ADT7460
Remote Thermal Monitor
and Fan Controller
The ADT7460 controller is a thermal monitor and multiple PWM
fan controller for noise-sensitive applications requiring active system
cooling. It can monitor the temperature of up to two remote sensor
diodes plus its own internal temperature. It can measure and control
the speed of up to four fans so that they operate at the lowest possible
speed for minimum acoustic noise. The automatic fan speed control
loop optimizes fan speed for a given temperature. A unique dynamic
T
MIN
control mode enables the system thermals/acoustics to be
intelligently managed. The effectiveness of the system’s thermal
solution can be monitored using the THERM input. The ADT7460
also provides critical thermal protection to the system by using the
bidirectional THERM pin as an output to prevent system or
component overheating.
Features
http://onsemi.com
QSOP−16
CASE 492
PIN ASSIGNMENT
SCL
GND
V
CC
TACH3
PWM2/
SMBALERT
TACH1
TACH2
PWM3/
ADDR ENABLE
SDA
PWM1/XTO
V
CCP
D1+
D1−
D2+
D2−
TACH4/ADDR
SELECT/
THERM
•
Controls and Monitors Up to 4 Fans
•
1 On-chip and 2 Remote Temperature Sensors
•
Dynamic T
MIN
Control Mode Optimizes System Acoustics
•
•
•
•
•
•
•
•
1
2
3
4
5
6
7
8
16
15
14
ADT7460
13
12
11
10
9
Intelligently
Automatic Fan Speed Control Mode Controls System Cooling
Based on Measured Temperature
Enhanced Acoustic Mode Dramatically Reduces User Perception
of Changing Fan Speeds
Thermal Protection Feature via THERM Output
Monitors Performance Impact of Intel
®
Pentium
®
4 Processor
Processor Thermal Control Circuit via THERM Input
2-wire and 3-wire Fan Speed Measurement
Limit Comparison of All Monitored Values
This is a Pb-Free Device
(Top View)
MARKING DIAGRAM
Applications
T7460A
RQZ
#YYWW
•
Low Acoustic Noise PCs
•
Networking and Telecommunications Equipment
T7460ARQZ= Specific Device Code
#
= Pb-Free Package
YY
= Date Code
WW
= Work Week
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 46 of this data sheet.
©
Semiconductor Components Industries, LLC, 2013
September, 2013
−
Rev. 9
1
Publication Order Number:
ADT7460/D
ADT7460
ADDR
SELECT
ADDR_EN
SCL
SDA
SMBALERT
SMBUS
ADDRESS
SELECTION
AUTOMATIC
FAN SPEED
CONTROL
DYNAMIC
T
MIN
CONTROL
FAN SPEED
COUNTER
SERIAL BUS
INTERFACE
ADDRESS
POINTER
REGISTER
PWM1
PWM2
PWM3
TACH1
TACH2
TACH3
TACH4
PWM REGISTERS
AND
CONTROLLERS
ACOUSTIC
ENHANCEMENT
CONTROL
PWM
CONFIGURATION
REGISTERS
INTERRUPT
MASKING
PERFORMANCE
MONITORING
THERM
V
CC
D1+
D1−
D2+
D2−
+2.5V
IN
BAND GAP
TEMP SENSOR
V
CC
TO ADT7460
THERMAL
PROTECTION
ADT7460
INPUT
SIGNAL
CONDITIONING
AND
ANALOG
MULTIPLEXER
INTERRUPT
STATUS
REGISTERS
10-BIT
ADC
LIMIT
COMPARATORS
VALUE AND
LIMIT
REGISTERS
BAND GAP
REFERENCE
GND
Figure 1. Functional Block Diagram
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Positive Supply Voltage (V
CC
)
Voltage on Any Input or Output Pin
Input Current at Any Pin
Package Input Current
Maximum Junction Temperature (T
J MAX
)
Storage Temperature Range
Lead Temperature, Soldering
IR Reflow Peak Temperature
IR Reflow Peak Temperature for Pb-Free
Lead Temperature (Soldering, 10 sec)
Rating
6.5
−0.3
to +6.5
±5
±20
150
−65
to +150
220
260
300
Unit
V
V
mA
mA
°C
°C
°C
ESD Rating
1500
V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
NOTE: This device is ESD sensitive. Use standard ESD precautions when handling.
http://onsemi.com
2
ADT7460
Table 2. THERMAL CHARACTERISTICS
Package Type
16-lead QSOP
q
JA
150
q
JC
39
Unit
°C/W
1.
q
JA
is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages.
Table 3. PIN ASSIGNMENT
Pin No.
