General Description
The MAX6693 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 MAX6693 is specified for an operating temperature
range of -40°C to +125°C and is available in a 20-pin
TSSOP package.
Applications
Desktop Computers
Notebook Computers
Workstations
Servers
Features
o Six Thermal-Diode Inputs
o Beta Compensation (Channel 1)
o Local Temperature Sensor
o 1.5°C Remote Temperature Accuracy (+60°C to
+100°C)
o Temperature Monitoring Begins at POR for Fail-
Safe System Protection
o ALERT and OVERT Outputs for Interrupts,
Throttling, and Shutdown
o STBY Input for Hardware Standby Mode
o Small, 20-Pin TSSOP Package
o 2-Wire SMBus Interface
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
________________________________________________________________
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.
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
MAX6693
ALERT
OVERT
STBY
100pF
100pF
100pF
100pF
100pF
CPU
100pF
GPU
0.1μF
TO SYSTEM
SHUTDOWN
INTERRUPT
TO μP
DATA
CLK
4.7kΩ
EACH
+3.3V
Typical Application Circuit
19-4096; Rev 0; 5/08
SMBus is a trademark of Intel Corp.
Pin Configuration appears at end of data sheet.
Ordering Information
+
Denotes a lead-free package.
Note: Slave address is 1001 101.
PART TEMP RANGE PIN-PACKAGE
MAX6693UP9A+ -40°C to +125°C 20 TSSOP
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
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, SMBCLK, SMBDATA, ALERT, OVERT,
STBY to GND ....................................................-0.3V to +6.0V
DXP_ to GND..............................................-0.3V to (V
CC
+ 0.3V)
DXN_ to GND ........................................................-0.3V to +0.8V
SMBDATA, ALERT, OVERT Current....................-1mA to +50mA
DXN_ Current......................................................................±1mA
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP
(derate 13.6mW/°C above +70°C) .............................1084mW
Junction-to-Case Thermal Resistance (θ
JC
) (Note 1)
20-Pin TSSOP...............................................................20°C/W
Junction-to-Ambient Thermal Resistance (θ
JA
) (Note 1)
20-Pin TSSOP............................................................73.8°C/W
ESD Protection (all pins, Human Body Model) ....................±2kV
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +3.6V, V
STBY
= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA=
+25°C.) (Note 2)
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage V
Software Standby Supply Current I
Operating Current I
Temperature Resolution
3 σ Temperature Accuracy
(Remote Channel 1)
3 σ Temperature Accuracy
(Remote Channels 2–6)
3 σ Temperature Accuracy
(Local)
6 σ Temperature Accuracy
(Remote Channel 1)
6 σ Temperature Accuracy
(Remote Channels 2–6)
6 σ Temperature Accuracy
(Local)
Supply Sensitivity of Temperature
Accuracy
Remote Channel 1 Conversion
Time
Remote Channels 2–6
Conversion Time
CC
SS
CC
t
CONV1
t
CONV_
SMBus static 3 10 µA
During conversion (Note 3) 500 2000 µA
Channel 1 only 11
Other diode channels 8
VCC = 3.3V,
ß = 0.5
V
= 3.3V
CC
V
= 3.3V
CC
VCC = 3.3V,
ß = 0.5
V
= 3.3V
CC
V
= 3.3V
CC
TA = TRJ = +60°C to +100°C -1.5 +1.5
= TRJ = 0°C to +125°C -2.375 +2.375
T
A
TA = TRJ = +60°C to +100°C -2 +2
= TRJ = 0°C to +125°C -2.5 +2.5
T
A
TA = +60°C to +100°C -2 +2
= 0°C to +125°C -2.5 +2.5
T
A
TA = TRJ = +60°C to +100°C -3 +3
T
= TRJ = 0°C to +125°C -4 +4
A
TA = TRJ = +60°C to +100°C -3 +3
= TRJ = 0°C to +125°C -3.5 +3.5
T
A
TA = +60°C to +100°C -2.5 +2.5
= 0°C to +125°C -3 +3
T
A
3.0 3.6 V
190 250 312 ms
95 125 156 ms
±0.2
Bits
°C
°C
°C
°C
°C
°C
o
C/V
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +3.6V, V
STBY
= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA=
+25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
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 1.20 2 2.25 V
POR Threshold Hysteresis 90 mV
ALERT, OVERT
Output Low Voltage V
Output Leakage Current 1µA
SMBus INTERFACE (SMBCLK, SMBDATA), 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 4)
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
High level, channel 1 500
RJ
OL
OL
SMBCLK
t
BUF
t
SU:STA
HD:STA
SU:STO
Low level, channel 1 20
High level, channels 2–6 80 100 120
Low level, channels 2–6 8 10 12
disables ADC 2.30 2.80 2.95 V
CC
I
= 1mA 0.3
SINK
I
= 6mA 0.5
SINK
IL
VCC = 3.0V 2.2 V
IH
I
= 6mA 0.3 V
SINK
IN
(Note 5) 400 kHz
f
f
f
f
90% of SMBCLK to 90% of SMBDATA,
f
90% of SMBCLK to 90% of SMBDATA,
f
10% of SMBDATA to 90% of SMBCLK 0.6 µs
90% of SMBCLK to 90% of SMBDATA,
f
90% of SMBCLK to 90% of SMBDATA,
f
= 100kHz 4.7
SMBCLK
= 400kHz 1.6
SMBCLK
= 100kHz 4.7
SMBCLK
= 400kHz 0.6
SMBCLK
= 100kHz
SMBCLK
= 400kHz
SMBCLK
= 100kHz
SMBCLK
= 400kHz
SMBCLK
0.6
0.6
4
0.6
5pF
0.8 V
µA
V
µs
µs
µs
µs
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
4 _______________________________________________________________________________________
Note 2: All parameters are tested at TA= +85°C. Specifications over temperature are guaranteed by design.
