Datasheet

Noise-Filtering Capacitors
A quality ceramic capacitor must be connected across
the DXP/DXN inputs to maintain temperature threshold
accuracy by filtering out noise. The capacitor should be
located physically close to the DXP/DXN pins and
should typically have a value of 2200pF. Larger capaci-
tor values can cause temperature measurement errors.
A 50% variation from the recommended capacitor
value can cause up to ±1°C error.
MAX6685/MAX6686
Dual-Output Remote-Junction
Temperature Switches
_______________________________________________________________________________________ 5
N
T
LOW
T
HIGH
DXN
S2
S1
GND
T
HIGH
+120°C OR +125°C
REMOTE
TEMPERATURE
CONVERTER
T
LOW
+40°C TO +115°C
DXP
V
DD
MAX6685
DIGITAL
DRIVER
Figure 1. MAX6685 Functional Diagram
N
N
T
LOW
T
HIGH
DXN
S2
S1
GND
T
HIGH
+120°C OR +125°C
REMOTE
TEMPERATURE
CONVERTER
T
LOW
+40°C TO +115°C
DXP
V
DD
MAX6686
Figure 2. MAX6686 Functional Diagram
MAX6685AUA40L
MAX6685AUA40H
MAX6686AUA40L
MAX6686AUA40H
MAX6685AUA75L
MAX6685AUA75H
MAX6686AUA75L
MAX6686AUA75H
S1 S2
LOWER TEMPERATURE
TRIP THRESHOLD (°C)
LOWER TEMPERATURE
TRIP THRESHOLD (°C)
GND GND +40 +75
GND FLOAT +45 +80
GND V
DD
+50 +85
FLOAT GND +55 +90
FLOAT FLOAT +60 +95
FLOAT V
DD
+65 +100
V
DD
GND +70 +105
V
DD
FLOAT +75 +110
V
DD
V
DD
+80 +115
Table 1. Lower Temperature Trip Threshold Selection
MANUFACTURER MODEL NO.
Central Semiconductor (USA) CMPT3904
ON Semiconductor (USA) 2N3904, 2N3906
Rohm Semiconductor (Japan) SST3904
Samsung (Korea) KST3904-TF
Siemens (Germany) SMBT3904
Table 2. Sensor Transistor Manufacturers
Note: Discrete transistors must be diode connected (base
shorted to collector).