User guide

MAX6678
2-Channel Temperature Monitor with Dual Automatic
PWM Fan-Speed Controller and Five GPIOs
4 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
-3
-1
-2
1
0
2
3
05025 75 100 125
LOCAL TEMPERATURE ERROR
vs. DIE TEMPERATURE
MAX6678 toc04
TEMPERATURE (
°
C)
TEMPERATURE ERROR (
°
C)
-1.5
0
-0.5
-1.0
1.0
0.5
1.5
2.0
0.01 10.1 10 100 1000
REMOTE TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6678 toc05
FREQUENCY (kHz)
TEMPERATURE ERROR (
°
C)
V
IN
= 250mV
P-P
SQUARE WAVE APPLIED
TO V
CC
WITH NO BYPASS CAPACITOR
-2.5
-1.0
-1.5
-2.0
0
-0.5
0.5
1.0
0.01 10.1 10 100 1000
LOCAL TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6678 toc06
FREQUENCY (kHz)
TEMPERATURE ERROR (
°
C)
V
IN
= 250mV
P-P
SQUARE WAVE APPLIED
TO V
CC
WITH NO BYPASS CAPACITOR
0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
1.8
1.6
2.0
0.01 10.1 10 100 1000
REMOTE TEMPERATURE ERROR
vs. COMMON-MODE NOISE FREQUENCY
MAX6678 toc07
FREQUENCY (kHz)
TEMPERATURE ERROR (
°
C)
V
IN
= AC-COUPLED TO DXP AND DXN
V
IN
= 100mV
P-P
SQUARE WAVE
0
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.9
0.8
1.0
0.01 10.1 10 100 1000
REMOTE TEMPERATURE ERROR
vs. DIFFERENTIAL NOISE FREQUENCY
MAX6678 toc08
FREQUENCY (kHz)
TEMPERATURE ERROR (
°
C)
V
IN
= AC-COUPLED TO DXP
V
IN
= 100mV
P-P
SQUARE WAVE
-6
-3
-5
-4
-1
-2
1
0
2
0.1 1 10 100
TEMPERATURE ERROR
vs. DXP-DXN CAPACITANCE
MAX6678 toc09
DXP-DXN CAPACITANCE (nF)
TEMPERATURE ERROR (
°
C)
T
A
= +25°C
30
31
33
32
34
35
-40 10 35-15 60 11085
PWMOUT FREQUENCY
vs. DIE TEMPERATURE
MAX6678 toc10
TEMPERATURE (
°
C)
PWMOUT FREQUENCY (Hz)
30
31
33
32
34
35
3.0 4.03.5 4.5 5.0 5.5
PWMOUT FREQUENCY
vs. SUPPLY VOLTAGE
MAX6678 toc11
SUPPLY VOLTAGE (V)
PWMOUT FREQUENCY (Hz)
0
100
300
200
400
500
0101552025303540
GPIO OUTPUT VOLTAGE
vs. GPIO SINK CURRENT
MAX6678 toc12
GPIO SINK CURRENT (mA)
GPIO OUTPUT VOLTAGE (mV)