MIC284
Micrel, Inc.
MIC284
Two-Zone Thermal Supervisor
General Description
The MIC284 is a versatile digital thermal supervisor capable of
measuring temperature using its own internal sensor and an
inexpensive external sensor or embedded silicon diode such
as those found in the Intel Pentium III™ CPU. A 2-wire serial
interface is provided to allow communication with either I
2
C™
or SMBus™ masters. Features include an open-drain over-
temperature output with dedicated registers for implementing
fan control or over-temperature shutdown circuits.
Interrupt status and mask bits are provided for reduced soft-
ware overhead. The open-drain interrupt output pin can be
used as either an overtemperature alarm or a thermostatic
control signal. A programmable address pin permits two
devices to share the bus. (Alternate base addresses avail-
able-contact Micrel.) Superior performance, low power and
small size makes the MIC284 an excellent choice for the most
demanding thermal management applications. The MIC284
is part of the SilentSense™ family of thermal supervisors.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
SilentSense™
Features
• Optimized for CPU Thermal Supervision in Computing
Applications
• Measures Local and Remote Temperature
• Sigma-Delta ADC for 8-Bit Temperature Results
• 2-Wire SMBus-compatible Interface
• Programmable Thermostat Settings for both Internal and
External Zones
• Open-Drain Interrupt Output Pin
• Open-Drain Over Temperature Output Pin for Fan Con-
trol or Hardware Shutdown
• Interrupt Mask and Status Bits
• Low Power Shutdown Mode
• Failsafe response to diode faults
• 2.7V to 5.5V Power Supply Range
• 8-Lead SOIC and MSOP Packages
Applications
•
•
•
•
•
Desktop, Server and Notebook Computers
Power Supplies
Test and Measurement Equipment
Wireless Systems
Networking/Datacom Hardware
Typical Application
3.3V
4
10k
pull-ups
FROM
SERIAL BUS
HOST
OVER-TEMP
SHUTDOWN
0.1F
MIC284
DATA
VDD
CLK
T1
/INT
/CRIT
A0
GND
2200pF
REMOTE
DIODE
2-Channel SMBus Temperature Measurement System
SMBus and Pentium III are trademarks of Intel Corporation.
I
2
C is a trademark of Philips Electronics, N.V.
SilentSense is a trademark of Micrel, Inc.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
September 2005
1
MIC284
MIC284
Micrel, Inc
Part Number
Base Address (*) Junction Temp. Range
100 100x
100 101x
100 110x
100 111x
100 100x
100 101x
100 110x
100 111x
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
Package
8-Lead SOIC
8-Lead SOIC
8-Lead SOIC
8-Lead SOIC
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
8-Lead MSOP
Contact Factory
Contact Factory
Contact Factory
Contact Factory
Contact Factory
Contact Factory
Availability
Ordering Information
Standard
MIC284-0BM
MIC284-1BM
MIC284-2BM
MIC284-3BM
MIC284-0BMM
MIC284-1BMM
MIC284-2BMM
MIC284-3BMM
Pb-Free
MIC284-0YM
MIC284-1YM
MIC284-2YM
MIC284-3YM
MIC284-0YMM
MIC284-1YMM
MIC284-2YMM
MIC284-3YMM
* The least-significant bit of the slave address is determined by the state of the A0 pin.
Pin Configuration
DATA
1
8 VDD
7 A0
6 T1
5 /CRIT
CLK 2
/INT 3
GND 4
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Pin Name
DATA
CLK
/INT
GND
/CRIT
T1
A0
VDD
Pin Function
Digital I/O: Open-drain. Serial data input/output.
Digital Input: The host provides the serial bit clock on this input.
Digital Output: Open-drain. Interrupt or thermostat output.
Ground: Power and signal return for all IC functions.
Digital Output: Open-Drain. Over-temperature indication
Analog Input: Connection to remote temperature sensor (diode junc-
tion)
Digital Input: Slave address selection input. See Table 1. MIC284 Slave
Address Settings.
