MAX6664AEE+ Maxim Integrated Products, MAX6664AEE+ Datasheet - Page 10

• Manufacturer Part Number: MAX6664AEE+
• Description: IC TEMP MON FAN CNTRL 16-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6664AEE+

• Function: Fan Control, Temp Monitor
• Topology: ADC, Multiplexer, Register Bank, Tachometer
• 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-QSOP
• Full Temp Accuracy: +/- 1 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

INT is an open-drain digital output that reports the sta-
tus of temperature interrupt limits and fan out-of-limit
conditions. Set bit 1 of configuration register 1 (00h) to
1 to enable INT output or reset this bit to zero to disable
the INT output function. Status register 1 contains sta-
tus information for the conditions that cause INT to
assert. Reading status register 1 resets INT, but INT is
reasserted if the fault condition still exists. Connect a
10kΩ pullup resistor between INT and V
SDL and SDR are open-drain digital outputs on the
MAX6653 that can be used to shut the system down
based on the local (die) temperature of the MAX6653 or
the temperature of the remote sensor, respectively. The
trip thresholds for SDL and SDR are normally set above
the THERM and INT limits. Their power-up values are
set by the CRIT1 and CRIT0 pins, as shown in Table 1.
The MAX6653/MAX6663/MAX6664 fan-control section
can operate in one of three modes depending on the set-
ting of bit 7 to bit 5 of configuration register 1 (00h).
Regardless of the mode of operation, the PWM output fre-
quency is programmable, and the fan speed is measured
with the result stored in the fan-speed register (08h).
The PWM output frequency is programmed by bit 5, bit
4, and bit 3 of the fan characteristics register (20h),
regardless of the mode of operation. See Table 7.
The mode of fan-speed control operation is set by bit 7,
bit 6, and bit 5 in configuration register 1 (00h), as
shown in Table 8.
Bits [3:0] of the fan-speed configuration register set the
PWM duty cycle. See Table 9 for more details.
Temperature Monitors and
PWM Fan Controllers
Table 8. Setting the Fan-Speed Control Mode (Default = 100)
10
Bits [7:5]
0x0
0x1
100
111
______________________________________________________________________________________
MODE OF OPERATION
PWM duty-cycle mode
PWM Duty-Cycle Fan-Control Mode
RPM select mode
Automatic mode
Automatic mode
PWM Output Frequency
Fan-Speed Control
Fan-Control Mode
CC
Directly program the PWM duty cycle by writing to bits [3:0] of the fan-speed
configuration register (22h).
Program the desired fan speed by writing to the fan tachometer high-limit register
(10h). This value should be written after selecting the RPM mode. The
MAX6653/MAX6663/MAX6664 then adjust the PWM duty cycle to cause the fan to
spin at the programmed speed.
PWM duty cycle is automatically controlled by the remote temperature.
PWM duty cycle is automatically controlled by both the remote and the local
temperatures. See the Automatic Fan-Control Mode section.
.
In RPM select mode, the MAX6653/MAX6663/MAX6664
adjust their PWM output duty cycle to match a selected
fan speed measured by a tachometer count value. Before
selecting this mode by setting bits [7:5] of configuration
register 1 (00h) to 0x1, the desired tachometer count
value should be written to the fan tachometer high-limit
register (10h). In this mode, the MAX6653/MAX6663/
MAX6664 are not able to detect underspeed fan faults
because the fan tachometer high-limit register (10h) func-
tions as the target tachometer count.
The MAX6653/MAX6663/MAX6664 detect fan stall
faults by comparing the fan-speed reading to the full-
scale constant of 254 (FEh). Therefore, the
MAX6653/MAX6663/MAX6664 signal a fan fault when
the fan-speed reading is 255 (FFh). Note that the RPM
mode cannot be used for speeds below 10% of the
fan’s maximum speed. It is important to verify that a fan
works properly at lower RPM values if a low-RPM oper-
ation in this mode is desired.
Table 7. Setting PWM Output Frequency
FAN CHARACTERISTICS REGISTER
BIT 5
0
0
0
0
1
1
1
1
DESCRIPTION
(20H) POR = 011
BIT 4
0
0
1
1
0
0
1
1
RPM Select Fan-Control Mode
BIT 3
0
1
0
1
0
1
0
1
FREQUENCY
PWM
31.25
(Hz)
11.7
15.6
23.4
37.5
46.9
62.5
93.5