Rainbow Electronics MAX6681 - Manual

General Description
The MAX6680/MAX6681 are precise, two-channel digi-
tal thermometers. Each accurately measures the tem-
perature of its own die and one remote PN junction and
reports the temperature on a 2-wire serial interface. The
remote junction can be a diode-connected transistor
like the low-cost NPN type 2N3904 or PNP type
2N3906. The remote junction can also be a common-
collector PNP, such as a substrate PNP of a micro-
processor.
The MAX6680/MAX6681 include pin-programmable
default temperature thresholds for the OVERT output,
which provides fail-safe clock throttling or system shut-
down. In addition, the devices are pin programmable to
select whether the OVERT output responds to either the
local, remote, or both temperatures.
The 2-wire serial interface accepts standard System
Management Bus (SMBus)™ commands such as Write
Byte, Read Byte, Send Byte, and Receive Byte to read
the temperature data and program the alarm thresholds
and conversion rate. The MAX6680/MAX6681 can func-
tion autonomously with a programmable conversion
rate, which allows the control of supply current and
temperature update rate to match system needs. For
conversion rates of 4Hz or less, the remote sensor tem-
perature can be represented in extended mode as 10
bits + sign with a resolution of 0.125°C. When the con-
version rate is 8Hz, output data is 7 bits + sign with a
resolution of 1°C. The MAX6680/MAX6681 also include
an SMBus timeout feature to enhance system reliability.
The MAX6681 is an upgrade to the MAX6654. The
MAX6680/MAX6681 remote accuracy is ±1°C with no
calibration needed. They are available in a 16-pin
QSOP package and operate throughout the -55°C to
+125°C temperature range.
Applications
Features
♦ Two Alarm Outputs: ALERT and OVERT
♦ Pin-Programmable Threshold for OVERT Limit
♦ Programmable Under/Overtemperature ALERT
Limit
♦ Dual Channel: Measures Remote and Local
Temperature
♦ 11-Bit, 0.125°C Resolution for Remote Temperature
Measurements
♦ High Accuracy ±1°C (max) from +60°C to +100°C
(Remote)
♦ No Calibration Required
♦ SMBus/I
2 C™-Compatible Interface
♦ SMBus Timeout Prevents SMBus Lockup
MAX6680/MAX6681
±1°C Fail-Safe Remote/Local Temperature
Sensors with SMBus Interface
________________________________________________________________ Maxim Integrated Products 1
CLOCK
DATA
TO SYSTEM
SHUTDOWN
STBY
CRIT1 CRIT0 GND
OVERT
SMBCLK
RESET
SMBDATA
V CC
INTERRUPT
TO
µP
0.1 µF
2200pF
DXN
MICROPROCESSOR
DXP
200 Ω
10k Ω
EACH
ALERT
3.3V
INT_SEL
SENS_SEL
ADD1
ADD0
MAX6680
MAX6681
Typical Operating Circuit
Ordering Information
19-2305; Rev 0; 4/02
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE PIN-PACKAGE
MAX6680MEE -55 °C to +125°C 16 QSOP
MAX6681MEE -55 °C to +125°C 16 QSOP
SMBus is a trademark of Intel Corp.
I 2 C is a trademark of Philips Corp.
Pin Configurations appear at end of data sheet.
Desktop Computers
Notebook
Computers
Servers
Thin Clients
Workstations