MAX6576,77 Datasheet by Maxim Integrated

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General Description
The MAX6576/MAX6577 are low-cost, low-current tem-
perature sensors with a single-wire output. The MAX6576
converts the ambient temperature into a square wave with
a period proportional to absolute temperature (°K). The
MAX6577 converts the ambient temperature into a square
wave with a frequency proportional to absolute tempera-
ture. The MAX6576 offers accuracy of ±3°C at +25°C,
±4.5°C at +85°C, and ±5°C at +125°C. The MAX6577
offers accuracy of ±3°C at +25°C, ±3.5°C at +85°C, and
±4.5°C at +125°C.
Both devices feature a single-wire output that minimizes
the number of pins necessary to interface with a micropro-
cessor. The period/frequency range of the output square
wave can be selected by hard-wiring the two time-select
pins (TS0, TS1) to either VDD or GND. The MAX6576/
MAX6577 are available in space-saving 6-pin SOT23
packages.
Applications
Critical μP and μC Temperature Monitoring
Portable Battery-Powered Equipment
Cell Phones
Battery Packs
Hard Drives/Tape Drives
Networking and Telecom Equipment
Medical Equipment
Features
Simple Single-Wire Output
Two Output Types Available
Temperature to Period (μs) (MAX6576)
Temperature to Frequency (Hz) (MAX6577)
±0.8°C Accuracy at +25°C (±3°C max)
No External Components
Operates from +2.7V to +5.5V Supply Voltage
Low 140μA Typical Supply Current
Standard Operating Temperature Range:
-40°C to +125°C
Small 6-Pin SOT23 Package
19-1484; Rev 1; 10/14
PART TEMP. RANGE PIN-
PACKAGE
SOT TOP
MARK
MAX6576ZUT -40°C to +125°C 6 SOT23 AABI
MAX6577ZUT -40°C to +125°C 6 SOT23 AABJ
GND
TS0N.C.
1 6 OUT
5 TS1
VDD
SOT23-6
TOP VIEW
2
3 4
MAX6576
MAX6577
+2.7V TO +5.5V
GND
TS0
TS1
OUT
0.1µF0.1µF VDD
µP
GND
I/O
VCC
MAX6576
MAX6577
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
Pin Configuration Typical Operating Circuit
Ordering Information
Terminal Voltage (with respect to GND)
VDD.......................................................................-0.3V to +6V
TS1, TS0, OUT.......................................-0.3V to (VDD + 0.3V)
Input/Output Current, All Pins............................................±20mA
Continuous Power Dissipation (TA = +70°C)
6-pin SOT23 (derate 7.10mW/°C above +70°C)..........571mW
Operating Temperature Range...........................-40°C to +125°C
Storage Temperature Range..............................-65°C to +150°C
Lead Temperature (soldering, 10sec)...............................+300°C
(VDD = +2.7V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are specified at TA = +25°C and VDD = +5V,
unless otherwise noted.)
Note 1: See the Temperature Accuracy histograms in the Typical Operating Characteristics.
Note 2: The output duty cycle is guaranteed to be 50% by an internal flip-flop.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
VDD Range VDD 2.7 5.5 V
Supply Current IDD VDD = 5.5V TA = -40°C to +85°C 140 250 µA
TA = -40°C to +125°C 400
Temperature Sensor
Error (Note 1)
MAX6576
TA = -20°C -7.5 ±1.1 +7.5
°C
TA = 0°C -5.5 ±0.9 +5.5
TA = +25°C -3.0 ±0.8 +3.0
TA = +85°C -4.5 ±0.5 +4.5
TA = +125°C -5.0 ±0.5 +5.0
MAX6577
TA = -20°C -7.5 ±1.1 +7.5
°C
TA = 0°C -6.5 ±0.9 +6.5
TA = +25°C -3.0 ±0.8 +3.0
TA = +85°C -3.5 ±0.5 +3.5
TA = +125°C -4.5 ±0.5 +4.5
Output Clock Period tOUT
MAX6576,
T (temp) in °K,
Figure 1
VTS1 = GND, VTS0 = GND 10T
µs
VTS1 = GND, VTS0 = VDD 40T
VTS1 = VDD, VTS0 = GND 160T
VTS1 = VDD, VTS0 = VDD 640T
Output Clock Frequency fOUT
MAX6577,
T (temp) in °K,
Figure 2
VTS1 = GND, VTS0 = GND 4T
Hz
VTS1 = GND, VTS0 = VDD 1T
VTS1 = VDD, VTS0 = GND T/4
VTS1 = VDD, VTS0 = VDD T/16
OUT Duty Cycle (Note 2) 0.5
Time-Select Pin Logic Levels VIL 0.8 V
VIH 2.3
OUT Voltage
VOL
VDD > 4.5V, ISINK = 3.2mA 0.4
V
VDD > 2.7V, ISINK = 1.2mA 0.3
VOH
VDD > 4.5V, ISRC = 800μA VDD - 1.5
VDD > 2.7V, ISRC = 500μA 0.8VDD
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
www.maximintegrated.com Maxim Integrated
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Absolute Maximum Ratings
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
(VDD = +5V, TA = +25°C, unless otherwise noted.)
