MAX6657 [MAXIM]
【1∑C, SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms; ± 1 ° C， SMBus兼容，远端/本地温度传感器，带有高温报警
| 型号： | MAX6657 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 【1∑C, SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms |
| 文件： | 总17页 (文件大小：274K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2034; Rev 2; 3/02
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
General Description
Features
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.
ꢀ Dual Channel: Measures Remote and Local
Temperature
ꢀ 11-Bit, 0.125°C Resolution
ꢀ High Accuracy 1°C ꢀmaꢁx ꢂrom ꢃ+0°C to ꢃ100°C
ꢀRemotex
ꢀ No Calibration Required
ꢀ Programmable Under/Overtemperature Alarms
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.
ꢀ Programmable Conversion Rate
ꢀ0.0+25Hz to 1+Hzx
ꢀ SMBus/I2C™-Compatible Interꢂace
ꢀ Two Alarm Outputs: ALERT and OVERT1
ꢀMAX++57 and MAX++58x
ꢀ Three Alarm Outputs: ALERT, OVERT1,
and OVERT2 ꢀMAX++59x
Ordering Inforꢃation
TEMP.
RANGE
PIN-
MEASURED
PART
PACKAGE TEMP. RANGE
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.
MAX6657MSA -55°C to +125°C 8 SO
MAX6658MSA -55°C to +125°C 8 SO
0°C to +125°C
-55°C to +125°C
MAX6659MEE -55°C to +125°C 16 QSOP -55°C to +125°C
Pin °onfigurations
Applications
Desktop Computers
Notebook Computers
Servers
Workstations
TOP VIEW
V
CC
1
2
3
4
5
6
7
8
16 N.C.
N.C.
DXP
15 STBY
V
1
2
3
4
8
7
6
5
SMBCLK
SMBDATA
ALERT
CC
14 SMBCLK
13 N.C.
DXP
DXN
DXN
MAX6659
MAX6657
MAX6658
ADD
12 SMBDATA
11 N.C.
Typical Operating Circuit appears at the end of the
data sheet.
OVERT1
GND
OVERT1
GND
10 OVERT2
SO
GND
9 ALERT
QSOP
SMBus is a trademark of Intel Corp.
2
I C is a trademark of Philips Corp.
________________________________________________________________ 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.
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ABSOLUTE MAXIMUM RATINGS
All Voltages Referenced to GND
DXN Current ...................................................................... 1mA
V
..........................................................................-0.3V to +6V
Continuous Power Dissipation (T = +70°C)
CC
A
DXP ............................................................-0.3V to (V
DXN ......................................................................-0.3V to +0.8V
SMBCLK, SMBDATA, ALERT, OVERT1,
OVERT2 ..............................................................-0.3V to +6V
SMBDATA, ALERT, OVERT1, OVERT2
+ 0.3V)
8-Pin SO (derate 5.9mW/°C above +70°C) .................471mW
16-Pin QSOP (derate 8.3mW/°C above +70°C) ..........664mW
Junction Temperature .....................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
CC
Current ..........................................................-1mA to +50mA
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.
ELECTRICAL CHARACTERISTICS
(Circuit of Typical Operating Circuit, V
= +3.0V to +5.5V, T = 0°C to +125°C, unless otherwise specified. Typical values are at
A
CC
V
CC
= +3.3V and T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
8
MAX
UNITS
°C
1
Temperature Resolution,
Legacy Mode
Bits
°C
0.125
Temperature Resolution,
Extended Mode
11
Bits
T
= +60°C to +100°C, V
= +3.3V
RJ
CC
-1.0
+1.0
(Note 1)
Remote Temperature Error
(MAX6657)
°C
°C
°C
°C
T
T
T
T
T
= 0°C to +100°C, V
= +3.3V (Note 1)
-3.0
-5.0
-2.0
-3.0
-5.0
+3.0
+5.0
+2.0
+3.0
+5.0
RJ
CC
= 0°C to +125°C, V = +3.3V (Note 1)
RJ
CC
= +60°C to +100°C, V
= +3.3V
A
A
A
CC
Local Temperature Error
(MAX6657)
= 0°C to +100°C, V
= 0°C to +125°C, V
= +3.3V
CC
CC
= +3.3V
= +3.3V
T
= +60°C to +100°C, V
RJ
CC
-1.0
1.0
(Note 1)
Remote Temperature Error
(MAX6658/MAX6659)
T
T
T
T
T
= 0°C to +100°C, V
= +3.3V (Note 1)
-3.0
-5.0
-2.0
-3.0
-5.0
3.0
+5.0
+2.0
+3.0
+5.0
0.6
RJ
CC
= -55°C to +125°C, V
= +3.3V (Note 1)
= +3.3V
RJ
CC
= +60°C to +100°C, V
A
A
A
CC
Local Temperature Error
(MAX6658/MAX6659)
= 0°C to +100°C, V
= +3.3V
CC
= -55°C to +125°C, V
= +3.3V (Note 2)
CC
Line Regulation
3.0V ≤ V
≤ 5.5V
0.2
m°C/V
V
CC
Supply Voltage Range
