General Description
The MAX6689 precision multichannel temperature sensor monitors its own temperature and the temperatures
of up to six external diode-connected transistors. All
temperature channels have programmable alert thresholds. Channels 1, 4, 5, and 6 also have programmable
overtemperature thresholds. When the measured temperature of a channel exceeds the respective threshold, a status bit is set in one of the status registers. Two
open-drain outputs, OVERT and ALERT, assert corresponding to these bits in the status register.
The 2-wire serial interface supports the standard system
management bus (SMBus™) protocols: write byte, read
byte, send byte, and receive byte for reading the temperature data and programming the alarm thresholds.
The MAX6689 is specified for an operating temperature
range of -40°C to +125°C and is available in 20-pin
QSOP and TSSOP packages.
Applications
Desktop Computers
Notebook Computers
Workstations
Servers
Features
♦ Six Thermal-Diode Inputs
♦ Local Temperature Sensor
♦ 1°C Remote Temperature Accuracy (+60°C to +100°C)
♦ Temperature Monitoring Begins at POR for Fail-
Safe System Protection
♦ ALERT and OVERT Outputs for Interrupts,
Throttling, and Shutdown
♦ STBY Input for Hardware Standby Mode
♦ Small, 20-Pin QSOP and TSSOP Packages
♦ 2-Wire SMBus Interface
MAX6689
7-Channel Precision Temperature Monitor
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
GND
SMBCLK
SMBDATA
DXN2
DXP2
DXN1
DXP1
V
CC
N.C.
DXN4
DXP4
DXN3
DXP3
12
11
9
10
DXP6
DXN6DXN5
DXP5
MAX6689
ALERT
OVERT
STBY
2200pF
2200pF
2200pF
2200pF
2200pF
CPU
2200pF
GPU
0.1μF
TO SYSTEM
SHUTDOWN
INTERRUPT
TO μP
DATA
CLK
4.7kΩ
EACH
+3.3V
Typical Application Circuit
19-0567; Rev 1; 8/07
SMBus is a trademark of Intel Corp.
Note: All devices are specified over the -40°C to +125°C
temperature range.
+Denotes lead-free package.
Pin Configuration appears at end of data sheet.
PART
PINPACKAGE
MAX6689EP34+ 20 QSOP 0011 010 E20-1
MAX6689EP38+ 20 QSOP 0011 100 E20-1
MAX6689EP9A+ 20 QSOP 1001 101 E20-1
MAX6689EP9E+ 20 QSOP 1001 111 E20-1
MAX6689UP34+ 20 TSSOP 0011 010 U20-2
MAX6689UP38+ 20 TSSOP 0011 100 U20-2
MAX6689UP9A+ 20 TSSOP 1001 101 U20-2
MAX6689UP9E+ 20 TSSOP 1001 111 U20-2
SLAVE
ADDRESS
PKG
CODE
MAX6689
7-Channel Precision Temperature Monitor
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.
