Rainbow Electronics MAX6645 - Manual (Page 15)

MAX6643/MAX6644/MAX6645
Automatic PWM Fan-Speed Controllers with
Overtemperature Output
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MAX6643
MAX6644
MAX6645
DXP1/(DXP)
DXP2
TEMPERATURE
SENSOR
TEMPERATURE
LOGIC
PWM
GENERATOR
FAN-FAIL
DETECTION
DUTY CYCLE
ANALOG SENSE
TACHOMETER
LOCKED ROTOR IN
ANALOG SENSE
TACHOMETER
LOCKED ROTOR IN OT TH TL
THRESHOLD
SELECTION
FULLSPD/(FULLSPD)
PWM_OUT
FAN_IN1
FAN_IN2
FANFAIL TACHSET OT1 OT2 TH1 TH2 TL1 TL2
() ARE FOR MAX6643 ONLY.
Block Diagram
TO FANFAIL
ALARM
MAX6643_A_
TH1
16
15
14
13
12
11 (TACHOMETER MODE)
(TACHOMETER MODE)
TO OVERTEMPERATURE ALARM
10
9
TL2
TL1
FANFAIL
TACHSET
FULLSPD
GND
DXP
V DD
V
DD
(+3.0V TO +5.5V)
+V FAN (5V OR 12V)
1
2
3
4
5
6
7
8
TH2
OT1
OT2
PWM_OUT
FAN_IN1
FAN_IN2
OT
4.7k Ω
4.7k Ω
4.7k Ω
N
Typical Operating Circuit