19-3382; Rev 4; 10/10
IT
TION K
VALUA
E
BLE
AVAILA
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
General Description
The MAX7500–MAX7504 temperature sensors accu-
rately measure temperature and provide an overtem-
perature alarm/interrupt/shutdown output. These
devices convert the temperature measurements to digi-
tal form using a high-resolution, sigma-delta, analog-to-
digital converter (ADC). Communication is through an
I
2
C-compatible 2-wire serial interface. The MAX7500/
MAX7501/MAX7502 integrate a timeout feature that
offers protection against I
2
C bus lockups. The
MAX7503/MAX7504 do not include the timeout feature.
The 2-wire serial interface accepts standard write byte,
read byte, send byte, and receive byte commands to
read the temperature data and configure the behavior
of the open-drain overtemperature shutdown output.
The MAX7500 features three address select lines, while
the MAX7501–MAX7504 feature two address select
lines and a
RESET
input. The MAX7500/MAX7501/
MAX7502s’ 3.0V to 5.5V supply voltage range, low
250µA supply current, and a lockup-protected I
2
C-com-
patible interface make them ideal for a wide range of
applications, including personal computers (PCs), elec-
tronic test equipment, and office electronics.
The MAX7500–MAX7504 are available in 8-pin µMAX
®
and SO packages and operate over the -55°C to
+125°C temperature range.
Features
♦
Timeout Prevents Bus Lockup (MAX7500,
MAX7501, MAX7502)
♦
Hardware Reset for Added Protection
♦
I
2
C Bus Interface
♦
3.0V to 5.5V Supply Voltage Range
♦
250µA (typ) Operating Supply Current
♦
3µA (typ) Shutdown Supply Current
♦
±1.5°C (max) Temperature Accuracy (-25°C to
+100°C, 3-σ)
♦
µMAX,
SO Packages Save Space
♦
Separate Open-Drain OS Output Operates as
Interrupt or Comparator/Thermostat Input
♦
Register Readback Capability
♦
Improved LM75 Second Source
MAX7500–MAX7504
Ordering Information/
Selector Guide
PART
MAX7500MSA
TEMP PIN-
RESET
RANGE PACKAGE
-55°C to
8 SO
+125°C
X
TIMEOUT
X
Applications
PCs
Servers
Office Electronics
Electronic Test Equipment
Industrial Process Control
Ordering Information/Selector Guide continued at end of
data sheet.
Pin Configurations appear at end of data sheet.
Typical Application Circuits
+3.0V TO +5.5V
+3.0V TO +5.5V
4.7kΩ
+V
S
A0
A1
4.7kΩ
+V
S
A0
SDA
TO I
2
C MASTER
SCL
OS
GND
SDA
TO I
2
C MASTER
SCL
OS
MAX7500
A2
GND
MAX7501
MAX7502
MAX7503
MAX7504
A1
RESET
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
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.
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
MAX7500–MAX7504
ABSOLUTE MAXIMUM RATINGS
(Note 1)
+V
S
to GND ............................................................. -0.3V to +6V
OS, SDA, SCL to GND.......................................... -0.3V to +6.0V
All Other Pins to GND ................................ -0.3V to (+V
S
+ 0.3V)
Input Current at Any Pin (Note 2) ..................................... +5mA
Package Input Current (Note 2) ..................................... +20mA
ESD Protection (all pins, Human Body Model, Note 3)...
±2000V
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) ............ 362mW
8-Pin SO (derate 5.9mW/°C above +70°C)................. 471mW
Operating Temperature Range ....................... -55°C to +125°C
Junction Temperature .................................................... +150°C
Storage Temperature Range ........................... -65°C to +150°C
Lead Temperature (soldering, 10s) ............................... +300°C
Soldering Temperature (reflow)
Lead(Pb)-free.............................................................. +260°C
Containing lead(Pb) .................................................... +240°C
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifica-
tions do not apply when operating the device beyond its rated operating conditions.
Note 2:
When the input voltage (V
I
) at any pin exceeds the power supplies (V
I
< V
GND
or V
I
> + V
S
), the current at that pin should be
limited to 5mA. The 20mA maximum package input current rating limits the number of pins that can safely exceed the power
supplies with an input current of 5mA to 4.
Note 3:
Human Body Model, 100pF discharged through a 1.5kΩ resistor.
