Document
DATA SHEET www.onsemi.com
Remote Thermal Controller and Voltage Monitor
ADT7476A
The ADT7476A controller is a thermal monitor and multiple PWM fan controller for noise-sensitive or power-sensitive applications requiring active system cooling. The ADT7476A can drive a fan using either a low or high frequency drive signal and can monitor the temperature of up to two remote sensor diodes plus its own internal temperature. The part also measures and controls the speed of up to four fans, so the fans 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 THERM input. The ADT7476A also provides critical thermal protection to the system using the bidirectional THERM pin as an output to prevent system or component overheating.
Features
• Monitors Up to Five Voltages • Improved TACH and PWM Performance • Controls and Monitors Up to Four Fans • High and Low Frequency Fan Drive Signal • One On-Chip and Two Remote Temperature Sensors • Extended Temperature Measurement Range Up to 191°C • 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 THERM Input • 3-wire and 4-wire Fan Speed Measurement • Limit Comparison of All Monitored Values • 5.0 V Support on all TACH and PWM Channels • Meets SMBus 2.0 Electrical Specifications • This Device is Pb-Free, Halogen Free and is RoHS Compliant
QSOP−24 NB CASE 492B
PIN ASSIGNMENT
SDA 1
24 PWM1/XTO
SCL 2 GND 3 VCC 4 VID0/GPIO0 5 VID1/GPIO1 6 VID2/GPIO2 7 VID3/GPIO3 8
ADT7476A (Top View)
23 VCCP 22 +2.5VIN/THERM 21 +12VIN/VID5 20 +5VIN 19 VID4/GPIO4 18 D1+ 17 D1−
TACH3 9 PWM2/
10 SMBALERT
TACH1 11
16 D2+ 15 D2− 14 *
TACH2 12
13 PWM3/ADDREN
*TACH4/THERM/SMBALERT/GPIO6/ADDR SELECT
MARKING DIAGRAMS
ADT7476AARQZ #YYWW xxxx
ADT7476AARQZ = Specific Device Code
#
= Pb-Free Package
YYWW
= Date Code
xxxx
= Assembly Lot Code
ORDERING INFORMATION
See detailed ordering and shipping information in the package dimensions section on page 68 of this data sheet.
© Semiconductor Components Industries, LLC, 2016
1
May, 2022 − Rev. 8
Publication Order Number: ADT7476A/D
VID5/GPIO5 VID4/GPIO4 VID3/GPIO3 VID2/GPIO2 VID1/GPIO1 VID0/GPIO0
GPIO6 PWM1 PWM2 PWM3 TACH1 TACH2 TACH3 TACH4
THERM
VCC D1+ D1− D2+ D2− +5VIN +12VIN +2.5VIN VCCP
ADT7476A
ADDR ADDREN SELECT SCL SDA SMBALERT
ADT7476A
VID/GPIO REGISTER
SMBus ADDRESS SELECTION
PWM REGISTERS AND CONTROLLERS
(HF AND LF)
AUTOMATIC FAN SPEED CONTROL
FAN SPEED COUNTER
SERIAL BUS INTERFACE
ADDRESS POINTER REGISTER
PWM CONFIGURATION
REGISTERS
INTERRUPT MASKING
VCC TO ADT7476A
BAND GAP TEMP. SENSOR
PERFORMANCE MONITORING
THERMAL PROTECTION
INPUT SIGNAL CONDITIONING
AND ANALOG MULTIPLEXER
ACOUSTIC ENHANCEMENT
CONTROL
10-BIT ADC
BAND GAP REFERENCE
INTERRUPT STATUS
REGISTERS
LIMIT COMPARATORS
VALUE AND LIMIT
REGISTERS
GND Figure 1. Functional Block Diagram
SCL
SDA
tBUF
P
S
t LOW tR
tHD; STA
tHD; DAT
tF tHIGH
tSU; DAT
t HD; STA tSU; STA
S
Figure 2. Serial Bus Timing Diagram
tSU; STO P
www.onsemi.com 2
ADT7476A
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Rating
Unit
Positive Supply Voltage (VCC) Maximum Voltage on +12VIN Pin Maximum Voltage on +5.0VIN Pin Maximum Voltage on SDA, SCL, THERM (Pin 22) and GPIO1−5 Pins
Maximum Voltage on all Tach and PWM Pins
Voltage on Remaining Input or Output Pins
Input Current at Any Pin
Package Input Current
Maximum Junction Temperature (TJ MAX) Storage Temperature Range
Lead Temperature, Soldering IR Reflow Peak Temperature Pb-Free Peak Temperature Lead Temperature (Soldering, 10 sec)
3.6
V
16
V
6.25
V
3.6
V
+5.5
V
−0.3 to +4.2
V
±5
mA
±20
mA
150
°C
−65 to +150
°C
°C 220 260 300
ESD Rating
1,500
V
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected.
NOTE: This device is ESD sensitive. Use standard ESD precautions when handling.
Table 2. THERMAL CHARACTERISTICS (Note 1)
Package Type
qJA
qJC
24-lead QSOP
122
31.25
1. JA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages.
Table 3. ELECTRICAL CHARACTERISTICS (TA = TMIN to TMAX, VCC = VMIN to VMAX, unless otherwise noted) (Note 1)
Parameter
Conditions
Power Supply
Supply Voltage
Supply Current, ICC Temperature-to-Digital Converter
Interface Inactive, ADC Active
Local Sensor Accuracy Resolution
0°C ≤ TA ≤ 85°C −40°C ≤ TA ≤ 125°C
Remote Diode Sensor Accuracy Resolution
0°C.