
+1°C
+4°C
0°C
x = don’t care bits, and y = SMBus timeout bit.
Default = 0. See SMBus section for more information.
1000 0000
0000 0000
0000 0000
0000 0001
0000 0100
1111 1100
0111 1111
1111 1111
1111 1111
0x11
Number of Out−of−Limit
Measurements Required
1
2
3
4
00 00 0000
00 00 0000
10 00 0000
00 00 0000
01 00 0000
00 00 0000
00 00 0000
11 00 0000
00 000000
0x12