Rainbow Electronics LM85 - Manual (Page 3)

Pin Descriptions
(Continued)
Symbol Pin Typ Name and Function/Connection
Remote
Remote1+ 18 Remote Thermal
Diode Positive
Input
Positive input (current source) from the first remote thermal diode.
Serves as the positive input into the A/D. Connected to
THERMDA pin of Pentium processor or the base of a diode
connected MMBT3904 NPN transistor.
Remote1− 17 Remote Thermal
Diode Negative
Input
Negative input (current sink) from the first remote thermal diode.
Serves as the negative input into the A/D. Connected to
THERMDC pin of Pentium processor or the emmiter of a diode
connected MMBT3904 NPN transistor.
Remote2+ 16 Remote Thermal
Diode Positive
Output
Positive input (current source) from the first remote thermal diode.
Serves as the positive input into the A/D. Connected to
THERMDA pin of Pentium processor or the base of a diode
connected MMBT3904 NPN transistor.
Remote2− 15 Remote Thermal
Diode Negative
Input
Negative input (current sink) from the first remote thermal diode.
Serves as the negative input into the A/D. Connected to
THERMDC pin of Pentium processor or the emmiter of a diode
connected MMBT3904 NPN transistor.
Fan
Tachometer
Inputs
TACH1 11 Digital Input Input for monitoring tachometer output of fan 1.
TACH2 12 Digital Input Input for monitoring tachometer output of fan 2.
TACH3 9 Digital Input Input for monitoring tachometer output of fan 3.
TACH4/Address
Select
14 Digital Input Input for monitoring tachometer output of fan 4. If in Address
Select Mode, determines the SMBus address of the LM85.
Fan
Control
PWM1/xTest
Out
24 Digital Open-Drain
Output
Fan speed control 1. When in XOR tree test mode, functions as
XOR Tree output.
PWM2 10 Digital Open-Drain
Output
Fan speed control 2.
PWM3/Address
Enable
13 Digital Open-Drain
Output
Fan speed control 3. Pull to ground at power on to enable
Address Select Mode (Address Select pin controls SMBus
address of the device).
LM85
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