19-1959; Rev 1; 8/01
Temperature Sensor and System Monitor
in a 10-Pin µMAX
General Description
The MAX6652 system supervisor monitors multiple
power-supply voltages, including its own, and also fea-
tures an on-board temperature sensor. Voltages and
temperature are converted to an 8-bit code using an
analog-to-digital converter (ADC). A multiplexer automat-
ically sequences through the voltage and temperature
measurements. The digitized signals are then stored in
registers and compared to the over/under threshold lim-
its programmed over the 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 MAX6652
generates a latched interrupt output
ALERT.
Three inter-
rupt modes are available for temperature excursions:
default mode, one-time interrupt mode, and comparator
mode. The
ALERT
output is cleared, except for tempera-
ture interrupts generated in comparator mode, by read-
ing the interrupt status register (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 0. The
MAX6652 I
2
C
™
-compatible/SMBus interface also
responds to the SMB alert response address.
The 2-wire serial interface accepts both I
2
C and standard
system management bus (SMBus) write byte, read byte,
send byte, and receive byte commands to program the
alarm thresholds and to read voltage and temperature
data. Voltage data is scaled so that when the nominal
voltage is present at a pin (e.g., 3.3V for the 3.3V
IN
pin),
the conversion result is equal to 3/4 of the ADC full-scale
range or a decimal count of 192 (Table 3). The tempera-
ture data format is 7 bits plus sign, with each data bit
representing 1°C, in two's complement format (Table 2).
The MAX6652 has only one address pin, ADD. One of
four different address codes can be selected by con-
necting the ADD pin to GND, V
CC
, SDA, or SCL.
2
Whenever an I C-compatible/SMBus transaction is initiat-
ed, the two LSBs of the slave address register are deter-
mined by connection, setting the chip address to one of
four possible values. In addition, an address code can
also be directly written to the serial address register. This
code will overwrite the code set by connection of the
ADD pin, until the MAX6652 is taken through a power-on
reset cycle.
The MAX6652 features 60Hz or 50Hz line-frequency
rejection for optimal performance. The device operates
from +2.7V to +5.5V and is specified for operation from
-40°C to +125°C. It is available in a tiny 10-pin µMAX
package.
I
2
C is a trademark of Philips Corp.
Features
o
Monitors Four Voltages (2.5V, 3.3V, 12V, V
CC
)
o
Monitors Local Temperature
o
Temperature Measurement Accuracy,
±2°C (T
A
= +25°C)
o
User-Programmable Voltage and Temperature
Thresholds
o
Alert Function with Ability to Respond to SMB
Alert Response Address
o
+2.7V to +5.5V Supply Range
o
-40°C to +125°C Temperature Range
o
60Hz or 50Hz Line-Frequency Rejection
o
Tiny 10-Pin µMAX Package
MAX6652
Applications
Workstations
Servers
Networking
Telecommunications
Ordering Information
PART
MAX6652AUB
TEMP. RANGE
-40°C to +125°C
PIN-PACKAGE
10 µMAX
Pin Configuration
TOP VIEW
12V
IN
1
2.5V
IN
3.3V
IN
N.C.
GND
2
3
4
5
10
V
CC
9
SCL
SDA
ADD
ALERT
MAX6652
8
7
6
µMAX
Typical Application Circuit and Functional Diagram appear
at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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
MAX6652
ABSOLUTE MAXIMUM RATINGS
All Voltages Are Referenced to GND
V
CC
........................................................................-0.3V to +6.0V
Voltage on 12V
IN
...................................................-0.3V to +16V
All Other Pins ........................................................-0.3V to +6.0V
Output Current (SDA,
ALERT)
............................-1mA to +50mA
Junction Temperature .....................................................+150°C
Operating Temperature Range ........................-40°C to +125°C
Storage Temperature Range ............................-65°C to +150°C
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ..........444mW
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
= +5V, T
A
= +25°C.)
