ADT7476ARQZ ON Semiconductor, ADT7476ARQZ Datasheet - Page 57

• 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. This register becomes read−only when the Configuration Register 1 lock bit is set to 1. Any further attempts to write to this register have no effect.
2. Setting the relevant bit of Configuration Register 6 (0x10, [2:0]) further decreases these ramp rates by a factor of 4.
Table 32. Register 0x62 — Enhanced Acoustics Register 1 (Power−On Default = 0x00)
Bit No.
[2:0]
[3]
[4]
[5]
[6]
[7]
Mnemonic
(Note 2)
ACOU
SYNC
MIN1
MIN2
MIN3
EN1
R/W (Note 1)
R/W
R/W
R/W
R/W
R/W
R/W
When Bit 7 of Configuration Register 6 (0x10) is 0
Time Slot Increase
When Bit 7 of Configuration Register 6 (0x10) is 1
Time Slot Increase
000 = 1
001 = 2
010 = 3
011 = 4
100 = 8
101 = 12
110 = 24
111 = 48
000 = 1
001 = 2
010 = 3
011 = 4
100 = 8
101 = 12
110 = 24
111 = 48
Assuming that PWMx is associated with the Remote 1 temperature channel, these bits define
the maximum rate of change of the PWMx output for Remote 1 temperature related changes.
Instead of the fan speed jumping instantaneously to its newly determined speed, it ramps
gracefully at the rate determined by these bits. This feature ultimately enhances the acoustics of
the fan.
When this bit is 1, smoothing is enabled on Remote 1 temperature channel.
SYNC = 1 synchronizes fan speed measurements on TACH2, TACH3, and TACH4 to PWM3.
This allows up to three fans to be driven from PWM3 output and their speeds to be measured.
SYNC = 0 synchronizes only TACH3 and TACH4 to PWM3 output.
When the ADT7476 is in automatic fan control mode, this bit defines whether PWM1 is off
(0% duty cycle) or at PWM1 minimum duty cycle when the controlling temperature is below
its T
0 = 0% duty cycle below T
1 = PWM1 minimum duty cycle below T
When the ADT7476 is in automatic fan speed control mode, this bit defines whether PWM2 is
off (0% duty cycle) or at PWM2 minimum duty cycle when the controlling temperature is
below its T
0 = 0% duty cycle below T
1 = PWM2 minimum duty cycle below T
When the ADT7476 is in automatic fan speed control mode, this bit defines whether PWM3 is
off (0% duty cycle) or at PWM3 minimum duty cycle when the controlling temperature is
below its T
0 = 0% duty cycle below T
1 = PWM3 minimum duty cycle below T
MIN
− hysteresis value.
MIN
MIN
http://onsemi.com
− hysteresis value.
– hysteresis value.
57
MIN
MIN
MIN
– hysteresis.
– hysteresis.
– hysteresis.
MIN
MIN
MIN
Description
– hysteresis.
– hysteresis.
– hysteresis.
Time for 0% to 100%
Time for 0% to 100%
37.5 sec
18.8 sec
12.5 sec
7.5 sec
4.7 sec
3.1 sec
1.6 sec
0.8 sec
52.2 sec
26.1 sec
17.4 sec
10.4 sec
6.5 sec
4.4 sec
2.2 sec
1.1 sec