19-2226; Rev 1; 7/04
KIT
ATION
EVALU
E
BL
AVAILA
Temperature Sensor and
System Monitor in a 10-Pin µMAX
General Description
Features
♦
Monitors Local Temperature
♦
Monitors Three External Voltages (1.8V, 2.5V, 5V
Nominal)
♦
Monitors V
CC
(3.3V Nominal)
♦
User-Programmable Voltage and Temperature
Thresholds
♦
Alert Function with Ability to Respond to SMB
Alert Response Address
♦
+2.7V to +5.5V Supply Range
♦
-40°C to +125°C Temperature Range
♦
60Hz or 50Hz Line-Frequency Rejection
♦
Tiny 10-Pin µMAX Package
♦
MAX6683EVKIT Available
MAX6683
The MAX6683 system supervisor monitors multiple
power-supply voltages, including its own, and also fea-
tures an on-board temperature sensor. The MAX6683
converts voltages to an 8-bit code and temperatures to
an 11-bit (10-bit-plus-sign) code using an analog-to-
digital converter (ADC). A multiplexer automatically
sequences through the voltage and temperature mea-
surements. The digitized signals are then stored in reg-
isters and compared to the over/underthreshold limits
programmed over the SMBus™/I
2
C™-compatible 2-
wire serial interface.
When a temperature measurement exceeds the pro-
grammed threshold, or when an input voltage falls out-
side the programmed voltage limits, the MAX6683
generates a latched interrupt output
ALERT.
Three
interrupt modes are available for temperature excur-
sions. These are default mode, one-time interrupt
mode, and comparator mode. The
ALERT
output is
cleared, except for temperature interrupts generated in
comparator mode, by reading the Interrupt Status reg-
ister (Table 5). The
ALERT
output can also be masked
by writing to the appropriate bits in the Interrupt Mask
register (Table 6) or by setting bit 1 of the Configuration
register (Table 4) to zero. The MAX6683 SMBus/I
2
C-
compatible interface also responds to the SMB alert
response address.
Ordering Information
PART
MAX6683AUB
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
10 µMAX
Applications
Workstations
Servers
Networking
Telecommunications
Typical Application Circuit
1.8V
V
CC
= +3.3V
CPU
0.1μF
Pin Configuration
TOP VIEW
1.8V
IN
1
2.5V
IN
2
3
4
5
10
V
CC
9
SCL
SDA
ADD
ALERT
10kΩ
TO 1.8V
TO 2.5V
TO 5V
1.8V
IN
2.5V
IN
5V
IN
N.C.
GND
V
CC
SCL
SDA
ADD
ALERT
I
2
C/SMBus
CONTROLLER
5V
IN
N.C.
GND
MAX6683
8
7
6
SMBus is a trademark of Intel Corp.
I
2
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.
Temperature Sensor and
System Monitor in a 10-Pin µMAX
MAX6683
ABSOLUTE MAXIMUM RATINGS
All Voltages Referenced to GND
All Pins...................................................................-0.3V to +6.0V
SDA,
ALERT
Current ...........................................-1mA to +50mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
Junction Temperature ......................................................+150°C
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
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
(T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
CC
= +3.3V, T
A
= +25°C.)
PARAMETER
POWER SUPPLY
Supply Voltage
Supply Current
Power-On Reset (POR) Voltage
TEMPERATURE
T
A
= +25°C, V
CC
= +3.3V
Accuracy
Resolution
Supply Sensitivity
ADC CHARACTERISTICS
Total Unadjusted Error
Differential Nonlinearity
Supply Sensitivity
Input Resistance
Total Monitoring Cycle Time
SCL, SDA, ADD
Logic Input Low Voltage
Logic Input High Voltage
Input Leakage Current
Output Low Voltage
ALERT
Output Low Voltage
V
OLA
I
SINK
= 1.2mA, V
CC
> 2.7V
I
SINK
= 3.2mA, V
CC
> 4.5V
0.3
0.4
V
V
IL
V
IH
I
LEAK
V
OL
V
CC
≤
3.6V
V
CC
>
3.6V
V
IN
= 0 or 5V
I
SINK
= 3mA
2.0
2.6
±1
400
0.8
V
V
µA
mV
TUE
DNL
PSS
R
IN
t
c
1.8V
IN
, 2.5V
IN
, 5V
IN
(Note 1)
100
V
IN
> 10LSBs
V
IN
> 10LSBs
±1
150
200
200
300
±1.5
±1
%
LSB
LSB/V
kΩ
ms
PSS
0°C
≤
T
A
≤
+125°C, V
CC
= +3.3V
-40°C
≤
T
A
≤
+125°C, V
CC
= +3.3V
Read word mode
0.125
0.7
±1.5
±3
±4
±6
°C
°C/V
°C
V
CC
I
CC
I
SD
Operating
Shutdown mode, interface inactive
V
CC
, rising or falling edge
2
2.7
200
5.5
500
10
V
µA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Temperature Sensor and
System Monitor in a 10-Pin µMAX
ELECTRICAL CHARACTERISTICS (continued)
(T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V
CC
= +3.3V, T
A
= +25°C.)