PARAMETER
POWER SUPPLY
Supply Voltage
Supply Current
Power-On Reset Voltage
TEMPERATURE
T
A
= +25°C
Accuracy (Note 5)
PSRR
Resolution
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
SDA Output Low Voltage
Input Leakage Current
ALERT
Output Low Voltage
TIMING
Serial Clock Frequency
Bus Free Time Between STOP and
START
f
SCL
t
BUF
0
1.3
400
kHz
µs
V
OLA
I
SINK
= 1.2mA, V
CC
> 2.7V
I
SINK
= 3.2mA, V
CC
> 4.5V
0.3
0.4
V
V
V
IL
V
IH
V
OL
I
LEAK
V
CC
≤
3.6V
V
CC
> 3.6V
I
SINK
= 3mA
V
IN
= 0 or 5V
2.0
2.6
400
±1
0.8
V
V
V
mV
µA
TUE
DNL
PSS
R
IN
tc
V
IN
> 10LSB
V
IN
> 10LSB
V
CC
= +2.7V to +5.5V
12V
IN
, 2.5V
IN
, 3.3V
IN
(Note 1)
100
±1
150
200
200
300
±1
±1.5
±1
%
LSB
V
kΩ
ms
V
CC
= +5V
V
CC
= +2.7V to +5.5V
-20°C
≤
T
A
≤
+80°C
-40°C
≤
T
A
≤
+125°C
0.7
±1
±2
±3
±5
1.3
°C/V
°C
°C
V
CC
I
CC
I
SD
Active
Shutdown mode, all digital inputs are
grounded
V
CC
_ rising or falling edge
2.7
200
<1
2
5.5
500
10
V
µA
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
= +5V, T
A
= +25°C.)
PARAMETER
START Condition Hold Time
STOP Condition Hold Time
Clock Low Period
Clock High Period
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
SYMBOL
t
HD:STA
t
SU:STO
t
LOW
t
HIGH
t
SP: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)
400pF, I
SINK
= 3mA
(Note 4)
20 +
0.1C
B
50
CONDITIONS
MIN
0.6
0.6
1.3
0.6
100
0
20 +
0.1C
B
300
20 +
0.1C
B
300
300
0.9
TYP
MAX
UNITS
µs
µs
µs
µs
ns
µs
ns
ns
ns
ns
ns
ns
MAX6652
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 x V
CC
to 0.7 x V
CC
.
Note 4:
Input filters on SDA, SCL, and ADD suppress noise spikes <50ns.
Note 5:
Guaranteed but not tested over the entire temperature range.
Typical Operating Characteristics
(V
CC
= +5V, ADD = GND,
ALERT
= 10kΩ to V
CC
, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6652 toc01
SUPPLY CURRENT
vs. SCL CLOCK FREQUENCY
MAX6652 toc02
TEMPERATURE ERROR
vs. SUPPLY VOLTAGE
4
TEMPERATURE ERROR (°C)
3
2
1
0
-1
-2
-3
-4
T
A
= -40°C
T
A
= 0°C
T
A
= +85°C
MAX6652 toc03
300
A
250
SUPPLY CURRENT (µA)
200
150
100
50
0
2.5
3.0
3.5
4.0
4.5
5.0
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
250
V
CC
= +5V
SCL = 0 to +5V
SUPPLY CURRENT (µA)
225
5
200
175
150
5.5
1
1000
CLOCK FREQUENCY (kHz)
SUPPLY VOLTAGE (V)
-5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
Temperature Sensor and System Monitor
in a 10-Pin µMAX
MAX6652
Typical Operating Characteristics (continued)
(V
CC
= +5V, ADD = GND,
ALERT
= 10kΩ to V
CC
, T
A
= +25°C, unless otherwise noted.)
TEMPERATURE ERROR
vs. SUPPLY NOISE FREQUENCY
1
0
TEMPERATURE ERROR (°C)
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
1
1k
SUPPLY NOISE FREQUENCY (kHz)
10
100
10k
V
CC
= +5V
BYPASS CAP REMOVED
200mVp-p
MAX6652 toc04
TEMPERATURE ERROR
vs. TEMPERATURE
0.75
TEMPERATURE ERROR (°C)
0.50
0.25
0
-0.25
-0.50
-0.75
-1.00
-50
-25
0
25
75
50
TEMPERATURE (°C)
100
125
MAX6652 toc05
2
1.00
Pin Description
PIN
1
2
3
4
5
6
NAME
12V
IN
2.5V
IN
3.3V
IN
N.C.
