MAX6677AUT3-T [MAXIM]
Low-Voltage, 1.8kHz PWM Output Temperature Sensors; 低电压， 1.8kHz PWM输出的温度传感器
| 型号： | MAX6677AUT3-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Low-Voltage, 1.8kHz PWM Output Temperature Sensors |
| 文件： | 总7页 (文件大小：163K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2660; Rev 1; 1/03
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
General Description
Features
The MAX6676/MAX6677 are high-accuracy, low-power
temperature sensors with a single-wire output. The
MAX6676/MAX6677 convert the ambient temperature
into a ratiometric PWM output with temperature informa-
tion contained in the duty cycle of the output square
wave. The MAX6676 has an open-drain output and the
MAX6677 has a push-pull output.
ꢀ Simple Single-Wire, 1.8kHz PWM Output
ꢀ Operates Down to 1.8V
ꢀ High Accuracy
±1.ꢀ5° at ꢁ = +2ꢀ5°
A
±±.ꢂ5° at ꢁ = ꢂ5° to +8ꢀ5°
A
ꢀ Operates from -4ꢂ5° to +12ꢀ5°
ꢀ Low 8ꢂµA ꢁypical °urrent °onsumption
ꢀ Small 6-Pin SOꢁ2± Package
The MAX6676/MAX6677 are specified for operation with
power-supply voltages from 1.8V to 3.6V, or from 3.6V to
5.5V (MAX6676 only). The typical unloaded supply cur-
rent is 80µA. All devices feature a single-wire output that
minimizes the number of pins necessary to interface
with a microprocessor (µP). The output is a square wave
with a nominal frequency of 1.8kHz (±±0ꢀ) at ꢁ±5ꢂ°.
The output format is decoded as follows:
Ordering Information
TEMP
RANGE
PIN-
PACKAGE
PART
✕
Temperature (ꢂ°) = 398.15 (t1 / t±) - ±73.15
MAX6676AUT3-T
MAX6676AUT5-T
MAX6677AUT3-T
-40ꢂC to +125ꢂC
-40ꢂC to +125ꢂC
-40ꢂC to +125ꢂC
6 SOT23-6
6 SOT23-6
6 SOT23-6
Where t is fixed with a typical value of 0.±4ms and t is
1
±
modulated by the temperature. The MAX6676/
MAX6677 operate from -40ꢂ° to ꢁ1±5ꢂ° and are avail-
able in space-saving 6-pin SOT±3 packages.
Applications
Selector Guide
Process °ontrol
SUPPLY
OUTPUT
TYPE
TOP
VOLTAGE
MARK
PART
Industrial
RANGE (V)
HVA° and Environmental °ontrol
Automotive
MAX6676AUT3
MAX6676AUT5
MAX6677AUT3
Open drain
Open drain
Push-pull
1.8 to 3.6
3.6 to 5.5
1.8 to 3.6
ABBF
ABBG
ABBH
Portable Devices
µP and µ° Temperature Monitoring
Isolated Temperature Sensing
Typical Operating Circuit
Pin Configuration
V
CC
TOP VIEW
5.1kΩ*
V
CC
DOUT
1
2
3
6
5
4
GND
GND
GND
INPUT TO
DOUT
TIMER/COUNTER
MAX6676
MAX6677
t
GND
0.1µF
2
MAX6676
µC
t
1
V
CC
GND
SOT23
*REQUIRED ONLY FOR MAX6676.
________________________________________________________________ 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.
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
ABSOLUTE MAXIMUM RATINGS
(Voltages Referenced to GND)
Continuous Power Dissipation (T = +70ꢂC)
A
V
........................................................................-0.3V to +6.0V
6-Pin SOT23 (derate 8.7mW/ꢂC above +70ꢂC).........695.7mW
Operating Temperature Range .........................-40ꢂC to +125ꢂC
Storage Temperature Range.............................-65ꢂC to +150ꢂC
Junction Temperature......................................................+150ꢂC
Lead Temperature (soldering, 10s) .................................+300ꢂC
CC
DOUT (MAX6676)..................................................-0.3V to +6.0V
DOUT (MAX6677).......................................-0.3V to (V + 0.3V)
DOUT Current .....................................................-1mA to +50mA
CC
ESD Protection (DOUT, Human Body Model) ................. 2000V
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
CC
(V
= 1.8V to 3.6V (MAX6676AUT3/MAX6677AUT3), V
= 3.6V to 5.5V (MAX6676AUT5), T = -40ꢂC to +125ꢂC, unless otherwise
CC A
noted. Typical values are at V = 3.0V (MAX6676AUT3/MAX6677AUT3), V = 5.0V (MAX6676AUT5), T = +25ꢂC.)