V
3.0
5.5
CC
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
Power-On Reset (POR) Threshold
POR Threshold Hysteresis
Standby Supply Current
Operating Current
UVLO
Falling edge of V
disables ADC
2.60
2.80
90
2.95
V
CC
mV
V
V
, falling edge
CC
1.5
2.0
90
2.5
mV
µA
mA
SMBus static
3
10
1.0
70
During conversion
0.25 conversions/s
2 conversions/s
0.5
40
Average Operating Current
µA
150
250
2
_______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Typical Operating Circuit, V
= +3.0V to +5.5V, T = 0°C to +125°C, unless otherwise specified. Typical values are at
A
CC
V
CC
= +3.3V and T = +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
From stop bit to conversion completed
(Note 4)
Conversion Time
t
95
125
156
ms
CONV
Conversion Timing Error
25
100
120
12
%
DXP and DXN Leakage Current
In standby mode
High level
nA
80
8
100
10
Remote-Diode Source Current
(ALERT, OVERT)
I
RJ
µA
Low level
V
V
V
= 0.4V
= 0.6V
= 5.5V
1
6
OL
OL
OH
Output Low Sink Current
mA
µA
Output High Leakage Current
1
SMBus-COMPATIBLE INTERFACE (SMBCLK, SMBDATA, STBY)
Logic Input Low Voltage
V
0.8
V
V
IL
V
V
V
V
= +3.0V
= +5.5V
2.2
2.4
CC
CC
Logic Input High Voltage
V
IH
Input Leakage Current
Output Low Sink Current
Input Capacitance
I
= GND or V
= 0.6V
1
µA
mA
pF
LEAK
IN
CC
I
6
OL
OL
C
5
IN
SMBus-COMPATIBLE TIMING (Note 4)
Serial Clock Frequency
f
(Note 5)
100
kHz
µs
SCL
Bus Free Time Between STOP
and START Condition
t
4.7
4.7
50
BUF
START Condition Setup Time
µs
Repeat START Condition Setup
Time
t
90% to 90%
ns
SU:STA
START Condition Hold Time
STOP Condition Setup Time
Clock Low Period
t
t
10% of SMBDATA to 90% of SMBCLK
90% of SMBCLK to 90% of SMBDATA
10% to 10%
4
4
µs
µs
µs
µs
µs
µs
ns
ns
ms
HD:STA
SU:STO
t
4.7
4
LOW
Clock High Period
t
90% to 90%
HIGH
Data Setup Time
t
(Note 6)
0
HD:DAT
Receive SCL/SDA Rise Time
Receive SCL/SDA Fall Time
Pulse Width of Spike Suppressed
SMBus Timeout
t
1
R
t
300
50
F
t
SP
0
SMBDATA low period for interface reset
25
37
45
Note 1: T = +25°C to +85°C.
A
Note 2: If both the local and the remote junction are below T = -20°C, then V
> 3.15V.
A
CC
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.
_______________________________________________________________________________________
3
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ꢇypical Operating °haracteristics
(V
= +3.3V, T = +25°C, unless otherwise noted.)
CC
A
MAX6659
REMOTE TEMPERATURE ERROR
vs. REMOTE-DIODE TEMPERATURE
OPERATING SUPPLY CURRENT
vs. CONVERSION RATE
STANDBY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
600
400
200
0
4.5
3
2
8Hz AND 16Hz ARE 1°C RESOLUTION
4.0
3.5
3.0
2.5
1
0
-1
-2
-3
FAIRCHILD 2N3906
0.063 0.125 0.25 0.5
1
2
4
8
16
3.0
3.5
4.0
4.5
5.0
5.5
-55 -30
-5
20
45
70
95 120
CONVERSION RATE (Hz)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE ERROR vs.
COMMON-MODE NOISE FREQUENCY
LOCAL TEMPERATURE ERROR
vs. DIE TEMPERATURE
TEMPERATURE ERROR vs.
POWER-SUPPLY NOISE FREQUENCY
1
0
3
2
1
0
-1
-2
-3
1
-1
-2
-3
0
V
= SQUARE WAVE APPLIED TO V
CC
IN
-1
-2
-3
WITH NO 0.1µF V CAPACITOR
CC
V
IN
V
IN
= AC-COUPLED TO DXN
= 100mVp-p
0.01k
1k
100k
10M
1G
10k
100k
1M
10M
100M
-55 -30 -5
20
45
70
95 120
FREQUENCY (Hz)
FREQUENCY (Hz)
TEMPERATURE (°C)
TEMPERATURE ERROR vs.
DXP-DXN CAPACITANCE
TEMPERATURE ERROR vs.
DIFFERENTIAL-MODE NOISE FREQUENCY
0
1
0
-1
-2
-3
-4
-5
-1
-2
-3
V
= 10mV SQUARE WAVE
P-P
IN
APPLIED TO DXP-DXN
0
10 20 30 40 50 60 70 80 90 100
DXP-DXN CAPACITANCE (nF)
10k
100k
1M
10M
100M
FREQUENCY (Hz)
4
_______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Pin Description
PIN
NAME
FUNCTION
MAX6657
MAX6658
MAX6659
Supply Voltage Input, +3V to +5.5V. Bypass to GND with a 0.1µF capacitor. A 200Ω
series resistor is recommended but not required for additional noise filtering. See
Typical Operating Circuit.
1
1
V
CC
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.
2
3
3
4
DXP
DXN
Combined Remote-Diode Current Sink and A/D Negative Input. DXN is internally
biased to one diode drop above ground.
