MAX6680MEE+T Maxim Integrated Products, MAX6680MEE+T Datasheet - Page 12

• Manufacturer Part Number: MAX6680MEE+T
• Description: IC TEMP SENSOR SMBUS 16-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6680MEE+T

• Function: Thermometer, Thermostat
• Topology: ADC, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -55°C ~ 125°C, External Sensor
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 5 C, +/- 3 C
• Digital Output - Bus Interface: Serial (2-Wire)
• Digital Output - Number Of Bits: 10 bit + Sign
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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.
Two registers, RWOE and RWOI, store remote and local
alarm threshold data corresponding to the OVERT out-
put. The values stored in these registers are high-tem-
perature thresholds. If any one of the measured
temperatures equals or exceeds the corresponding
alarm threshold value, an OVERT output is asserted.
The overtemperature thresholds are both hardware and
software programmable. The overtemperature thresh-
olds can be hardware programmed by pin strapping
CRIT0 and CRIT1. Use Table 4 to set the desired
remote and local threshold temperatures. Upon POR or
driving the RESET pin high, the Overtemperature regis-
ter takes on the hardware-programmed values.
Afterward, any write to the Overtemperature registers
overwrites the hardware-programmable values.
OVERT always operates in comparator mode and is
asserted when the temperature rises to a value pro-
grammed in the appropriate threshold register. It is
deasserted when the temperature drops below this
threshold minus the programmed value in the Hysteresis
(HYST) register. An OVERT output can be used to acti-
vate a cooling fan, send a warning, initiate clock throt-
tling, or trigger a system shutdown to prevent component
damage. The HYST byte sets the amount of hysteresis
to deassert the OVERT output. The data format for the
HYST byte is 7 bits + sign with 1°C resolution. Bit 7 of
the HYST register should always be zero.
The 8-bit Command Byte register (Table 5) is the mas-
ter index that points to the various other registers within
the MAX6680/MAX6681. This register’s POR state is
0000 0000, so a Receive Byte transmission (a protocol
that lacks the command byte) occurring immediately
after POR returns the current local temperature data.
The One-Shot command immediately forces a new con-
version cycle to begin. If the One-Shot command is
received when the MAX6680/MAX6681 is in software
standby mode (RUN/STOP bit = 1), a new conversion is
begun, after which the device returns to standby mode.
If a conversion is in progress when a One-Shot com-
mand is received, the command is ignored. If a One-Shot
command is received in autoconvert mode (RUN/STOP
±1°C Fail-Safe Remote/Local Temperature
Sensors with SMBus Interface
12
______________________________________________________________________________________
OVERT Overtemperature Alarm
Command Byte Functions
One Shot
bit = 0) between conversions, a new conversion
begins, the conversion rate timer is reset, and the next
automatic conversion takes place after a full delay
elapses.
The Configuration Byte register, Table 6, is a read-write
register with several functions. Bit 7 is used to mask
(disable) ALERT interrupts. Bit 6 puts the device into
software standby mode (STOP) or autonomous (RUN)
mode. Bit 5 selects the type of external junction (set to
0 for a substrate PNP on an IC or set to 1 for a discrete
diode-connected transistor) for optimized measure-
ments. Bit 4 selects the extended temperature mea-
surement for the remote sensor. If high, the temperature
data is available as 10 bits + sign with a 0.125°C reso-
lution, otherwise, 7 bits + sign with 1°C resolution. Bit 4
extends the temperature range of the remote and local
temperature sensor to -64°C. Bit 2 disables the SMBus
timeout, as well as the Alert Response. Bit 1 provides a
software reset from the SMBus. Bit 0 is reserved and
returns a zero when read.
The status byte (Table 7) indicates which (if any) tem-
perature thresholds have been exceeded. This byte
also indicates whether the ADC is converting and if
there is an open-circuit fault detected with the external
sense junction. After POR, the normal state of the regis-
ters’ bits is zero, assuming no alert or overtemperature
conditions are present. When operating the
MAX6680/MAX6681 in ALERT interrupt mode, bits 2
through 6 of the Status register are cleared by any suc-
cessful read of the Status register, unless the fault per-
sists. The ALERT output follows the status flag bit. Both
are cleared when successfully read, but if the condition
Table 4. OVERT Temperature Threshold
Programming
CRIT1
Open
Open
Open
GND
GND
GND
V
V
V
CC
CC
CC
CRIT0
Open
Open
Open
GND
GND
GND
V
V
V
CC
CC
CC
Configuration Byte Functions
Status Byte Functions
REMOTE
OVERT THRESHOLD (°C)
+100
+105
+110
+115
+120
+125
+85
+90
+95
LOCAL
+100
+105
+110
+70
+75
+80
+85
+90
+95