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
(+V
S
= +3.0V to +5.5V, T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at +V
S
= +3.3V, T
A
= +25°C.) (Notes 4, 5)
PARAMETER
Accuracy, 6-σ
Accuracy, 3-σ (Note 5)
Resolution
Conversion Time
Quiescent Supply Current
+V
S
Supply Voltage Range
OS Output Saturation Voltage
OS Delay
T
OS
Default Temperature
T
HYST
Default Temperature
LOGIC (SDA, SCL, A0, A1, A2)
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
Input Capacitance
Output High Current
Output Low Voltage
V
IH
V
IL
I
IH
I
IL
V
IN
= 5V
V
IN
= 0V
All digital inputs
V
IN
= 5V
I
OL
= 3mA
0.005
0.005
5
1
0.4
+V
S
x
0.7
+V
S
x
0.3
1.0
1.0
V
V
µA
µA
pF
µA
V
I
OUT
= 4.0mA (Note 7)
(Note 8)
(Note 9)
(Note 9)
1
80
75
(Note 6)
I
2
C inactive
Shutdown mode, +V
S
= 3V
Shutdown mode, +V
S
= 5V
3.0
SYMBOL
CONDITIONS
-25°C
≤
T
A
≤
+100°C
-55°C
≤
T
A
≤
+125°C
-25°C
≤
T
A
≤
+100°C
-55°C
≤
T
A
≤
+125°C
MIN
-2.0
-3.0
-1.5
-2.0
9
100
0.25
3
5
5.5
0.8
6
0.5
TYP
MAX
±2.0
±3.0
+1.5
+2.0
UNITS
°C
°C
bits
ms
mA
µA
V
V
Conver-
sions
°C
°C
2
_______________________________________________________________________________________
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
ELECTRICAL CHARACTERISTICS (continued)
(+V
S
= +3.0V to +5.5V, T
A
= -55°C to +125°C, unless otherwise noted. Typical values are at +V
S
= +5V, T
A
= +25°C.) (Notes 4, 5)
PARAMETER
SYMBOL
I
2
C-COMPATIBLE TIMING
(Note 10)
Serial Clock Frequency
Minimum
RESET
Pulse Width
Bus Free Time Between STOP
and START Conditions
START Condition Hold Time
STOP Condition Setup Time
Clock Low Period
Clock High Period
START Condition Setup Time
Data Setup Time
Data Hold Time
Maximum Receive SCL/SDA Rise
Time
Minimum Receive SCL/SDA Rise
Time
Maximum Receive SCL/SDA Fall
Time
Minimum Receive SCL/SDA Fall
Time
Transmit SDA Fall Time
Pulse Width of Suppressed Spike
SDA Time Low for Reset of Serial
Interface
f
SCL
CONDITIONS
Bus timeout inactive
MIN
DC
1
t
BUF
t
HD:STA
t
SU:STO
t
LOW
t
HIGH
t
SU:STA
t
SU:DAT
t
HD:DAT
t
R
90% of SCL to 90% of SDA
10% of SDA to 10% of SCL
10% of SCL to 10% of SDA (Note 11)
90% of SCL to 10% of SDA
1.3
0.6
100
1.3
0.6
100
100
0
300
20 +
0.1 x
C
B
300
20 +
0.1 x
C
B
20 +
0.1 x
C
B
0
150
250
50
300
0.9
TYP
MAX
400
UNITS
kHz
µs
µs
µs
ns
µs
µs
ns
ns
µs
ns
MAX7500–MAX7504
t
R
(Note 12)
ns
t
F
ns
t
F
(Note 12)
ns
t
F
t
SP
t
TIMEOUT
(Note 12)
(Note 13)
MAX7500/MAX7501/MAX7502 (Note 14)
ns
ns
ms
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Note 13:
Note 14:
All parameters are measured at +25°C. Values over the temperature range are guaranteed by design.
There are no industry-wide standards for temperature accuracy specifications. These values allow comparison to ven-
dors who use 3-σ limits.
This specification indicates how often temperature data is updated. The devices can be read at any time without regard
to conversion state, while yielding the last conversion result.
For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy due to internal heating.
OS delay is user programmable up to six “over-limit” conversions before OS is set to minimize false tripping in noisy
environments.
Default values set at power-up.
All timing specifications are guaranteed by design.
A master device must provide a hold time of at least 300ns for the SDA signal to bridge the undefined region of SCL’s
falling edge.
C
B
= total capacitance of one bus line in pF. Tested with C
B
= 400pF.
Input filters on SDA, SCL, and A_ suppress noise spikes less than 50ns.
Holding the SDA line low for a time greater than t
TIMEOUT
causes the devices to reset SDA to the IDLE state of the serial
bus communication (SDA set high).
