MICREL MIC284-0BM, MIC284-2BMM, MIC284-3BM, MIC284-3BMM, MIC284-1BMM Datasheet

MIC284 Micrel

MIC284

Two-Zone Thermal Supervisor

Advance Information

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
I2C** 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
software 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 avail­able-contact Micrel.) Superior performance, low power and
small size makes the MIC284 an excellent choice for the most
demanding thermal management applications.

*SMBus and Pentium III are trademarks of Intel Corporation.

**I2C is a trademark of Philips Electronics, N.V.

Ordering Information

Part Number Base Address(*
MIC284-0BM 100 100x –55°C to +125°C 8-Lead SOP
MIC284-1BM 100 101x –55°C to +125°C 8-Lead SOP Contact Factory
MIC284-2BM 100 110x –55°C to +125°C 8-Lead SOP Contact Factory
MIC284-3BM 100 111x –55°C to +125°C 8-Lead SOP Contact Factory
MIC284-0BMM 100 100x –55°C to +125°C 8-Lead MSOP
MIC284-1BMM 100 101x –55°C to +125°C 8-Lead MSOP Contact Factory
MIC284-2BMM 100 110x –55°C to +125°C 8-Lead MSOP Contact Factory
MIC284-3BMM 100 111x –55°C to +125°C 8-Lead MSOP Contact Factory

* The least-significant bit of the slave address is determined by the state of the A0 pin.

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
Control 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

)

Junction Temp. Range Package Notes

Typical Application

3.3V

4 × 10k

FROM

SERIAL BUS

HOST

OVER-TEMP
SHUTDOWN

pull-ups

DATA

CLK

/INT

/CRIT

MIC284

VDD

T1

A0

GND

2-Channel SMBus Temperature Measurement System

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

September 29, 2000 1 MIC284

0.1µF

2200pF

REMOTE
DIODE

MIC284 Micrel

Pin Configuration

CLK

/INT

GND

Pin Description

Pin Number Pin Name Pin Function

1 DATA Digital I/O: Open-drain. Serial data input/output.

2 CLK Digital Input: The host provides the serial bit clock on this input.

3 /INT Digital Output: Open-drain. Interrupt or thermostat output.

4 GND Ground: Power and signal return for all IC functions.

5 /CRIT Digital Output: Open-Drain. Over-temperature indication

6 T1 Analog Input: Connection to remote temperature sensor (diode junction)

7 A0 Digital Input: Slave address selection input. See Table 1. MIC284 Slave

8 VDD Analog Input: Power supply input to the IC.

1DATA

2

3

4

Address Settings.

8 VDD

A0

7

T1

6

/CRIT

5

MIC284 2 September 29, 2000

MIC284 Micrel

Absolute Maximum Ratings (Note 1)

Power Supply Voltage, V

Voltage on Any Pin................................ –0.3V to V

Current Into Any Pin ................................................ ±10 mA

Power Dissipation, T

A

Junction Temperature ............................................. +150°C

................................................... 6.0V

DD

+0.3V

DD

= +125°C ...............................30mW

Operating Ratings (Note 2)

Power Supply Voltage, V
Ambient Temperature Range (T
Package Thermal Resistance (θ

SOP .................................................................+152°C/W

MSOP ..............................................................+206°C/W

.............................. +2.7V to +5.5V

DD

) ............ -55°C to +125°C

A

)

JA

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

Electrical Characteristics

2.7V ≤ VDD ≤ 5.5; TA = +25°C, bold values indicate –55°C ≤ TA ≤ +125°C, Note 4; unless noted.

