D ts e t
aa h e
R c e t r lc r nc
o h se Ee to is
Ma u a t r dCo o e t
n fc u e
mp n n s
R c e tr b a d d c mp n ns ae
o h se rn e
o oet r
ma ua trd u ig ete dewaes
n fcue sn i r i/ fr
h
p rh s d f m te oiia s p l r
uc a e r
o h r n l u pi s
g
e
o R c e tr waes rce td f m
r o h se
fr e rae r
o
te oiia I. Al rce t n ae
h
r nl P
g
l e rai s r
o
d n wi tea p o a o teOC
o e t h p rv l f h
h
M.
P r aetse u igoiia fcoy
at r e td sn r n la tr
s
g
ts p o rmso R c e tr e eo e
e t rga
r o h se d v lp d
ts s lt n t g aa te p o u t
e t oui s o u rne
o
rd c
me t o e c e teOC d t s e t
es r x e d h
M aa h e.
Qu l yOv riw
ai
t
e ve
• IO- 0 1
S 90
•A 92 cr ct n
S 1 0 et ai
i
o
• Qu l e Ma ua trr Ls (
ai d
n fcues it QML MI- R -
) LP F
385
53
•C a sQ Mitr
ls
lay
i
•C a sVS a eL v l
ls
p c ee
• Qu l e S p l r Ls o D sr uos( L )
ai d u pi s it f it b tr QS D
e
i
•R c e trsacic l u pir oD A a d
o h se i
r ia s p l t L n
t
e
me t aln u t a dD A sa d r s
es lid sr n L tn ad .
y
R c e tr lcrnc , L i c mmi e t
o h se Ee t is L C s o
o
tdo
t
s p ligp o u t ta s t f c so r x e t-
u pyn rd cs h t ai y u tme e p ca
s
t n fr u lya daee u loto eoiial
i s o q ai n r q a t h s r n l
o
t
g
y
s p l db id sr ma ua trr.
u pi
e yn ut
y n fcues
T eoiia ma ua trr d ts e t c o a yn ti d c me t e e t tep r r n e
h r n l n fcue’ aa h e a c mp n ig hs o u n r cs h ef ma c
g
s
o
a ds e ic t n o teR c e tr n fcue v rino ti d vc . o h se Ee t n
n p c ai s f h o h se ma ua trd eso f hs e ie R c e tr lcr -
o
o
isg aa te tep r r n eo i s mio d co p o u t t teoiia OE s e ic -
c u rne s h ef ma c ft e c n u tr rd cs o h r n l M p c a
o
s
g
t n .T pc lv le aefr eee c p r o e o l. eti mii m o ma i m rt g
i s ‘y ia’ au s r o rfrn e up s s ny C r n nmu
o
a
r xmu ai s
n
ma b b s do p o u t h rceiain d sg , i lt n o s mpetsig
y e a e n rd c c aa tr t , e in smuai , r a l e t .
z o
o
n
© 2 1 R cetr l t n s LC Al i t R sre 0 1 2 1
0 3 ohs E cr i , L . lRg s eevd 7 1 0 3
e e oc
h
T l r m r, l s v iw wrcl . m
o e n oe p ae it w . e c o
a
e
s
o ec
Intelligent Temperature Monitor
and Dual PWM Fan Controller
ADM1031
FEATURES
Optimized for Pentium® III
Reduced guardbanding software
Automatic fan speed control, independent of CPU
intervention after initial setup
Control loop to minimal acoustic noise and battery
consumption
Remote temperature measurement accurate to 1°C using
remote diode (two channels)
0.125°C resolution on external temperature channels
Local sensor with 0.25°C resolution
Pulse width modulation (PWM) fan control for two fans
Programmable PWM frequency and PWM duty cycle
Tach fan speed measurement (two channels)
Analog input to measure fan speed of 2-wire fans (using
sense resistor)
2-wire system management Bus (SMBus) with ARA
support
Overtemperature THERM output pin for CPU throttling
Programmable INT output pin
Configurable offsets for temperature channels 3 V to
5.5 V supply range
Shutdown mode to minimize power consumption
Limit comparison of all monitored values
GENERAL DESCRIPTION
The ADM1031 is an ACPI-compliant, three-channel digital
thermometer and under/over temperature alarm for use in
personal computers and thermal management systems.