1
2
3
Mnemonic
SCL
GND
V
CC
Description
Digital Input (Open-Drain). SMBus serial clock input. Requires SMBus pullup.
Ground Pin for the ADT7460.
Power Supply. Can be powered by 3.3 V standby if monitoring in low power states is required.
V
CC
is also monitored through this pin. The ADT7460 can also be powered from a 5.0 V
supply. Setting Bit 7 of Configuration Register 1 (Reg. 0x40) rescales the V
CC
input attenuators
to correctly measure a 5.0 V supply.
Digital Input (Open-Drain). Fan tachometer input to measure speed of Fan 3. Can be
reconfigured as an analog input (AIN3) to measure the speed of 2-wire fans.
Digital Output (Open-Drain). Requires 10 kW typical pullup. Pulse-width modulated output to
control Fan 2 speed.
Digital Output (Open-Drain). This pin may be reconfigured as an SMBALERT interrupt output
to signal out-of-limit conditions.
Digital Input (Open-Drain). Fan tachometer input to measure speed of Fan 1. Can be
reconfigured as an analog input (AIN1) to measure the speed of 2-wire fans.
Digital Input (Open-Drain). Fan tachometer input to measure speed of Fan 2. Can be
reconfigured as an analog input (AIN2) to measure the speed of 2-wire fans.
Digital I/O (Open-Drain). Pulse-width modulated output to control Fan 3/4 speed. Requires
10 kW typical pullup.
If pulled low on powerup, this places the ADT7460 into address select mode, and the state of
Pin 9 determines the ADT7460’s slave address.
Digital Input (Open-Drain). Fan tachometer input to measure speed of Fan 4. Can be
reconfigured as an analog input (AIN4) to measure the speed of 2-wire fans.
If in address select mode, this pin determines the SMBus device address.
Alternatively, the pin may be reconfigured as a bidirectional THERM pin. Can be used to time
and monitor assertions on the THERM input. For example, can be connected to the
PROCHOT output of Intel’s Pentium
®
4 processor or to the output of a trip point temperature
sensor. Can be used as an output to signal overtemperature conditions.
Cathode Connection to Second Thermal Diode.
Anode Connection to Second Thermal Diode.
Cathode Connection to First Thermal Diode.
Anode Connection to First Thermal Diode.
Analog Input. Monitors 2.5 V supply, typically a chipset voltage.
Digital Output (Open-Drain). This pin may be reconfigured as an SMBALERT interrupt output
to signal out-of-limit conditions.
Digital Output (Open-Drain). Pulse-width modulated output to control Fan 1 speed. Requires
10 kW typical pullup.
Digital I/O (Open-Drain). SMBus bidirectional serial data. Requires SMBus pullup.
4
5
TACH3
PWM2
SMBALERT
6
7
8
TACH1
TACH2
PWM3
ADDRESS ENABLE
9
TACH4
ADDRESS SELECT
THERM
10
11
12
13
14
D2−
D2+
D1−
D1+
+2.5 V
IN
SMBALERT
15
16
PWM1/XTO
SDA
http://onsemi.com
3
ADT7460
Table 4. ELECTRICAL CHARACTERISTICS
(T
A
= T
MIN
to T
MAX
, V
CC
= V
MIN
to V
MAX
, unless otherwise noted.)
