ADT7476AARQZ-REEL ON Semiconductor, ADT7476AARQZ-REEL Datasheet - Page 46

• Manufacturer Part Number: ADT7476AARQZ-REEL
• Description: IC REMOTE THERMAL CTRLR 24-QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7476AARQZ-REEL

• 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
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Fan Sync
to synchronize them so that one PWM channel from each
device can be effectively OR’ed together to create a PWM
output that reflects the maximum speed of the two OR’ed
PWMs. This OR’ed PWM can in turn be used to drive a
chassis fan.
Standby Mode
respond to the STBY supply. In computers that support S3
and S5 states, the core voltage of the processor is lowered in
these states. When monitoring THERM, the THERM timer
should be disabled during these states.
the following occurs:
limit, everything is re-enabled and the system resumes
normal operation.
XNOR Tree Test Mode
mode is useful for in-circuit test equipment at board-level
testing. By applying stimulus to the pins included in the
XNOR tree, it is possible to detect opens, or shorts, on the
system board.
the XNOR Tree Test Enable Register (0x6F).
Register Tables
Table 14. ADT7476A Registers
Addr
0x10
0x20
0x21
0x22
0x23
0x24
0x25
0x11
When two ADT7476As are used in a system, it is possible
The ADT7476A has been specifically designed to
When the V
Once the core voltage, V
The ADT7476A includes an XNOR tree test mode. This
The XNOR tree test is invoked by setting Bit 0 (XEN) of
1. Status Bit 1 (V
2. SMBALERT is generated, if enabled.
3. THERM monitoring is disabled. The THERM
is set.
timer should hold its value prior to the S3 or S5
state.
R/W
R/W
R/W
R
R
R
R
R
R
CCP
Measurement
Measurement
Measurement
Measurement
Measurement
Configuration
Configuration
Temperature
Register 6
Register 7
Remote 1
voltage drops below the V
Desc
V
2.5 V
5.0 V
12 V
V
CCP
CC
CCP
) in Interrupt Status Register 1
CCP
, goes above the V
Bit 7
Extra
Slow
RES
9
9
9
9
9
9
Bit 6
V
RES
Low
CCP
8
8
8
8
8
8
CCP
low limit,
CCP
Master
Bit 5
RES
http://onsemi.com
En
7
7
7
7
7
7
low
SlaveEn
46
Bit 4
RES
6
6
6
6
6
6
XNOR tree test mode.
Power-On Default
default and the PWM outputs go to 100%. All necessary
registers then need to be configured via the SMBus for the
appropriate functions to operate.
Figure 66 shows the signals that are exercised in the
When the ADT7476A is powered up, monitoring is off by
THERM
Manual
Bit 3
RES
in
5
5
5
5
5
5
SlowFan
Remote
Figure 66. XNOR Tree Test
Bit 2
RES
1
4
4
4
4
4
4
TACH1
TACH2
TACH3
TACH4
PWM2
PWM3
VID0
VID1
VID2
VID3
VID4
SlowFan
Bit 1
Local
RES
3
3
3
3
3
3
PWM1/XTO
SlowFan
Remote
THERM
Bit 0
Hys
Dis
1
2
2
2
2
2
2
fault
0x00
0x00
0x00
0x00
0x00
0x00
0x00
0x80
De-
Lock-
able
Yes
Yes
−
−
−
−
−
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