_______________________________________________________________________________________
3
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
MAX7500–MAX7504
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
QUIESCENT SUPPLY CURRENT
vs. TEMPERATURE
MAX7500 toc01
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX7500 toc02
ACCURACY vs. TEMPERATURE
4 TYPICAL PARTS
1.5
1.0
ACCURACY (°C)
0.5
0
-0.5
-1.0
MAX7500 toc03
300
QUIESCENT SUPPLY CURRENT (μA)
290
280
270
260
+V
S
= +3V
250
240
230
-55
-25
5
35
65
95
+V
S
= +5V
6
SHUTDOWN SUPPLY CURRENT (μA)
5
4
3
+V
S
= +3V
2
1
0
+V
S
= +5V
2.0
-1.5
-2.0
-55
-25
5
35
65
95
125
-55
-25
5
35
65
95
125
TEMPERATURE (°C)
TEMPERATURE (°C)
125
TEMPERATURE (°C)
Pin Description
PIN
MAX7500
1
2
3
4
5
—
6
7
8
MAX7501–
MAX7504
1
2
3
4
—
5
6
7
8
NAME
SDA
SCL
OS
GND
A2
RESET
A1
A0
+V
S
FUNCTION
Serial Data Input/Output Line. Open drain. Connect SDA to a pullup resistor.
Serial Data Clock Input. Open drain. Connect SCL to a pullup resistor.
Overtemperature Shutdown Output. Open drain. Connect OS to a pullup resistor.
Ground
2-Wire Interface Address Input. Connect A2 to GND or +V
S
to set the desired I
2
C bus
address. Do not leave unconnected (see Table 1).
Active-Low Reset Input. Pull
RESET
low for longer than the minimum reset pulse width
to reset the I
2
C bus and all internal registers to their POR values.
2-Wire Interface Address Input. Connect A1 to GND or +V
S
to set the desired I
2
C bus
address. Do not leave unconnected (see Table 1).
2-Wire Interface Address Input. Connect A0 to GND or +V
S
to set the desired I
2
C bus
address. Do not leave unconnected (see Table 1).
Positive Supply Voltage Input. Bypass to GND with a 0.1µF bypass capacitor.
Detailed Description
The MAX7500–MAX7504 temperature sensors measure
temperature, convert the data into digital form using a
sigma-delta ADC, and communicate the conversion
results through an I
2
C-compatible 2-wire serial inter-
face. These devices accept standard I
2
C commands to
read the data, set the overtemperature alarm (OS) trip
thresholds, and configure other characteristics. The
MAX7500 features three address select lines (A0, A1,
A2) while the MAX7501–MAX7504 feature two address
select lines (A0, A1) and a
RESET
input. The
MAX7500–MAX7504 operate from +3.0V to +5.5V sup-
ply voltages and consume 250µA of supply current.
4
_______________________________________________________________________________________
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
MAX7500–MAX7504
Table 1. I
2
C Slave Addresses
DEVICE
MAX7500
MAX7501
MAX7502
MAX7503
MAX7504
BIT 7
1
1
1
1
1
BIT 6
0
0
0
0
0
BIT 5
0
0
0
0
0
BIT 4
1
1
1
1
1
BIT 3
A2
1
0
1
0
BIT 2
A1
A1
A1
A1
A1
BIT 1
A0
A0
A0
A0
A0
BIT 0
RD/W
RD/W
RD/W
RD/W
RD/W
SDA
t
SU:DAT
t
LOW
SCL
t
HD:DAT
t
BUF
t
SU:STA
t
HD:STA
t
SU:STO
t
HIGH
t
HD:STA
t
R
START
CONDITION
(S)
PARAMETERS ARE MEASURED FROM 10% TO 90%.
t
F
REPEATED START
CONDITION
(SR)
ACKNOWLEDGE
(A)
STOP
CONDITION
(P)
START
CONDITION
(S)
Figure 1. Serial Bus Timing
I
2
C-Compatible Bus Interface
From a software perspective, the MAX7500–MAX7504
appear as a set of byte-wide registers that contain tem-
perature data, alarm threshold values, and control bits.
A standard I
2
C-compatible 2-wire serial interface reads
temperature data and writes control bits and alarm
threshold data. Each device responds to its own I
2
C
slave address, which is selected using A0, A1, and A2.
See Table 1.
The MAX7500–MAX7504 employ four standard I
2
C
protocols: write byte, read byte, send byte, and receive
byte (Figures 1, 2, and 3). The shorter receive byte pro-
tocol allows quicker transfers, provided that the correct
data register was previously selected by a read-byte
instruction. Use caution when using the shorter proto-
cols in multimaster systems, as a second master could
overwrite the command byte without informing the first
master. The MAX7500 has eight different slave
addresses available; therefore, a maximum of eight
MAX7500 devices can share the same bus. The
MAX7501–MAX7504 each have four different slave
addresses available.
_______________________________________________________________________________________
5
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