VCC, SCK, SDA, ALERT, OVERT, STBY to GND .....-0.3V to +6V
DXP_ to GND..............................................-0.3V to (V
CC
+ 0.3V)
DXN_ to GND ........................................................-0.3V to +0.8V
SDA, ALERT, OVERT Current .............................-1mA to +50mA
DXN Current .......................................................................±1mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin QSOP
(derate 9.1mW/°C above +70°C) ..................................727.3mW
20-Pin TSSOP
(derate 11.0mW/°C above +70°C)..............................879.1mW
ESD Protection (all pins, Human Body Model) ................±2000V
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +5.5V, V
STBY
= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA=
+25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage V
Software Standby Supply Current I
Operating Current I
Temperature Resolution
Remote Temperature Accuracy VCC = 3.3V
Local Temperature Accuracy VCC = 3.3V
Supply Sensitivity of Temperature
Accuracy
Remote Channel 1 Conversion
Time
Remote Channels 2 Through 6
Conversion Time
Remote-Diode Source Current I
Undervoltage-Lockout Threshold UVLO Falling edge of V
Undervoltage-Lockout Hysteresis 90 mV
Power-On Reset (POR) Threshold VCC falling edge 1.2 2.0 2.5 V
POR Threshold Hysteresis 90 mV
ALERT, OVERT
Output Low Voltage V
Output Leakage Current 1µA
CC
SS
CC
SMBus static 30 µA
During conversion 500 1000 µA
3.0 5.5 V
Channel 1 only 11
Other diode channels 8
TA = T
TA = T
DXN_ grounded,
T
= +60°C to +100°C -1.0 +1.0
RJ
= 0°C to +125°C -3.0 +3.0
RJ
= TA = 0°C to +85°C
RJ
±2.5
TA = +60°C to +100°C -3.3 +0.7
T
= 0°C to +125°C -5.0 +1.0
A
±0.2
t
CONV1
t
CONV_
RJ
OL
Resistance cancellation off 95 125 156
Resistance cancellation on 190 250 312
95 125 156 ms
High level 80 100 120
Low level 8 10 12
disables ADC 2.30 2.80 2.95 V
CC
I
= 1mA 0.3
SINK
I
= 6mA 0.5
SINK
Bits
o
o
o
C/V
ms
µA
C
C
V
MAX6689
7-Channel Precision Temperature Monitor
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +5.5V, V
STBY
= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA=
+25°C.) (Note 1)
Note 1: All parameters are tested at TA= +85°C. Specifications over temperature are guaranteed by design.
Note 2: Timing specifications are guaranteed by design.
Note 3: The serial interface resets when SCL is low for more than t
TIMEOUT
.
Note 4: A transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SCL’s falling edge.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SMBus INTERFACE (SCL, SDA), STBY
Logic-Input Low Voltage V
Logic-Input High Voltage V
Input Leakage Current -1 +1 µA
Output Low Voltage V
Input Capacitance C
SMBus-COMPATIBLE TIMING (Figures 3 and 4) (Note 2)
Serial-Clock Frequency f
Bus Free Time Between STOP
and START Condition
START Condition Setup Time
Repeat START Condition Setup
Time
START Condition Hold Time t
STOP Condition Setup Time t
Clock-Low Period t
Clock-High Period t
Data Hold Time t
Data Setup Time t
Receive SCL/SDA Rise Time t
Receive SCL/SDA Fall Time t
Pulse Width of Spike Suppressed t
SMBus Timeout t
IL
IH
OL
IN
SCL
t
BUF
t
SU:STA
HD:STA
SU:STO
LOW
HIGH
HD:DAT
SU:DAT
R
F
SP
TIMEOUT
VCC = 3.0V 2.2
VCC = 5.0V 2.4
I
= 6mA 0.3 V
SINK
5pF
(Note 3) 400 kHz
f
= 100kHz 4.7
SCL
f
= 400kHz 1.6
SCL
f
= 100kHz 4.7
SCL
= 400kHz 0.6
f
SCL
90% of SCL to 90% of SDA,
f
= 100kHz
SCL
90% of SCL to 90% of SDA,
f
= 400kHz
SCL
0.6
0.6
10% of SDA to 90% of SCL 0.6 µs
90% of SCL to 90% of SDA,
f
= 100kHz
SCL
90% of SCL to 90% of SDA,
f
= 400kHz
SCL
10% to 10%, f
10% to 10%, f
= 100kHz 1.3
SCL
= 400kHz 1.3
SCL
4
0.6
90% to 90% 0.6 µs
f
= 100kHz 300
SCL
f
= 400kHz (Note 4) 900
SCL
f
= 100kHz 250
SCL
f
= 400kHz 100
SCL
f
= 100kHz 1
SCL
f
= 400kHz 0.3
SCL
050ns
SDA low period for interface reset 25 37 45 ms
0.8 V
300 ns
V
µs
µs
µs
µs
µs
ns
ns
µs
MAX6689
7-Channel Precision Temperature Monitor
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC= 3.3V, V
STBY
= VCC, TA= +25°C, unless otherwise noted.)