Parameter
(Note 1)
POWER SUPPLY
Supply Voltage
Supply Current, I
CC
Interface Inactive, ADC Active
Standby Mode
0°C
≤
T
A
≤
70°C
−40°C
≤
T
A
≤
+120°C
0°C
≤
T
A
≤
70°C; 0°C
≤
T
D
≤
120°C
0°C
≤
T
A
≤
105°C; 0°C
≤
T
D
≤
120°C
0°C
≤
T
A
≤
120°C; 0°C
≤
T
D
≤
120°C
High Level
Low Level
3.0
−
−
−
−
−
−
−
−
−
−
−
−
8 Bits
Averaging Enabled
Averaging Enabled
Averaging Enabled
Averaging Enabled (Incl. Delay) (Note 3)
Averaging Disabled
−
−
−
−
−
−
−
80
0°C
≤
T
A
≤
70°C
0°C
≤
T
A
≤
105°C
−40°C
≤
T
A
≤
+120°C
Fan Count = 0xBFFF
Fan Count = 0x3FFF
Fan Count = 0x0438
Fan Count = 0x021C
−
−
−
−
−
−
−
−
82.8
−
I
OUT
=
−8.0
mA, V
CC
= 3.3 V
V
OUT
= V
CC
I
OUT
=
−4.0
mA, V
CC
= 3.3 V
V
OUT
= V
CC
−
−
−
−
2.0
−
−
2.0
−
−
−0.3
5.0
−
−
−
−
0.25
−
−
−
0.25
180
11
−
−
±0.1
11.38
12.09
25.59
120.17
13.51
140
−
−
−
−
109
329
5000
10000
90.0
−
−
0.1
−
0.1
−
−
500
−
−
−
−
5.5
3.0
20
±1.5
±3.0
−
±1.5
±2.5
±3.0
−
−
−
±1.5
±1.0
−
13
13.50
28
134.50
15
200
±7
±11
±13
65,535
−
−
−
−
97.2
8.0
0.4
1.0
0.4
1.0
−
0.4
−
−
5.5
+0.8
−
RPM
V
mA
mA
°C
°C
°C
Test Conditions/Comments
Min
Typ
(Note 2)
Max
Unit
TEMPERATURE-TO-DIGITAL CONVERTER
Local Sensor Accuracy
Resolution
Remote Diode Sensor Accuracy
Resolution
Remote Sensor Source Current
°C
mA
ANALOG-TO-DIGITAL CONVERTER (INCLUDING MUX AND ATTENUATORS)
Total Unadjusted Error, TUE
Differential Non-linearity, DNL
Power Supply Sensitivity
Conversion Time (Voltage Input)
Conversion Time (Local Temperature)
Conversion Time (Remote Temperature)
Total Monitoring Cycle Time
Input Resistance
FAN RPM-TO-DIGITAL CONVERTER
Accuracy
%
%
LSB
%/V
ms
ms
ms
ms
kW
Full-scale Count
Nominal Input RPM
Internal Clock Frequency
OPEN-DRAIN DIGITAL OUTPUTS, PWM1–PWM3, XTO
Current Sink, I
OL
Output Low Voltage, V
OL
High Level Output Current, I
OH
Output Low Voltage, V
OL
High Level Output Current, I
OH
SMBUS DIGITAL INPUTS (SCL, SDA)
Input High Voltage, V
IH
Input Low Voltage, V
IL
Hysteresis
DIGITAL INPUT LOGIC LEVELS (TACH INPUTS)
Input High Voltage, V
IH
Input Low Voltage, V
IL
Maximum Input Voltage
Minimum Input Voltage
kHz
mA
V
mA
V
mA
V
V
mV
V
V
OPEN-DRAIN SERIAL DATA BUS OUTPUT (SDA)
http://onsemi.com
4
ADT7460
Table 4. ELECTRICAL CHARACTERISTICS
(T
A
= T
MIN
to T
MAX
, V
CC
= V
MIN
to V
MAX
, unless otherwise noted.)
Parameter
(Note 1)
DIGITAL INPUT LOGIC LEVELS (TACH INPUTS)
Hysteresis
DIGITAL INPUT LOGIC LEVELS (THERM)
Input High Voltage, V
IH
Input Low Voltage, V
IL
DIGITAL INPUT CURRENT
Input High Current, I
IH
Input Low Current, I
IL
Input Capacitance, C
IN
SERIAL BUS TIMING
(Note 4)
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
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
Detect Clock Low Timeout, t
TIMEOUT
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
See Figure 2
Can be Optionally Disabled
See Figure 2
−
−
1.3
0.6
0.6
1.3
0.6
−
−
100
15
−
−
−
−
−
−
−
−
−
−
−
400
50
−
−
−
−
−
300
300
−
35
kHz
ns
ms
ms
ms
ms
ms
ns
ms
ns
ms
V
IN
= V
CC
V
IN
= 0
−1.0
−
−
−
−
5.0
−
+1.0
−
mA
mA
pF
1.7
−
−
−
−
0.8
V
V
−
0.5
−
Vp−p
Test Conditions/Comments
Min
Typ
(Note 2)
Max
Unit
1. All voltages are measured with respect to GND, unless otherwise specified. Logic inputs accept input high voltages up to V
MAX
even when
the device is operating below V
MIN
. Timing specifications are tested at logic levels of V
IL
= 0.8 V for a falling edge and at V
IH
= 2.0 V for a
rising edge.
2. Typicals are at T
A
= 25°C and represent the most likely parametric norm.
3. The delay is the time between the round robin finishing one set of measurements and starting the next.
4. Guaranteed by design; not production tested
t
LOW
SCL
t
F
t
R
t
HD; STA
t
HD; STA
t
HD; DAT
t
HIGH
t
SU; DAT
t
SU; STA
t
SU; STO
SDA
P
t
BUF
S
S
P
Figure 2. Serial Bus Timing Diagram
http://onsemi.com
5
京公网安备 11010802033920号
EEWORLD