PARAMETER
TIMING
(Figures 3 and 4)
Serial Clock Frequency
Bus Free Time Between Stop
and Start
Start Condition Hold Time
Stop Condition Hold Time
Clock Low Time
Clock High Time
Data Setup Time
Data Hold Time
Receive SCL/SDA Minimum
Rise Time
Receive SCL/SDA Maximum
Rise Time
Receive SCL/SDA Minimum Fall
Time
Receive SCL/SDA Maximum Fall
Time
Transmit SDA Fall Time
Pulse Width of Spike
Suppressed
f
SCL
T
BUF
t
HD
:
STA
t
SU
:
STO
T
LOW
T
HIGH
t
SU
:
DAT
t
HD
:
DAT
t
R
t
R
t
F
t
F
t
F
t
SP
(Note 2)
(Note 3)
(Note 3)
(Note 3)
(Note 3)
C
b
= 400pF, I
SINK
= 3mA
(Note 4)
20 +
0.1C
b
50
0
1.3
0.6
0.6
1.3
0.6
100
0
20 +
0.1C
b
300
20 +
0.1C
b
300
300
0.9
400
kHz
µs
µs
µs
µs
µs
ns
µs
ns
ns
ns
ns
ns
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX6683
Note 1:
Total monitoring time includes temperature conversion and four analog input voltage conversions.
Note 2:
A master device must provide at least a 300ns hold time for the SDA signal, referred to V
IL
of the SCL signal, to bridge the
undefined region of SCL’s falling edge.
Note 3:
C
b
= total capacitance of one bus line in pF. Rise and fall times are measured between 0.3
✕
V
CC
to 0.7
✕
V
CC
.
Note 4:
Input filters on SDA, SCL, and ADD suppress noise spikes <50ns.
_______________________________________________________________________________________
3
Temperature Sensor and
System Monitor in a 10-Pin µMAX
MAX6683
Typical Operating Characteristics
(V
CC
= +3.3V, ADD = GND, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
INTERFACE INACTIVE
A
B
C
D
E
A: T
A
= +125°C
B: T
A
= +85°C
C: T
A
= +25°C
D: T
A
= 0°C
E: T
A
= -40°C
2.5
3.0
3.5
4.0
4.5
5.0
5.5
MAX6683 toc01
SUPPLY CURRENT
vs. SCL CLOCK FREQUENCY
MAX6683 toc02
TEMPERATURE ERROR
vs. SUPPLY VOLTAGE
3
TEMPERATURE ERROR (°C)
2
1
T
A
= 0°C
0
-1
-2
-3
-4
T
A
= -40°C
2.5
3.0
3.5
4.0
4.5
5.0
5.5
T
A
= +85°C
MAX6683 toc03
350
300
SUPPLY CURRENT (μA)
250
200
150
100
50
0
450
425
SUPPLY CURRENT (μA)
400
375
350
325
300
275
250
1
V
CC
= +5V
SCL = 3Vp-p
4
10
100
1000
SUPPLY VOLTAGE (V)
CLOCK FREQUENCY (kHz)
SUPPLY VOLTAGE (V)
TEMPERATURE ERROR
vs. SUPPLY NOISE FREQUENCY
MAX6683 toc04
TEMPERATURE ERROR
vs. TEMPERATURE
4
TEMPERATURE ERROR (°C)
3
2
1
0
-1
-2
-3
-4
MAX6683 toc05
6
5
TEMPERATURE ERROR (°C)
4
3
2
1
0
1
V
CC
= +5V
BYPASS CAP REMOVED
200mVp-p
5
-5
10
100
1k
10k
-50
-25
0
25
50
75
100
125
SUPPLY NOISE FREQUENCY (Hz)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Temperature Sensor and
System Monitor in a 10-Pin µMAX
Pin Description
PIN
1
2
3
4
5
6
NAME
1.8V
IN
2.5V
IN
5V
IN
N.C.
