Click here to ask an associate for production status of specific part numbers.
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
General Description
Features
The MAX6575L/H is a low-cost, low-current temperature
sensor with a single-wire digital interface. It features
accuracy of ±3°C at +25°C, ±4.5°C at +85°C, and ±5°C
at +125°C. The MAX6575L/H is a monostable, externally
triggered temperature sensor that allows a microproces
sor (μP) to interface with up to eight temperature sensors
using a single control line. Temperatures are sensed by
measuring the time delay between the falling edge of the
external triggering pulse and the falling edge of the subsequent pulse delays reported from the devices. Different
sensors on the same I/O line use different timeout multipliers to avoid overlapping signals.
● Simple Single-Wire Interface to μP or μC
● Multidrop up to Eight Sensors on One Wire
● ±0.8°C Accuracy at +25°C (±3°C max)
● Operates from +2.7V to +5.5V Supply Voltage
● Low 150μA (typ) Supply Current
● Standard Operating Temperature Range
-40°C to +125°C
● Small 6-Pin SOT23 Package
Ordering Information
The MAX6575L/H features eight different timeout multipliers; these are selectable by using the two time-select pins
on each device and choosing the “L” or “H” version. The
“L” version provides four delay ranges less than 50ms.
The “H” version provides four delay ranges greater than
50ms. The MAX6575L/H is available in a space-saving
6-pin SOT23 package.
PART
MAX6575LZUT -40°C to +125°C
6 SOT23
AABG
MAX6575HZUT -40°C to +125°C
6 SOT23
AABH
Selector Guide
Applications
●
●
●
●
●
●
●
PINSOT
PACKAGE TOP MARK
TEMP.RANGE
Critical μP and μC Temperature Monitoring
Portable Battery-Powered Equipment
Cell Phones
Battery Packs
Hard Drives/Tape Drives
Networking and Telecom Equipment
Medical Equipment
PART
TIMEOUT MULTIPLIERS
(µs/°K)
MAX6575L
5, 20, 40, 80
MAX6575H
160, 320, 480, 640
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
+2.7V TO +5.5V
VCC
0.1µF
0.1µF
VDD
0.1µF
VDD
MAX6575L
TS1
VCC
10kΩ
TS0
CHIP #1
MAX6575H
TS1
TS0
GND
CHIP #8
GND
I/O
I/O
µP
I/O
GND
19-1485; Rev 2; 1/21
© 2021 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.
One Analog Way, Wilmington, MA 01887 U.S.A.
|
Tel: 781.329.4700
|
© 2021 Analog Devices, Inc. All rights reserved.
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Absolute Maximum Ratings
Terminal Voltage (with respect to GND)
VDD......................................................................-0.3V to +6V
TS1, TS0...............................................-0.3V to (VDD + 0.3V)
I/O.........................................................................-0.3V to +6V
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, 10s) ..................................+300°C
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
(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.)
PARAMETER
VDD Range
Supply Current
SYMBOL
VDD
IDD
Temperature Sensor Error
(Note 1)
tD1
tD2
tD3
Output Pulse Delay
tD4
tD5
tD6
tD7
tD8
CONDITIONS
VDD = 5.5V
TA = -20°C
UNITS
5.5
V
150
250
400
-7.5
±1.1
+7.5
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
MAX6575L,
T (temp) in °K,
Figure 1
MAX6575H,
T (temp) in °K,
Figure 1
VTS1 = GND, VTS0 = GND
5T
VTS1 = GND, VTS0 = VDD
20T
VTS1 = VDD, VTS0 = GND
40T
VTS1 = VDD, VTS0 = VDD
80T
VTS1 = GND, VTS0 = GND
160T
VTS1 = GND, VTS0 = VDD
320T
VTS1 = VDD, VTS0 = GND
480T
VTS1 = VDD, VTS0 = VDD
640T
Reset Pulse Width (Note 2)
tRESET
Figure 1
Setup Time
tSETUP
Figure 1
Start Pulse (Note 3)
tSTART
Figure 1, TA = +25°C
Delay Time from Trigger to
Ready (Note 4)
tREADY
Figure 1
4.6
16.0
10
I/O Output Voltage Low
VOL
µs
520
I/O Input Voltage Low
VIL
I/O Input Voltage High
VIH
2.3
0.4
0.3
0.8
2.3
ms
ns
0.8
VDD > 4.5V, ISINK = 3.2mA
VDD > 2.7V, ISINK = 1.2mA
ms
µs
2.5
VIL
°C
µs
500
VIH
µA
µs
5T
Glitch Immunity on I/O Input
Note
Note
Note
Note
MAX
TA = -40°C to +125°C
Figure 1
Time-Select Pin Logic Levels
TYP
2.7
TA = -40°C to +85°C
tL1-8
Output Pulse Low Time
MIN
V
V
V
V
1: See Temperature Accuracy histograms in Typical Operating Characteristics.
