MAX6620ATI MAXIM [Maxim Integrated Products], MAX6620ATI Datasheet - Page 18

• Manufacturer Part Number: MAX6620ATI
• Description: Quad Linear Fan-Speed Controller
• Manufacturer: MAXIM [Maxim Integrated Products]

Quad Linear Fan-Speed Controller
18
BIT
7
6
5
4
3
2
1
0
______________________________________________________________________________________
R/W
R/W
R/W
R/W
R/W
R
R
R
R
Fan 4 Fault Status:
Indicates which fans have had faults detected. When a fan fault is detected, the drive to the fan is disabled and
the corresponding fault bit is set. The fault bits latch until they are cleared by reading, thus allowing short-term
faults to be identified. After a fault status bit is cleared by reading, the corresponding output voltage will
remain zero until a Fan_ Target Drive Voltage register or Fan_ Target TACH Register is written. Writing a
new target drive voltage or target TACH count will cause drive to be applied to the fan again, at which time a
new failure-detection cycle will begin.
Fault Conditions Are:
FAN_FAIL will be asserted when four consecutive faults are detected.
Fan 3 Fault Status
Fan 2 Fault Status
Fan 1 Fault Status
Fan 4 Fault Mask:
Masks faults on selected fans from asserting the FAN_FAIL output. Faults will still be indicated by the fault
status bits:
Fan 3 Fault Mask
Fan 2 Fault Mask
Fan 1 Fault Mask
0 = not masked
1 = masked
MODE
DAC
RPM
VOLTAGE REGISTER
FAN_ DRIVE
1FF (full)
<1FF
Any
Fan Fault Register (01h)—POR = 0000 1111
TACH count exceeds value of Fan_ Target
TACH count
Locked rotor asserts
TACH count exceeds value of Fan_ Target
TACH Count
TACH count exceeds two times of Fan_ Target
TACH Count value
TACH count reaches it full count of 7FF
FUNCTION
CONDITION
TIME
(s)
>1
>1