Note 3: Beta = 0.5 for channel 1 remote transistor.
Note 4: Timing specifications are 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)
(VCC= +3.0V to +3.6V, V
STBY
= VCC, TA= -40°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V and TA=
+25°C.) (Note 2)
Clock-Low Period t
Clock-High Period t
Data Hold Time t
Data Setup Time t
Receive SMBCLK/SMBDATA
Rise Time
Receive SMBCLK/SMBDATA Fall
Time
Pulse Width of Spike Suppressed t
SMBus Timeout t
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LOW
HIGH
HD:DAT
SU:DAT
t
R
t
F
SP
TIMEOUT
10% to 10%, f
10% to 10%, f
90% to 90% 0.6 µs
f
f
f
f
f
f
SMBDATA low period for interface reset 25 37 45 ms
= 100kHz 300
SMBCLK
= 400kHz (Note 6) 900
SMBCLK
= 100kHz 250
SMBCLK
= 400kHz 100
SMBCLK
= 100kHz 1
SMBCLK
= 400kHz 0.3
SMBCLK
= 100kHz 1.3
SMBCLK
= 400kHz 1.3
SMBCLK
300 ns
050ns
µs
ns
ns
µs
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
_______________________________________________________________________________________ 5
Typical Operating Characteristics
(VCC= 3.3V, V
STBY
= VCC, TA= +25°C, unless otherwise noted.)
SOFTWARE STANDBY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6693 toc01
SUPPLY VOLTAGE (V)
STANDBY SUPPLY CURRENT (μA)
3.2 3.53.43.33.1
3.6
3.2
3.1
3.3
3.4
3.5
3.6
3.7
3.8
3.0
3.0
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6693 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (μA)
3.2
3.63.4
440
420
460
480
500
540
520
560
580
400
3.0
LOW BETA DIODE CONNECTED TO
CHANNEL 1 WITH RESISTANCE
CANCELLATION AND LOW BETA
-3
-2
-1
0
1
2
3
4
0 255075100125
LOCAL TEMPERATURE ERROR
vs. DIE TEMPERATURE
MAX6693 toc04
DIE TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
-5
-2
-3
0
-1
2
1
-4
4
3
5
05025 75 100 125
REMOTE-DIODE TEMPERATURE ERROR
vs. REMOTE-DIODE TEMPERATURE
MAX6693 toc03
REMOTE-DIODE TEMPERATURE (°C)
TEMPERATURE ERROR (°C)
CHANNEL 2
CHANNEL 1
REMOTE-DIODE TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6693 toc05
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
-4
-3
-2
-1
0
1
2
3
4
5
-5
0.001 1.000 10.0000.010 0.100
100mV
P-P
CHANNEL 2
CHANNEL 1
LOCAL TEMPERATURE ERROR
vs. POWER-SUPPLY NOISE FREQUENCY
MAX6693 toc06
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
0.010 1.000
-4
-3
-2
-1
0
1
2
3
4
5
-5
0.001 10.0000.100
100mV
P-P
CH 2 REMOTE-DIODE TEMPERATURE ERROR
vs. COMMON-MODE NOISE FREQUENCY
MAX6693 toc07
FREQUENCY (MHz)
TEMPERATURE ERROR (°C)
1.0
-4
-3
-2
-1
0
1
2
3
4
-5
0.1 10.0
100mV
P-P
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VCC= 3.3V, V
STBY
= VCC, TA= +25°C, unless otherwise noted.)
CH 2 REMOTE-DIODE TEMPERATURE
ERROR vs. CAPACITANCE
MAX6693 toc09
CAPACITANCE (nF)
TEMPERATURE ERROR (°C)
10
-4
-3
-2
-1
0
1
2
3
4
5
-5
1 100
Pin Description
CH 1 REMOTE-DIODE TEMPERATURE
5
4
3
2
1
0
-1
-2
TEMPERATURE ERROR (°C)
-3
-4
-5
ERROR vs. CAPACITANCE
1 100
10
CAPACITANCE (nF)
MAX6693 toc08
PIN NAME FUNCTION
1 DXP1
2 DXN1 Base Inp ut for C hannel 1 Rem ote D i od e. C onnect to the b ase of a P N P tem p er atur e- sensi ng tr ansi stor .
3 DXP2
4 DXN2
5 DXP3
6 DXN3
7 DXP4
8 DXN4
Combined Current Source and A/D Positive Input for Channel 1 Remote Transistor. Connect to the
emitter of a low-beta transistor. Leave unconnected or connect to VCC if no remote transistor is used.
Place a 100pF capacitor between DXP1 and DXN1 for noise filtering.