2: Guaranteed by design. Not production tested.
3: Limit maximum start pulse at 1ms to avoid timing overlap.
4: If no reset pulse is applied.
www.analog.com
Analog Devices │ 2
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Typical Operating Characteristics
(VDD = +5V, TA = +25°C, unless otherwise noted.)
TEMPERATURE ACCURACY
(TA = +85°C)
20
15
10
5
0
-5 -4
0
1
2
4
25
20
15
10
0
-5 -4
5
MAX6576 toc3a
0.5
0
-0.5
5
-3 -2 -1
0
1
2
3
4
-1.0
5
-40 -25 -10 5 20 35 50 65 80 95 110 125
ACCURACY (°C)
TEMPERATURE (°C)
SUPPLY CURRENT vs. TEMPERATURE
THERMAL STEP RESPONSE
IN PERFLUORINATED FLUID
THERMAL STEP RESPONSE
IN STILL AIR
MAX6575 toc05
MAX6575 toc04
+100°C
+100°C
170
160
+12.5°C/div
+15°C/div
150
140
MOUNTED ON 0.75 in.2
OF 2oz. COPPER
130
120
1.0
ACCURACY (°C)
180
SUPPLY CURRENT (µA)
3
30
MAX6575 toc03b
190
-3 -2 -1
SAMPLE SIZE = 200
ACCURACY (°C)
25
35
ACCURACY vs. TEMPERATURE
1.5
MAX6575 toc02
SAMPLE SIZE = 200
30
40
PERCENTAGE OF PARTS SAMPLED (%)
PERCENTAGE OF PARTS SAMPLED (%)
35
MAX6575 toc01
TEMPERATURE ACCURACY
(TA = +25°C)
+25°C
-40 -25 -10 5 20 35 50 65 80 95 110 125
5sec/div
MOUNTED ON 0.75 in.2
OF 2oz. COPPER
20sec/div
TEMPERATURE (°C)
Pin Configuration
PIN
NAME
1
VDD
Positive Supply Voltage
2
GND
Ground
3
N.C.
No Connect. Connect pin to GND or leave open.
4, 5
TS0, TS1
Time-Select Pins. Set the time delay factor by connecting TS1 and TS0 to either VDD or GND. See Table 1.
6
I/O
Bidirectional Interface Pin. A time delay between when the part is initiated externally by pulling I/O low and
when the part subsequently pulls I/O low, is proportional to absolute temperature (°K).
www.analog.com
FUNCTION
Analog Devices │ 3
+25°C
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Detailed Description
Table 1. Time-Select Pin Configuration
The MAX6575L/H low-cost, low-current (150μA typ)
temperature sensor is ideal for interfacing with microcon
trollers or microprocessors. The MAX6575L/H is a monostable, externally triggered temperature sensor that uses
a Temp→Delay conversion to communicate with a μP
over a single I/O line. Time-select pins (TS1, TS0) permit the internal temperature-controlled oscillator (TCO)
to be scaled by four preset timeout multipliers, allowing
eight separate temperature sensors to share one I/O line.