GND
ALERT
Analog Input. Monitors 12V supply.
Analog Input. Monitors 2.5V supply.
Analog Input. Monitors 3.3V supply.
No Connection. Can be connected 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 Address Select Input. ADD is sampled at the beginning of each I C-compatible/SMBus
transaction, and the 2 LSBs of the slave address register are detemined by ADD's connection to
GND, SDA, SCL, or V
CC
.
I C-Compatible/SMBus Serial Data Interface
I C-Compatible/SMBus Serial 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.
2
2
2
FUNCTION
7
8
9
10
ADD
SDA
SCL
V
CC
4
_______________________________________________________________________________________
Temperature Sensor and System Monitor
in a 10-Pin µMAX
Detailed Description
The MAX6652 is a voltage and temperature monitor
designed to communicate through an I
2
C-compatible/
SMBus interface with an external microcontroller (µC).
A µC with no built-in I
2
C-compatible or SMBus capabili-
ties can generate SMBus serial commands by “bit-
banging” general-purpose input-output (GPIO) pins.
The MAX6652 can monitor external supply voltages of typi-
cally 2.5V, 3.3V, and 12V, as well as its own supply voltage
and temperature. This makes it ideal for supervisor and
thermal management applications in telecommunications,
desktop and notebook computers, workstations, and net-
working equipment. All inputs are converted to an 8-bit
code using an ADC with an oversampling ratio of 8 to
improve noise rejection. The oversampling ratio can be
reduced by a factor of 4, with a corresponding reduc-
tion in the monitoring cycle time, by setting bit 5 of the
configuration register to 1. Each input voltage is scaled
down by an on-chip resistive 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). Table
1 is the register map and Table 2 is the temperature
data format.
MAX6652
Table 1. Register Map
ADDRESS
READ/WRITE
POWER-ON DEFAULT
DESCRIPTION
20h
21h
22h
23h
27h
2Bh
2Ch
2Dh
2Eh
2Fh
30h
31h
32h
39h
3Ah
40h
41h
43h
R
R
R
R
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R/W
—
—
—
—
—
1101 0011 (1.1
✕
2.5V)
1010 1101 (0.9
✕
2.5V)
1101 0011 (1.1
✕
12V)
1010 1101 (0.9
✕
12V)
1101 0011 (1.1
✕
3.3V)
1010 1101 (0.9
✕
3.3V)
1101 0011 (1.1
✕
5V)
1010 1101
✕
(0.9
✕
5V)
0101 0000
✕
(+80°C)
0100 0001
✕
(+65°C)
0000 1000
0000 0000
0000 0000
Data register for 2.5 V
IN
measurement
Data register for 12V
IN
measurement
Data register for 3.3V
IN
measurement
Data register for V
CC
measurement
Data register for temperature measurement
High limit for 2.5V
IN
Low limit for 2.5V
IN
High limit for 12V
IN
Low limit for 12V
IN
High limit for 3.3V
IN
Low limit for 3.3V
IN
High limit for V
CC
Low limit for V
CC
Hot temperature limit
Hot temperature hysteresis
Configuration register
Interrupt status register
Interrupt mask register
Device address register. The values of XX are
dependent on the status of the ADD pin.
Power-On Default ADD Connection
0010 100Y
To GND
0010 101Y
To V
CC
0010 110Y
To SDA
0010 111Y
To SCL
Y (bit 0) is the SMBus read/write bit. When the 7-
bit chip address is read back from the serial
address register, an 8-bit word will be presented
with a 0 in bit 0 (Y).
Temperature configuration register
48h
R/W
0010 1XXY
4Bh
R/W
0000 0000
_______________________________________________________________________________________
5
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