MAX6602UE9A+ Maxim Integrated Products, MAX6602UE9A+ Datasheet - Page 14

• Manufacturer Part Number: MAX6602UE9A+
• Description: IC TEMP MONITOR 5CH 16-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6602UE9A+

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Buffer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Full Temp Accuracy: +/- 1 C, +/- 3 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 11 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX6602 directly measures the die temperature of
CPUs and other ICs that have on-chip temperature-
sensing diodes (see the Typical Application Circuit) or
it can measure the temperature of a discrete diode-
connected transistor.
The accuracy of the remote temperature measure-
ments depends on the ideality factor (n) of the remote
“diode” (actually a transistor). The MAX6602 is opti-
mized for n = 1.012. A thermal diode on the substrate
of an IC is normally a pnp with the base and emitter
brought out the collector (diode connection) grounded.
DXP_ must be connected to the anode (emitter) and
DXN_ must be connected to the cathode (base) of this
pnp. If a sense transistor with an ideality factor other
than 1.012 is used, the output data is different from the
data obtained with the optimum ideality factor.
Fortunately, the difference is predictable. Assume a
remote-diode sensor designed for a nominal ideality
factor n
a diode with a different ideality factor n1. The measured
temperature T
Five-Channel Precision Temperature Monitor
Table 9. Status 3 Register
14
7 (MSB)
BIT
______________________________________________________________________________________
6
5
4
3
2
1
0
NOMINAL
M
T
Applications Information
M
can be corrected using:
is used to measure the temperature of
Diode fault 4
Diode fault 3
Diode fault 2
Diode fault 1
=
Reserved
Reserved
Reserved
Reserved
T
NAME
ACTUAL
Remote-Diode Selection
Effect of Ideality Factor
⎛
⎜
⎝
n
NOMINAL
n
1
STATE
POR
0
0
0
0
0
0
0
0
⎞
⎟
⎠
—
Not Used. 0 at POR, then 1.
Not Used. 0 at POR, then 1.
Channel 4 Remote-Diode Fault Bit. This bit is set to 1 when DXP4 and DXN4
are open circuit or when DXP4 is connected to V
Channel 3 Remote-Diode Fault Bit. This bit is set to 1 when DXP3 and DXN3
are open circuit or when DXP3 is connected to V
Channel 2 Remote-Diode Fault Bit. This bit is set to 1 when DXP2 and DXN2
are open circuit or when DXP2 is connected to V
Channel 1 Remote-Diode Fault Bit. This bit is set to 1 when DXP1 and DXN1
are open circuit or when DXP1 is connected to V
—
where temperature is measured in Kelvin and
n
assume you want to use the MAX6602 with a CPU that
has an ideality factor of 1.002. If the diode has no
series resistance, the measured data is related to the
real temperature as follows:
For a real temperature of +85°C (358.15K), the mea-
sured temperature is +81.46°C (354.61K), an error of
-3.539°C.
Some thermal diodes on high-power ICs can have
excessive series resistance, which can cause tempera-
ture measurement errors with conventional remote tem-
perature sensors. Channel 1 of the MAX6602 has a
series resistance cancellation feature (enabled by bit 3
of the configuration 1 register) that eliminates the effect
of diode series resistance. Set bit 3 to 1 if the series
resistance is large enough to affect the accuracy of
channel 1. The series resistance cancellation function
increases the conversion time for channel 1 by 125ms.
This feature cancels the bulk resistance of the sensor
and any other resistance in series (wire, contact resis-
tance, etc.). The cancellation range is from 0 to 100Ω.
NOMIMAL
T
ACTUAL
=
T
for the MAX6602 is 1.012. As an example,
M
×
Series Resistance Cancellation
⎛
⎜
⎝
FUNCTION
n
NOMINAL
n
1
⎞
⎟ =
⎠
T
CC
CC
CC
CC
M
.
.
.
.
×
⎛
⎜
⎝
1 012
1 002
.
.
⎞
⎟ =
⎠
T
M
( .
1 00998
)