19-2034; Rev 2; 3/02
±1°C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
General Description
The MAX6657/MAX6658/MAX6659 are precise, two-
channel digital temperature sensors. Each accurately
measures the temperature of its own die and one
remote PN junction, and reports the temperature in digi-
tal form on a 2-wire serial interface. The remote junction
can be a diode-connected transistor like the low-cost
NPN type 2N3904 or 2N3906 PNP type. The remote
junction can also be a common-collector PNP, such as
a substrate PNP of a microprocessor.
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 MAX6657/MAX6658/
MAX6659 can function autonomously with a program-
mable conversion rate, which allows the control of sup-
ply current and temperature update rate to match
system needs. For conversion rates of 4Hz or less, the
temperature is represented in extended mode as 10
bits + sign with a resolution of 0.125°C. When the con-
version rate is faster than 4Hz, output data is 7 bits +
sign with a resolution of 1°C. The MAX6657/
MAX6658/MAX6659 also include an SMBus timeout
feature to enhance system reliability.
Remote accuracy is ±1°C between +60°C and +100°C
with no calibration needed. The MAX6657 measures
temperatures from 0°C to +125°C and the MAX6658/
MAX6659 from -55°C to +125°C. The MAX6659 has the
added benefit of being able to select one of three
addresses through an address pin, and a second over-
temperature alarm pin for greater system reliability.
Features
o
Dual Channel: Measures Remote and Local
Temperature
o
11-Bit, 0.125°C Resolution
o
High Accuracy ±1°C (max) from +60°C to +100°C
(Remote)
o
No Calibration Required
o
Programmable Under/Overtemperature Alarms
o
Programmable Conversion Rate
(0.0625Hz to 16Hz)
o
SMBus/I
2
C™-Compatible Interface
o
Two Alarm Outputs:
ALERT
and
OVERT1
(MAX6657 and MAX6658)
o
Three Alarm Outputs:
ALERT, OVERT1,
and
OVERT2
(MAX6659)
MAX6657/MAX6658/MAX6659
Ordering Information
PART
TEMP.
RANGE
PIN-
MEASURED
PACKAGE TEMP. RANGE
0°C to +125°C
-55°C to +125°C
-55°C to +125°C
MAX6657
MSA -55°C to +125°C 8 SO
MAX6658
MSA -55°C to +125°C 8 SO
MAX6659
MEE -55°C to +125°C 16 QSOP
Applications
Desktop Computers
Notebook Computers
Servers
Workstations
TOP VIEW
Pin Configurations
V
CC
1
N.C. 2
DXP 3
DXN 4
16 N.C.
15 STBY
14 SMBCLK
V
CC
1
DXP 2
DXN 3
OVERT1 4
8 SMBCLK
7 SMBDATA
MAX6659
13 N.C.
12 SMBDATA
11 N.C.
10 OVERT2
9 ALERT
Typical Operating Circuit appears at the end of the
data sheet.
ADD 5
OVERT1 6
GND 7
GND 8
MAX6657
MAX6658
6 ALERT
5 GND
SO
SMBus is a trademark of Intel Corp.
I
2
C is a trademark of Philips Corp.
QSOP
________________________________________________________________
Maxim Integrated Products
1
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.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
