MAX6699UE34+ Maxim Integrated Products, MAX6699UE34+ Datasheet - Page 13

• Manufacturer Part Number: MAX6699UE34+
• Description: IC TEMP MONITOR 5CH 16TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6699UE34+

• 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: +/- 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

sensor designed for a nominal ideality factor n
is used to measure the temperature of a diode with a
different ideality factor n1. The measured temperature
T
where temperature is measured in Kelvin and
n
assume you want to use the MAX6699 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 +82.87°C (356.02K), an error of
-2.13°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 MAX6699 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
Table 6. Configuration 3 Register
M
NOMIMAL
T
ACTUAL
7(MSB)
can be corrected using:
BIT
6
5
4
3
2
1
0
=
for the MAX6699 is 1.008. As an example,
T
M
×
T
Series Resistance Cancellation
5-Channel Precision Temperature Monitor
⎛
⎜
⎝
M
n
Mask OVERT 4
Mask OVERT 1
NOMINAL
=
______________________________________________________________________________________
T
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
n
ACTUAL
NAME
1
⎞
⎟ =
⎠
⎛
⎜
⎝
T
n
M
NOMINAL
×
⎛
⎜
⎝
n
1 008
1 002
1
.
.
STATE
POR
⎞
⎟ =
⎠
—
—
0
0
0
0
0
0
⎞
⎟
⎠
T
M
( .
1 00599
NOMINAL
—
—
—
—
Channel 4 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 4
OVERT.
—
—
Channel 1 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 1
OVERT.
)
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.
When the remote-sensing diode is a discrete transistor,
its collector and base must be connected together.
Table 10 lists examples of discrete transistors that are
appropriate for use with the MAX6699. The transistor
must be a small-signal type with a relatively high forward
voltage; otherwise, the A/D input voltage range can be
violated. The forward voltage at the highest expected
temperature must be greater than 0.25V at 10µA, and at
the lowest expected temperature, the forward voltage
must be less than 0.95V at 100µA. Large power transis-
tors must not be used. Also, ensure that the base resis-
tance is less than 100Ω. Tight specifications for forward
current gain (50 < ß <150, for example) indicate that the
manufacturer has good process controls and that the
devices have consistent V
Manufacturers of discrete transistors do not normally
specify or guarantee ideality factor. This is normally not
a problem since good-quality discrete transistors tend to
have ideality factors that fall within a relatively narrow
range. A variety of discrete transistors have variations in
remote temperature readings of less than ±2°C. Still, it is
good design practice to verify good consistency of tem-
perature readings with several discrete transistors from
any manufacturer under consideration.
FUNCTION
Discrete Remote Diodes
BE
characteristics.
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