ADM1031ARQ-REEL7 ON Semiconductor, ADM1031ARQ-REEL7 Datasheet - Page 15

• Manufacturer Part Number: ADM1031ARQ-REEL7
• Description: IC SENSOR 2-TEMP/FAN CTRL 16QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1031ARQ-REEL7

• Rohs Status: RoHS non-compliant
• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: 0°C ~ 100°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: 0°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP

duty cycle) is given by:
where:
T
T
Max DC = Maximum duty cycle (100%) = 15 decimal.
Min DC = Duty cycle at T
configuration register (default = 33% = 5 decimal).
T
Example 1
Calculate T
Example 2
Calculate T
Example 3
Calculate T
Table 7. Programming PWM Duty Cycle
MAX
MIN
RANGE
The temperature at which the fan runs full−speed (100%
T
T
Min DC = 53% = 8 decimal (Table 7)
T
T
T
T
T
Min DC = 73% = 11 decimal (Table 7)
T
T
T
T
T
Min DC = 33% = 5 decimal (Table 7)
T
MAX
= Temperature at which fan turns on.
MIN
MAX
MAX
MAX
MAX
MIN
MAX
MAX
MAX
MAX
MIN
MAX
= Temperature at which fan runs full−speed.
Decimal Value
= PWM duty cycle vs. temperature slope.
12 (0×0C)
13 (0×0D)
10 (0×0A)
11 (0×0B)
14 (0×0E)
15 (0×0F)
= 0°C, T
= 0°C, T
= 0°C, T
= T
= 0 + ((15 − 8) × 4) = 28
= T
= 0 + ((100% DC − 53% DC) × 40/10)
= 28°C (as seen on Slope 2 of Figure 26)
= T
= 0 + ((100% DC – 73% DC) × 40/10)
= 0 + ((15 – 11) × 4) = 16
= 16°C (as seen on Slope 3 of Figure 26)
= T
MAX
MAX
MAX
00
01
02
03
04
05
06
07
08
09
MIN
MIN
MIN
MIN
.
.
.
RANGE
+ ((Max DC − Min DC) × T
RANGE
RANGE
+ ((Max DC – Min DC) × T
+ ((Max DC – Min DC) × T
+ ((Max DC – Min DC) × T
MIN
= 40°C
= 40°C
= 40°C
, programmed in to fan speed
PWM Duty Cycle
33% (Default)
100%
14%
20%
27%
40%
47%
53%
60%
67%
73%
80%
87%
93%
0%
7%
RANGE
RANGE
RANGE
RANGE
http://onsemi.com
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/10)
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15
33%, the equation for T
Relevant Registers for Automatic Fan Speed Control
Mode
Register 0y00 Configuration Register 1
<7> Logic 1 selects automatic fan speed control, Logic 0
selects software control (Default = 1).
<6:5> 00 = Remote Temp 1 controls Fan 1, Remote Temp 2
controls Fan 2.
Register 0y20, 0y21 Fan Characteristics Registers 1, 2
<2:0> Fan X Spin−Up Time.
<5:3> PWM Frequency Driving the Fan.
<7:6> Speed Range N; defines the lowest fan speed that can
be measured by the device.
Register 0y22 Fan Speed Configuration Register
<3:0> Min Speed: This nibble contains the speed at which
the fan runs when the temperature is at T
0×05, meaning that the fan runs at 33% duty cycle when the
temperature is at T
<7:4> Min Speed: Determines the minimum PWM cycle for
Fan 2 in automatic fan speed control mode.
In this case, since the minimum duty cycle is the default
T
T
T
T
T
T
T
01 = Remote Temp 1 controls Fan 1 and Fan 2
10 = Remote Temp 2 controls Fan 1 and Fan 2
11 = Fastest Calculated Speed controls Fan 1 and 2
000 = 200 ms
001 = 400 ms
010 = 600 ms
011 = 800 ms
100 = 1 sec
101 = 2 sec (Default)
110 = 4 sec
111 = 8 sec
000 = 11.7 Hz
001 = 15.6 Hz
010 = 23.4 Hz
011 = 31.25 Hz (Default)
100 = 37.5 Hz
101 = 46.9 Hz
110 = 62.5 Hz
111 = 93.5 Hz
00 = 1: Lowest Speed = 2647 RPM
01 = 2: Lowest Speed = 1324 RPM
10 = 4: Lowest Speed = 662 RPM
11 = 8: Lowest Speed = 331 RPM
MAX
MAX
MAX
MAX
MAX
MAX
MAX
= 0 + ((100% DC – 33% DC) × 40/10)
= 0 + ((15 – 5) × 4) = 40
= 40°C (as seen on Slope 1 of Figure 26)
= T
= T
= T
= T
MIN
MIN
MIN
MIN
MIN
+ ((Max DC – Min DC) × T
+ ((15 – 5) × T
+ (10 × T
+ T
.
RANGE
MAX
RANGE
reduces to:
RANGE
/10)
MIN
/10)
. The default is
RANGE
/10)