Overtemperature Active-Low Output, Open-Drain. Output is logic low only when
temperature is above the software programmed threshold.
4
5
6
OVERT1
7, 8
GND
Ground
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.
6
9
ALERT
7
8
12
14
SMBDATA
SMBCLK
SMBus Serial-Data Input/Output, Open-Drain
SMBus Serial-Clock Input
SMBus Address-Select Pin. The MAX6659 is set to one of three available addresses
—
—
5
ADD
(connect to V , GND, or leave open). See Slave Addresses section.
CC
Overtemperature Active-Low Output, Open-Drain. Output is logic low only when
temperature is above the software programmed threshold.
10
OVERT2
Hardware Standby Input. Temperature and comparison threshold data are retained in
standby mode. If STBY is low, the IC is put into standby mode.
—
—
15
STBY
2, 11, 13, 16
N.C.
Not internally connected. Do not make connections to these pins.
_______________________________________________________________________________________
5
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Functional Diagraꢃ
V
CC
MAX6657
MAX6658
MAX6659
2
DXP
DXN
MUX
REMOTE
CONTROL
LOGIC
(STBY)
ADC
LOCAL
DIODE
FAULT
SMBus
SMBDATA
SMBCLK
8
8
READ
ALERT
S
R
WRITE
Q
Q
Q
REGISTER BANK
COMMAND BYTE
REMOTE TEMPERATURE
LOCAL TEMPERATURE
ALERT THRESHOLD
7
OVERT1
S
R
(ADD)
ADDRESS
DECODER
ALERT RESPONSE
ADDRESS
(OVERT2)
OVERT1 THRESHOLD
(OVERT2 THRESHOLD)
S
R
MAX6659 ONLY
( ) ARE FOR MAX6659 ONLY
10 bits + sign bit and is available for autonomous con-
versions that are 4Hz and slower and single-shot con-
versions. Legacy resolution represents temperature as
7 bits + sign bit and allows for faster autonomous con-
version rates of 8Hz and 16Hz.
Detailed Description
The MAX6657/MAX6658/MAX6659 are temperature
sensors designed to work in conjunction with a micro-
processor or other intelligence in thermostatic,
process-control, or monitoring applications. Com-
munication with the MAX6657/MAX6658/MAX6659
occurs through the SMBus serial interface and dedicat-
ed alert pins. Two independent overtemperature alarms
(OVERT1 and OVERT2) are asserted if their software
programmed temperature thresholds are exceeded.
OVERT1 and OVERT2 can be connected to fans, a sys-
tem shutdown, or other thermal management circuitry.
AD° and Multiplexer
The averaging ADC integrates over a 60ms period
(each channel, typically, in the 7-bit + sign legacy
mode). Using an averaging ADC attains excellent noise
rejection.
The multiplexer automatically steers bias currents
through the remote and local diodes. The ADC and
associated circuitry measure each diode’s forward volt-
age and compute the temperature based on this volt-
age. If the remote channel is not used, connect DXP to
DXN. Do not leave DXP and DXN unconnected. When a
conversion is initiated, both channels are converted
The MAX6657/MAX6658/MAX6659 convert tempera-
tures to digital data either at a programmed rate or a
single conversion. Conversions have a 0.125°C resolu-
tion (extended resolution) or 1°C resolution (legacy res-
olution). Extended resolution represents temperature as
6
_______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
that the base resistance is less than 100Ω. Tight speci-
Table 1. Remote-Sensor Transistor
fications for forward current gain (50 < β < 150, for
MANUFACTURER
Central Semiconductor (USA)
Fairchild Semiconductor (USA)
On Semiconductor (USA)
Rohm Semiconductor (USA)
Samsung (Korea)
MODEL NUMBER
CMPT3904
2N3904, 2N3906
2N3904, 2N3906
SST3904
example) indicate that the manufacturer has good
process controls and that the devices have consistent
V
BE
characteristics.
ꢇherꢃal Mass and ꢀelfꢂHeating
When sensing local temperature, these devices are
intended to measure the temperature of the PC board
to which they are soldered. The leads provide a good
thermal path between the PC board traces and the die.
Thermal conductivity between the die and the ambient
air is poor by comparison, making air temperature mea-
surements impractical. Because the thermal mass of
the PC board is far greater than that of the MAX6657/
MAX6658/MAX6659, the devices follow temperature
changes on the PC board with little or no perceivable
delay.
KST3904-TF
Siemens (Germany)
SMBT3904
Zetex (England)
FMMT3904CT-ND
Note: Transistors must be diode connected (base shorted to
collector).
whether they are used or not. The DXN input is biased
at one V above ground by an internal diode to set up
BE
the ADC inputs for a differential measurement.
Resistance in series with the remote diode causes
about +1/2°C error per ohm.
When measuring the temperature of a CPU or other IC
with an on-chip sense junction, thermal mass has virtu-
ally no effect; the measured temperature of the junction
tracks the actual temperature within a conversion cycle.
When measuring temperature with discrete remote sen-
sors, smaller packages (i.e., a SOT23) yield the best
thermal response times. Take care to account for ther-
mal gradients between the heat source and the sensor,
and ensure that stray air currents across the sensor
package do not interfere with measurement accuracy.
A/D °onversion ꢀequence
A conversion sequence consists of a local temperature
measurement and a remote temperature measurement.