0
20
10
30
40
50
60
-5 -3 -2-4 -1 012345
TEMPERATURE ACCURACY
(TA = +85°C)
MAX6576 toc02
ACCURACY (°C)
PERCENTAGE OF PARTS SAMPLED (%)
MAX6576
MAX6577
SAMPLE SIZE = 200
100
130
120
110
150
140
170
160
180
-40 -10 5 20-25 35 50 65 80 95 110 125
SUPPLY CURRENT vs. TEMPERATURE
MAX6576/77toc03
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
MAX6577
MAX6576
-1.0
0
-0.5
1.0
0.5
1.5
-40 -10 5 20-25 35 50 65 80 95 110 125
ACCURACY vs. TEMPERATURE
MAX6575 toc04
TEMPERATURE (°C)
ACCURACY (°C)
MAX6576
MAX6577
+15°C/div
+100°C
+25°C
THERMAL STEP RESPONSE
IN PERFLUORINATED FLUID
MAX6576/77 toc05
5sec/div
MOUNTED ON 0.75 in.2
OF 2oz. COPPER
0
10
5
15
20
25
30
35
-5 -3 -2-4 -1 012345
TEMPERATURE ACCURACY
(TA= +25°C)
MAX6576 toc01
ACCURACY (°C)
PERCENTAGE OF PARTS SAMPLED (%)
MAX6576
MAX6577
SAMPLE SIZE = 200
+12.5°C/div
+100°C
+25°C
THERMAL STEP RESPONSE
IN STILL AIR
MAX6576/77 toc06
20sec/div
MOUNTED ON 0.75 in.2
OF 2oz. COPPER
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
Maxim Integrated
3
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Typical Operating Characteristics
Detailed Description
The MAX6576/MAX6577 low-cost, low-current (140μA
typ) temperature sensors are ideal for interfacing with
microcontrollers (μCs) or microprocessors (μPs). The
MAX6576 converts ambient temperature into a 50%
dutycycle square wave with a period proportional to
absolute temperature. The MAX6577 converts ambient
temperature into a 50% duty-cycle square wave with a
frequency proportional to absolute temperature. Time-
select pins (TS1, TS0) permit the internal temperature-
controlled oscillator (TCO) to be scaled by four preset
multipliers. The MAX6576/MAX6577 feature a single-wire
interface to minimize the number of port pins necessary
for interfacing with a μP.
MAX6576 Characteristics
The MAX6576 temperature sensor converts temperature
to period. The output of the device is a free-running, 50%
duty-cycle square wave with a period that is proportional
to the absolute temperature (°K) of the device (Figure 1).
The MAX6576 has a push/pull CMOS output with sharp
edges. The speed of the output square wave can be
selected by hard-wiring TS1 and TS0 as shown in Table 1.
One of four scaled output periods can be selected using
TS1 and TS0.
MAX6577 Characteristics
The MAX6577 temperature sensor converts temperature
to frequency. The output of the device is a free-running,
50% duty-cycle square wave with a frequency that is pro-
portional to the absolute temperature (°K) of the device
(Figure 2). The MAX6577 has a push/pull CMOS output
with sharp edges. The speed of the output square wave
can be selected by hard-wiring TS1 and TS0 as shown
in Table 2. One of four scaled output frequencies can be
selected using TS1 and TS0.