GND
ALERT
Analog Input. Monitors 1.8V nominal supply.
Analog Input. Monitors 2.5V nominal supply.
Analog Input. Monitors 5V nominal supply.
No Connect. Not internally connected. Connect to GND to improve thermal conductivity.
Ground
SMBus Alert (Interrupt) Output, Open Drain. Alerts the master that a temperature or voltage limit has been
violated.
SMBus/I
2
C-Compatible Address Select Input. ADD is sampled at the beginning of each SMBus/I
2
C
transaction, and the 2LSBs of the Slave Address register are detemined by ADD’s connection to GND, SDA,
SCL, or V
CC
.
SMBus/I
2
C-Compatible Serial Data Interface
SMBus/I
2
C-Compatible Clock Input
Supply Voltage Input, +2.7V to +5.5V. Also serves as a voltage monitor input. Bypass V
CC
to GND with a
0.1µF capacitor.
FUNCTION
MAX6683
7
8
9
10
ADD
SDA
SCL
V
CC
Detailed Description
The MAX6683 is a voltage and temperature monitor
designed to communicate through an SMBus/I
2
C inter-
face with an external microcontroller (µC). A µC with no
built-in I
2
C or SMBus capabilities can generate SMBus
serial commands by “bit-banging” general-purpose
input-output (GPIO) pins.
The MAX6683 can monitor external supply voltages of
typically 1.8V, 2.5V, 5V, as well as its own supply volt-
age and temperature. This makes it ideal for supervisor
and thermal management applications in telecommuni-
cations, desktop and notebook computers, worksta-
tions, and networking equipment. Voltage inputs are
converted to an 8-bit code and temperature is convert-
ed to an 11-bit code. The high-order 8 bits of the tem-
perature conversion can be read using a read byte
operation through the I
2
C interface. The full 11-bit tem-
perature conversion is read using a read word opera-
tion and disregarding the lower 5 bits of the low byte.
By setting bit 5 of the Configuration Register to 1, the
temperature conversion can be reduced to 9 bits with a
four-fold reduction in conversion time. In this case, the
lower 7 bits of the low byte should be disregarded; 8-
bit temperature data has a resolution of 1°C/LSB, while
11-bit temperature data has a resolution of 0.125°C/
LSB. Setting bit 5 of the Configuration Register to 1
reduces the monitoring cycle time by a factor of 4. In
this case, a read word operation for temperature data
yields a 9-bit code in which the lower 7 bits of the low
byte should be disregarded. The LSB of the 9-bit tem-
perature data has a value of 0.5°C.
Each input voltage is scaled down by an on-chip resis-
tive voltage-divider so that its output, at the nominal
input voltage, is 3/4 of the ADC’s full-scale range, or a
decimal count of 192 (Table 3). Input voltages other
than the nominal values may be used; ensure that they
fall within the usable ranges of pins to which they are
applied. Attenuate voltages greater than 6V with an
external resistive voltage-divider.
Writing a 1 to bit 0 of the Configuration Register starts
the monitoring function. The device performs a sequen-
tial sampling of all the inputs, starting with the internal
temperature sensor and continuing with 2.5V
IN
, 1.8V
IN
,
5V
IN
, and V
CC
. If the master terminates the conversion,
the sequential sampling does not stop until the sam-
pling cycle is completed and the results are stored.
When it starts again, it always starts with the tempera-
ture measurement.
An interrupt signal is generated when a temperature
measurement goes above the hot limit or when a volt-
age measurement is either above the high limit or
below the low limit. This causes the open-drain output
ALERT
to go to the active-low state and set each corre-
sponding interrupt status bit (bits 0 through 4) to 1
(Table 5). The interrupt is cleared by reading the
Interrupt Status Register except for temperature inter-
rupts generated in comparator mode. Reading the
Interrupt Status Register also clears the register itself,
except for temperature interrupt bits set in comparator
mode.
_______________________________________________________________________________________
5
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