Different sensors on the same I/O line will use different
timeout multipliers to avoid overlapping signals.
tRESET
tSTART
CHIP# 1
RESPONSE
tL1
tD1
TS0
MAX6575L
MAX6575H
GND
GND
5
160
GND
VDD
GND
20
320
40
480
VDD
80
640
maximum delay of 520ms, at which point it will again be
in a ready state awaiting a start pulse.
Definition of Terms:
Figure 1 illustrates the timing for the MAX6575L/H. When
the device is powered up, it assumes a ready state where
it awaits an external trigger at the I/O pin. The I/O pin
of the MAX6575L/H has an open-drain output structure
that requires a pullup resistor to maintain the proper logic
levels. Once the I/O pin is pulled low and then released,
control of the I/O pin is transferred to the MAX6575L/H.
The temperature conversion begins on the falling edge
of the externally triggered pulse. The I/O line is pulled
low at a later time. That time is determined by the device
temperature and the Time Select pins (TS1, TS0). The
I/O line remains low for 5Tμs, where T is the temperature
in degrees Kelvin. The temperature of the device is represented by the edgeto-edge delay of the externally triggered pulse and the falling edge of the subsequent pulse
originating from the device. The device can be manually
reset by pulling the I/O line low for more than tRESET
(16ms max). The device will automatically reset after a
APPLIED START
PULSE
TS1
VDD
VDD
Operating the MAX6575L/H
tSETUP
TIMEOUT MULTIPLIERS
(μs/°K)
TIME-SELECT PINS
tRESET: Time I/O must be externally pulled low to
guarantee the MAX6575L/H is in a ready state
awaiting external trigger. (Part will assume a
ready state after 520ms without a reset pulse.)
tSETUP: Time I/O must be high prior to a start pulse.
tSTART: Trigger pulse which starts the on-chip timing
sequence on its falling edge.
tDx:
Timing delay between the falling edge of the
start pulse and the falling edge initiated by
CHIP#x.
tLx:
I/O pulse low time (5Tμs).
tREADY: Time after falling edge of start pulse when the
MAX6575L/H will reset itself and await the next
external trigger.
The temperature, in degrees Celsius, may be calculated
as follows:
T(°C) = [tDx(μs) / timeout multiplier(μs/°K)] - 273.15°K
Time-Select Pins (TS1, TS0)
CHIP# 2
RESPONSE
CHIP# 3
RESPONSE
tL3
tL2
CHIP# 4
RESPONSE
tL4
tD2
tD3
tD4
tREADY
Figure 1. Timing Diagram
www.analog.com
Analog Devices │ 4
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Table 2. Allowable Temperature Differential (°C)
TIMEOUT
MULTIPLIER
MAX6575L
5
5
MAX6575H
20
40
80
160
320
480
640
>165
>165
>165
>165
>165
>165
>165
>165
>165
>165
>165
>165
132.0
>165
>165
>165
>165
153.5
>165
>165
>165
>165
>165
>165
70.2
>165
20
95.5
40
80
160
320
480
37.9
640
Table 3. Typical Peak Noise Amplitude
PARAMETER
MAX6575L
MAX6575H
Timeout
Multiplier
5
20
40
80
160
320
480
640
Noise
Amplitude
(°C)
±0.33
±0.15
±0.15
±0.098
±0.091
±0.063
±0.043
±0.037
Table 1 shows the configuration of the Time-select pins
for the MAX6575L/H. Each device allows four selectable
timeout multipliers intended to prevent overlapping when
multiple devices are used on the same I/O line. Tie TS1
and TS0 to either GND or VDD to select the desired temperature multiplier.
To monitor several chips on the same I/O line, different
timeout multipliers should be selected using the TS1 and
TS0 pins. The timeout periods are then scaled so that the
response times will not overlap (see Timeout Selection).
