MAX6664AEE+ Maxim Integrated Products, MAX6664AEE+ Datasheet - Page 8

• 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

The MAX6663 resets its INT output and some of the
status bits in the status register after responding to an
alert response address; however, if the error condition
that caused the interrupt is still present, INT is reassert-
ed on the next monitoring cycle. INT is maskable to
allow full control of ALERT conditions.
The MAX6653/MAX6663/MAX6664 contain on-chip tem-
perature sensors to sense their own die (local) tempera-
tures. These devices can also measure remote
temperatures such as the die temperature of CPUs or
other ICs having on-chip temperature-sensing diodes, or
discrete diode-connected transistors as shown in the
Typical Operating Circuits. For best accuracy, the dis-
crete diode-connected transistor should be a small-signal
device with its collector and base connected together.
The on-chip ADC converts the sensed temperature and
outputs the temperature data in the format shown in
Tables 3 and 4. The temperature measurement resolution
is 0.125°C for both local and remote temperatures. The
temperature accuracy is within ±1°C for remote tempera-
ture measurements from +60°C to +100°C.
The Local Temperature Offset (0Dh) and Remote
Temperature Offset (0Eh) registers allow the measured
temperature to be increased or decreased by a fixed
value to compensate for errors due to variations in diode
resistance and ideality factor (see the Remote Diode
Considerations section). The reported temperature is the
measured temperature plus the correction value. Both the
measured temperature and the reported value are limited
by the sensor’s temperature range. For example, if a
remote thermal diode is being measured and its tempera-
ture is 135°C, the measured temperature is the maximum
Temperature Monitors and
PWM Fan Controllers
Figure 3. SMBus Read Timing Diagram
8
_______________________________________________________________________________________
SMBCLK
SMBDATA
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMBDATA LINE LOW
t
SU:STA
A
t
HD:STA
Temperature Measurement
t
LOW
B
t
HIGH
t
SU:DAT
C
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO MASTER
H = LSB OF DATA CLOCKED INTO MASTER
I = MASTER PULLS DATA LINE LOW
D
E
F
value of 127.875°C. If the remote offset value is set to -
10°C, the reported value is 117.875°C, not 125°C.
The temperature conversion rate is programmable using
bits [4:2] of the fan filter register (23h) as shown in Table 5.
The DXN input is biased at 0.65V above ground by an
internal diode to set up the analog-to-digital inputs for a
differential measurement. The worst-case DXP-DXN dif-
ferential input voltage range is from 0.25V to 0.95V.
Excess resistance in series with the remote diode caus-
es about 0.5°C error per ohm. Likewise, a 200µV offset
voltage forced on DXP-DXN causes about 1°C error.
High-frequency EMI is best filtered at DXP and DXN with
an external 2200pF capacitor. This value can be
increased to about 3300pF, including cable capacitance.
Capacitance higher than 3300pF introduces errors due to
the rise time of the switched current source.
Table 3. Temperature Data High Byte Format
t
HD:DAT
(short or open)
TEMP (°C)
Diode fault
130.00
127.00
126.00
G
25.25
-125
-128
0.50
0.00
-1
H
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLEAR PULSE
L = STOP CONDITION, EXECUTED BY SLAVE
M = NEW START CONDITION
OUTPUT (°C)
DIGITAL
+127
+127
+126
I
+25
—
—
—
—
0
0
J
K
DIGITAL OUTPUT
t
SU:STO
0111 1111
0111 1111
0111 1110
0001 1001
1000 0011
1000 0000
1000 0000
(BINARY)
0000 0000
0000 0000
1111 1111
L
t
BUF
M