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 (SMBusTM) 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 0.125C. When the con-
version rate is faster than 4Hz, output data is 7 bits +
sign with a resolution of 1C. The MAX6657/
MAX6658/MAX6659 also include an SMBus timeout
feature to enhance system reliability.
Remote accuracy is 1C between +60C and +100C
with no calibration needed. The MAX6657 measures
temperatures from 0C to +125C and the MAX6658/
MAX6659 from -55C to +125C. 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.
Applications
Desktop Computers
Workstations
Notebook Computers
Servers
Features
o Dual Channel: Measures Remote and Local
Temperature
o 11-Bit, 0.125C Resolution
o High Accuracy 1C (max) from +60C to +100C
(Remote)
o No Calibration Required
o Programmable Under/Overtemperature Alarms
o Programmable Conversion Rate
(0.0625Hz to 16Hz)
o SMBus/I
2
CTM-Compatible Interface
o Two Alarm Outputs: ALERT and OVERT1
(MAX6657 and MAX6658)
o Three Alarm Outputs: ALERT, OVERT1,
and OVERT2 (MAX6659)
MAX6657/MAX6658/MAX6659
1C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
________________________________________________________________ Maxim Integrated Products
1
19-2034; Rev 2; 3/02
Ordering Information
PART
TEMP.
RANGE
PIN-
PACKAGE
MEASURED
TEMP. RANGE
M A X6 6 5 7 M S A -55C to +125C 8 SO
0C to +125C
M A X6 6 5 8 M S A -55C to +125C 8 SO
-55C to +125C
M A X6 6 5 9 M E E -55C to +125C 16 QSOP
-55C to +125C
SMBus is a trademark of Intel Corp.
I
2
C is a trademark of Philips Corp.
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
V
CC
N.C.
STBY
SMBCLK
N.C.
SMBDATA
N.C.
OVERT2
ALERT
TOP VIEW
MAX6659
QSOP
N.C.
DXP
OVERT1
DXN
ADD
GND
GND
ALERT
GND
OVERT1
1
2
8
7
SMBCLK
SMBDATA
DXP
DXN
V
CC
SO
3
4
6
5
MAX6657
MAX6658
Pin Configurations
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.
Typical Operating Circuit appears at the end of the
data sheet.
MAX6657/MAX6658/MAX6659
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
All Voltages Referenced to GND
V
CC
..........................................................................-0.3V to +6V
DXP ............................................................-0.3V to (V
CC
+ 0.3V)
DXN ......................................................................-0.3V to +0.8V
SMBCLK, SMBDATA, ALERT, OVERT1,
OVERT2 ..............................................................-0.3V to +6V
SMBDATA, ALERT, OVERT1, OVERT2
Current ..........................................................-1mA to +50mA
DXN Current ......................................................................1mA
Continuous Power Dissipation (T
A
= +70C)
8-Pin SO (derate 5.9mW/C above +70C) .................471mW
16-Pin QSOP (derate 8.3mW/C above +70C) ..........664mW
Junction Temperature .....................................................+150C
Storage Temperature Range ............................-65C to +150C
Lead Temperature (soldering, 10s) ................................+300C
ELECTRICAL CHARACTERISTICS
(Circuit of Typical Operating Circuit, V
CC
= +3.0V to +5.5V, T
A
= 0C to +125C, unless otherwise specified. Typical values are at
V
CC
= +3.3V and T
A
= +25C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1
C
Temperature Resolution,
Legacy Mode
8
Bits
0.125
C
Temperature Resolution,
Extended Mode
11
Bits
T
RJ
= +60C to +100C, V
CC
= +3.3V
(Note 1)
-1.0
+1.0
T
RJ
= 0C to +100C, V
CC
= +3.3V (Note 1)
-3.0
+3.0
Remote Temperature Error
(MAX6657)
T