CC
CC
A
PARAMETER
Supply Voltage Range
Supply Current
SYMBOL
CONDITIONS
MAX6676AUT3/MAX6677AUT3
MAX6676AUT5
MIN
1.8
TYP
MAX
3.6
UNITS
V
V
CC
CC
3.6
5.5
I
R = ∞
L
80
200
µA
T
= +25ꢂC
-1.5
-3.0
-4.2
-5.5
+1.5
+3.0
+4.2
+5.5
A
T = 0ꢂC to +85ꢂC
A
Temperature Error
ꢂC
T = -20ꢂC to +100ꢂC
A
T
= -40ꢂC to +125ꢂC
A
Nominal t Pulse Width
1
240
0.1
µs
V
V
0.3
-
CC
Output High Voltage
V
I
= 800µA, MAX6677
OH
OH
Output Leakage Current
Output Low Voltage
Fall Time
V
= V
µA
V
OUT
CC
V
I
= 3mA
OL
0.3
OL
t
C = 100pF, R = 10kΩ
20
300
30
ns
F
L
L
MAX6676, C = 15pF, R = 10kΩ
L
L
Rise Time
t
ns
R
MAX6677, C = 100pF, R = 10kΩ
L
L
Digital Output Capacitance
C
15
pF
OUT
Power-Supply Rejection Ratio
PSRR
V
= 1.8V - 3.6V
-1.2
+0.4
+1.2
ꢂC/V
CC
Note 1: Parts are tested at +25ꢂC. Specifications are guaranteed by design over temperature.
2
_______________________________________________________________________________________
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
Typical Operating Characteristics
(V
= 3.0V, T = +25ꢂC, unless otherwise noted.)
CC
A
t AND t TIMES
vs. TEMPERATURE
1
2
OUTPUT FREQUENCY
vs. TEMPERATURE
2.50
MAX6676AUT3 OUTPUT FREQUENCY
vs. SUPPLY VOLTAGE
450
400
350
300
250
200
3.0
t
2
2.25
2.00
1.75
1.50
2.5
2.0
1.5
1.0
TEMP = +125°C
TEMP = +25°C
TEMP = -40°C
t
1
-40 -15
10
35
60
85
110
-40 -15
10
35
60
85 110
1.8
2.1
2.4
2.7
3.0
3.3
3.6
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
OUTPUT ACCURACY
vs. TEMPERATURE
MAX6676AUT3 SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX6676AUT3 SUPPLY CURRENT
vs. TEMPERATURE
5
450
400
350
300
250
200
150
100
50
600
500
400
300
200
100
0
3
1
V
= 3.6V
CC
5.1kΩ PULLUP
V
= 3.0V
= 1.8V
CC
-1
V
CC
-3
-5
NO PULLUP
5.1kΩ PULLUP RESISTOR
0
110
-40 -15
10
35
60
85
1.8
2.1
2.4
2.7
3.0
3.3
3.6
-40 -15
10
35
60
85
110
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. TEMPERATURE
OUTPUT FALL TIME
(C = 100pF, R = 100kΩ)
L
L
2
1
1.0
0.5
0
-1
-2
-3
-4
-5
-6
0
1V/div
0V
-0.5
V
= 100mV
10
AC
P-P
-1.0
1k
1
100
FREQUENCY (Hz)
10k
-50 -25
0
25
50
75 100 125
10ns/div
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
Typical Operating Characteristics (continued)
(V
= 3.0V, T = +25ꢂC, unless otherwise noted.)
CC
A
MAX6677 OUTPUT RISE AND FALL TIMES
vs. CAPACITIVE LOAD
MAX6677 OUTPUT RISE TIME
MAX6676 toc10
200
160
120
80
C
L
= 100pF
LOAD
R = 100kΩ
1V/div
RISE
FALL
0
40
0
100
300
(pF)
500
0
200
400
600
40ns/div
C
LOAD
MAX6677 OUTPUT HIGH VOLTAGE
vs. TEMPERATURE
MAX6677 OUTPUT LOW VOLTAGE
vs. TEMPERATURE
3.50
3.25
3.00
2.75
2.50
350
300
250
200
150
100
50
I
= 800µA
SOURCE
I
= 5mA
SINK
I
= 1.5mA
30
SINK
I
= 1mA
100
SINK
0
60
85
110
-40 -15
10
35
65
-40
-5
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
Pin Description
Applications Information
Accurate temperature monitoring requires a good ther-
mal contact between the MAX6676/MAX6677 and the
object being monitored. A precise temperature mea-
surement depends on the thermal resistance between
the object being monitored and the MAX6676/
MAX6677 die. Heat flows in and out of plastic pack-
ages primarily through the leads. If the sensor is intend-
ed to measure the temperature of a heat-generating
component on the circuit board, mount the device as
close as possible to that component and share the
ground traces (if they are not too noisy) with the com-
ponent. This maximizes the heat transfer from the com-
ponent to the sensor.