Each time a conversion begins, whether initiated auto-
matically in the free-running autoconvert mode
(RUN/STOP = 0) or by writing a “one-shot” command,
both channels are converted, and the results of both
measurements are available after the end of conver-
sion. A BUSY status bit in the Status register shows that
the device is actually performing a new conversion. The
results of the previous conversion sequence are still
available when the ADC is busy.
Self-heating does not significantly affect measurement
accuracy. Remote-sensor self-heating due to the diode
current source is negligible. For the local diode, the
worst-case error occurs when autoconverting at the
fastest rate and simultaneously sinking maximum cur-
ꢅeꢃoteꢂDiode ꢀelection
The MAX6657/MAX6658/MAX6659 can directly mea-
sure the die temperature of CPUs and other ICs that
have on-board temperature-sensing diodes (see
Typical Operating Circuit) or they can measure the tem-
perature of a discrete diode-connected transistor. The
type of remote diode used is set by bit 5 of the
Configuration Byte. If bit 5 is set to zero, the remote
sensor is a diode-connected transistor, and if bit 5 is set
to 1, the remote sensor is a substrate or common collec-
tor PNP transistor. For best accuracy, the discrete tran-
sistor should be a small-signal device with its collector
and base connected together. Accuracy has been
experimentally verified for all the devices listed in Table 1.
rent at the ALERT output. For example, with V
=
CC
+5.0V, a 16Hz conversion rate and ALERT sinking
1mA, the typical power dissipation is:
V
CC
x 450µA + 0.4V x 1mA = 2.65mW
θ
for the 8-pin SO package is about +170°C/W, so
assuming no copper PC board heat sinking, the result-
ing temperature rise is:
J-A
∆T = 2.65mW x +170°C/W = +0.45°C
Even under these engineered circumstances, it is diffi-
cult to introduce significant self-heating errors.
The transistor must be a small-signal type with a rela-
tively high forward voltage; otherwise, the A/D input
voltage range can be violated. The forward voltage at
the highest expected temperature must be greater than
0.25V at 10µA, and at the lowest expected tempera-
ture, forward voltage must be less than 0.95V at 100µA.
Large power transistors must not be used. Also, ensure
AD° Noise Filtering
The integrating ADC used has good noise rejection for
low-frequency signals such as 60Hz/120Hz power-sup-
ply hum. In noisy environments, high-frequency noise
reduction is needed for high-accuracy remote mea-
_______________________________________________________________________________________
7
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
surements. The noise can be reduced with careful PC
board layout and proper external noise filtering.
5) When introducing a thermocouple, make sure that
both the DXP and the DXN paths have matching
thermocouples. A copper-solder thermocouple
exhibits 3µV/°C, and it takes about 200µV of voltage
error at DXP-DXN to cause a +1°C measurement
error. Adding a few thermocouples causes a negli-
gible error.
High-frequency EMI is best filtered at DXP and DXN
with an external 2200pF capacitor. Larger capacitor
values can be used for added filtering, but do not
exceed 3300pF because it can introduce errors due to
the rise time of the switched current source.
6) Use wide traces. Narrow traces are more inductive
and tend to pick up radiated noise. The 10mil widths
and spacings that are recommended in Figure 1 are
not absolutely necessary, as they offer only a minor
improvement in leakage and noise over narrow
traces. Use wider traces when practical.
GND
10MILS
7) Add a 200Ω resistor in series with V
for best
CC
10MILS
DXP
noise filtering (see Typical Operating Circuit).
MINIMUM
ꢇwistedꢂPair and ꢀhielded °aꢄles
Use a twisted-pair cable to connect the remote sensor
for remote-sensor distances longer than 8in or in very
noisy environments. Twisted-pair cable lengths can be
between 6ft and 12ft before noise introduces excessive
errors. For longer distances, the best solution is a
shielded twisted pair like that used for audio micro-
phones. For example, Belden #8451 works well for dis-
tances up to 100ft in a noisy environment. At the
device, connect the twisted pair to DXP and DXN and
the shield to GND. Leave the shield unconnected at the
remote sensor.
10MILS
DXN
GND
10MILS
Figure 1. Recommended DXP-DXN PC Traces
P° ꢁoard ꢆayout
Follow these guidelines to reduce the measurement
error of the temperature sensors:
For very long cable runs, the cable’s parasitic capaci-
tance often provides noise filtering, so the 2200pF
capacitor can often be removed or reduced in value.
Cable resistance also affects remote-sensor accuracy.
For every 1Ω of series resistance, the error is approxi-
mately +1/2°C.
1) Place the MAX6657/MAX6658/MAX6659 as close
as is practical to the remote diode. In noisy environ-
ments, such as a computer motherboard, this dis-
tance can be 4in to 8in (typ). This length can be
increased if the worst noise sources are avoided.
Noise sources include CRTs, clock generators,
memory buses, and ISA/PCI buses.
ꢆowꢂPower ꢀtandꢄy Mode
Standby mode reduces the supply current to less than
10µA by disabling the ADC. Enter hardware standby
(MAX6659 only) by forcing the STBY pin low, or enter
software standby by setting the RUN/STOP bit to 1 in
the Configuration Byte register. Hardware and software
standbys are very similar—all data is retained in memo-
ry, and the SMB interface is alive and listening for
SMBus commands. The only difference is that in soft-
ware standby mode, the one-shot command initiates a
conversion. With hardware standby, the one-shot com-
mand is ignored. Activity on the SMBus causes the
device to draw extra supply current.