Combined Current Source and A/D Positive Input for Channel 2 Remote Diode. Connect to the anode
of a remote-diode-connected temperature-sensing transistor. Leave unconnected or connect to V
if no remote diode is used. Place a 100pF capacitor between DXP2 and DXN2 for noise filtering.
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
of a remote-diode-connected temperature-sensing transistor. Leave unconnected or connect to V
if no remote diode is used. Place a 100pF capacitor between DXP3 and DXN3 for noise filtering.
Cathode Input for Channel 3 Remote Diode. Connect the cathode of the channel 3 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 unconnected or connect to V
if no remote diode is used. Place a 100pF capacitor between DXP4 and DXN4 for noise filtering.
Cathode Input for Channel 4 Remote Diode. Connect the cathode of the channel 4 remote-diodeconnected transistor to DXN4.
CC
CC
CC
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
_______________________________________________________________________________________ 7
Detailed Description
The MAX6693 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 MAX6693
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 MAX6693 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.
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 3µA. 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 interrupted, and the temperature registers are not updated.
The previous data is not changed and remains available.
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 unconnected or connect to V
if no remote diode is used. Place a 100pF capacitor between DXP5 and DXN5 for noise filtering.
Cathode Input for Channel 5 Remote Diode. Connect the cathode of the channel 5 remote-diodeconnected transistor to DXN5.
Cathode Input for Channel 6 Remote Diode. Connect the cathode of the channel 6 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 unconnected or connect to V
if no remote diode is used. Place a 100pF capacitor between DXP6 and DXN6 for noise filtering.
Acti ve- Low S tand b y Inp ut. D r i ve S TBY l og i c- l ow to p l ace the M AX 6693 i n stand b y m od e, or l og i c- hi g h
for op er ate m od e. Tem p er atur e and thr eshol d d ata ar e r etai ned i n stand b y m od e.
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
CC
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
8 _______________________________________________________________________________________
Operating-Current Calculation
The MAX6693 operates at different operating-current
levels depending on how many external channels are in
use. Assume that I
CC1
is the operating current when
the MAX6693 is converting the remote channel 1 and
I
CC2
is the operating current when the MAX6693 is converting the other channels. For the MAX6693 with
remote channel 1 and n other remote channels connected, the operating current is:
ICC= (2 x I
CC1
+ I
CC2
+ n x I
CC2
)/(n + 3)
SMBus Digital Interface
From a software perspective, the MAX6693 appears as
a series of 8-bit registers that contain temperature measurement 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 same SMBus slave
address also provides access to all functions.
Figure 1. Internal Block Diagram
V
CC
DXP1
MAX6693
DXN1
DXP2
ALARM
DXN2
DXP3
DXN3
DXP4
DXN4
DXP5
CURRENT
SOURCES,
BETA
COMPEN-
SATION
AND MUX
INPUT
BUFFER
REF
ADC
ALU
REGISTER BANK
COMMAND BYTE
REMOTE TEMPERATURES
LOCAL TEMPERATURES
ALERT THRESHOLD
OVERT
ALERT
DXN5
DXP6
DXN6
SMBCLK SMBDATA
OVERT THRESHOLD
ALERT RESPONSE ADDRESS
SMBus
INTERFACE
STBY
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
_______________________________________________________________________________________ 9
The MAX6693 employs four standard SMBus protocols:
write byte, read byte, send byte, and receive byte
(Figure 2). The shorter receive byte protocol allows
quicker transfers, provided 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 without informing the first master. Figure
3 is the SMBus write-timing diagram and Figure 4 is the
SMBus read-timing diagram.
The remote diode 1 measurement channel provides 11
bits of data (1 LSB = 0.125°C). All other temperaturemeasurement channels provide 8 bits of temperature
data (1 LSB = 1°C). The 8 most significant bits (MSBs)
can be read from the local temperature and remote
temperature registers. The remaining 3 bits for remote
diode 1 can be read from the extended temperature
register. If extended resolution is desired, the extended
resolution register should be read first. This prevents
the most significant bits from being overwritten by new
conversion results until they have been read. If the most
significant bits have not been read within an SMBus
timeout period (nominally 37ms), normal updating continues. Table 1 shows the main temperature register
(high-byte) data format, and Table 2 shows the extended resolution register (low-byte) data format.
Figure 2. SMBus Protocols
Table 1. Main Temperature Register
(High-Byte) Data Format
Table 2. Extended Resolution Temperature
Register (Low-Byte) Data Format
WRITE BYTE FORMAT
S ADDRESS WR ACK ACK PDATA ACKCOMMAND
7 BITS 18 BITS8 BITS
SLAVE ADDRESS: EQUIVALENT TO CHIP-SELECT LINE OF
A 3-WIRE INTERFACE
READ BYTE FORMAT
S ADDRESSADDRESS WR ACK ACK PS RD ACK ///DATACOMMAND
7 BITS 7 BITS 8 BITS8 BITS
SLAVE ADDRESS: EQUIVALENT TO CHIP SELECT LINE
SEND BYTE FORMAT
SPADDRESS WR ACK ACKCOMMAND
7 BITS 8 BITS
S = START CONDITION.
P = STOP CONDITION.
SHADED = SLAVE TRANSMISSION.
/// = NOT ACKNOWLEDGED.
