MAX6672_V01 [MAXIM]
PWM Output Temperature Sensors in SC70 Packages;
| 型号： | MAX6672_V01 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | PWM Output Temperature Sensors in SC70 Packages |
| 文件： | 总7页 (文件大小：1120K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
General Description
Features
● Simple Single-Wire PWM Output
The MAX6672/MAX6673 are low-current temperature
sensors with a single-wire output. These temperature
sensors convert the ambient temperature into a 1.4kHz
PWM output, which contains the temperature information
in its duty cycle. The MAX6672 has an open-drain output
and the MAX6673 has a push-pull output.
● Tiny SC70 Package
● Low 60µA (typ) Supply Current Consumption
● 1.4kHz Nominal Frequency
● Choice of Outputs
Open Drain (MAX6672)
Push-Pull (MAX6673)
The MAX6672/MAX6673 operate from 2.4V to 5.5V with a
maximum supply current of 150µA. Both devices feature
a single-wire output that minimizes the number of pins
necessary to interface with a microprocessor.
● 2.4V to 5.5V Supply Range
The MAX6672/MAX6673 are available in 5-pin SC70
packages.
Ordering Information
Applications
● Industrial and Process Control
● HVAC
PIN-
TOP
PART
TEMP RANGE
PACKAGE
MARK
● Environmental Control
● Isolated Temperature Sensing
MAX6672AXK-T
MAX6673AXK-T
-40°C to +125°C 5 SC70
-40°C to +125°C 5 SC70
ACQ
ACR
Typical Application Circuit
Pin Configuration
TOP VIEW
µC
V
GPIO TO CONTROL
SHUTDOWN
CC
DOUT
1
2
3
5
4
V
CC
*
MAX6672
MAX6673
0.1µF
MAX6672
MAX6673
INPUT TO TIMER/
COUNTER
N.C.
GND
GND
GND
SC70
* PULLUP RESISTOR REQUIRED ONLY FOR THE MAX6672.
19-2458; Rev 1; 4/14
MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Absolute Maximum Ratings
Supply Voltage (V
to GND)................................ -0.3V to +6V
Operating Temperature Range......................... -40°C to +125°C
Storage Temperature Range............................ -65°C to +150°C
Junction Temperature......................................................+150°C
SC70 Package
Vapor Phase (60s)...................................................... +215°C
Infrared (15s).............................................................. +220°C
Lead Temperature (soldering, 10s) ................................ +300°C
CC
DOUT to GND (MAX6672)......................................-0.3V to +6V
DOUT to GND (MAX6673)....................... -0.3V to (V + 0.3V)
DOUT Short to GND..................................................Continuous
ESD Protection (Human Body Model)............................ ±2000V
CC
Continuous Power Dissipation (T = +70°C)
A
5-Pin SC70 (derate 2.5mW/°C above +70°C).............200mW
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
= 2.4V to 5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values specified at +25°C and V of 3.3V.) (Note 1)
CC
A
CC
PARAMETER
SYMBOL
CONDITIONS
MIN
-3
TYP
MAX UNITS
T
T
T
T
= +25°C to +100°C
= 0°C to +125°C
= -20°C to +125°C
= -40°C to -20°C
+3
A
A
A
A
-4
+4
°C
+5
Temperature Error
(Note 2)
V
= 3.3V
CC
-5
±3
Nominal t Pulse Width
1
280
µs
Output Low Voltage
Output High Voltage
Fall Time
V
I
I
= 3mA
0.4
V
V
OL
SINK
V
= 800µA (MAX6673)
V
- 0.5
OH
SOURCE
CC
t
C
C
= 100pF
14
96
ns
ns
FALL
LOAD
LOAD
Rise Time
t
= 100pF (MAX6673)
RISE
DOUT Open-Drain Leakage
Current
V
= 6V (MAX6672)
0.1
µA
DOUT
Output Capacitance
2.5
0.3
60
pF
Power-Supply Rejection Ratio
PSRR
2.4V to 5.5V, T = -25°C to +125°C
A
0.8
100
150
°C/V
2.4V to 3.6V
3.6V to 5.5V
Supply Current
I
µA
CC
70
Note 1: All specifications are 100% tested at T = +25°C. Specification limits over temperature (T = -40°C to +125°C) are guaranteed
A
A
by design, not production tested.