SOFTWARE STANDBY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6689 toc01
SUPPLY VOLTAGE (V)
STANDBY SUPPLY CURRENT (μA)
5.34.84.3
3.8
1
2
3
4
5
6
7
8
9
10
11
12
0
3.3
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6689 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (μA)
5.34.8
3.8 4.3
325
330
335
340
350
345
355
360
320
3.3
-4
-2
-3
0
-1
2
1
3
05025 75 100 125
REMOTE TEMPERATURE ERROR
vs. REMOTE-DIODE TEMPERATURE
MAX6689 toc03
REMOTE-DIODE TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
-4
-3
-2
-1
0
1
2
3
4
0 25 50 75 100 125
LOCAL TEMPERATURE ERROR
vs. DIE TEMPERATURE
MAX6689 toc04
DIE TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
REMOTE-DIODE TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6689 toc05
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
-4
-3
-2
-1
0
1
2
3
4
5
-5
0.1 1
100mV
P-P
LOCAL TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6689 toc06
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
0.10.01
-4
-3
-2
-1
0
1
2
3
4
5
-5
0.001 1
100mV
P-P
REMOTE TEMPERATURE ERROR
vs. COMMON-MODE NOISE FREQUENCY
MAX6689 toc07
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
10.10.01
-4
-3
-2
-1
0
1
2
3
4
5
-5
0.001 10
100mV
P-P
MAX6689
7-Channel Precision Temperature Monitor
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(VCC= 3.3V, V
STBY
= VCC, TA= +25°C, unless otherwise noted.)
TEMPERATURE ERROR
vs. DXP-DXN CAPACITANCE
MAX6689 toc09
DXP-DXN CAPACITANCE (nF)
TEMPERATURE ERROR (°C)
10
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0
-5.0
1100
PIN NAME FUNCTION
1 DXP1
REMOTE TEMPERATURE ERROR
vs. COMMON-MODE NOISE FREQUENCY
5
100mV
4
3
2
1
0
-1
-2
TEMPERATURE ERROR (°C)
-3
-4
-5
0.001 10
P-P
10.10.01
FREQUENCY (MHz)
Combined Current Source and A/D Positive Input for Channel 1 Remote Diode. Connect to the anode
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to VCC if no
remote diode is used. Place a 2200pF capacitor between DXP1 and DXN1 for noise filtering.
MAX6689 toc08
2 DXN1
Cathode Input for Channel 1 Remote Diode. Connect the cathode of the channel 1 remote-diodeconnected transistor to DXN1.
Combined Current Source and A/D Positive Input for Channel 2 Remote Diode. Connect to the anode
3 DXP2
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to V
remote diode is used. Place a 2200pF capacitor between DXP2 and DXN2 for noise filtering.
4 DXN2
Cathode Input for Channel 2 Remote Diode. Connect the cathode of the channel 2 remote-diodeconnected transistor to DXN2.
Combined Current Source and A/D Positive Input for Channel 3 Remote Diode. Connect to the anode
5 DXP3
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to VCC if no
remote diode is used. Place a 2200pF capacitor between DXP3 and DXN3 for noise filtering.
6 DXN3
7 DXP4
8 DXN4
Cathode Input for Channel 3 Remote Diode. Connect the cathode of the channel 1 remote-diodeconnected transistor to DXN3.
Combined Current Source and A/D Positive Input for Channel 4 Remote Diode. Connect to the anode
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to V
remote diode is used. Place a 2200pF capacitor between DXP4 and DXN4 for noise filtering.
Cathode Input for Channel 4 Remote Diode. Connect the cathode of the channel 1 remote-diodeconnected transistor to DXN4.