RJ
= 0C to +125C, V
CC
= +3.3V (Note 1)
-5.0
+5.0
C
T
A
= +60C to +100C, V
CC
= +3.3V
-2.0
+2.0
T
A
= 0C to +100C, V
CC
= +3.3V
-3.0
+3.0
Local Temperature Error
(MAX6657)
T
A
= 0C to +125C, V
CC
= +3.3V
-5.0
+5.0
C
T
RJ
= +60C to +100C, V
CC
= +3.3V
(Note 1)
-1.0
1.0
T
RJ
= 0C to +100C, V
CC
= +3.3V (Note 1)
-3.0
3.0
Remote Temperature Error
(MAX6658/MAX6659)
T
RJ
= -55C to +125C, V
CC
= +3.3V (Note 1)
-5.0
+5.0
C
T
A
= +60C to +100C, V
CC
= +3.3V
-2.0
+2.0
T
A
= 0C to +100C, V
CC
= +3.3V
-3.0
+3.0
Local Temperature Error
(MAX6658/MAX6659)
T
A
= -55C to +125C, V
CC
= +3.3V (Note 2)
-5.0
+5.0
C
Line Regulation
3.0V
V
CC
5.5V
0.2
0.6
mC/V
Supply Voltage Range
V
CC
3.0
5.5
V
Undervoltage Lockout Threshold
UVLO
Falling edge of V
CC
disables ADC
2.60
2.80
2.95
V
Undervoltage Lockout Hysteresis
90
mV
Power-On Reset (POR) Threshold
V
CC
, falling edge
1.5
2.0
2.5
V
POR Threshold Hysteresis
90
mV
Standby Supply Current
SMBus static
3
10
A
Operating Current
During conversion
0.5
1.0
mA
0.25 conversions/s
40
70
Average Operating Current
2 conversions/s
150
250
A
1C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
MAX6657/MAX6658/MAX6659
_______________________________________________________________________________________
3
Note 1: T
A
= +25C to +85C.
Note 2: If both the local and the remote junction are below T
A
= -20C, then V
CC
> 3.15V.
Note 3: For conversion rates of 4Hz or slower, the conversion time doubles.
Note 4: Timing specifications guaranteed by design.
Note 5: The serial interface resets when SMBCLK is low for more than t
TIMEOUT
.
Note 6: A transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SMBCLK's falling edge.
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Typical Operating Circuit, V
CC
= +3.0V to +5.5V, T
A
= 0C to +125C, unless otherwise specified. Typical values are at
V
CC
= +3.3V and T
A
= +25C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Conversion Time
t
CONV
From stop bit to conversion completed
(Note 4)
95
125
156
ms
Conversion Timing Error
25
%
DXP and DXN Leakage Current
In standby mode
100
nA
High level
80
100
120
Remote-Diode Source Current
I
RJ
Low level
8
10
12
A
(ALERT, OVERT)
V
OL
= 0.4V
1
Output Low Sink Current
V
OL
= 0.6V
6
mA
Output High Leakage Current
V
OH
= 5.5V
1
A
SMBus-COMPATIBLE INTERFACE (SMBCLK, SMBDATA, STBY)
Logic Input Low Voltage
V
IL
0.8
V
V
CC
= +3.0V
2.2
Logic Input High Voltage
V
IH
V
CC
= +5.5V
2.4
V
Input Leakage Current
I
LEAK
V
IN
= GND or V
CC
1
A
Output Low Sink Current
I
OL
V
OL
= 0.6V
6
mA
Input Capacitance
C
IN
5
pF
SMBus-COMPATIBLE TIMING (Note 4)
Serial Clock Frequency
f
SCL
(Note 5)
100
kHz
Bus Free Time Between STOP
and START Condition
t
BUF
4.7
s
START Condition Setup Time
4.7
s
Repeat START Condition Setup
Time
t
SU:STA
90% to 90%
50
ns
START Condition Hold Time
t
HD:STA
10% of SMBDATA to 90% of SMBCLK
4
s
STOP Condition Setup Time
t
SU:STO
90% of SMBCLK to 90% of SMBDATA
4
s
Clock Low Period
t
LOW
10% to 10%
4.7
s
Clock High Period
t
HIGH
90% to 90%
4
s
Data Setup Time
t
HD:DAT
(Note 6)
0
s
Receive SCL/SDA Rise Time
t
R
1
s
Receive SCL/SDA Fall Time
t
F
300
ns
Pulse Width of Spike Suppressed
t
SP
0
50
ns
SMBus Timeout
SMBDATA low period for interface reset
25
37
45
ms
1C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
MAX6657/MAX6658/MAX6659
4
_______________________________________________________________________________________
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25C, unless otherwise noted.)
