MAX6650 Maxim, MAX6650 Datasheet - Page 18

• Manufacturer Part Number: MAX6650
• Description: Fan-Speed Regulators and Monitors with SMBus/I2C-Compatible Interface
• Manufacturer: Maxim

Fan-Speed Regulators and Monitors
with SMBus/I
Figure 11. MAX6501 Hardware Fail-Safe
Figure 12. MAX6501 Hardware Fail-Safe
independently control each fan. The disadvantage is
cost, size, and complexity.
For single fan control, use the MAX6650 (unless addi-
tional GPIOs are needed).
If multiple fans are required but independent control is
not, then a single MAX6650/MAX6651 connected to
two or more fans in parallel may make sense (Figure 7).
The obvious advantage is simplicity, size, and cost
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MAX6501
MAX6501
MAX6501
MAX6501
INTERFACE
3V TO 5.5V
SMBus/I
TOVER
TOVER
TOVER
TOVER
V
2
CC
2
C
C-Compatible Interface
Parallel Fan Control
INTERFACE
3V TO 5.5V
SMBus/I
V
CC
2
C
FULL ON
ALERT
FULL ON
V
SCL
SDA
GPIO0
GPIO1
ALERT
CCIN
MAX6650
V
SCL
SDA
GPIO0
GPIO1
CCIN
savings. If all the fans connected in parallel are the
same type, they will tend to run at similar speeds.
However, if one or more of the fans are wearing out,
speed mismatches can occur. The MAX6651 allows the
system to monitor up to four fans, ensuring any signifi-
cant speed mismatches can be detected.
For parallel fan control while monitoring up to four fan
speeds, select the MAX6651.
MAX6650
TACH0
GND
ADD
OUT
FB
TACH0
ADD
GND
OUT
FB
10kΩ
10kΩ
5V OR 12V
5V OR 12V
V
FAN
V
FAN
FAN
C
10µF
COMP
FAN
C
10µF
COMP