Optimized for the Pentium III, the part offers a 1°C higher
accuracy, which allows system designers to safely reduce
temperature guardbanding and increase system performance.
Two PWM fan control outputs control the speed of two cooling
fans by varying output duty cycle. Duty cycle values between
33% and 100% allow smooth control of the fans. The speed of
each fan can be monitored via TACH inputs, which can be
reprogrammed as analog inputs to allow speeds for 2-wire fans
to be measured via sense resistors. The device also detects a
stalled fan. A dedicated fan speed control loop provides control
without the intervention of CPU software. It also ensures that if
the CPU or system locks up, each fan can still be controlled
based on temperature measurements, and the fan speed is
adjusted to correct any changes in system temperature. Fan
speed can also be controlled using existing ACPI software.
Two inputs (four pins) are dedicated to remote temperature-
sensing diodes with an accuracy of
±1°C,
and an on-chip
temperature sensor allows ambient temperature to be monitored.
The device has a programmable INT output to indicate error
conditions, and a dedicated FAN_FAULT output to signal fan
failure. The THERM pin is a fail-safe output for overtemperature
conditions that can be used to throttle a CPU clock.
APPLICATIONS
Notebook PCs, network servers, and personal computers
Telecommunications equipment
V
CC
6
FUNCTIONAL BLOCK DIAGRAM
13
ADD
ADM1031
SLAVE
ADDRESS
REGISTER
FAN FILTER
REGISTER
FAN
CHARACTERISTICS
REGISTER
SERIAL BUS
INTERFACE
ADDRESS
POINTER
REGISTER
15
SDA
16
SCL
14
INT (SMBALERT)
PWM_OUT1
PWM_OUT2
1
3
PWM
CONTROLLERS
FAN SPEED
CONFIG
REGISTER
FAN SPEED
COUNTER
INTERRUPT
STATUS
REGISTERS
LIMIT
COMPARATOR
7
THERM
TACH2/AIN2
4
TACH1/AIN1
2
D1+
10
D1–
9
TACH SIGNAL
CONDITIONING
8
FAN_FAULT
VALUE AND LIMIT
REGISTERS
OFFSET
REGISTERS
CONFIGURATION
REGISTERS
D2+
12
D2–
11
BANDGAP
TEMPERATURE
SENSOR
ANALOG
MULTIPLEXER
ADC
2.5V
BANDGAP
REFERENCE
5
GND
Figure 1.
Rev. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that can result from its use. Specifications subject to change without notice.
No license is granted by implication or otherwise under any patent or patent rights of Analog
Devices.Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
© 2005 Analog Devices, Inc. All rights reserved
02402-001
ADM1031
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 7
Functional Description .................................................................... 9
Internal Registers.......................................................................... 9
Serial Bus Interface....................................................................... 9
Alert Response Address............................................................. 11
Temperature Measurement System.............................................. 12
Internal Measurement................................................................ 12
External Measurement............................................................... 12
Layout Considerations............................................................... 13
Addressing the Device ............................................................... 13
The Interrupt System ................................................................. 13
Using THERM as an Input........................................................ 14
Status Registers ........................................................................... 14
Fan Control Modes of Operation................................................. 15
Automatic Fan Speed Control .................................................. 15
Filtered Control Mode ............................................................... 19
PWM Duty Cycle Select Mode................................................. 22
RPM Feedback Mode................................................................. 22
Fan Drive and Speed Measurement ............................................. 24
Fan Speed Measurement Equations......................................... 24
Fan Drive Using PWM Control ............................................... 24
Fan Speed Measurement ........................................................... 25
Fan Faults..................................................................................... 25
Outline Dimensions ....................................................................... 33
Ordering Guide............................................................................... 33
REVISION HISTORY
9/05—Rev. A to Rev. B
Updated Format..................................................................Universal
Changes to Ordering Guide .......................................................... 33
4/03—Rev. 0 to Rev. A
Added ESD Caution..........................................................................3
Updated Outline Dimensions....................................................... 30
Rev. B | Page 2 of 36
ADM1031
SPECIFICATIONS
T
A
= T
MIN
to T
MAX
, V
CC
= V
MIN
to V
MAX
, unless otherwise noted.
