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ADT7466ARQZ-RL7

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36P37-P39P40-P42P43-P45P46-P48
dB
Cool
®
Remote Thermal
Controller and Voltage Monitor
ADT7466
©2008 SCILLC. All rights reserved. Publication Order Number:
January 2008 – Rev. 2 ADT7466/D
FEATURES
Monitors two analog voltages or thermistor temperature
inputs
One on-chip and up to two remote temperature sensors with
series resistance cancellation
Controls and monitors the speed of up to two fans
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
thermal control circuit via
PROCHOT
input
3-wire fan speed measurement
Limit comparison of all monitored values
SMBus 1.1 serial interface
APPLICATIONS
Low acoustic noise notebook PCs
GENERAL DESCRIPTION
The ADT7466 dBCool controller is a complete thermal monitor
and dual fan controller for noise-sensitive applications
requiring active system cooling. It can monitor two analog
voltages or the temperature of two thermistors, plus its own
supply voltage. 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 two 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. The effectiveness of the system’s
thermal solution can be monitored using the
PROCHOT
input
to time and monitor the
PROCHOT
output of the processor.
FUNCTIONAL BLOCK DIAGRAM
SERIAL BUS
INTERFACE
CONFIGURATION
REGISTERS
THERM
REGISTER
INTERRUPT
MASKING
ADDRESS
POINTER
REGISTER
INTERRUPT
STATUS
REGISTERS
VALUE AND
LIMIT
REGISTERS
ACOUSTIC
ENHANCEMENT
CONTROL
AUTOMATIC
FAN SPEED
CONTROL
LIMIT
COMPARATORS
FAN
SPEED
MONITOR
V_FAN_MIN
V_FAN_ON
CONTROL
8-BIT
DAC
8-BIT
DAC
V
CC
GND REFOUT
SCL SDA ALERT
BAND GAP
REFERENCE
10-BIT
ADC
DRIVE1
DRIVE2
TACH1
TACH2
FANLOCK
FAN1_ON/
PROCHOT/
THERM
D1+
D1–
AIN1/TH1/D2–
AIN2/TH2/D2+
SERIES
RESISTANCE
CANCELLATION
BAND GAP
TEMPERATURE
SENSOR
SERIES
RESISTANCE
CANCELLATION
INPUT
SIGNAL
CONDITIONING
AND
ANALOG
MULTIPLEXER
FAN1
ENABLE
PROCHOT
ADT7466
04711-001
Figure 1.
Protected by U.S. Patent Numbers 6,188,189; 6,169,442; 6,097,239; 5,982,221; 5,867,012.
ADT7466
Rev. 2 | Page 2 of 48 | www.onsemi.com
TABLE OF CONTENTS
Specifications .....................................................................................3
Serial Bus Timing..........................................................................5
Absolute Maximum Ratings ............................................................6
Thermal Characteristics...............................................................6
ESD Caution ..................................................................................6
Pin Configuration and Function Descriptions .............................7
Typical Performance Characteristics..............................................8
Functional Description...................................................................11
Measurement Inputs...................................................................11
Sequential Measurement............................................................11
Fan Speed Measurement and Control......................................11
Internal Registers of the ADT7466...........................................11
Theory of Operation.......................................................................12
Serial Bus Interface .....................................................................12
Write and Read Operations .......................................................14
Alert Response Address (ARA) ................................................15
SMBus Timeout...........................................................................15
Voltage Measurement.................................................................15
Reference Voltage Output ..........................................................16
Configuration of Pin 11 and Pin 12..........................................16
Temperature Measurement........................................................17
Series Resistance Cancellation ..................................................17
Temperature Measurement Method.........................................17
Using Discrete Transistors .........................................................17