2) Do not route the DXP-DXN lines next to the deflec-
tion coils of a CRT. Also, do not route the traces
across fast digital signals, which can easily intro-
duce +30°C error, even with good filtering.
3) Route the DXP and DXN traces in parallel and in
close proximity to each other, away from any higher
voltage traces, such as +12VDC. Leakage currents
from PC board contamination must be dealt with
carefully since a 20MΩ leakage path from DXP to
ground causes about +1°C error. If high-voltage
traces are unavoidable, connect guard traces to GND
on either side of the DXP-DXN traces (Figure 1).
Driving the STBY pin low overrides any software con-
version command. If a hardware or software standby
command is received while a conversion is in progress,
the conversion cycle is interrupted, and the tempera-
4) Route through as few vias and crossunders as pos-
sible to minimize copper/solder thermocouple
effects.
8
_______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ture registers are not updated. The previous data is not
changed and remains available.
The temperature data format is 7 bits + sign in two's-
complement form for each channel, with the LSB repre-
senting 1°C (Table 2). The MSB is transmitted first.
ꢀMꢁus Digital Interface
From a software perspective, each of the MAX6657/
MAX6658/MAX6659 appears as a series of 8-bit regis-
ters that contain temperature data, alarm threshold
values, and control bits. A standard SMBus-compatible
2-wire serial interface is used to read Temperature Data
and Write Control bits and alarm threshold data. The
device responds to the same SMBus slave address for
access to all functions.
When the conversion rate is 4Hz or less, the first 8 bits
of temperature data can be read from the Read Internal
Temperature (00h) and Read External Temperature
(01h) registers, the same as for faster conversion rates.
An additional 3 bits can be read from the Read External
Extended Temperature (10h) and Read Internal
Extended Temperature (11h) registers, which extends
the data to 10 bits + sign and the resolution to
+0.125°C per LSB (Table 3).
The MAX6657/MAX6658/MAX6659 employ four stan-
dard SMBus protocols: Write Byte, Read Byte, Send
Byte, and Receive Byte (Figures 2, 3, and 4). The short-
er Receive Byte protocol allows quicker transfers, pro-
vided that the correct data register was previously
selected by a Read Byte instruction. Use caution with
the shorter protocols in multimaster systems, since a
second master could overwrite the command byte with-
out informing the first master.
When a conversion is complete, the Main register and
the Extended register are updated almost simultane-
ously. Ensure that no conversions are completed
between reading the Main and Extended registers so
that when data that is read, both registers contain the
result of the same conversion.
To ensure valid extended data, read extended resolu-
tion temperature data using one of the following
approaches:
When the conversion rate is greater than 4Hz, temperature
data can be read from the Read Internal Temperature
(00h) and Read External Temperature (01h) registers.
1) Put the MAX6657/MAX6658/MAX6659 into standby
mode by setting bit 6 of the Configuration register to
Write ꢁyte Forꢃat
S
ADDRESS
WR
ACK
COMMAND
ACK
DATA
ACK
P
7 bits
8 bits
8 bits
1
Slave Address: equiva-
lent to chip-select line of
a 3-wire interface
Command Byte: selects which
register you are writing to
Data Byte: data goes into the register
set by the command byte (to set
thresholds, configuration masks, and
sampling rate)
ꢅead ꢁyte Forꢃat
ADDRESS
WR
ACK
COMMAND
ACK
S
ADDRESS
RD
ACK
DATA
///
P
7 bits
8 bits
7 bits
8 bits
Slave Address: equiva-
lent to chip-select line
Command Byte: selects
which register you are
reading from
Slave Address: repeated
due to change in data-
flow direction
Data Byte: reads from
the register set by the
command byte
ꢀend ꢁyte Forꢃat
ADDRESS WR ACK COMMAND ACK
ꢅeceive ꢁyte Forꢃat
P
S
ADDRESS
RD
ACK DATA
8 bits
///
P
7 bits
8 bits
7 bits
Data Byte: reads data from
the register commanded
by the last Read Byte or
Write Byte transmission;
also used for SMBus Alert
Response return address
Command Byte: sends com-
mand with no data, usually
used for one-shot command
S = Start condition
P = Stop condition
Shaded = Slave transmission
/// = Not acknowledged
Figure 2. SMBus Protocols
______________________________________________________________________________________
9
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
A
B
C
D
E
F
G
H
I
J
K
L
M
t
t
HIGH
LOW
SMBCLK
SMBDATA
t
t
t
t
HD:DAT
HD:STA
SU:STA
SU:DAT
t
t
SU:STO
BUF
A = START CONDITION
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO SLAVE
H = LSB OF DATA CLOCKED INTO SLAVE
I = MASTER PULLS DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
M = NEW START CONDITION
E = SLAVE PULLS SMBDATA LINE LOW
Figure 3. SMBus Write Timing Diagram
A
B
C
D
E
F
G
H
I
J
K
L
M
t
t
HIGH
LOW
SMBCLK
SMBDATA
t
t
t
t
HD:DAT
HD:STA
SU:STA
SU:DAT
t
t
SU:STO
BUF
A = START CONDITION
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO MASTER
H = LSB OF DATA CLOCKED INTO MASTER
I = MASTER PULLS DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
M = NEW START CONDITION
E = SLAVE PULLS SMBDATA LINE LOW
Figure 4. SMBus Read Timing Diagram
1. Initiate a one-shot conversion using Command
Byte 0Fh. When this conversion is complete, read
the contents of the Temperature Data registers.
