Note 1: Guaranteed but not 100% tested.

diode-connected 2N3906 transistor with ideality factor = 1.013. Variations in the ideality factor “m” of the actual transistor

used will increase the temperature error by *. See the Temperature Error vs. Remote Diode Temperature graph in the

Typical Operating Characteristics for typical temperature errors using several random 2N3906s. See Remote Diode

Selection for remote diode forward-voltage requirements.

Note 3: The SMBus logic block is a static design that works with clock frequencies down to DC. While slow operation is possible, it

violates the 10kHz minimum clock frequency and SMBus specifications, and may monopolize the bus.

Note 4: Note that a transition must internally provide at least a hold time in order to bridge the undefined region (300ns max) of

SMBCLK’s falling edge.

Note 5: Specifications to -40°C are guaranteed by design and not production tested.

Fan Controller and Remote Temperature Sensor

with SMBus Serial Interface

4

_______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

Pin forced to 0.4V

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;

Pin forced to 5.5V

µA

-1

1

Logic Input Current

µA

1

ALERT, OVERT, I/O1, I/O2 Output

High Leakage Current

V

0.2

FAN Output Voltage Low

mA

6

SMBDATA, ALERT, OVERT, I/O1, I/O2

Output Low Sink Current

V

0.8

Logic Input Low Voltage

V

2.1

Logic Input High Voltage

DAC mode, FAN duty factor = 1111b,

Ω to GND

PWM mode, any setting

Monotonicity guaranteed

Autoconvert mode

From stop bit to conversion complete

Autoconvert mode, average measured over

1sec, FAN output set to 150Hz mode

CONDITIONS

V

2.94

FAN Output Voltage High

%FS

-5

5

FAN Total Unadjusted Error

%

-25

+25

FAN PWM Frequency Error

mA

-10

FAN Output Sink Current

mA

10

FAN Output Source Current

Hz

1.6

2.4

Conversion Rate

ms

47

Conversion Time

µA

100

Average Operating Supply Current

Bits

8

Temperature Resolution (Note 1)

°C

-5

5

Temperature Error, Remote Diode (Note 2)

UNITS

MIN

MAX

PARAMETER

DAC mode, FAN duty factor = 0000b,

V

3

5.5

Supply Voltage Range

ADC AND POWER SUPPLY

FAN OUTPUT

SMBus INTERFACE

*

.

.

∆T

m

kT

C

R

=−









+

1 013

1

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