PIN
NAME
FUNCTION
Digital Output Pin. The duty
cycle of the output waveform is
modulated by temperature.
1
DOUT
Ground. All four ground pins
must be connected to GND.
2, 4, 5, 6
3
GND
Supply Voltage. Bypass V
to
CC
V
CC
GND with a 0.1µF capacitor.
Detailed Description
Power Supply from µP Port Pin
The low quiescent current of the MAX6676/MAX6677
enables them to be powered from a logic line, which
meets the requirements for supply voltage range. This
provides a simple shutdown function to totally eliminate
quiescent current by taking the logic line low. The logic
line must be able to withstand the 0.1µF power-supply
bypass capacitance.
The MAX6676/MAX6677 are high-accuracy, low-current
(80µA, typ) temperature sensors ideal for interfacing
with µCs or µPs. The MAX6676/MAX6677 convert the
ambient temperature into a ratiometric PWM output at a
nominal frequency of 1.8kHz ( 20ꢀ) at +25ꢂC.
The time periods, t (low) and t (high) (Figure 1), are
1
2
easily read by a µP’s timer/counter port. To calculate
the temperature, use the following expression:
Temperature (ꢂC) = 398.15 x (t / t ) - 273.15
1
2
t
2
The µC or µP measures the output of the MAX6676/
MAX6677 by counting t and t and computing the
1
2
temperature based on their ratio. The resolution of the
count is a function of the processor clock frequency
and the resolution of the counter. Always use the same
clock for t and t counters so that the temperature is
1
2
t
1
strictly based on a ratio of the two times, thus eliminat-
ing errors due to different clocks’ frequencies.
Figure 1. MAX6676/MAX6677 PWM Output
The MAX6677 (Figure 2a) has a push-pull output with
full CMOS output swings. The ability to source and sink
current allows the MAX6677 to drive capacitive loads
up to 100pF with less than 1ꢂC error.
V
V
CC
CC
The MAX6676 (Figure 2b) has an open-drain output.
The output capacitance should be minimized in
MAX6676 applications because the sourcing current is
set by the pullup resistor. If the output capacitance
becomes too large, lengthy rise and fall times distort
the pulse width, resulting in inaccurate measurements.
P
DOUT
DOUT
N
N
(a)
MAX6677
(b)
MAX6676
Figure 2. Output Configurations
_______________________________________________________________________________________
5
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
3.3V
V
ISO
V
DD
V
CC
MAX6676AUT3
DOUT
5.1kΩ
MAX6676
DOUT
Figure 3. Galvanic Isolation Using an Optocoupler
Figure 4. Low-Voltage Logic
Galvanic Isolation
Use an optocoupler to isolate the MAX6676/MAX6677
whenever a high common-mode voltage is present.
Choose an optocoupler with equal turn-on and turn-off
times. Unequal turn-on/turn-off times produce an error
in the temperature reading (Figure 3).
Multiple Logic Voltages
Use the MAX6676 open-drain output to drive devices
operating at supply voltages other than the MAX6676’s
V
. As shown in Figure 4, connect a pullup resistor
CC
from the other supply voltage to the MAX6676 output.
Limit the resistor’s current to less than 1mA, thus main-
taining an output low logic level of less than 200mV.
Thermal Considerations
Self-heating may cause the temperature measurement
accuracy of the MAX6676/MAX6677 to degrade in
some applications. The quiescent dissipation and the
power dissipated by the digital output may cause
errors in obtaining the accurate temperature measure-
ment. The temperature errors depend on the thermal
conductivity of the package (SOT23, +140ꢂC/W), the
mounting technique, and the airflow. Static dissipation
is typically 4.0µW operating at 5V with no load. For
example, an out load of 3mA creates a maximum error
of less than 0.1ꢂC.
Chip Information
TRANSISTOR COUNT: 2096
PROCESS: BiCMOS
6
_______________________________________________________________________________________
Low-Voltage, 1.8kHz PWM Output Temperature
Sensors
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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