Symbol Parameter Condition Min Typ Max Units

Power Supply

I

DD

t

POR

V

POR

V

HYST

Temperature-to-Digital Converter Characteristics

t

CONV0

t

CONV1

Remote Temperature Input (T1)

I

F

Address Input (A0)

V

IL

V

IH

C

IN

I

LEAK

Supply Current /INT, open, A0 = VDD or GND, 350 750 µA

CLK = DATA = high, normal mode

/INT, /CRIT open, A0 = V
shutdown mode, CLK = 100kHz 3 µA

/INT, /CRIT open, A0 = V
shutdown mode, CLK = DATA = high 1 10 µA

Power-On Reset Time, Note 7 VDD > V

POR

or GND

DD

or GND

DD

200 µs

Power-On Reset Voltage all registers reset to default values, 2.0 2.7 V

A/D conversions initiated

Power-On Reset Hysteresis Voltage 250 mV

Accuracy—Local Temperature 0°C ≤ T

≤ +100°C, /INT and /CRIT open, ±1 ±2 °C

A

Note 4, 9 3V ≤ VDD ≤ 3.6V

–55°C ≤ T

≤ +125°C, /INT and /CRIT open, ±2 ±3 °C

A

3V ≤ VDD ≤ 3.6V

Accuracy—Remote Temperature 0°C ≤ T

≤ +100°C, /INT and /CRIT open, ±1 ±3 °C

D

Note 4, 5, 9 3V ≤ VDD ≤ 3.6V, 0°C ≤ TA ≤ +85°C

–55°C ≤ T

≤ +125°C, /INT and /CRIT open, ±2 ±5 °C

D

3V ≤ VDD ≤ 3.6V, 0°C ≤ TA ≤ +85°C

Conversion Time, local zone 50 80 ms
Note 7

Conversion Time, remote zone
Note 7 100 160 ms

Current to External Diode high level, T1 forced to 1.5V 224 400 µA

Note 7

low level 7.5 14 µA

Low Input Voltage 2.7V ≤ VDD ≤ 5.5V 0.6 V
High Input Voltage 2.7V ≤ VDD ≤ 5.5V 2.0 V

Input Capacitance 10 pF
Input Current ±0.01 ±1 µA

September 29, 2000 3 MIC284

MIC284 Micrel

Symbol Parameter Condition Min Typ Max Units

Serial Data I/O Pin (DATA)

V

OL

V

IL

V

IH

C

IN

I

LEAK

Serial Clock Input (CLK)

V

IL

V

IH

C

IN

I

LEAK

Status Output (/INT)

V

OL

t

INT

t

nINT

T_SET0 Default T_SET0 Value t

T_HYST0 Default T_HYST0 Value t

T_SET1 Default T_SET1 Value t

T_HYST1 Default T_HYST1 Value t

Over-Temperature Output (/CRIT)

V

OL

t

CRIT

t

nCRIT

CRIT1 Default CRIT1 Value t

nCRIT1 Default nCRIT1 Value t

Serial Interface Timing (Note 7)

t

1

t

2

t

3

t

4

t

5

Low Output Voltage IOL = 3mA 0.4 V

Note 6 IOL = 6mA 0.8 V
Low Input Voltage 2.7V ≤ VDD ≤ 5.5V 0.3V
High Input Voltage 2.7V ≤ VDD ≤ 5.5V 0.7V

DD

DD

V

V

Input Capacitance 10 pF
Input current ±0.01 ±1 µA

Low Input Voltage 2.7V ≤ VDD ≤ 5.5V 0.3V
High Input Voltage 2.7V ≤ VDD ≤ 5.5V 0.7V

DD

DD

V

V

Input Capacitance 10 pF
Input current ±0.01 ±1 µA

Low Output Voltage, IOL = 3mA 0.4 V

Note 6

Interrupt Propagation Delay, from TEMP > T_SET or TEMPx < T_HYSTx
Note 7, 8 to INT < VOL, FQ = 00, R

Interrupt Reset Propagation Delay, from any register read to /INT > V
Note 7 FQ = 00, R

IOL = 6mA 0.8 V

t

+1

CONV

1 µs

after VDD > V

POR

after VDD > V

POR

after VDD > V

POR

after VDD > V

POR

PULLUP

= 10kΩ

POR

POR

POR

POR

PULLUP

= 10kΩ

OH

81 81 81 °C
76 76 76 °C
97 97 97 °C
92 92 92 °C

µs

Low Output Voltage, IOL = 3mA 0.4 V

Note 6

/CRIT Propagation Delay,
Note 7, 8 to INT < VOL, FQ = 00, R

/CRIT Reset Propagation Delay, from TEMPx < nCRITx to /CRIT > V
Note 7 FQ = 00, R

