Datasheet

2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller
Maxim Integrated 5
MAX6639/MAX6639F
PIN
T Q FN - EP
QSOP
NAME
FUNCTION
1, 15 3, 1
PWM2,
PWM1
Open-Drain Output to Power-Transistor Driving Fan. Connect to the gate of a MOSFET or base of a
bipolar transistor. PWM_ requires a pullup resistor. The pullup resistor can be connected to a
supply voltage as high as 13.5V, regardless of the MAX6639’s supply voltage.
2, 16 4, 2
TACH2,
TACH1
Tachometer Inputs. Connect to the tachometer output of the fan. TACH_ requires a pullup resistor.
The pullup resistor can be connected to a supply voltage as high as 13.5V, regardless of the
MAX6639’s supply voltage.
35
FANFAIL
Active-Low, Open-Drain, Fan-Failure Output. Open circuit when V
CC
= 0.
46
THERM
Active-Low, Open-Drain Thermal Alarm Output. Typically used for clock throttling. Open circuit
when V
CC
= 0.
57OT
Active-Low, Open-Drain Overtemperature Output. Typically used for system shutdown or clock
throttling. Can be pulled up to 5.5V regardless of V
CC
. Open circuit when V
CC
= 0.
68V
CC
Power-Supply Input. 3.3V nominal. Bypass V
CC
to GND with a 0.1µF capacitor.
7 10 GND Ground. Connect to a clean ground reference.
8, 10 9, 12
DXP1,
DXP2
C om b i ned C ur r ent S our ce and A/D P osi ti ve Inp ut for Rem ote D i od e. C onnect to anod e of r em ote-
d i od e- connected tem p er atur e- sensi ng tr ansi stor . D o not l eave unconnected ; connect to D X N i f no
r em ote d i od e i s used . P l ace a 2200p F cap aci tor b etw een D X P _ and D X N for noi se fi l ter i ng .
911DXN
Rem ote D i od e C ur r ent S i nk Inp ut. C onnect C athod e of the Rem ote- D i od e- C onnected Tr ansi stor to D X N
11 13 ADD
Address Input. Sets device slave address. Connect to GND, V
CC
, or leave unconnected to give
three unique addresses. See Table 1.
12 14
ALERT
Active-Low, Open-Drain SMBus Alert Output
13 16 SCL
SMBus Serial-Clock Input. Can be pulled up to 5.5V regardless of V
CC
. Open circuit when V
CC
=
14 15 SDA
SMBus Serial-Data Input/Output, Open Drain. Can be pulled up to 5.5V regardless of V
CC
. Open
circuit when V
CC
= 0.
——EP
Exposed Pad (TQFN package only). Internally connected to GND. Connect EP to a large PCB pad
for optimum performance and enhanced thermal dissipation. Not intended as an electrical
connection point.
Pin Description
Typical Operating Characteristics (continued)
(V
CC
= 3.3V, T
A
= +25°C.)
PWMOUT FREQUENCY
vs. DIE TEMPERATURE
MAX6639 toc10
TEMPERATURE (°C)
PWMOUT FREQUENCY (Hz)
85603510-15
31
32
33
34
35
30
-40 110
PWMOUT FREQUENCY
vs. SUPPLY VOLTAGE
MAX6639 toc11
SUPPLY VOLTAGE (V)
PWMOUT FREQUENCY (Hz)
5.04.54.03.5
31
32
33
34
35
30
3.0 5.5