Diode Fault Alarꢃ
There is a continuity fault detector at DXP that detects
an open circuit between DXP and DXN, or a DXP short
to V , GND, or DXN. If an open or short circuit exists,
CC
2) If the MAX6657/MAX6658/MAX6659 are in run mode,
read the Status register. If a conversion is in
progress, the BUSY bit is set to 1. Wait for the con-
version to complete as indicated by the BUSY bit
being set to 0, then read the Temperature Data reg-
isters. Note that the power-on reset sets the conver-
sion rate to 16Hz, so no extended data is valid
without reducing the conversion rate to 4Hz or less.
the external temperature register is loaded with 1000
0000. Additionally, if the fault is an open circuit, bit 2
(OPEN) of the status byte is set to 1 and the ALERT con-
dition is activated at the end of the conversion.
Immediately after POR, the Status register indicates that
no fault is present until the end of the first conversion.
10 ______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Table 2. Data Format (Two's Complement)
Table 3. Extended Resolution Register
FRACTIONAL
CONTENTS OF
DIGITAL OUTPUT
TEMPERATURE
EXTENDED REGISTER
TEMP (°C)
MAX6658
MAX6659
MAX6657
0.000
0.125
0.250
0.375
0.500
0.625
0.750
0.875
000X XXXX
001X XXXX
010X XXXX
011X XXXX
100X XXXX
101X XXXX
110X XXXX
111X XXXX
130.00
127.00
126.00
25
0 111 1111
0 111 1111
0 111 1111
0 001 1001
0 000 0000
1 000 0000
1 000 0000
1 000 0000
0 111 1111
0 111 1111
0 111 1111
0 001 1001
0 000 0000
1 111 1111
1 110 0111
1 100 1001
0.00
-1
-25
Note: Extended resolution applies only for conversion rates of
4Hz and slower.
-55
Diode Fault
(Short or Open)
1 000 0000
1 000 0000
Alert ꢅesponse Address
The SMBus Alert Response interrupt pointer provides
quick fault identification for simple slave devices that
lack the complex, expensive logic needed to be a bus
master. Upon receiving an ALERT interrupt signal, the
host master can broadcast a Receive Byte transmission
to the Alert Response slave address (0001100). Then,
any slave device that generated an interrupt attempts
to identify itself by putting its own address on the bus
(Table 8).
Alarꢃ ꢇhreshold ꢅegisters
Four registers store ALERT threshold values—one high-
temperature (T ) and one low-temperature (T
register each for the local and remote channels. If
either measured temperature equals or exceeds the
corresponding ALERT threshold value, the ALERT out-
put is asserted.
)
LOW
HIGH
The POR state of both ALERT T
0110 or +70°C and the POR state of T
1100 1001 or -55°C.
registers is 0100
LOW
HIGH
The Alert Response can activate several different slave
devices simultaneously, similar to the I2C General Call.
If more than one slave attempts to respond, bus arbitra-
tion rules apply, and the device with the lower address
code wins. The losing device does not generate an
acknowledge and continues to hold the ALERT line low
until cleared. (The conditions for clearing an alert vary,
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.
registers is
Four additional registers store remote and local alarm
threshold data corresponding to the OVERT1 and
OVERT2 (MAX6659 only) outputs. The values stored in
these registers are high-temperature thresholds. If any
one of the measured temperatures equals or exceeds
the corresponding alarm threshold value, an OVERT
output is asserted. The POR state of the OVERT thresh-
old is 0101 0101 or +85°C.
Alert Interrupts
An ALERT interrupt occurs when the internal or external
temperature reading exceeds a high or low tempera-
ture limit (user programmed) or when the remote diode
is disconnected (for continuity fault detection). The
ALERT interrupt output signal is latched and can be
cleared only by either reading the Status register or by
successfully responding to an Alert Response address.
In both cases, the alert is cleared even if the fault con-
dition still exists, but is reasserted at the end of the next
conversion. The interrupt does not halt automatic con-
versions. The interrupt output pin is open-drain so that
multiple devices can share a common interrupt line.
The interrupt rate never exceeds the conversion rate.
OVERT Overteꢃperature
Alarꢃ/Warning Outputs
OVERT1 and OVERT2 (MAX6659 only) are asserted
when the temperature rises to a value programmed in
the appropriate threshold register. They are deasserted
when the temperature drops below this threshold minus
the hysteresis. An OVERT output can be used to acti-
vate a cooling fan, send a warning, or trigger a system
shutdown to prevent component damage. The HYST
byte sets the amount of hysteresis for both OVERT out-
puts. The data format for the HYST byte is the same for
the other temperature registers (Table 2).
