LM81BIMTX-3/NOPB National Semiconductor, LM81BIMTX-3/NOPB Datasheet - Page 19

• Manufacturer Part Number: LM81BIMTX-3/NOPB
• Description: IC MPU SYSTEM HDWR MON 24-TSSOP
• Manufacturer: National Semiconductor

Specifications of LM81BIMTX-3/NOPB

• Function: Hardware Monitor
• Topology: ADC (Sigma Delta), Comparator, Fan Speed Control, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: No
• Voltage - Supply: 2.8 V ~ 3.8 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Monitored Voltage: 2.5 V , 3.3 V , 5 V , 12 V
• Manual Reset: Not Resettable
• Watchdog: Watchdog
• Battery Backup Switching: No
• Supply Voltage (max): 3.8 V
• Supply Voltage (min): 2.8 V
• Supply Current (typ): 400 uA (Typ)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM81BIMTX-3

Functional Description
8.0 TEMPERATURE MEASUREMENT SYSTEM
The LM81 temperature sensor and ADC produce 9-bit or
12-bit two’s-complement temperature data. A digital com-
parator
user-programmable High, Low, Critical setpoints and Hyster-
esis values.
(Non-Linear Scale for Clarity)
(Non-Linear Scale for Clarity)
FIGURE 10. 12-bit Temperature-to-Digital Transfer
FIGURE 9. 9-bit Temperature-to-Digital Transfer
compares
the
Function
Function
temperature
(Continued)
data
DS100072-27
to
DS100072-24
the
19
8.1 Temperature Data Format
Temperature data can be read from the Temperature, T
setpoint, T
T
T
registers. T
temperature data is represented by an 8-bit, two’s comple-
ment word with an LSB (Least Significant Bit) equal to 1˚C:
By default Temperature Register data is represented by a
9-bit two’s complement digital word with the LSB having a
resolution of 0.5˚C:
In the extended mode temperature Register data can also be
represented by a 12-bit two’s complement digital word with
an LSB of 0.0625˚C:
T
with an LSB (Least Significant Bit) equal to 1˚C.
HYST
HIHYST
HYST
Temperature
Temperature
Temperature
+0.0625˚C
−0.0625˚C
+125˚C
+125˚C
+125˚C
+1.0˚C
−1.0˚C
+1.5˚C
−0.5˚C
+1.0˚C
−1.0˚C
+25˚C
−25˚C
−40˚C
+25˚C
−25˚C
−40˚C
+25˚C
−25˚C
−40˚C
Offset temperature data is represented by a 3-bit word
Offset registers; and written to the T
+0˚C
+0˚C
0˚C
, T
LOW
HIHYST
HIGH
setpoint, T_CRIT setpoint and T
setpoint, T
setpoint, T
0111 1100 0000
0001 1001 0000
0000 0001 0000
0000 0000 0001
0000 0000 0000
1111 1111 1111
1111 1111 0000
1110 0111 0000
1101 1000 0000
0 1111 1010
0 0011 0010
0 0000 0011
0 0000 0000
1 1111 1111
1 1100 1110
1 1011 0000
0111 1101
0001 1001
0000 0001
0000 0000
1111 1111
1110 0111
1101 1000
Binary
Binary
Binary
LOW
LOW
Digital Output
Digital Output
Digital Output
setpoint, T_CRIT setpoint
setpoint, T
C
HIGH
setpoint and
1 CEh
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0 FAh
1 FFh
1 B0h
7 D0h
F FFh
F F0h
E 70h
D 80h
HYST
0 32h
0 03h
0 00h
1 90h
0 10h
0 01h
0 00h
Hex
7Dh
D8h
Hex
Hex
FFh
E7h
19h
01h
00h
setpoint,
offset
HIGH