Temperature Measurement Using Thermistors......................19
Reading Temperature from the ADT7466 ..............................21
Additional ADC Functions .......................................................22
Limit Values.................................................................................22
Alert Interrupt Behavior ............................................................23
Configuring the ADT7466
THERM
Pin as an Output .........26
Fan Drive......................................................................................27
PWM or Switch Mode Fan Drive .............................................27
Fan Speed Measurement............................................................27
Fan Start-Up Timeout ................................................................29
Automatic Fan Speed Control...................................................30
Starting the Fan ...........................................................................31
XOR Test Mode ...............................................................................32
Application Circuit .........................................................................33
ADT7466 Register Map..................................................................34
Register Details............................................................................36
Outline Dimensions........................................................................48
Ordering Guide ...........................................................................48
REVISION HISTORY
01/08—Rev 2: Correction to ON Semiconductor Logo
12/07—Rev 1: Conversion to ON Semiconductor
06/05—Revision 0: Initial Version
ADT7466
Rev. 2 | Page 3 of 48 | www.onsemi.com
SPECIFICATIONS
T
A
= T
MIN
to T
MAX
, V
CC
= V
MIN
to V
MAX
, unless otherwise noted.
1
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
POWER SUPPLY
Supply Voltage 3.0 3.3 5.5 V
Supply Current, I
CC
1.4 3 mA Interface inactive, ADC active
30 70 μA Standby mode, digital inputs low
TEMPERATURE-TO-DIGITAL
CONVERTER
Local Sensor Accuracy ±1 °C 20°C ≤ T
A
≤ 60°C; V
CC
= 3.3 V
±3 °C −40°C ≤ T
A
≤ +125°C; V
CC
= 3.3 V
Resolution 0.25 °C
Remote Diode Sensor Accuracy ±1 °C 20°C ≤ T
A
≤ 60°C; −40°C ≤ T
D
≤ +125°C; V
CC
= 3.3 V
±3 °C −40°C ≤T
A
≤ +105°C; −40°C ≤ T
D
≤ +125°C; V
CC
= 3.3 V
±5 °C −40°C ≤ T
A
≤ +125°C; −40°C ≤ T
D
≤ +125°C
Resolution 0.25 °C
Remote Sensor Source Current 192 μA High level
72 μA Mid level
12 μA Low level
Series Resistance Cancellation 0 2 kΩ Maximum resistance in series with thermal diode that can be
cancelled out
THERMISTOR-TO-DIGITAL CONVERTER
Temperature Range 30 100 °C Range over which specified accuracy is achieved. Wider range
can be used with less accuracy.
Resolution 0.25 °C
Accuracy ±2 °C Using specified thermistor and application circuit over specified
temperature range
ANALOG-TO-DIGITAL CONVERTER
Input Voltage Range 0 V
REF
V V
REF
= 2.25V
Total Unadjusted Error (TUE) ±1 ±2.5 %
Differential Nonlinearity (DNL) ±1 LSB
Power Supply Sensitivity ±1 %/V
Conversion Time (A
IN
Input) 8.30 8.65 ms Averaging enabled
Conversion Time (Local
Temperature)
8.63 8.99 ms Averaging enabled
Conversion Time (Remote
Temperature)
35.22 36.69 ms Averaging enabled
Conversion Time (V
CC
) 7.93 8.26 ms Averaging enabled
Total Monitoring Cycle Time 68.38 71.24 ms Averaging enabled, Pin 11 and Pin 12 configured for AIN/TH
monitoring (see Table 15)
Total Monitoring Cycle Time 87 90.63 ms Averaging enabled, Pin 11 and Pin 12 configured for REM2
monitoring (see Table 15)
FAN RPM-TO-DIGITAL CONVERTER
Accuracy ±4 %
Full-Scale Count 65,535
Nominal Input RPM 109 RPM Fan count = 0xBFFF
329 RPM Fan count = 0x3FFF
5000 RPM Fan count = 0x0438
10000 RPM Fan count = 0x021C
Internal Clock Frequency 78.64 81.92 85.12 kHz
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36P37-P39P40-P42P43-P45P46-P48

ADT7466ARQZ-RL7

Mfr. #:
Buy ADT7466ARQZ-RL7
Manufacturer:
ON Semiconductor
Description:
Board Mount Temperature Sensors RMT THRM CTR VLT MON
Lifecycle:
New from this manufacturer.
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