Analog Input: Power supply input to the IC.
MIC284
2
September 2005
MIC284
Micrel, Inc.
Absolute Maximum Ratings
(Note 1)
Power Supply Voltage, V
DD
.......................................... 6.0V
Voltage on Any Pin ................................ –0.3V to V
DD
+0.3V
Current Into Any Pin ................................................ ±10 mA
Power Dissipation, T
A
= +125°C ................................ 30mW
Junction Temperature .............................................. +150°C
Storage Temperature ................................ –65°C to +150°C
ESD Ratings
(Note 3)
Human Body Model ...................................................TBD V
Machine Model ..........................................................TBD V
Soldering
Vapor Phase (60 sec.) .............................. +220°C
+5
⁄
–0
°C
Infrared (15 sec.) ...................................... +235°C
+5
⁄
–0
°C
Operating Ratings
(Note 2)
Power Supply Voltage, V
DD
......................... +2.7V to +5.5V
Ambient Temperature Range (T
A
) ............. -55°C to +125°C
Package Thermal Resistance (θ
JA
)
SOP ................................................................. +152°C/W
MSOP .............................................................. +206°C/W
Electrical Characteristics
2.7V ≤ V
DD
≤ 5.5; T
A
= +25°C,
bold
values indicate –55°C ≤ T
A
≤ +125°C,
Note 4;
unless noted.
Symbol
I
DD
Parameter
Condition
Power Supply
Supply Current
/INT, open, A0 = V
DD
or GND,
CLK = DATA = high, normal mode
/INT, /CRIT open, A0 = V
DD
or GND
shutdown mode, CLK = 100kHz
/INT, /CRIT open, A0 = V
DD
or GND
shutdown mode, CLK = DATA = high
t
POR
Power-On Reset Time,
Note 7
Power-On Reset Voltage
Power-On Reset
Hysteresis Voltage
Accuracy—Local Temperature
Note 4, 9
3V ≤ V
DD
≤ 3.6V
0°C ≤ T
A
≤ +100°C, /INT and /CRIT open,
3V ≤ V
DD
≤ 3.6V
V
POR
V
HYST
all registers reset to default values,
A/D conversions initiated
V
DD
> V
POR
350
750
µA
Min
Typ
Max
Units
3
1
2.0
10
200
2.7
µA
µA
µs
V
250
±1
±2
±1
±2
50
±2
±3
±3
±5
80
mV
°C
°C
°C
°C
ms
Temperature-to-Digital Converter Characteristics
–55°C ≤ T
A
≤ +125°C, /INT and /CRIT open,
Accuracy—Remote Temperature
Note 4, 5, 9
3V ≤ V
DD
≤ 3.6V, 0°C ≤ T
A
≤ +85°C
Conversion Time, local zone
Note 7
0°C ≤ T
D
≤ +100°C, /INT and /CRIT open,
3V ≤ V
DD
≤ 3.6V, 0°C ≤ T
A
≤ +85°C
–55°C ≤ T
D
≤ +125°C, /INT and /CRIT open,
t
CONV0
t
CONV1
Conversion Time, remote zone
Note 7
Current to External Diode
Note 7
Low Input Voltage
High Input Voltage
Input Capacitance
Input Current
high level, T1 forced to 1.5V
low level
2.7V ≤ V
DD
≤ 5.5V
7.5
100
224
14
160
400
ms
µA
µA
Remote Temperature Input (T1)
I
F
Address Input (A0)
V
IL
0.6
2.0
10
±0.01
±1
V
V
pF
µA
V
IH
2.7V ≤ V
DD
≤ 5.5V
C
IN
I
LEAK
September 2005
3
MIC284
MIC284
Symbol
V
OL
V
IL
Parameter
Low Output Voltage
Note 6
Low Input Voltage
High Input Voltage