3
Note 2: Temperature = -200 × (0.85 - T /T ) + (425 5 T /T ) - 273. T is the low time period. T is the high time period (Figure 1).
1
2
1
2
1
2
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MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Typical Operating Characteristics
(V
= 3.3V, T = +25°C, unless otherwise noted.)
A
CC
OUTPUT FREQUENCY
vs. TEMPERATURE
NORMALIZED OUTPUT FREQUENCY
vs. SUPPLY VOLTAGE
t AND t TIMES
1 2
vs. TEMPERATURE
2.00
600
500
400
300
200
1.010
1.005
1.000
0.995
0.990
1.75
1.50
1.25
1.00
T
= +125°C
= +25°C
A
t
t
2
T
A
T
= -40°C
A
1
-50 -25
0
25
50
75 100 125
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-50 -25
0
25
50
75 100 125
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
OUTPUT ACCURACY
vs. TEMPERATURE
SUPPLY CURRENT
vs. TEMPERATURE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
150
120
90
60
30
0
4
2
100
90
80
70
60
50
V
= 3.3V
CC
V
= 5V
CC
0
V
= 3.3V
CC
-2
-4
2.0
2.5
3.0
3.5
4.0
4.5
5.0
-50 -25
0
25
50
75 100 125
-50 -25
0
25
50
75 100 125
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
POWER-SUPPLY REJECTION
vs. TEMPERATURE
POWER-SUPPLY REJECTION
vs. FREQUENCY
OUTPUT RISE AND FALL TIMES
vs. CAPACITIVE LOAD
1.0
0.5
0
1.0
0.5
0
150
120
90
60
30
0
MAX6673 RISE TIME
-0.5
-1.0
-0.5
-1.0
FALL TIME
V
= 100mV
P-P
AC
0.01
0.10
1
10
-50 -25
0
25
50
75 100 125
0.01 0.10
1
10
100
1k
10k
TEMPERATURE (°C)
FREQUENCY (Hz)
CAPACITIVE LOAD (nF)
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MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Typical Operating Characteristics (continued)
(V
= 3.3V, T = +25°C, unless otherwise noted.)
A
CC
THERMAL RESPONSE
IN STIRRED OIL BATH
OUTPUT SINK CURRENT
vs. TEMPERATURE
MAX6673 OUTPUT SOURCE CURRENT
vs. TEMPERATURE
100
30
3.0
2.5
2.0
1.5
1.0
0.5
V
OL
= 0.4V
V
= V - 0.5V
OH CC
25
20
15
10
5
75
50
25
V
V
= 5V
CC
V
V
= 5V
CC
= 3.3V
CC
= 3.3V
CC
TRANSITION FROM +25°C AIR
TO +100°C STIRRED OIL BATH
0
0
0
4
8
12
TIME (s)
16
20
-50 -25
0
25
50
75 100 125
-50 -25
0
25
50
75 100 125
TEMPERATURE (°C)
TEMPERATURE (°C)
Pin Description
PIN
NAME
DOUT
N.C.
FUNCTION
1
Digital Output Pin. PWM output, open-drain output (MAX6672), or push-pull output (MAX6673).
No Connection. Not internally connected.
2
3, 4
5
GND
Pin 3 and Pin 4 must be tied together and connected to ground.
Positive Supply. Bypass with a 0.1µF capacitor to GND.
V
CC
The MAX6673 has a push-pull output. The rise and fall
times of the MAX6673 output are negligible with
respect to the period; therefore, errors caused by
capacitive loading are minimized.