______________________________________________________________________________________ 11
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Table 4. Command Byte Register Assignments
REGISTER
RLTS
ADDRESS
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Ah
0Bh
0Ch
0Dh
0Eh
0Fh
10h
11h
16h
17h
19h
20h
21h
FEh
POR STATE
0000 0000
0000 0000
1000 0000
0010 0000
0000 1000
0100 0110
1100 1001
0100 0110
1100 1001
0010 0000
0000 1000
0100 0110
1100 1001
0100 0110
1100 1001
N/A
FUNCTION
Read Internal Temperature
Read External Temperature
Read Status Register
RRTE
RSL
RCL
Read Configuration Byte
Read Conversion Rate Byte
Read Internal High Limit
Read Internal Low Limit
Read External High Limit
Read External Low Limit
Write Configuration Byte
Write Conversion Rate Byte
Write Internal High Limit
Write Internal Low Limit
Write External High Limit
Write External Low Limit
One Shot
RCRA
RLHN
RLLI
RRHI
RRLS
WCA
WCRW
WLHO
WLLM
WRHA
WRLN
OSHT
REET
RIET
0000 0000
0000 0000
0101 0101
0101 0101
0101 0101
0101 0101
0000 1010
4Dh
Read External Extended Temperature
Read Internal Extended Temperature
Read/Write External OVERT2 Limit (MAX6659 only)
Read/Write Internal OVERT2 Limit (MAX6659 only)
Read/Write External OVERT1 Limit
Read/Write Internal OVERT1 Limit
Overtemperature Hysteresis
RWO2E
RW02I
RWOE
RWOI
HYST
—
Read Manufacture ID
For example, OVERT1 has a threshold set to +50°C
and is connected to a fan. OVERT2 has a threshold of
+75°C and is connected to a system shutdown. If the
system reaches +50°C, the fan turns on, trying to cool
the system. If the system continues to heat up to the
critical temperature of +75°C, OVERT2 causes the sys-
tem to shut down.
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 command is received, the command is
ignored. If a one-shot command is received in autocon-
vert mode (RUN/STOP 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.
°oꢃꢃand ꢁyte Functions
The 8-bit Command Byte register (Table 4) is the master
index that points to the various other registers within the
MAX6657/MAX6658/MAX6659. 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.
°onfiguration ꢁyte Functions
The Configuration Byte register (Table 5) is a Read-Write
register with several functions. Bit 7 is used to mask (dis-
able) interrupts. Bit 6 puts the device into software stand-
by mode (STOP) or autonomous (RUN) mode. Bit 5
selects the type of external junction (set to 1 for a sub-
strate PNP on an IC or set to 0 for a discrete diode-con-
nected transistor) for optimized measurements. Bits 0 to
4 are reserved and return a zero when read.
Oneꢂꢀhot
The one-shot command immediately forces a new con-
version cycle to begin. If the one-shot command is
received when the MAX6657/MAX6658/MAX6659 are in
12 ______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ALERT output follows the status flag bit. Both are
cleared when successfully read, but if the condition still
exists, they reassert at the end of the next conversion.
ꢀtatus ꢁyte Functions
The status byte (Table 6) 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 MSB is 1 and
all the other flag bits are 0, assuming no alert or
overtemperature conditions are present. Bits 2 through
6 of the Status register are cleared by any successful
read of the Status register, unless the fault persists. The
The bits indicating OVERT1 (bits 0 and 1) are cleared
only when the condition no longer exists. Reading the
status byte does not clear the OVERT1 outputs or fault
bits. One way to eliminate the fault condition is for the
measured temperature to drop below the temperature
threshold minus the hysteresis value. Another way to
eliminate the fault condition is by writing new values for
the OVERT1 threshold or hysteresis so that a fault con-
dition is no longer present. Note that the status byte
does not provide status of OVERT2.
Table 5. Configuration-Byte Bit
Assignments
The MAX6657/MAX6658/MAX6659 incorporate collision
avoidance so that completely asynchronous operation
is allowed between SMBus operations and temperature
conversions.
POR
STATE
BIT
NAME
FUNCTION
7
MASK1
0
Masks ALERT interrupts if a 1.
(MSB)
When autoconverting, if the T
and T
limits are
HIGH
LOW
close together, it’s possible for both high-temp and low-
temp status bits to be set, depending on the amount of
time between status read operations. In these circum-
stances, it is best not to rely on the status bits to indi-
cate reversals in long-term temperature changes.
Instead, use a current temperature reading to establish
the trend direction.
Standby mode control bit; if a
1, standby mode is initiated.
6
RUN/STOP
0
Set to 1 when the remote
sensor is a substrate or
common collector PNP. Set to 0
when the remote sensor is a
diode-connected discrete
transistor.
5
SPNP
RFU
1
0
°onversion ꢅate ꢁyte
The Conversion Rate register (Table 7) programs the
time interval between conversions in free-running
autonomous mode (RUN/STOP = 0). This variable rate
4 to 0
Reserved
Table 6. Status Register Bit Assignments
BIT
NAME
POR STATE
FUNCTION
7 (MSB)
BUSY
1
A/D is busy converting when high.
Internal high-temperature alarm has tripped when high; cleared by POR or readout of
the Status register if the fault condition no longer exists.
6
5
4
3
2
1
0
LHIGH
LLOW
RHIGH
RLOW
OPEN
EOT1
0
0
0
0
0
0
0
Internal low-temperature alarm has tripped when high; cleared by POR or readout of
the Status register if the fault condition no longer exists.
External high-temperature alarm has tripped when high; cleared by POR or readout of
the Status register if the fault condition no longer exists.