CC
CC
if no
if no
MAX6689
Detailed Description
The MAX6689 is a precision multichannel temperature
monitor that features one local and six remote temperature-sensing channels with a programmable alert
threshold for each temperature channel and a programmable overtemperature threshold for channels 1, 4, 5,
and 6 (see Figure 1). Communication with the MAX6689
is achieved through the SMBus serial interface and a
dedicated alert pin. The alarm outputs, OVERT and
ALERT, assert if the software-programmed temperature
thresholds are exceeded. ALERT typically serves as an
interrupt, while OVERT can be connected to a fan, system shutdown, or other thermal-management circuitry.
ADC Conversion Sequence
In the default conversion mode, the MAX6689 starts the
conversion sequence by measuring the temperature on
channel 1, followed by 2, 3, local channel, 4, 5, and 6.
The conversion result for each active channel is stored
in the corresponding temperature data register.
In some systems, one of the remote thermal diodes may
be monitoring a location that experiences temperature
changes that occur much more rapidly than in the other
channels. If faster temperature changes must be monitored in one of the temperature channels, the MAX6689
allows channel 1 to be monitored at a faster rate than
the other channels. In this mode (set by writing a 1 to bit
4 of the configuration 1 register), measurements of
channel 1 alternate with measurements of the other
channels. The sequence becomes channel 1, channel
2, channel 1, channel 3, channel 1, etc. Note that the
time required to measure all seven channels is considerably greater in this mode than in the default mode.
Low-Power Standby Mode
Enter software standby mode by setting the STOP bit to
1 in the configuration 1 register. Enter hardware standby
by pulling STBY low. Software standby mode disables
the ADC and reduces the supply current to approximately 30µA. Hardware standby mode halts the ADC
clock, but the supply current is approximately 350µA.
During either software or hardware standby, data is
retained in memory. During hardware standby, the
SMBus interface is inactive. During software standby, the
SMBus interface is active and listening for commands.
The timeout is enabled if a start condition is recognized
on SMBus. Activity on the SMBus causes the supply current to increase. If a standby command is received while
a conversion is in progress, the conversion cycle is inter-
7-Channel Precision Temperature Monitor
6 _______________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
Combined Current Source and A/D Positive Input for Channel 5 Remote Diode. Connect to the anode
9 DXP5
10 DXN5
11 DXN6
12 DXP6
13 STBY
14 N.C. No Connection. Must be connected to ground.
15 OVERT
16 V
17 ALERT
18 SMBDATA SMBus Serial-Data Input/Output. Connect to a pullup resistor.
19 SMBCLK SMBus Serial-Clock Input. Connect to a pullup resistor.
20 GND Ground
CC
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to V
remote diode is used. Place a 2200pF capacitor between DXP5 and DXN5 for noise filtering.
Cathode Input for Channel 5 Remote Diode. Connect the cathode of the channel 1 remote-diodeconnected transistor to DXN5.
Cathode Input for Channel 6 Remote Diode. Connect the cathode of the channel 1 remote-diodeconnected transistor to DXN6.
Combined Current Source and A/D Positive Input for Channel 6 Remote Diode. Connect to the anode
of a remote-diode-connected temperature-sensing transistor. Leave floating or connect to VCC if no
remote diode is used. Place a 2200pF capacitor between DXP6 and DXN6 for noise filtering.
Active-Low Standby Input. Drive STBY logic-low to place the MAX6689 in standby mode, or logic-high
for operate mode. Temperature and threshold data are retained in standby mode.
Overtemperature Active-Low, Open-Drain Output. OVERT asserts low when the temperature of
channels 1, 4, 5, and 6 exceeds the programmed threshold limit.
Supply Voltage Input. Bypass to GND with a 0.1µF capacitor.
SMBus Alert (Interrupt), Active-Low, Open-Drain Output. ALERT asserts low when the temperature of
any channel exceeds the programmed ALERT threshold.
CC
if no