Datasheet

21Maxim Integrated
±1°C Accurate 8-Channel Temperature Sensor
MAX6581
Series-Resistance Cancellation
Some thermal diodes on high-power ICs have exces-
sive series resistance that can cause temperature-mea-
surement errors when used with conventional remote-
temperature sensors. Channels 1–7 of the MAX6581
have a series-resistance cancellation feature (enabled
by bits [7:0] of the Resistance Cancellation register)
that eliminates the effect of diode series resistance and
interconnection resistance. Set these bits to 1 if the series
resistance is large enough to affect the accuracy of the
channels. The series-resistance cancellation function
increases the conversion time for the remote channels by
125ms (typ). This feature cancels the bulk resistance of
the sensor and any other resistance in series (e.g., wire,
contact resistance, etc.). The cancellation range is from
0I to 100I.
Table 12. Resistance Cancellation Register (4Ah)
X = Don’t care.
BIT NAME
POR
STATE
FUNCTION
7 (MSB) X 0 —
6
Resistance
Cancellation 7
0
Channel 7 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
5
Resistance
Cancellation 6
0
Channel 6 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
4
Resistance
Cancellation 5
0
Channel 5 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
3
Resistance
Cancellation 4
0
Channel 4 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
2
Resistance
Cancellation 3
0
Channel 3 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
1
Resistance
Cancellation 2
0
Channel 2 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.
0
Resistance
Cancellation 1
0
Channel 1 Resistance Cancellation Enable Bit. Set this bit to logic 1 to enable
resistance cancellation. Set this bit to logic 0 to disable resistance cancellation.