COMMAND BYTE: SELECTS
WHICH REGISTER YOU ARE
REDING FROM
COMMAND BYTE: SENDS COMMAND WITH NO DATA, USUALLY
USED FOR ONE-SHOT COMMAND
TEMP (°C) DIGITAL OUTPUT
> +127 0111 1111
+127 0111 1111
+126 0111 1110
+25 0001 1001
0 0000 0000
< 0 0000 0000
Diode fault (open or short) 1111 1111
DATA BYTE: DATA GOES INTO THE REGISTER
SET BY THE COMMAND BYTE (TO SET
THRESHOLDS, CONFIGURATION MASKS, AND
SAMPLING RATE)
SLAVE ADDRESS: REPEATED
DUE TO CHANGE IN DATAFLOW DIRECTION
RECEIVE BYTE FORMAT
SPADDRESS RD ACK ///DATA
7 BITS 8 BITS
DATA BYTE: READS FROM
THE REGISTER SET BY THE
COMMAND BYTE
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
TEMP (°C) DIGITAL OUTPUT
0 000X XXXX
+0.125 001X XXXX
+0.250 010X XXXX
+0.375 011X XXXX
+0.500 100X XXXX
+0.625 101X XXXX
+0.750 110X XXXX
+0.875 111X XXXX
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
10 ______________________________________________________________________________________
Diode Fault Detection
If a channel’s input DXP_ and DXN_ are left open, the
MAX6693 detects a diode fault. An open diode fault does
not cause either ALERT or OVERT to assert. A bit in the sta-
tus register for the corresponding channel is set to 1 and the
temperature data for the channel is stored as all 1s (FFh). It
takes approximately 4ms for the MAX6693 to detect a diode
fault. Once a diode fault is detected, the MAX6693 goes to
the next channel in the conversion sequence.
Alarm Threshold Registers
There are 11 alarm threshold registers that store over-temperature ALERT and OVERT threshold values. Seven of
these registers are dedicated to storing one local alert temperature threshold limit and six remote alert temperature
threshold limits (see the
ALERT Interrupt Mode
section).
The remaining four registers are dedicated to remote channels 1, 4, 5, and 6 to store overtemperature threshold limits
(see the
OVERT Overtemperature Alarms
section). Access
to these registers is provided through the SMBus interface.
ALERT
Interrupt Mode
An ALERT interrupt occurs when the internal or external
temperature reading exceeds a high-temperature limit
(user programmable). The ALERT interrupt output signal
can be cleared by reading the status register(s) associated with the fault(s) or by successfully responding to an
alert response address transmission by the master. In
both cases, the alert is cleared but is reasserted at the
end of the next conversion if the fault condition still
exists. The interrupt does not halt automatic conversions.
The ALERT output is open-drain so that multiple devices
can share a common interrupt line. All ALERT interrupts
can be masked using the configuration 2 register. The
POR state of these registers is shown in Table 3.
Figure 3. SMBus Write-Timing Diagram
Figure 4. SMBus Read-Timing Diagram
AB CDEFG HIJ
t
LOWtHIGH
SMBCLK
SMBDATA
t
t
HD:STA
SU:STA
A = START CONDITION.
B = MSB OF ADDRESS CLOCKED INTO SLAVE.
C = LSB OF ADDRESS CLOCKED INTO SLAVE.
D = R/W BIT CLOCKED INTO SLAVE.
E = SLAVE PULLS SMBDATA LINE LOW.
AB CDEFG
t
LOW
SMBCLK
SMBDATA
t
SU:STAtHD:STA
A = START CONDITION.
B = MSB OF ADDRESS CLOCKED INTO SLAVE.
C = LSB OF ADDRESS CLOCKED INTO SLAVE.
D = R/W BIT CLOCKED INTO SLAVE.
t
HIGH
t
SU:DAT
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.
t
SU:DAT
E = SLAVE PULLS SMBDATA LINE LOW.
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER.
G = MSB OF DATA CLOCKED INTO SLAVE.
H = LSB OF DATA CLOCKED INTO SLAVE.
t
HD:DAT
K
J = ACKNOWLEDGE CLOCKED INTO SLAVE.
K = ACKNOWLEDGE CLOCK PULSE.
L = STOP CONDITION.
M = NEW START CONDITION.
HIJ
I = MASTER PULLS DATA LINE LOW.
J = ACKNOWLEDGE CLOCKED INTO SLAVE.
K = ACKNOWLEDGE CLOCK PULSE.
L = STOP CONDITION.
M = NEW START CONDITION.
L
t
SU:STO
LMK
t
SU:STOtBUF
M
t
BUF
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
______________________________________________________________________________________ 11
ALERT
Response Address
The SMBus alert response interrupt pointer provides
quick fault identification for simple slave devices that
lack the complex logic needed to be a bus master.
Upon receiving an interrupt signal, the host master can
broadcast a receive byte transmission to the alert
response slave address (see the
Slave Address
section). Then, any slave device that generated an interrupt attempts to identify itself by putting its own
address on the bus.
The alert response can activate several different slave
devices simultaneously, similar to the I
2
C General Call.
If more than one slave attempts to respond, bus arbitration rules apply, and the device with the lower address
code wins. The losing device does not generate an
acknowledgment 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 output latch. If the condition that caused the
alert still exists, the MAX6693 reasserts the ALERT
interrupt at the end of the next conversion.
OVERT
Overtemperature Alarms
The MAX6693 has four overtemperature registers that
store remote alarm threshold data for the OVERT output.
