MAX6660AEE+ Maxim Integrated Products, MAX6660AEE+ Datasheet - Page 11

• Manufacturer Part Number: MAX6660AEE+
• Description: IC REG FAN SPEED 16-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6660AEE+

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Control, Multiplexer, Register Bank
• Sensor Type: External
• Sensing Temperature: 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: +/- 5 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 10 bit + Sign
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

*Pe
ud
S.
master. Upon receiving an ALERT interrupt signal, the
host master can broadcast a Receive Byte transmission
to the Alert Response slave address (see Slave
Addresses section). Then, any slave device that gener-
ated an interrupt attempts to identify itself by putting its
own address on the bus (Table 3).
The Alert Response can activate several different slave
devices simultaneously, similar to the I
If more than one slave attempts to respond, bus arbitra-
tion rules apply, and the device with the lower address
code wins. The losing device does not generate an
Acknowledge and continues to hold the ALERT line low
until cleared. (The conditions for clearing an alert vary
depending on the type of slave device.) Successful
completion of the Alert Response protocol clears the
interrupt latch, provided the condition that caused the
alert no longer exists. If the condition still exists, the
device reasserts the ALERT interrupt at the end of the
next conversion.
Table 3. Read Format for Alert Response
Address
The 8-bit Command Byte register (Table 4) is the mas-
ter index that points to the other registers within the
MAX6660. The register’s POR is 0000 0000, so that a
receive byte transmission (a protocol that lacks the
command byte) that occurs immediately after POR
returns the current remote temperature data.
The one-shot command immediately forces a new conver-
sion cycle to begin. In software standby mode
(RUN/STOP bit = high), a new conversion is begun, after
which the device returns to standby mode. If a conversion
is in progress when a one-shot command is received, the
command is ignored. If a one-shot command is between
conversions, in autoconvert mode (RUN/STOP bit = low),
a new conversion begins immediately.
7 (MSB)
0 (LSB)
BIT
6
5
4
3
2
1
Fan-Speed Regulator with SMBus Interface
NAME
ADD7
ADD6
ADD5
ADD4
ADD3
ADD2
ADD1
Remote-Junction Temperature-Controlled
1
______________________________________________________________________________________
Command Byte Functions
Provide the current MAX6660
slave address
Logic 1
FUNCTION
2
C* General Call.
One-Shot
The Configuration Byte register (Table 5) is used to
mask (disable) the ALERT signal to place the device in
software standby mode, to change the polarity of
OVERT, to set MAX6660 to thermal open/closed-loop
mode, to inhibit the OVERT signal, to mask OVERT out-
put, and to clear the ALERT signal. The MAX6660 has a
write protection feature (bit 4) that prohibits write com-
mands to bits 6–3 of the Configuration register. It also
prohibits writes to the T
Conversion Rate registers.
The status byte (Table 6) reports several fault condi-
tions. It indicates when the fan driver transistor of the
MAX6660 has overheated and/or is thermal shutdown,
when the temperature thresholds, T
have been exceeded, and whether there is an open cir-
cuit in the DXP-DXN path. The register also reports the
state of the ALERT and OVERT lines and indicates
when the fan driver is fully on. The final bit in the Status
register indicates when a fan failure has occurred.
After POR, the normal state of the flag bits is zero,
assuming no alert or overtemperature conditions are
present. Bits 2 through 6 of the Status register are
cleared by any successful read of the Status register,
unless the fault persists. The ALERT output follows the
status flag bit. Both are cleared when successfully
read, but if the condition still exists, the ALERT is
reasserted at the end of the next conversion.
The MAX6660 incorporates collision avoidance so that
completely asynchronous operation is allowed between
SMBus operations and temperature conversions.
When autoconverting, if the T
close together, it is possible for both high-temperature
and low-temperature status bits to be set, depending
on the amount of time between status read operations.
In these circumstances, it is best not to rely on the sta-
tus bits to indicate reversals in long-term temperature
changes. Instead, use a current temperature reading to
establish the trend direction.
Two ROM registers provide manufacturer and device
ID codes. Reading the manufacturer ID returns 4D,
which is the ASCII code M (for Maxim). Reading the
device ID returns 09h, indicating the MAX6660 device.
If READ WORD 16-bit SMBus protocol is employed
(rather than the 8-bit READ BYTE), the LSB contains the
data and the MSB contains 00h in both cases.
Manufacturer and Device ID Codes
Configuration Byte Functions
Status Byte Functions
HIGH
MAX
, T
and T
HYST
LOW
LOW
, and Fan
and T
limits are
HIGH
11
,