Applications Information
Timeout Selection
Under extreme temperature conditions, it is possible for
an overlap to occur between the timeout delays of different sensors in a multidrop configuration. This overlap can
occur only if the temperature differential recorded between
two devices is very large. Timeout overlaps can be avoided in multidrop configurations by selecting the appropriate
timeout multipliers. Table 2 illustrates the allowable temperature differential between devices when the maximum
error is present on each device. Allowable temperature
differentials greater than 165°C indicate no overlap.
www.analog.com
For example, if the maximum temperature differential
in a system is 80°C, the only combinations of timeout
multipliers that could result in timeout overlap would be a
320:480μs/°K (70.2°C) or a 480:640μs/°K (37.9°C) combination. As long as these combinations of timeout multipliers are not used in the same multidrop configuration,
no overlap can occur. Thus, seven MAX6575L/H parts
can be used in the same multidrop configuration if the
maximum temperature differential between parts is 80°C.
A similar analysis shows that four MAX6575L/H parts
can be used when the maximum temperature differential
extends over the entire 165°C range of the part.
Noise Considerations
The accuracy of the MAX6575L/H timeout delay 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 device’s
supply pin. Internal noise is inherent in the operation of
the device and is detailed in Table 3. Internal averaging minimizes the effect of this noise when using longer
timeout multipliers. The effects of this noise are included
in the overall accuracy of the device as specified in the
Electrical Characteristics table.
Analog Devices │ 5
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
+2.7V TO +5.5V
+2.7V TO +5.5V
0.1µF
VDD
MAX6575L
40µs/°K
TS1
MAX6575L
I/O
TS0
0.1µF
VDD
T1
80µs/°K
TS1
I/O
TS0
T2
GND
GND
VCC
P1.0
10kΩ
470Ω (8)
P1.1
P3.7
8051
VCC
P1.2
P1.3
P1.4
P1.5
OPEN: T1
CLOSED: T2
P1.6
10kΩ
P1.7
P3.5
22pF
X1
12MHz
GND
X2
22pF
Figure 2. Interfacing Multiple Devices with a Microcontroller
Interfacing Multiple Devices
with a Microcontroller
Figure 2 shows how to interface multiple MAX6575L/H
devices with an 8051 microcontroller. The first device, T1,
is configured for a timeout multiplier of 40μs/°K, while the
second device, T2, is configured for a timeout multiplier of
80μs/°K to avoid overlap. The microcontroller takes in temperature values from both sensors, T1 and T2, on a single
port pin, P3.7. The microcontroller displays five times the
temperature in degrees Celsius in binary on Port 1. A
switch connected to a pull-up resistor at Port 3.5 selects
which temperature is displayed: open = T1, closed = T2.
Code is provided for this application as Listing 1.
www.analog.com
Analog Devices │ 6
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Listing 1. 8051 Code Example
www.analog.com
Analog Devices │ 7
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Listing 1. 8051 Code Example (continued)
www.analog.com
Analog Devices │ 8
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Listing 1. 8051 Code Example (continued)
Pin Configuration
Package Information
TOP VIEW
VDD
1
6
GND
2
MAX6575L
MAX6575H 5
TS1
N.C.
3
4
TS0
I/O
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
OUTLINE
NO.
6 SOT23
U6-4
21-0058
LAND
PATTERN
NO.
90-0175
SOT23-6
www.analog.com
Analog Devices │ 9
MAX6575L/H
SOT Temperature Sensor with Multidrop
Single-Wire Digital Interface
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION
PAGES
CHANGED
0
4/99
Initial release
—
1
11/14
Removed automotive reference from data sheet
1
2
1/21
Updated Pin Configuration
9
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is
assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that
may result from its use.Specifications subject to change without notice. No license is granted by implicationor
otherwise under any patent or patent rights of Analog Devices. Trademarks andregistered trademarks are the
property of their respective owners.
w w w . a n a l o g . c o m
Analog Devices │ 10
