MAX6636UP9A+ Maxim Integrated Products, MAX6636UP9A+ Datasheet - Page 16

• Manufacturer Part Number: MAX6636UP9A+
• Description: IC PREC TEMP MONITOR 7CH 20TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6636UP9A+

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Buffer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: 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: 20-TSSOP
• Full Temp Accuracy: - 0.1 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

7-Channel Precision Temperature Monitor
The integrating ADC has good noise rejection for low-
frequency signals, such as power-supply hum. In envi-
ronments with significant high-frequency EMI, connect
an external 2200pF capacitor between DXP_ and
DXN_. Larger capacitor values can be used for added
filtering, but do not exceed 3300pF because it can
introduce errors due to the rise time of the switched
current source. High-frequency noise reduction is
needed for high-accuracy remote measurements.
Noise can be reduced with careful PCB layout as dis-
cussed in the PCB Layout section.
The 7-bit slave address of the MAX6636UP9A+ is
1001 101 (binary).
Follow these guidelines to reduce the measurement
error when measuring remote temperature:
1) Place the MAX6636 as close as is practical to the
Table 10. Remote-Sensors Transistor
Manufacturer
Note: Discrete transistors must be diode connected (base
shorted to collector).
16
Central Semiconductor (USA)
Rohm Semiconductor (USA)
Samsung (Korea)
Siemens (Germany)
Zetex (England)
remote diode. In noisy environments, such as a
computer motherboard, this distance can be 4in to
8in (typ). This length can be increased if the worst
noise sources are avoided. Noise sources include
CRTs, clock generators, memory buses, and PCI
buses.
______________________________________________________________________________________
MANUFACTURER
ADC Noise Filtering
CMPT3904
SST3904
KST3904-TF
SMBT3904
FMMT3904CT-ND
Slave Address
MODEL NO.
PCB Layout
2) Do not route the DXP-DXN lines next to the deflec-
3) Route the DXP and DXN traces in parallel and in
4) Route through as few vias and crossunders as pos-
5) Use wide traces when practical. 5mil to 10mil traces
6) When the power supply is noisy, add a resistor (up
Figure 5. Recommended DXP-DXN PCB Traces. The two outer
guard traces are recommended if high-voltage traces will be
near the DXN and DXP traces.
5–10 mils
5–10 mils
tion coils of a CRT. Also, do not route the traces
across fast digital signals, which can easily intro-
duce +30°C error, even with good filtering.
close proximity to each other. Each parallel pair of
traces should go to a remote diode. Route these
traces away from any higher voltage traces, such as
+12VDC. Leakage currents from PCB contamination
must be dealt with carefully since a 20MΩ leakage
path from DXP to ground causes about +1°C error. If
high-voltage traces are unavoidable, connect guard
traces to GND on either side of the DXP-DXN traces
(Figure 5).
sible to minimize copper/solder thermocouple
effects.
are typical. Be aware of the effect of trace resistance
on temperature readings when using long, narrow
traces.
to 47Ω) in series with V
GND
DXP
DXN
GND
CC
.
5–10 mils
MINIMUM
5–10 mils