OVERT is asserted when a channel’s measured temperature is greater than the value stored in the corresponding threshold register. OVERT remains asserted until the
temperature drops below the programmed threshold
minus 4°C hysteresis. An overtemperature output can
be used to activate a cooling fan, send a warning, initiate clock throttling, or trigger a system shutdown to prevent component damage. See Table 3 for the POR state
of the overtemperature threshold registers.
Command Byte Functions
The 8-bit command byte register (Table 3) is the master
index that points to the various other registers within the
MAX6693. This register’s POR state is 0000 0000.
Configuration Byte Functions
There are three read-write configuration registers
(Tables 4, 5, and 6) that can be used to control the
MAX6693’s operation.
Configuration 1 Register
The configuration 1 register (Table 4) has several functions. Bit 7 (MSB) is used to put the MAX6693 either in
software standby mode (STOP) or continuous conversion mode. Bit 6 resets all registers to their POR conditions and then clears itself. Bit 5 disables the SMBus
timeout. Bit 3 enables resistance cancellation on channel 1. See the
Series Resistance Cancellation
section
for more details. Bit 2 enables beta compensation on
channel 1. See the
Beta Compensation
section for more
details. The remaining bits of the configuration 1 register are not used. The POR state of this register is 0000
1100 (0Ch).
Configuration 2 Register
The configuration 2 register functions are described in
Table 5. Bits [6:0] are used to mask the ALERT interrupt
output. Bit 6 masks the local alert interrupt and bits 5
through bit 0 mask the remote alert interrupts. The
power-up state of this register is 0000 0000 (00h).
Configuration 3 Register
Table 6 describes the configuration 3 register. Bits 5, 4, 3,
and 0 mask the OVERT interrupt output for channels 6, 5,
4, and 1. The remaining bits, 7, 6, 2, and 1, are reserved.
The power-up state of this register is 0000 0000 (00h).
Status Register Functions
Status registers 1, 2, and 3 (Tables 7, 8, and 9) indicate
which (if any) temperature thresholds have been
exceeded and if there is an open-circuit or short-circuit
fault detected with the external sense junctions. Status
register 1 indicates if the measured temperature has
exceeded the threshold limit set in the ALERT registers
for the local or remote-sensing diodes. Status register 2
indicates if the measured temperature has exceeded
the threshold limit set in the OVERT registers. Status
register 3 indicates if there is a diode fault (open or
short) in any of the remote-sensing channels.
Bits in the alert status register clear by a successful
read, but set again after the next conversion unless the
fault is corrected, either by a drop in the measured temperature or an increase in the threshold temperature.
The ALERT interrupt output follows the status flag bit.
Once the ALERT output is asserted, it can be
deasserted by either reading status register 1 or by
successfully responding to an alert response address.
In both cases, the alert is cleared even if the fault condi-
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
12 ______________________________________________________________________________________
Table 3. Command Byte Register Bit Assignment
REGISTER
Local 07 00 R Read local temperature register
Remote 1 01 00 R Read channel 1 remote temperature register
Remote 2 02 00 R Read channel 2 remote temperature register
Remote 3 03 00 R Read channel 3 remote temperature register
Remote 4 04 00 R Read channel 4 remote temperature register
Remote 5 05 00 R Read channel 5 remote temperature register
Remote 6 06 00 R Read channel 6 remote temperature register
Configuration 1 41 0C R/W Read/write configuration register 1
Configuration 2 42 00 R/W Read/write configuration register 2
Configuration 3 43 00 R/W Read/write configuration register 3
Status1 44 00 R Read status register 1
Status2 45 00 R Read status register 2
Status3 46 00 R Read status register 3
Local ALERT High Limit 17 5A R/W Read/write local alert high-temperature threshold limit register
Remote 1 ALERT High Limit 11 6E R/W
Remote 2 ALERT High Limit 12 7F R/W
Remote 3 ALERT High Limit 13 64 R/W
Remote 4 ALERT High Limit 14 64 R/W
Remote 5 ALERT High Limit 15 64 R/W
Remote 6 ALERT High Limit 16 64 R/W
Remote 1 OVERT High Limit 21 6E R/W
Remote 4 OVERT High Limit 24 7F R/W
Remote 5 OVERT High Limit 25 5A R/W
Remote 6 OVERT High Limit 26 5A R/W
Remote 1 Extended
Temperature
Manufacturer ID 0A 4D R Read manufacturer ID
ADDRESS
(HEX)
09 00 R Read channel 1 remote-diode extended temperature register
POR STATE
(HEX)
READ/
WRITE
DESCRIPTION
Read/write channel 1 remote-diode alert high-temperature
threshold limit register
Read/write channel 2 remote-diode alert high-temperature
threshold limit register
Read/write channel 3 remote-diode alert high-temperature
threshold limit register
Read/write channel 4 remote-diode alert high-temperature
threshold limit register
Read/write channel 5 remote-diode alert high-temperature
threshold limit register
Read/write channel 6 remote-diode alert high-temperature
threshold limit register
Read/write channel 1 remote-diode overtemperature threshold
limit register
Read/write channel 4 remote-diode overtemperature threshold
limit register
Read/write channel 5 remote-diode overtemperature threshold
limit register
Read/write channel 6 remote-diode overtemperature threshold
limit register
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
______________________________________________________________________________________ 13
tion exists, but the ALERT output reasserts at the end of
the next conversion. The bits indicating the fault for the
OVERT interrupt output clear only on reading the status 2
register even if the fault conditions still exist. Reading the
status 2 register does not clear the OVERT interrupt output. To eliminate the fault condition, either the measured
temperature must drop below the temperature threshold
minus the hysteresis value (4°C), or the trip temperature
must be set at least 4°C above the current temperature.
