MAX6646, MAX6647, MAX6649 pdf

The MAX6646/MAX6647/MAX6649 are precise, twochannel
digital temperature sensors. The devices accurately
measure the temperature of their own die and a
remote PN junction, and report the temperature in digital
form using a 2-wire serial interface. The remote PN junction
is typically the emitter-base junction of a commoncollector
PNP on a CPU, FPGA, or ASIC.
The 2-wire serial interface accepts standard system management
bus (SMBusTM) write byte, read byte, send byte,
and receive byte commands to read the temperature
data and to program the alarm thresholds. To enhance
system reliability, the MAX6646/MAX6647/MAX6649
include an SMBus timeout. A fault queue prevents the
ALERT and OVERT outputs from setting until a fault has
been detected one, two, or three consecutive times
(programmable).
The MAX6646/MAX6647/MAX6649 provide two system
alarms: ALERT and OVERT. ALERT asserts when any of
four temperature conditions are violated: local overtemperature,
remote overtemperature, local undertemperature,
or remote undertemperature. OVERT asserts when
the temperature rises above the value in either of the two
OVERT limit registers. The OVERT output can be used to
activate a cooling fan, or to trigger a system shutdown.
Measurements can be done autonomously, at the programmed
conversion rate, or in a single-shot mode. The
adjustable conversion rate allows optimizing supply current
and temperature update rate to match system needs.
Remote accuracy is ±1°C maximum error between +60°C
and +145°C with no calibration needed. The MAX6646/
MAX6647/MAX6649 operate from -55°C to +125°C, and
measure temperatures between 0°C and +145°C. The
MAX6646/MAX6647/MAX6649 are available in an 8-pin
μMAX® package.
Applications
Graphics Processors
Desktop Computers
Notebook Computers
Servers
Thin Clients
Workstations
Test and Measurement
Multichip Modules