Detailed Description
The MAX6672/MAX6673 are low-current (60µA, typ),
local temperature sensors ideal for interfacing with µCs
or µPs. The MAX6672/MAX6673 convert their own
temperature into a ratiometric PWM output. The square-
wave output waveform time ratio contains the
temperature information. The output is a square wave
with a nominal frequency of 1.4kHz at +25°C. The tem-
perature is obtained with the following formula:
The output load capacitance should be minimized in
MAX6672 applications because the sourcing current is
set by the pullup resistor. If the output capacitance
becomes too large, unequal rise and fall times distort
the pulse width, thus delivering inaccurate readings.
3
Temperature (°C) = -200 x (0.85 - t / t )
1
2
Applications Information
Pulse-Width Modulation
Interfacing with a µC
+ (425 x t / t ) - 273
1
2
Where t is a fixed value and t is modulated with the
temperature. Table 1 lists time ratio vs. temperature.
1
2
For temperatures greater than +50°C, the temperature
error is primarily first order and the following equation
can be used:
The Typical Application Circuit shows the MAX6672/
MAX6673 interfaced with a µC. In this example, the
MAX6672/MAX6673 convert the ambient temperature
to a PWM waveform. The µC reads the temperature by
Temperature (°C) = (425 x t / t ) - 273
1
2
measuring the t and t periods in software and hard-
1
2
ware. The only timing requirements are that the clock
frequency used for timing measurements is stable and
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MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Table 1. Time Ratio vs. Temperature
t
2
t
1
TIME RATIO
TEMPERATURE
(t /t )
(°C)
1 2
0.936
0.878
0.807
0.714
0.646
0.602
0.560
125
100
70
Figure 1. PWM Waveform Timing
30
0
Block Diagram
-25
-40
5
V
CC
high enough to provide the required measurement res-
olution. The interface for the MAX6672 requires a pullup
resistor.
1
DOUT
PWM
MODULATOR
TEMPERATURE
SENSOR
t
1
t
2
Thermal Response Time
The time periods t (low) and t (high) are values that
1
2
GND
are easily read by the µP timer/counter. The temperature
reading is then calculated using software. Since both
periods are obtained consecutively, using the same clock,
performing the division indicated in the above formulae
results in a ratiometric value that is independent of the
exact frequency.
3, 4
The thermal path between the plastic package and the
die is not as good as the path through the leads, so
the MAX6672/MAX6673, like all temperature sensors in
plastic packages, are less sensitive to the temperature
of the surrounding air than they are to the temperature
of their leads. They can be successfully used to sense
ambient temperature if the circuit board is designed to
track the ambient temperature.
Sensing Circuit Board and Ambient
Temperatures
Temperature sensor ICs such as the MAX6672/
MAX6673 that sense their own die temperatures must
be mounted on or close to the object whose tempera-
ture they are intended to measure. Because there is a
good thermal path between the SC70 package's metal
leads and the IC die, the MAX6672/MAX6673 can
accurately measure the temperature of the circuit
board to which they are soldered. If the sensor is
intended to measure the temperature of a heat-generat-
ing component on the circuit board, it should be mount-
ed as close as possible to that component and should
share supply and ground traces (if they are not noisy)
with that component where possible. This maximizes
the heat transfer from the component to the sensor.
As with any IC, the wiring and circuits must be kept
insulated and dry to avoid leakage and corrosion,
especially if the part is operated at cold temperatures
where condensation can occur.
The error caused by power dissipation in the MAX6672/
MAX6673 is negligible.
Chip Information
PROCESS: BiCMOS
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MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
21-0076
LAND PATTERN NO.
90-0188
5 SC70
X5-1
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MAX6672/MAX6673
PWM Output Temperature Sensors
in SC70 Packages
Revision History
REVISION REVISION
PAGES
DESCRIPTION
NUMBER
DATE
10/02
4/14
CHANGED
0
1
Initial release
Removed automotive reference from Applications
—
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2014 Maxim Integrated Products, Inc.
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