Input Capacitance
Input current
Low Input Voltage
High Input Voltage
Input Capacitance
Input current
Low Output Voltage,
Note 6
Interrupt Propagation Delay,
Note 7, 8
Interrupt Reset Propagation Delay,
Note 7
Default T_SET0 Value
Default T_HYST0 Value
Default T_SET1 Value
Default T_HYST1 Value
Low Output Voltage,
Note 6
/CRIT Propagation Delay,
Note 7, 8
/CRIT Reset Propagation Delay,
Note 7
Default CRIT1 Value
Default nCRIT1 Value
CLK (Clock) Period
Data In Setup Time to CLK High
Data Out Stable After CLK Low
DATA Low Setup Time to CLK Low
DATA High Hold Time
After CLK High
start condition
stop condition
I
OL
= 3mA
2.7V ≤ V
DD
≤ 5.5V
2.7V ≤ V
DD
≤ 5.5V
Condition
I
OL
= 3mA
Min
Typ
Serial Data I/O Pin (DATA)
Micrel, Inc
Max
0.4
0.8
0.7V
DD
0.3V
DD
10
±0.01
±1
0.3V
DD
10
±0.01
±1
0.4
0.8
t
CONV
+1
1
81
76
97
92
81
76
97
92
81
76
97
92
0.4
0.8
t
CONV
+1
1
97
92
2.5
100
0
100
100
97
92
97
92
Units
V
V
V
V
pF
µA
V
V
pF
µA
V
V
µs
µs
°C
°C
°C
°C
V
V
µs
µs
°C
°C
µs
ns
ns
ns
ns
I
OL
= 6mA
V
IH
2.7V ≤ V
DD
≤ 5.5V
2.7V ≤ V
DD
≤ 5.5V
C
IN
I
LEAK
V
IL
Serial Clock Input (CLK)
V
IH
0.7V
DD
C
IN
I
LEAK
V
OL
t
INT
t
nINT
Status Output (/INT)
I
OL
= 6mA
T_SET0
T_HYST0
T_SET1
T_HYST1
V
OL
t
CRIT
t
nCRIT
CRIT1
nCRIT1
t
1
t
2
t
3
t
4
t
5
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Note 7.
Note 8.
Note 9.
from any register read to /INT > V
OH
FQ = 00, R
PULLUP
= 10kΩ
t
POR
after V
DD
> V
POR
t
POR
after V
DD
> V
POR
t
POR
after V
DD
> V
POR
t
POR
after V
DD
> V
POR
I
OL
= 3mA
from TEMP > T_SET or TEMPx < T_HYSTx
to INT < V
OL
, FQ = 00, R
PULLUP
= 10kΩ
Over-Temperature Output (/CRIT)
I
OL
= 6mA
from TEMPx < nCRITx to /CRIT > V
OH
FQ = 00, R
PULLUP
= 10kΩ
t
POR
after V
DD
> V
POR
t
POR
after V
DD
> V
POR
from TEMPx > T_SETx or TEMPx < T_HYSTx
to INT < V
OL
, FQ = 00, R
PULLUP
= 10kΩ
Serial Interface Timing (Note 7)
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended.
Human body model: 1.5k in series with 100pF. Machine model: 200pF, no series resistance.
Final test on outgoing product is performed at T
A
= TBD°C.
T
D
is the temperature of the remote diode junction. Testing is performed using a single unit of one of the transistors listed in Table 6.
Current into this pin will result in self-heating of the MIC284. Sink current should be minimized for best accuracy.
Guaranteed by design over the operating temperature range. Not 100% production tested.
Accuracy specification does not include quantization noise, which may be as great as ±
1
⁄
2
LSB (±0.5°C).
t
CONV
= t
CONV0
+ t
CONV1
. t
CONV0
is the conversion time for the local zone; t
CONV1
is the conversion time for the remote zone.`
MIC284
4
September 2005
MIC284
Micrel, Inc.
t
1
SCL
SDA Data In
SDA Data Out
t
4
t
2
t
3
t
5
Timing Diagram
Serial Interface Timing
September 2005
5
MIC284
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