ADT7462ACPZ-REEL7 ON Semiconductor, ADT7462ACPZ-REEL7 Datasheet - Page 38

• Manufacturer Part Number: ADT7462ACPZ-REEL7
• Description: IC TEMP/VOLT MONITOR 32-LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADT7462ACPZ-REEL7

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, 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 ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

T
using Equation 7.
T
where (Max DC − Min DC) × T
T
T
setting affects fan speed vs. temperature. As shown in the
graph, the effect on fan speed is nonlinear.
PWM duty cycle. Clearly, the minimum PWM duty cycle,
PWM
actually performs in the system. Figure 61 shows how
T
It can be seen that the fan runs about 45% fan speed when the
temperature exceeds T
MAX
RANGE
RANGE
RANGE
RANGE
100
100
Figure 60 shows PWM duty cycle vs. temperature for each
The graphs in Figure 60 assume that the fan starts from 0%
90
80
70
60
50
40
30
20
10
90
80
70
60
50
40
30
20
10
0
0
Figure 60. T
0
0
+ T
MIN
value.
setting. The lower graph shows how each T
is affected when the PWM
for different PWM
, needs to be factored in to see how the loop
MIN
20
20
) (Max DC * Min DC)
TEMPERATURE ABOVE T
RANGE
TEMPERATURE ABOVE T
40
40
MIN
vs. Actual Fan Speed Profile
60
60
.
MIN
RANGE
values can be calculated
80
80
MIN
MIN
MIN
/170 is the effective
value is set to 20%.
T
100
100
RANGE
120
120
170
RANGE
http://onsemi.com
(eq. 7)
25C
2.55C
3.335C
45C
55C
6.675C
85C
105C
13.35C
165C
205C
26.65C
325C
405C
53.35C
805C
25C
2.55C
3.335C
45C
55C
6.675C
85C
105C
13.35C
165C
205C
26.65C
325C
405C
53.35C
805C
38
Example: Determining T
Channel
T
zones. In this example, the following T
the Step 1 − Configuring the MUX section. Both CPU
temperature and VRM temperature drive the CPU fan
connected to PWM1. Ambient temperature drives the front
chassis fan and rear chassis fan connected to PWM2 and
PWM3.
The rear chassis fan is configured to run at PWM
The CPU fan is configured to run at PWM
RANGE
100
100
The following example shows how the different T
This example uses the MUX configuration described in
The front chassis fan is configured to run at PWM
90
80
70
60
50
40
30
20
10
90
80
70
60
50
40
30
20
10
0
0
Figure 61. T
0
0
T
T
T
settings can be applied to three different thermal
RANGE
RANGE
RANGE
20
20
RANGE
TEMPERATURE ABOVE T
TEMPERATURE ABOVE T
= 80°C for ambient temperature
= 53.3°C for CPU temperature
= 40°C for VRM temperature
40
40
PWM
vs. % Fan Speed Slopes with
RANGE
60
60
MIN
= 20%
for Each Temperature
80
80
MIN
MIN
RANGE
MIN
100
100
= 10%.
values apply:
MIN
MIN
120
120
MIN
= 20%.
= 30%.
25C
2.55C
3.335C
45C
55C
6.675C
85C
105C
13.35C
165C
205C
26.65C
325C
405C
53.35C
805C
25C
2.55C
3.335C
45C
55C
6.675C
85C
105C
13.35C
165C
205C
26.65C
325C
405C
53.35C
805C
and