ADT7476ARQZ ON Semiconductor, ADT7476ARQZ Datasheet - Page 55

• Manufacturer Part Number: ADT7476ARQZ
• Description: IC REMOTE THERMAL CTRLR 24QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7476ARQZ

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Counter, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 24-QSOP
• Full Temp Accuracy: +/- 0.5 C
• Digital Output - Bus Interface: Serial (3-Wire, 4-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1. These registers become read−only when the Configuration Register 1 lock bit is set to 1. Any subsequent attempts to write to these registers fail.
Table 30. PWM Configuration Registers
Bit No.
[2:0]
[7:5]
Register Address
[3]
[4]
0x5C
0x5D
0x5E
Name
BHVR
SPIN
RES
INV
R/W (Note 1)
R/W
R/W
R/W
R/W
R/W
R/W
R/W
N/A
These bits control the startup timeout for PWMx. The PWM output stays high until two valid
TACH rising edges are seen from the fan. If there is not a valid TACH signal during the fan
TACH measurement directly after the fan startup timeout period, the TACH measurement
reads 0xFFFF and Interrupt Status Register 2 reflects the fan fault. If the TACH minimum
high and low bytes contain 0xFFFF or 0x0000, the Interrupt Status Register 2 bit is not set,
even if the fan has not started.
000 = No startup timeout
001 = 100 ms
010 = 250 ms (default)
011 = 400 ms
100 = 667 ms
101 = 1 sec
110 = 2 sec
111 = 4 sec
Reserved. Do not write to this bit.
This bit inverts the PWM output. The default is 0, which corresponds to a logic high output for
100% duty cycle. Setting this bit to 1 inverts the PWM output, so 100% duty cycle
corresponds to a logic low output.
These bits assign each fan to a particular temperature sensor for localized cooling.
000 = Remote 1 temperature controls PWMx (automatic fan control mode).
001 = Local temperature controls PWMx (automatic fan control mode).
010 = Remote 2 temperature controls PWMx (automatic fan control mode).
011 = PWMx runs full speed (default).
100 = PWMx disabled.
101 = Fastest speed calculated by local and Remote 2 temperature controls PWMx.
110 = Fastest speed calculated by all three temperature channel controls PWMx.
111 = Manual mode. PWM current duty cycle registers (0x30 to 0x32) become writable.
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PWM1 configuration
PWM2 configuration
PWM3 configuration
Description
55
Description
Power−On Default
0x62
0x62
0x62