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 Delay
T
OS
Default Temperature
T
HYST
Default Temperature
Input High Voltage
Input Low Voltage
Input High Current
Input Low Current
Input Capacitance
Output High Current
Output Low Voltage
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
(Note 6)
I
2
C inactive
Shutdown mode, +V
S
= 3V
Shutdown mode, +V
S
= 5V
I
OUT
= 4.0mA (Note 7)
(Note 8)
(Note 9)
(Note 9)
V
IH
V
IL
I
IH
I
IL
V
IN
= 5V
V
IN
= 0V
V
IN
= 5V
All digital inputs
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
1
80
75
3.0
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
OS Output Saturation Voltage
LOGIC (SDA, SCL, A0, A1, A2)
V
V
µA
µA
pF
µA
V
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Maxim Integrated
│
2
MAX7500–MAX7504
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
= +3.3V, T
A
= +25°C.) (Notes 4, 5)
PARAMETER
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
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Note 13:
Note 14:
SYMBOL
f
SCL
t
BUF
t
SU:STO
t
HIGH
t
LOW
t
HD:STA
90% of SCL to 10% of SDA
CONDITIONS
Bus timeout inactive
MIN
DC
1
1.3
0.6
100
1.3
0.6
90% of SCL to 90% of SDA
10% of SDA to 10% of SCL
10% of SCL to 10% of SDA (Note 11)
100
100
0
300
(Note 12)
20 +
0.1 x
C
B
300
(Note 12)
(Note 12)
(Note 13)
MAX7500/MAX7501/MAX7502 (Note 14)
20 + 0.1
x C
B
0
150
20 +
0.1 x
C
B
250
50
300
0.9
TYP
MAX
400
UNITS
kHz
µs
µs
µs
ns
µs
µs
ns
ns
µs
ns
ns
ns
ns
ns
ns
ms
I
2
C-COMPATIBLE TIMING
(Note 10)
t
HD:DAT
t
R
t
R
t
F
t
F
t
F
t
SP
t
TIMEOUT
t
SU:DAT
t
SU:STA
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 vendors
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 fall-
ing 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).
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Maxim Integrated
│
3
MAX7500–MAX7504
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
MAX7500 toc01
MAX7500 toc02
SHUTDOWN SUPPLY CURRENT (µA)
QUIESCENT SUPPLY CURRENT (µA)
290
280
270
260
250
240
230
-55
-25
5
35
65
95
+V
S
= +3V
+V
S
= +5V
5
4
3
+V
S
= +3V
2
1
0
+V
S
= +5V
1.5
1.0
ACCURACY (°C)
0.5
0
-0.5
-1.0
-1.5
4 TYPICAL PARTS
125
-55
-25
5
35
65
95
125
-2.0
-55
-25
5
35
65
95
125
TEMPERATURE (°C)
TEMPERATURE (°C)
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 interface.
These devices accept standard I
2
C commands to read
the data, set the overtemperature alarm (OS) trip thresh-
olds, 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 supply voltages and con-
sume 250μA of supply current.
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Maxim Integrated
│
4
MAX7500 toc03
300
QUIESCENT SUPPLY CURRENT
vs. TEMPERATURE
6
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
2.0
ACCURACY vs. TEMPERATURE
MAX7500–MAX7504
Digital Temperature Sensors and Thermal
Watchdog with Bus Lockup Protection
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
BUF
t
SU:DAT
t
LOW
SCL
t
HD:DAT
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 tem-
perature 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 pro-
tocols: write byte, read byte, send byte, and receive byte
(Figures 1, 2, and 3). The shorter receive byte protocol
allows quicker transfers, provided that the correct data
register was previously selected by a read-byte instruc-
tion. Use caution when using the shorter protocols 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;
单片机
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