Datasheet

MAX6653/MAX6663/MAX6664
Temperature Monitors and
PWM Fan Controllers
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Addr(H)
READ/WRITE POR STATE DESCRIPTION
23 R/W 0101 1101
Fan filter register:
Bit 7: Fan spin-up disable:
0: Spin-up enabled; 1: spin-up disabled.
Bits [6:5]: Fan ramp rate: These bits set the amount the PWM duty cycle can change
on each monitoring cycle:
00 = 1 (0.416%)
01 = 2 (0.833%)
10 = 4 (1.667%) (default)
11 = 8 (3.333%)
Bits [4:2]: Temperature measurement rate (see Table 5).
Bit 1: Unused.
Bit 0: Fan filter enable. Setting the bit to 1 enables the fan filter function.
24 R/W 0100 0001
Local temp T
MIN
/ T
RANGE
register:
Bits [7:3]: Local T
MIN
: Contains the temp threshold for the automatic fan-speed control
mode. When the local temperature exceeds this value, the PWM output
becomes active:
00000 = 0
0
C
00001 = +4
0
C
|
01000 = +32
0
C (default)
|
11110 = +120
0
C
11111 = +124
0
C
Bits [2:0]: Local T
RANGE
: Contains the local temperature range for automatic fan-
speed control mode. When the temperature reaches T
MIN
+ T
RANGE
, the
PWM duty cycle reaches 100%:
000 = +5
0
C
001 = +10
0
C (default)
010 = +20
0
C
011 = +40
0
C
100 = +80
0
C
25 R/W 0110 0001
Remote temp T
MIN
/T
RANGE
register:
Bits [7:3]: Remote T
MIN
. Contains the temp threshold for the automatic fan-speed
control mode. When the remote temperature exceeds this value, the PWM
output becomes active.:
00000 = 0
0
C
00001 = +4
0
C
|
01100 = +48
0
C (default)
|
11110 = +120
0
C
1111 = +124
0
C
Bits [2:0]: Remote T
RANGE
: Contains the remote temperature range for automatic fan-
speed control mode. When the temperature reaches T
MIN
+ T
RANGE
, the
PWM duty cycle reaches 100%:
000 = +5
0
C
001 = +10
0
C (default)
010 = +20
0
C
011 = +40
0
C
100 = +80
0
C
Register Summary (continued)