Table 1. MAX6576 Time-Select Pin
Configuration
Table 2. MAX6577 Time-Select Pin
Configuration
PIN NAME FUNCTION
1 VDD Positive Supply Voltage
2 GND Ground
3N.C. No Connection. Connect pin to GND or leave open.
4, 5 TS1, TS0 Time-Select Pins. TS1 and TS0 set the temperature scale factor by connecting TS1 and TS0 to either VDD
or GND. See Tables 1 and 2.
6 OUT Square-Wave Output with a Clock Period Proportional to Absolute Temperature (°K) (MAX6576)
Square-Wave Output with a Clock Frequency Proportional to Absolute Temperature (°K) (MAX6577)
TS1 TS0 SCALAR MULTIPLIER (μs/°K)
GND GND 10
GND VDD 40
VDD GND 160
VDD VDD 640
TS1 TS0 SCALAR MULTIPLIER (Hz/°K)
GND GND 4
GND VDD 1
VDD GND 1/4
VDD VDD 1/16
Note: The temperature, in °C, may be calculated as follows:
PERIOD(µs)
T( C) 273.15 K
SCALAR MULTIPLIER(µs/ K)
°= − °
°
FREQUENCY(µs)
T( C) 273.15 K
SCALAR MULTIPLIER(µs/ K)
°= − °
°
Note: The temperature, in °C, may be calculated as follows:
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
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4
Pin Description
L7 44
Applications Information
Quick-Look Circuits
Figure 3 shows a quick-look application circuit for the
MAX6576 using a universal counter measuring period.
TS1 and TS0 are both tied to ground to select a scalar
multiplier of 10μs/°K. The MAX6576 converts the ambi-
ent temperature into a square wave with a period that is
10 times the absolute temperature of the device in μs.
At room temperature, the universal counter will display
approximately 2980μs.
Figure 4 shows a quick-look application circuit for the
MAX6577 using a universal counter measuring frequency.
TS1 is tied to ground and TS0 is tied to VDD to select a
scalar multiplier of 1Hz/°K. The MAX6577 converts the
ambient temperature into a square wave with a frequency
that is equal to the absolute temperature of the device
in Hertz. At room temperature, the universal counter will
display approximately 298Hz.
Interfacing with a Microcontroller
Figure 5 shows the MAX6577 interfaced with an 8051 μC.
In this example, TS1 is tied to ground and TS0 is tied to
VDD to select a scalar multiplier of 1Hz/°K. The MAX6577
converts the ambient temperature into a square wave with
a frequency that is equal to the absolute temperature of
the device in Hertz. The 8051 μC reads the frequency of
the square-wave output of the MAX6577 into Timer 0 and
displays the temperature as degrees Celsius in binary on
Port 1. Listing 1 provides the code for this application. The
interface is similar for the MAX6576, except the μC will
perform a period measurement.
Noise Considerations
The accuracy of the MAX6576/MAX6577 is susceptible to
noise generated both internally and externally. The effects
of external noise can be minimized by placing a 0.1μF
ceramic bypass capacitor close to the supply pin of the
devices. Internal noise is inherent in the operation of the
devices and is detailed in Table 3. Internal averaging mini-
mizes the effect of this noise when using longer scalar
timeout multipliers. The effects of this noise are included
in the overall accuracy of the devices as specified in the
Electrical Characteristics.