1
Table 1.
Parameter
POWER SUPPLY
Supply Voltage, V
CC
Supply Current, I
CC
TEMPERATURE-TO-DIGITAL CONVERTER
Local Sensor Accuracy
Resolution
Remote Diode1 Sensor Accuracy
Remote Diode2 Sensor Accuracy
Resolution
Remote Sensor Source Current
OPEN-DRAIN DIGITAL OUTPUTS
(THERM, INT, FAN_FAULT, PWM_OUT)
Output Low Voltage, V
OL
High-Level Output Leakage Current, I
OH
OPEN-DRAIN SERIAL DATA BUS OUTPUT (SDA)
Output Low Voltage, V
OL
High-Level Output Leakage Current, I
OH
SERIAL BUS DIGITAL INPUTS (SCL, SDA)
Input High Voltage, V
IH
Input Low Voltage, V
IL
Hysteresis
DIGITAL INPUT LOGIC LEVELS
2
(ADD, THERM, TACH1/2)
Input High Voltage, V
IH
Input Low Voltage, V
IL
DIGITAL INPUT LEAKAGE CURRENT
Input High Current, I
IH
Input Low Current, I
IL
Input Capacitance, C
IN
FAN RPM-TO-DIGITAL CONVERTER
Accuracy
Full-Scale Count
TACH Nominal Input RPM
Min
3.0
Typ
3.30
1.4
32
±1
0.25
±0.5
±0.5
0.125
180
11
Max
5.5
3
50
±3
±1
±1.75
Unit
V
mA
μA
°C
°C
°C
°C
°C
μA
μA
Test Conditions/Comments
Interface inactive, ADC active
Standby mode
60°C ≤ T
D
≤ 100°C
60°C ≤ T
D
≤ 100°C
High level
Low level
0.1
0.4
1
0.4
1
V
μA
V
μA
V
V
mV
I
OUT
= –6.0 mA; V
CC
= 3 V
V
OUT
= V
CC
; V
CC
= 3 V
I
OUT
= –6.0 mA; V
CC
= 3 V
V
OUT
= V
CC
0.1
2.1
0.8
500
2.1
0.8
–1
1
5
±6
255
4400
2200
1100
550
637
V
V
μA
μA
pF
%
RPM
RPM
RPM
RPM
ms
V
IN
= V
CC
V
IN
= 0
60°C ≤ T
A
≤ 100°C
Divisor N = 1, Fan Count = 153
Divisor N = 2, Fan Count = 153
Divisor N = 4, Fan Count = 153
Divisor N = 8, Fan Count = 153
Conversion Cycle Time
Rev. B | Page 3 of 36
ADM1031
Parameter
SERIAL BUS TIMING
3
Clock Frequency, f
SCLK
Glitch Immunity, t
SW
Bus Free Time, t
BUF
Start Setup Time, t
SU;STA
Start Hold Time, t
HD
;
STA
Stop Condition Setup Time, t
SU;STO
SCL Low Time, t
LOW
SCL High Time, t
HIGH
SCL, SDA Rise Time, t
R
SCL, SDA Fall Time, t
F
Data Setup Time, t
SU;DAT
Data Hold Time, t
HD;DAT
1
2
Min
10
Typ
Max
100
Unit
kHz
ns
μs
μs
μs
μs
μs
μs
ns
ns
ns
ns
Test Conditions/Comments
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
50
4.7
4.7
4
4
1.3
4
50
1000
300
250
300
Typicals are at T
A
= 25°C and represent most likely parametric norm. Shutdown current typ is measured with V
CC
= 3.3 V.
ADD is a three-state input that can be pulled high, low, or left open-circuit.
3
Timing specifications are tested at logic levels of V
IL
= 0.8 V for a falling edge and V
IH
= 2.2 V for a rising edge.
Rev. B | Page 4 of 36
Microcontroller MCU
京公网安备 11010802033920号
EEWORLD
