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ON Semiconductor |
MC74
Serial Digital
Temperature Sensor
The MC74 is a serial digital temperature sensor suited for low cost
applications. Temperature data is converted from the integrated
thermal sensing element and made available as an 8–bit serial digital
word. Communication with the MC74 is accomplished via 2–wire
SMBus/I2C–compatible serial port. Temperature resolution is 1°C.
Conversion rate is a nominal 8 samples/sec. Power consumption is
only 200 µA (5.0 µA Standby).
Features
• Temperature Range: –40°C to +125°C
• Outputs Temperature as an 8–Bit Digital Word
• Simple Serial Port Interface
• Solid State Temperature Sensing:
±2°C Accuracy from +25°C to +85°C
±3°C Accuracy from 0°C to +125°C
• 3.3 V and 5.5 V Operating Range
• Low Power
200 µA Operations
5.0 µA Standby Mode
Typical Applications
• Thermal Protection for Hard Disk Drives and Other PC Peripherals
• Low–Cost Thermostat Controls
• Power Supplies
FUNCTIONAL BLOCK DIAGRAM
Internal Sensor
(Diode)
Serial Port
Interface
DS Modulator
Control
Logic
Temperature
Register
SDA
SCL
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5
1
2
3
4
SOT–23
SN SUFFIX
CASE 1212
1
5
TO–220
T SUFFIX
CASE 314D
PIN CONNECTIONS
NC 1
5 SDA
GND 2
VDD 3
4 SCL
(Top View)
SOT–23A*
NOTE: *SOT–23A is equivalent to EIAJ–SC74A
ORDERING INFORMATION
See detailed ordering and shipping information on page 9 of
this data sheet.
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 9 of this data sheet.
© Semiconductor Components Industries, LLC, 2000
November, 2000 – Rev. 1
1
Publication Order Number:
MC74/D
MC74
PIN DESCRIPTION FOR TO–220–5
Pin No. Symbol
Type
1 NC None
2
SDA
Bi–directional
3
GND
Power
4 SCL Input
5
VDD
Power
Not Connected
SMBus Serial Data
System Ground
SMBus Serial Clock
Power Supply Input
PIN DESCRIPTION FOR SOT–23–5
Pin No. Symbol
Type
1 NC None
2
GND
Power
3
VDD
Power
4 SCL Input
5
SDA
Bi–directional
Not Connected
System Ground
Power Supply Input
SMBus Serial Clock
SMBus Serial Data
Description
Description
PIN DESCRIPTION
SCL
SMBus Serial Clock Input. Clocks data into and out of the
MC74. See System Management Bus Specification, rev. 1.0,
for timing diagrams.
SDA
Bi–directional Input/Output. Serial data is transferred on
the SMBus in both directions using this pin. See System
Management Bus Specification rev. 1.0 for timing diagrams.
VDD
Power Supply Input. See electrical specifications.
GND
Ground return for all MC74 functions.
ABSOLUTE MAXIMUM RATINGS*
Rating
Symbol
Value
Unit
Power Supply Voltage
Voltage on Any Pin
Operating Temperature Range
Storage Temperature Range
Current on Any Pin
VDD 6.0 V
–
(GND –0.3 V) to (VDD +0.3 V)
V
TA
–40 to +125
°C
Tstg
–65 to +150
°C
– ±50 mA
Package Thermal Resistance
RθJA
330 °C/W
*Maximum Ratings are those values beyond which damage to the device may occur.
*Static–sensitive device. Unused devices must be stored in conductive material. Protect devices from static discharge and static fields. Stresses
above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied.
Exposure to Absolute Maximum Rating Conditions for extended periods may affect device reliability.
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