External low-temperature alarm has tripped when high; cleared by POR or readout of
the Status register if the fault condition no longer exists.
A high indicates an external diode open; cleared by POR or readout of the Status
register if the fault condition no longer exists.
A high indicates the external junction temperature exceeds the external OVERT1
threshold.
A high indicates the internal junction temperature exceeds the internal OVERT1
threshold.
IOT1
______________________________________________________________________________________ 13
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Table 8. Slave Address Decoding for
MAX6659
Table 7. Conversion-Rate
Control Byte
DATA
CONVERSION RATE (Hz)
ADD CONNECTION
ADDRESS
1001100
1001110
1001101
00h
0.0625
GND
01h
0.125
V
CC
02h
0.25
Floating
03h
0.5
04h
1
from corrupting the data in memory and causing erratic
behavior, a POR voltage detector monitors V and
05h
2
CC
06h
4
clears the memory if V
falls below 1.7V (typ, see
CC
Electrical Characteristics). When power is first applied
and V rises above 2.0V (typ), the logic blocks begin
07h
8
16
CC
08h
operating, although reads and writes at V
levels
CC
09h
16
below 3.0V are not recommended. A second V
com-
CC
0Ah-FFh
Reserved
parator and the ADC undervoltage lockout (UVLO)
comparator prevent the ADC from converting until there
Note: Extended resolution applies only for conversion rates of
4Hz or slower.
is sufficient headroom (V
= +2.8V typ).
CC
PowerꢂUp Defaults
control can be used to reduce the supply current in
portable-equipment applications. The conversion rate
byte’s POR state is 08h (16Hz). The MAX6657/
MAX6658/MAX6659 use only the 4 least-significant bits
(LSBs) of this register. The 4 most-significant bits
(MSBs) are “don’t care” and should be set to zero when
possible. The conversion rate tolerance is 25% at any
rate setting.
Power-up defaults include:
•
ADC begins autoconverting at a 16Hz rate (legacy
resolution).
•
THIGH and TLOW registers are set to default limits,
respectively.
•
•
•
Interrupt latch is cleared.
Address-select pin is sampled (MAX6659 only).
Valid A/D conversion results for both channels are
available one total conversion time (125ms nominal,
156ms maximum) after initiating a conversion, whether
conversion is initiated through the RUN/STOP bit, hard-
ware STBY pin, one-shot command, or initial power-up.
Command register is set to 00h to facilitate quick
internal Receive Byte queries.
•
•
Hysteresis is set to 10°C.
Transistor type is set to a substrate or common col-
lector PNP.
ꢀlave Addresses
The MAX6657/MAX6658 have a fixed address of
1001100. The MAX6659 can be programmed to have
one of three different addresses, allowing up to three
devices to reside on the same bus without address
conflicts. Table 8 lists address information.
Table 9. Read Format for Alert Response
Address (000 1100)
BIT
NAME
ADD7
ADD6
ADD5
ADD4
ADD3
ADD2
ADD1
1
FUNCTION
7 (MSB)
The address pin state is checked at POR only, and the
address data stays latched to reduce quiescent supply
current due to the bias current needed for high-Z state
detection.
6
Provide the current
5
MAX6659 slave address
that was latched at POR
(Table 8)
4
The MAX6657/MAX6658/MAX6659 also respond to the
SMBus Alert Response slave address (see Alert
Response Address section).
3
2
1
POꢅ and UVꢆO
The MAX6657/MAX6658/MAX6659 have a volatile
memory. To prevent unreliable power-supply conditions
0 (LSB)
Logic 1
14 ______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
ꢇypical Operating °ircuit
3.3V
0.1µF
200Ω
10kΩ
EACH
V
CC
(STBY)
DXP
DXN
SMBDATA
SMBCLK
ALERT
DATA
CLOCK
2200pF
INTERRUPTED TO µP
MAX6657
MAX6658
MAX6659
TO FAN DRIVER
OVERT1
µP
(OVERT2)
TO SYSTEM SHUTDOWN
(ADD)
GND
() ARE MAX6659 ONLY
°hip Inforꢃation
TRANSISTOR COUNT: 16,989
PROCESS: BiCMOS
______________________________________________________________________________________ 15
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Package Inforꢃation
16 ______________________________________________________________________________________
±±1°C ꢀMꢁusꢂ°oꢃpatiꢄle ꢅeꢃote/ꢆocal ꢇeꢃperature
ꢀensors with Overteꢃperature Alarꢃs
Package Inforꢃation (continued)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
17 ____________________Maxiꢃ Integrated ProductsC ±20 ꢀan Gaꢄriel DriveC ꢀunnyvaleC °A 94086 408ꢂ737ꢂ7600
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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MAX6657YMSA+
Serial Switch/Digital Sensor, 11 Bit(s), 1Cel, BICMOS, Rectangular, 8 Pin, Surface Mount, 0.150 INCH, LEAD FREE, MO-012AA, SOIC-8
MAXIM
MAX6657YMSA+T
Serial Switch/Digital Sensor, 11 Bit(s), 1Cel, BICMOS, Rectangular, 8 Pin, Surface Mount, 0.150 INCH, LEAD FREE, MO-012AA, SOIC-8
MAXIM
MAX6658MSA
【1∑C, SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms
MAXIM
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