Applications Information
Remote-Diode Selection
The MAX6693 directly measures the die temperature of
CPUs and other ICs that have on-chip temperaturesensing diodes (see the
Typical Application Circuit
) or
it can measure the temperature of a discrete diodeconnected transistor.
Effect of Ideality Factor
The accuracy of the remote temperature measurements depends on the ideality factor (n) of the remote
“diode” (actually a transistor). The MAX6693 is optimized for n = 1.006 (channel 1) and n = 1.008 (channels 2–6). A thermal diode on the substrate of an IC is
normally a pnp with the base and emitter brought out to
the collector (diode connection) grounded. DXP_ must
be connected to the anode (emitter) and DXN_ must be
connected to the cathode (base) of this pnp. If a sense
transistor with an ideality factor other than 1.006 or
1.008 is used, the output data is different from the data
obtained with the optimum ideality factor. Fortunately,
the difference is predictable. Assume a remote-diode
sensor designed for a nominal ideality factor n
NOMINAL
is used to measure the temperature of a diode with a
different ideality factor n1. The measured temperature
TMcan be corrected using:
Table 4. Configuration 1 Register
Table 5. Configuration 2 Register
BIT NAME
POR
STATE
FUNCTION
7 (MSB) Reserved 0 —
6
0 Local Alert Mask. Set to logic 1 to mask local channel ALERT.
5 Mask ALERT 6 0 Channel 6 Alert Mask. Set to logic 1 to mask channel 6 ALERT.
4 Mask ALERT 5 0 Channel 5 Alert Mask. Set to logic 1 to mask channel 5 ALERT.
3 Mask ALERT 4 0 Channel 4 Alert Mask. Set to logic 1 to mask channel 4 ALERT.
2 Mask ALERT 3 0 Channel 3 Alert Mask. Set to logic 1 to mask channel 3 ALERT.
1 Mask ALERT 2 0 Channel 2 Alert Mask. Set to logic 1 to mask channel 2 ALERT.
0 Mask ALERT 1 0 Channel 1 Alert Mask. Set to logic 1 to mask channel 1 ALERT.
BIT NAME
7 (MSB) STOP 0
6 POR 0
5 TIMEOUT 0 Timeout Enable Bit. Set to logic 0 to enable SMBus timeout.
4 RESERVED 0 Reserved. Must set to 0.
3
2 Beta compensation 1
1 Reserved 0 —
0 Reserved 0 —
Resistance
cancellation
POR
STATE
1
FUNCTION
Standby-Mode Control Bit. If STOP is set to logic 1, the MAX6693 stops
converting and enters standby mode.
Reset Bit. Set to logic 1 to put the device into its power-on state. This bit is selfclearing.
Resistance Cancellation Bit. When set to logic 1, the MAX6693 cancels series
resistance in the channel 1 thermal diode.
Beta Compensation Bit. When set to logic 1, the MAX6693 compensates for low
beta in the channel 1 thermal sensing transistor.
Mask Local ALERT
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
14 ______________________________________________________________________________________
where temperature is measured in Kelvin and
n
NOMIMAL
for channel 1 of the MAX6693 is 1.009. As
an example, assume you want to use the MAX6693 with
a CPU that has an ideality factor of 1.002. If the diode
has no series resistance, the measured data is related
to the real temperature as follows:
For a real temperature of +85°C (358.15K), the measured temperature is +84.41°C (357.56K), an error of
-0.590°C.
Series Resistance Cancellation
Some thermal diodes on high-power ICs can have
excessive series resistance, which can cause temperature measurement errors with conventional remote temperature sensors. Channel 1 of the MAX6693 has a
series resistance cancellation feature (enabled by bit 3
of the configuration 1 register) that eliminates the effect
of diode series resistance. Set bit 3 to 1 if the series
resistance is large enough to affect the accuracy of
channel 1. The series resistance cancellation function
increases the conversion time for channel 1 by 125ms.
This feature cancels the bulk resistance of the sensor
and any other resistance in series (wire, contact resistance, etc.). The cancellation range is from 0Ω to 100Ω.
Beta Compensation
The MAX6693 is optimized for use with a substrate PNP
remote-sensing transistor on the die of the target IC.
DXP1 connects to the emitter of the sensing transistor
and DXN1 connects to the base. The collector is
grounded. Such transistors can have very low beta
(less than 1) when built in processes with 65nm and
smaller geometries. Because of the very low beta, standard “remote diode” temperature sensors may exhibit
large errors when used with these transistors. Channel
1 of the MAX6693 incorporates a beta compensation
function that, when enabled, eliminates the effect of low
beta values. This function is enabled at power-up using
bit 2 of the configuration 1 register. Whenever low beta
compensation is enabled, series-resistance cancellation must be enabled.
Discrete Remote Diodes
When the remote-sensing diode is a discrete transistor,
its collector and base must be connected together.