4.5
4.0
3.5
3.0
2.5
3.0
4.0
3.5
4.5
5.0
5.5
STANDBY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6657 toc01
SUPPLY VOLTAGE (V)
STANDBY SUPPLY CURRENT (
A)
0.063
0.5
1
0.125 0.25
2
4
8
16
OPERATING SUPPLY CURRENT
vs. CONVERSION RATE
MAX6657 toc02
CONVERSION RATE (Hz)
OPERATING SUPPLY CURRENT (
A)
0
200
400
600
8Hz AND 16Hz ARE 1
C RESOLUTION
-3
-2
-1
0
1
2
3
-55
-5
-30
20
45
70
95
120
MAX6659
REMOTE TEMPERATURE ERROR
vs. REMOTE-DIODE TEMPERATURE
MAX6657 toc03
TEMPERATURE (
C)
TEMPERATURE ERROR (
C)
FAIRCHILD 2N3906
-3
-2
-1
0
1
2
3
-55
-5
-30
20
45
70
95
120
LOCAL TEMPERATURE ERROR
vs. DIE TEMPERATURE
MAX6657 toc04
TEMPERATURE (
C)
TEMPERATURE ERROR (
C)
1
0
-1
-2
-3
10k
1M
100k
10M
100M
TEMPERATURE ERROR vs.
POWER-SUPPLY NOISE FREQUENCY
MAX6657 toc05
FREQUENCY (Hz)
TEMPERATURE ERROR (
C)
V
IN
= SQUARE WAVE APPLIED TO V
CC
WITH NO 0.1
F V
CC
CAPACITOR
1
0
-1
-2
-3
0.01k
100k
1k
10M
1G
TEMPERATURE ERROR vs.
COMMON-MODE NOISE FREQUENCY
MAX6657 toc06
FREQUENCY (Hz)
TEMPERATURE ERROR (
C)
V
IN
= AC-COUPLED TO DXN
V
IN
= 100mVp-p
1
0
-1
-2
-3
10k
1M
100k
10M
100M
TEMPERATURE ERROR vs.
DIFFERENTIAL-MODE NOISE FREQUENCY
MAX6657 toc07
FREQUENCY (Hz)
TEMPERATURE ERROR (
C)
V
IN
= 10mV
P-P
SQUARE WAVE
APPLIED TO DXP-DXN
-5
-4
-3
-2
-1
0
0
40 50
20 30
10
60 70 80 90 100
TEMPERATURE ERROR vs.
DXP-DXN CAPACITANCE
MAX6657 toc08
DXP-DXN CAPACITANCE (nF)
TEMPERATURE ERROR (
C)
1C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
MAX6657/MAX6658/MAX6659
_______________________________________________________________________________________
5
PIN
MAX6657
MAX6658
MAX6659
NAME
FUNCTION
1
1
V
CC
Supply Voltage Input, +3V to +5.5V. Bypass to GND with a 0.1F capacitor. A 200
series resistor is recommended but not required for additional noise filtering. See
Typical Operating Circuit.
2
3
DXP
Combined Remote-Diode Current Source and A/D Positive Input for Remote-Diode
Channel. DO NOT LEAVE DXP FLOATING; connect DXP to DXN if no remote diode
is used. Place a 2200pF capacitor between DXP and DXN for noise filtering.
3
4
DXN
Combined Remote-Diode Current Sink and A/D Negative Input. DXN is internally
biased to one diode drop above ground.
4
6
OVERT1
Overtemperature Active-Low Output, Open-Drain. Output is logic low only when
temperature is above the software programmed threshold.
5
7, 8
GND
Ground
6
9
ALERT
SMBus Alert (Interrupt) Active-Low Output, Open-Drain. Asserts when temperature
exceeds user-set limits (high or low temperature). Stays asserted until acknowledged
by either reading the Status register or by successfully responding to an Alert
Response address. See ALERT Interrupts.
7
12
SMBDATA
SMBus Serial-Data Input/Output, Open-Drain
8
14
SMBCLK
SMBus Serial-Clock Input
--
5
ADD
SMBus Address-Select Pin. The MAX6659 is set to one of three available addresses
(connect to V
CC
, GND, or leave open). See Slave Addresses section.
--
10
OVERT2
Overtemperature Active-Low Output, Open-Drain. Output is logic low only when
temperature is above the software programmed threshold.
--
15
STBY
Hardware Standby Input. Temperature and comparison threshold data are retained in
standby mode. If STBY is low, the IC is put into standby mode.
--
2, 11, 13, 16
N.C.
Not internally connected. Do not make connections to these pins.
Pin Description
1C, SMBus-Compatible Remote/Local Temperature
Sensors with Overtemperature Alarms
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