Figure 1. MAX6576 Timing Diagram Figure 2. MAX6577 Timing Diagram
tOUT
MAX6576
CLOCK WAVEFORM OUTPUT
tOUT
MAX6577
CLOCK WAVEFORM OUTPUT
fOUT = 1 / tOUT
fOUT (°K)
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
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Figure 3. MAX6576 Quick-Look Circuit
Figure 4. MAX6577 Quick-Look Circuit
Figure 5. Interfacing with a μC
Table 3. Typical Peak Noise Amplitude
PARAMETER MAX6576 MAX6577
Scalar Multiplier 10 40 160 640 4 1 1/4 1/16
Noise Amplitude (°C) ±0.38 ±0.17 ±0.11 ±0.094 ±0.13 ±0.066 ±0.040 ±0.028
GND
TS0
TS1
OUT
0.1µF VDD
+2.7V TO +5.5V
UNIVERSAL COUNTER
"PERIOD"
MAX6576
GND
TS0
TS1
OUT
0.1µF
VDD
+2.7V TO +5.5V
UNIVERSAL COUNTER
"FREQUENCY"
MAX6577
GND
TS0
TS1
OUT
0.1µF
VDD
+2.7V TO +5.5V
GND X2
X1
T0
470Ω x 8
VCC
P1.1
P1.0
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
8051 12MHz
22pF
22pF
MAX6577
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
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6
Chip Information
TRANSISTOR COUNT: 302
,- Demonstration and test code for mssw Temp to Frequency ; Takes in temperature values from s sensor into time: u ,- and displays temp es degrees a in binary on port 1. ,- example; room temn= 21 c, display 2: or ooololul on P]. ,“n...“ss.m.s...m...“n....i...“nun"..."unn... iTEMPERATURE ,‘nulnber of so ms- counts to 1 second ;new temp flags bi: address in zen :noce one isr-s usedt timer overflow ,-jump over istvs ;TF) ISR ystaah ace mush paw iclear far subb ;lstsnsy fix ,-subtrsct timer low latency < 20="" :50="" ills="" reload="" value-="" low="" 0="" ms="" reload="" value-="" high="" ;jump="" over="" counter="" code="" ”reload="" ticks="" ;reaa="" counter="" to="" tenpl="" and="" temp="" high="" if="" 1="" seem-ad="" yequates="" tempe-i="" 500="" 10}!="" tkmpl="" mu="" lll-l="" ticks="" bqu="" 12h="" 113m="" in="" don="" main="" org="" a="" aj'm‘d="" seam="" org="" 13h="" tickv="" push="" acc="" 1705)!="" psw="" ;="" reload="" tlmer-="" so="" ms="" cm="" c="" nov="" amazon="" sues="" fmtli="" mv="" i'lla="" mov="" tlqubck="" djnz="" ticksmolll="" mw="" ticksdtzo="" gtas:="" mov="" afl'flfl="" nov="" 5.11.0="" cm="" amman;="" mov="" temph,a="" nov="" temple="" mv="" 11(qu="" mm="" no,“="" 5515="" mm="" noel:="" pop="" psw="" pop="" ac:="" mm="" begi="" .="" mv="" shanon="" ;setup="" timers="" to="" mov="" ,-get="" timer="" high="" :grsx:="" timer="" low="" ;gst="" again="" is="" rollover="" ;stash="" nigh="" ;stash="" leu="" :zero="" counter="" :tero="" counter="" :82:="" data="" ready="" flag="" :="" done="" :set="" 5::="" at="" 70h="" do="" timinge="" to="" input,="" :1="" timer="" so="" me="" tmodjmsh="" nu,="" hazel-l="" “laotian="" no,="" we="" mo,="" «0="" tcon,="" uson="" ticksjfzg="" 12,4988}!="" :in‘lts="" done»="" measure="" dump="" cm="" wmrr~="" ma="" ;="" temp="" is="" stored»="" display="" bin="" value="" nw="" newt,="" wn'n‘="" ;tl="" tlmet-="" to="" counter="" ,-so="" ms="" relcad="" value-="" high="" ;5a="" ms="" reload="" value-="" low="" :reael:="" counter="" low="" ;rsset="" counter="" nigh="" ;start="" both="" timers="" :20="" x="" 50="" ms="" 1="" sec="" :anable="" tl="" ints="" nnd="" global="" :clesr="" data="" flag="" .‘vait="" for="" outs="" cf="" selected="" on="" p1="">
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
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Listing 1. 8051 Code Example
; temp is in kelvin- subtract 273 mv Luann. ,ger. tam (K) CLR c Ready for sum: sum; 11,490le raub lav byte cf 272 Nov TEMPLA ,1:th back mv A,TEHPH 795: high byte for completeness sues AJDJH ,‘sub high byte and prop can-y mv TEMPLA iatash mispxay u: mv A,TEMPL -get temp (ct cm. A :compliment for led’a- active low mv PLA rautpu: i: mp pomp
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
6 SOT23 U6-4 21-0058 90-0175
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
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Listing 1. 8051 Code Example (continued)
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.
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 4/99 Initial release
1 10/14 Removed automotive reference from data sheet 1
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.
MAX6576/MAX6577 SOT Temperature Sensors with
Period/Frequency Output
© 2014 Maxim Integrated Products, Inc.
9
Revision History
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