IOL = 6mA 0.8 V

from

TEMPx > T_SETx or TEMPx < T_HYSTx

= 10kΩ

PULLUP

OH

after VDD > V

POR

after VDD > V

POR

PULLUP

= 10kΩ

POR

POR

97 97 97 °C
92 92 92 °C

t

CONV

1 µs

+1

µs

CLK (Clock) Period 2.5 µs

Data In Setup Time to CLK High 100 ns

Data Out Stable After CLK Low 0 ns

DATA Low Setup Time to CLK Low start condition 100 ns

DATA High Hold Time stop condition 100 ns
After CLK High

MIC284 4 September 29, 2000

MIC284 Micrel

Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. Devices are ESD sensitive. Handling precautions recommended.

Human body model: 1.5k in series with 100pF. Machine model: 200pF, no series resistance.

Note 4. Final test on outgoing product is performed at T

Note 5. T

is the temperature of the remote diode junction. Testing is performed using a single unit of one of the transistors listed in Table 6.

D

= TBD°C.

A

Note 6. Current into this pin will result in self-heating of the MIC284. Sink current should be minimized for best accuracy.

Note 7. Guaranteed by design over the operating temperature range. Not 100% production tested.

Note 8. t
Note 9. Accuracy specification does not include quantization noise, which may be as great as ±

CONV

= t

CONV0

+ t

CONV1

. t

is the conversion time for the local zone; t

CONV0

is the conversion time for the remote zone.`

CONV1

1

⁄2LSB (±0.5°C).

Timing Diagram

t

1

SCL

SDA Data In

SDA Data Out

t

4

t

2

t

3

t

5

Serial Interface Timing

September 29, 2000 5 MIC284

MIC284 Micrel

Functional Diagram

VDD

DATA

CLK

T1

A0

2:1

MUX

Bandgap

Sensor

and

Reference

2-Wire

Serial Bus

Interface

Pointer

Register

∑

1-Bit
DAC

Result

Registers

T_SET & /CRIT

Setpoint

Registers

Temperature

Hysteresis

Registers

Configuration

Register

TEMPERATURE-TO-DIGITAL

CONVERTER

∫

Digital Filter

and

Control

Logic

State

Machine

and

Digital

Comparator

MIC284

FUNCTIONAL DESCRIPTION

Pin Descriptions

VDD: Power supply input. See electrical specifications.

GND: Ground return for all MIC284 functions.

CLK: Clock input to the MIC284 from the two-wire serial bus.

The clock signal is provided by the host, and is shared by all
devices on the bus.

DATA: Serial data I/O pin that connects to the two-wire serial
bus. DATA is bi-directional and has an open-drain output
driver. An external pull-up resistor or current source some­where in the system is necessary on this line. This line is
shared by all devices on the bus.

A0: This inputs sets the least significant bit of the MIC284’s
7-bit slave address. The six most-significant bits are fixed
and are determined by the part number ordered. (See order­ing information table above.) Each MIC284 will only respond
to its own unique slave address, allowing up to eight MIC284s
to share a single bus. A match between the MIC284’s
address and the address specified in the serial bit stream
must be made to initiate communication. A0 should be tied
directly to VDD or ground. See "Temperature Measurement

/INT

/CRIT

GND

Open-Drain

Output

and Power On" for more information. A0 determines the slave
address as shown in Table 1:

rebmuNtraP

0-482CIM0 0001001

1-482CIM0 0101001

2-482CIM0 0011001

3-482CIM0 0111001

stupnIsserddAevalS482CIM

0AyraniBxeH

b

11001001

11101001

11011001

11111001

b

b

b

b

b

b

b

Table 1. MIC284 Slave Address Settings

/INT: Temperature events are indicated to external circuitry

via this output. Operation of the /INT output is controlled by
the MODE and IM bits in the MIC284’s configuration register.
See "Comparator and Interrupt Modes" below. This output is
open-drain and may be wire-OR’ed with other open-drain
signals. Most systems will require a pull-up resistor or current
source on this pin. If the IM bit in the configuration register is

84

h

94

h

A4

h

B4

h

C4

h

D4

h

E4

h

F4

h

MIC284 6 September 29, 2000