Datasheet

6-Channel Intelligent Fan Controller
MAX31785
7
DC ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 2.7V to 5.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
DD
= 3.3V, T
A
= +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ADC Internal Reference
Temperature Drift
-0.5 +0.5 %
ADC Internal Reference Initial
Accuracy (+25NC)
-1 +1 mV
ADC Full-Scale Input Voltage V
FS
1.213 1.225 1.237 V
ADC Measurement Resolution V
LSB
300
FV
ADC Bit Resolution 12 Bits
RS+ Input Resistance R
IN
15
MI
ADC Integral Nonlinearity INL (Note 4)
Q8
LSB
ADC Offset V
OFFSET
Q2
LSB
Internal Temperature
Measurement Error
T
A
= -40NC to +85NC
-3 +3
NC
Remote Temperature
Measurement Error
(MAX31785 Error Only)
T
A
= 0NC to +60NC,
T
DIODE
= +60NC to +120NC
-1.5 +1.5
NC
T
A
= 0NC to +60NC,
T
DIODE
= -45NC to +120NC
-1.75 +1.75
T
A
= -40NC to +85NC,
T
DIODE
= +60NC to +120NC
-2.75 +2.75
T
A
= -40NC to +85NC,
T
DIODE
= -45NC to +120NC
-3.0 +3.0
Store Default All Time 45 ms
Nonvolatile Log Write Time 12 ms
Nonvolatile Log Delete Time 200 ms
Flash Endurance N
FLASH
T
A
= +50NC
20,000
Write
Cycles
Data Retention
T
A
= +50NC
100 Years
Voltage Sample Rate 10 ms
RPM Sample Rate 1000 ms
Temperature Sample Rate 1000 ms
Device Startup Time
Measured from POR until monitoring
begins
12 ms
Fan PWM Frequency 30 25,000 Hz
Fan PWM Resolution 7 Bits