Table 10 lists examples of discrete transistors that are
appropriate for use with the MAX6693. The transistor
must be a small-signal type with a relatively 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 temperature, the forward voltage must be less than 0.95V at 100µA. Large
power transistors must not be used. Also, ensure that
the base resistance is less than 100Ω. Tight specifications for forward current gain (50 < ß < 150, for example) indicate that the manufacturer has good process
controls and that the devices have consistent VBEchar-
Table 6. Configuration 3 Register
BIT NAME
7 (MSB) Reserved 0 —
6 Reserved 0 —
5 Mask OVERT 6 0
4 Mask OVERT 5 0
3 Mask OVERT 4 0
2 Reserved 0 —
1 Reserved 0 —
0 Mask OVERT 1 0
POR
STATE
FUNCTION
Channel 6 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 6
OVERT.
Channel 5 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 5
OVERT.
Channel 4 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 4
OVERT.
Channel 1 Remote-Diode OVERT Mask Bit. Set to logic 1 to mask channel 1
OVERT.
TT
=
M ACTUAL
⎛
⎜
n
⎝
NOMINAL
⎞
n
1
⎟
⎠
⎛
n
TT
ACTUAL M
=×
NOMINAL
⎜
⎝
⎞
=×
⎟
n
⎠
1
1 009
.
⎛
⎜
⎝
1 002
⎞
=
1 00699
(. )
⎟
⎠
.
TT
MM
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
______________________________________________________________________________________ 15
acteristics. Manufacturers of discrete transistors do not
normally specify or guarantee ideality factor. This is
normally not a problem since good-quality discrete
transistors tend to have ideality factors that fall within a
relatively narrow range. We have observed variations in
remote temperature readings of less than ±2°C with a
variety of discrete transistors. Still, it is good design
practice to verify good consistency of temperature
readings with several discrete transistors from any
manufacturer under consideration.
Unused Diode Channels
If one or more of the remote diode channels is not
needed, disconnect the DXP and DXN inputs for that
channel, or connect the DXP input to VCC. The status
register indicates a diode "fault" for this channel and the
channel is ignored during the temperature-measurement sequence. It is also good practice to mask any
unused channels immediately upon power-up by setting the appropriate bits in the Configuration 2 and
Configuration 3 registers. This will prevent unused
channels from causing ALERT or OVERT to assert.
Thermal Mass and Self-Heating
When sensing local temperature, the MAX6693 measures the temperature of the PCB to which it is soldered.
The leads provide a good thermal path between the
PCB traces and the die. As with all IC temperature sensors, thermal conductivity between the die and the
ambient air is poor by comparison, making air temperature measurements impractical. Because the thermal
mass of the PCB is far greater than that of the
MAX6693, the device follows temperature changes on
the PCB with little or no perceivable delay. When measuring the temperature of a CPU or other IC with an onchip sense junction, thermal mass has virtually no
Table 7. Status 1 Register
BIT NAME
7 (MSB) Reserved 0 —
6 Local ALERT 0
5 Remote 6 ALERT 0
4 Remote 5 ALERT 0
3 Remote 4 ALERT 0
2 Remote 3 ALERT 0
1 Remote 2 ALERT 0
POR
STATE
FUNCTION
Local Channel High-Alert Bit. This bit is set to logic 1 when the local
temperature exceeds the temperature threshold limit in the local ALERT highlimit register.
Channel 6 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
channel 6 remote-diode temperature exceeds the temperature threshold limit
in the remote 6 ALERT high-limit register.
Channel 5 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
channel 5 remote-diode temperature exceeds the programmed temperature
threshold limit in the remote 5 ALERT high-limit register.
Channel 4 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
channel 4 remote-diode temperature exceeds the temperature threshold limit
in the remote 4 ALERT high-limit register.
Channel 3 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
channel 3 remote-diode temperature exceeds the programmed temperature
threshold limit in the remote 3 ALERT high-limit register.
Channel 2 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
channel 2 remote-diode temperature exceeds the temperature threshold limit
in the remote 2 ALERT high-limit register.
Channel 1 Remote-Diode High-Alert Bit. This bit is set to logic 1 when the
0 Remote 1 ALERT 0
channel 1 remote-diode temperature exceeds the temperature threshold limit
in the remote 1 ALERT high-limit register.
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
16 ______________________________________________________________________________________
Table 8. Status 2 Register
Table 9. Status 3 Register
BIT NAME
7 (MSB) Reserved 0 —
6 Reserved 0 —
5 Remote 6 OVERT 0
4 Remote 5 OVERT 0
3 Remote 4 OVERT 0
2 Reserved 0 —
1 Reserved 0 —
0 Remote 1 OVERT 0
POR
STATE
FUNCTION
Channel 6 Remote-Diode Overtemperature Status Bit. This bit is set to logic 1
when the channel 6 remote-diode temperature exceeds the temperature
threshold limit in the remote 6 OVERT high-limit register.
Channel 5 Remote Diode Overtemperature Status Bit. This bit is set to logic 1
when the channel 5 remote-diode temperature exceeds the temperature
threshold limit in the remote 5 OVERT high-limit register.
Channel 4 Remote Diode Overtemperature Status Bit. This bit is set to logic 1
when the channel 4 remote-diode temperature exceeds the temperature
threshold limit in the remote 4 OVERT high-limit register.
