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MC1066 ACPI-Compliant SMBus Temperature Sensor with Internal and External Diode Input
The MC1066 is a serially programmable temperature sensor optimized for monitoring modern high performance CPUs with http://onsemi.com on–board integrated temperature sensing diodes. Temperature data is converted from the CPU’s diode outputs and made available as an 8–bit digital word. Communication with the MC1066 is accomplished via the standard System Management Bus (SMBus) commonly used in modern computer systems. This permits reading the current internal/external temperature, programming the threshold setpoints, and configuring 16–Pin QSOP the device. Additionally, an interrupt is generated on the DB SUFFIX CASE TBD ALERT/COMP pin when temperature moves outside the preset PRELIMINARY INFORMATION threshold windows in either direction. A separate CRITICAL setpoint is provided through external hardwiring for “fail safe” operation per ACPI guidelines. PIN CONFIGURATION A Standby command may be sent via the SMBus or by signaling the (Top View) STBY input pin to activate the low–power Standby mode. Registers can be accessed while in Standby mode. Address selection inputs CRIT1 1 16 NC allow up to nine MC1066s to share the same 2–wire SMBus for VDD 2 15 STBY multi–zone monitoring. + 3 D 14 SCL All registers can be read by the host, and both polled and interrupt – 4 D 13 INT_SEL driven systems are easily accommodated. Small size, low installed MC1066 CRIT0 12 SDA 5 cost, and ease of use make the MC1066 an ideal choice for ADD1 6 11 ALERT/COMP implementing sophisticated system management schemes, such as GND 7 ACPI. 10 ADD0 Features GND 8 9 OS • Specifically ACPI–Compliant • Backward Compliant to Older APM Systems • Includes Internal and External Sensing Capability • Outputs Temperature As 8–Bit Digital Word • Solid State Temperature Sensing; 1°C Resolution • 3.0 — 5.5V Operating Range ORDERING INFORMATION • Independent Internal and External Threshold Set–Points With Device Package Shipping ALERT/COMP Interrupt Output • SMBus 2–Wire Serial Interface MC1066DBR2 16–Pin QSOP 2500 Tape/Reel • Optional CRITICAL Set–Point for Full ACPI Compliant Implementation • Up To Nine MC1066s May Share the Same Bus • Low Standby Power Mode • Low Power: 70 µA (max) Operating, 10 µA (max) Standby Mode • 16–Pin Plastic QSOP Package Typical Applications • Thermal Protection For Intel “Deschutes” Pentium™ II and Other High Performance CPUs with Integrated On–Board Diode - No Sensor Mounting Problems! • Accurate Temperature Sensing From Any Silicon Junction Diode • Thermal Management in Electronic Systems: Computers, Network Equipment, Power Supplies
© Semiconductor Components Industries, LLC, 1999
1
February, 2000 – Rev. 0
Publication Order Number: MC1066/D
MC1066
FUNCTIONAL BLOCK DIAGRAM
Internal Sensor (Diode) D+ D–
DS
Modulator Register Set Int. Temp Ext.Temp Status Byte Config. Byte Conv. Rate Ext. Hi Limit Ext. Lo Limit Int. Hi Limit Int. Lo Limit CRIT. Limit
Control Logic
CRIT 0 CRIT 1 INT_SEL OS ALERT/ COMP STBY
SCL SDA SMBus Interface ADD 0 ADD 1
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Pin No. 2 3 4 Symbol VDD D+ D– Type Description Power Power Supply Input Bi–Directional Bi–Directional Input Current Source and A/D Positive Input Current Sink and A/D Negative Input 6, 10 7, 8 11 ADD[1:0] GND Address Select Pins (See Address Decode Table) System Ground Power ALERT/COMP SDA SCL Output SMBus Interrupt (SMBALERT) or Comparator Output SMBus Serial Data 12 14 15 Bi–Directional Input Input Input SMBus Serial Clock Standby Enable STBY 1, 5 9 CRIT[1:0] OS CRITICAL Setpoint Bits (See CRITICAL Setpoint Decode Table) Open Collector, Low–True “Over–Temperature” Warning Output Selects ALERT or COMP Output on Pin 11 Not Connected Output Input — 13 16 INT_SEL NC
PIN DESCRIPTION
PIN DESCRIPTION
SCL
Input. SMBus serial clock. Clocks data into and out of the MC1066.
SDA
the address specified in the serial bit stream must be made to initiate communication. Many SMBus–compatible devices with other addresses may share the same 2–wire bus. These pins are only active at power–on reset, and will latch into the appropriate states.
ALERT/COMP*
Bidirectional. Serial data is transferred on the SMBus in both directions using this pin.
ADD1, ADD0
Inputs. Sets the 7–bit SMBus address. These pins are “tri–state,” and the SMBus addresses are specified in the Address Decode Table. (NOTE: The tri–state scheme allows up to nine MC1066s on a single bus. .