Channel 1 Remote-Diode Overtemperature Status Bit. This bit is set to logic 1
when the channel 1 remote-diode temperature exceeds the temperature
threshold limit in the remote 1 OVERT high-limit register.
BIT NAME
7 (MSB) Reserved 0 —
6 Diode fault 6 0
5 Diode fault 5 0
4 Diode fault 4 0
3 Diode fault 3 0
2 Diode fault 2 0
1 Diode fault 1 0
0 Reserved 0 —
POR
STATE
FUNCTION
Channel 6 Remote-Diode Fault Bit. This bit is set to 1 when DXP6 and DXN6
are open circuit or when DXP6 is connected to V
Channel 5 Remote-Diode Fault Bit. This bit is set to 1 when DXP5 and DXN5
are open circuit or when DXP5 is connected to V
Channel 4 Remote-Diode Fault Bit. This bit is set to 1 when DXP4 and DXN4
are open circuit or when DXP4 is connected to V
Channel 3 Remote-Diode Fault Bit. This bit is set to 1 when DXP3 and DXN3
are open circuit or when DXP3 is connected to V
Channel 2 Remote-Diode Fault Bit. This bit is set to 1 when DXP2 and DXN2
are open circuit or when DXP2 is connected to V
Channel 1 Remote-Diode Fault Bit. This bit is set to 1 when DXP1 and DXN1
are open circuit or when DXP1 is connected to V
CC
CC
CC
CC
CC
CC
.
.
.
.
.
.
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
______________________________________________________________________________________ 17
effect; the measured temperature of the junction tracks
the actual temperature within a conversion cycle.
When measuring temperature with discrete remote transistors, the best thermal response times are obtained
with transistors in small packages (i.e., SOT23 or SC70).
Take care to account for thermal gradients between the
heat source and the sensor, and ensure that stray air
currents across the sensor package do not interfere with
measurement accuracy. Self-heating does not significantly affect measurement accuracy. Remote-sensor
self-heating due to the diode current source is negligible.
ADC Noise Filtering
The integrating ADC has good noise rejection for lowfrequency signals, such as power-supply hum. In environments with significant high-frequency EMI, connect an
external 100pF capacitor between DXP_ and DXN_.
Larger capacitor values can be used for added filtering,
but do not exceed 100pF because it can introduce errors
due to the rise time of the switched current source. Highfrequency noise reduction is needed for high-accuracy
remote measurements. Noise can be reduced with careful
PCB layout as discussed in the
PCB Layout
section.
Slave Address
The slave address for the MAX6693 is shown in Table 11.
PCB Layout
Follow these guidelines to reduce the measurement
error when measuring remote temperature:
1) Place the MAX6693 as close as is practical to the
remote diode. In noisy environments, such as a computer motherboard, this distance 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 PCI buses.
2) Do not route the DXP-DXN lines next to the deflection coils of a CRT. Also, do not route the traces
across fast digital signals, which can easily introduce +30°C error, even with good filtering.
3) Route the DXP and DXN traces in parallel and in close
proximity to each other. Each parallel pair of traces
should go to a remote diode. Route these traces away
from any higher voltage traces, such as +12VDC.
Leakage currents from PCB 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 5).
4) Route through as few vias and crossunders as possible to minimize copper/solder thermocouple effects.
5) Use wide traces when practical. 5mil to 10mil traces
are typical. Be aware of the effect of trace resistance on
temperature readings when using long, narrow traces.
6) When the power supply is noisy, add a resistor (up
to 47Ω) in series with V
CC
.
Figure 5. Recommended DXP-DXN PCB Traces. The two outer
guard traces are recommended if high-voltage traces near the
DXN and DXP traces.
Table 10. Remote-Sensors Transistor
Manufacturer (for Channels 2–6)
Note: Discrete transistors must be diode connected (base
shorted to collector).
Table 11. Slave Address
MANUFACTURER MODEL NO.
Central Semiconductor (USA) CMPT3904
Rohm Semiconductor (USA) SST3904
Samsung (Korea) KST3904-TF
Siemens (Germany) SMBT3904
Zetex (England) FMMT3904CT-ND
DEVICE ADDRESS
A7 A6 A5 A4 A3 A2 A1 A0
1001101R/W
5–10 mils
5–10 mils
GND
DXP
DXN
GND
5–10 mils
MINIMUM
5–10 mils
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
18 ______________________________________________________________________________________
Twisted-Pair and Shielded Cables
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 microphones. For example, Belden #8451 works well for distances 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. For very long cable runs, the cable’s
parasitic capacitance often provides noise filtering, so
the 100pF 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
approximately +0.5°C.
Pin Configuration
Chip Information
PROCESS: BiCMOS
TOP VIEW
DXP1
DXN1
DXP2
DXN2
DXP3
DXN3
DXP4
DXP5
+
1
2
3
4
MAX6693
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
GND
SMBCLK
SMBDATA
ALERT
V
CC
OVERT
N.C.
STBYDXN4
DXP6
DXN6DXN5
TSSOP
MAX6693
7-Channel Precision Temperature Monitor
with Beta Compensation
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________
19
© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
20 TSSOP U20-2
21-0066
Package Information
For the latest package outline information, go to www.maxim-ic.com/packages.
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