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
PARAMETER
V
DD
Range
Supply Current
(V
DD
= +2.7V to +5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are specified at T
A
= +25°C and V
DD
= +5V,
unless otherwise noted.)
SYMBOL
V
DD
I
DD
V
DD
= 5.5V
T
A
= -20°C
Temperature Sensor
Error
(Note
1)
T
A
= 0°C
T
A
= +25°C
CONDITIONS
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
-7.5
-5.5
-3.0
-4.5
-5.0
V
TS1
= GND, V
TS0
=
GND
V
TS1
= GND, V
TS0
= V
DD
V
TS1
= V
DD
, V
TS0
=
GND
V
TS1
= V
DD
, V
TS0
= V
DD
V
TS1
= GND, V
TS0
=
GND
V
TS1
= GND, V
TS0
= V
DD
V
TS1
= V
DD
, V
TS0
=
GND
V
TS1
= V
DD
, V
TS0
= V
DD
4.6
10
2.5
520
500
V
IL
V
IH
V
OL
V
IL
V
IH
2.3
V
DD
> 4.5V, I
SINK
= 3.2mA
V
DD
> 2.7V, I
SINK
= 1.2mA
2.3
0.4
0.3
0.8
0.8
±1.1
±0.9
±0.8
±0.5
±0.5
5T
20T
40T
80T
160T
320T
480T
640T
5T
16.0
µs
ms
µs
µs
ms
ns
V
V
V
V
µs
MIN
2.7
150
TYP
MAX
5.5
250
400
+7.5
+5.5
+3.0
+4.5
+5.0
°C
UNITS
V
µA
T
A
= +85°C
t
D1
t
D2
t
D3
t
D4
t
D5
t
D6
t
D7
t
D8
T
A
= +125°C
MAX6575L,
T (temp) in
°K,
Figure 1
Output Pulse
Delay
MAX6575H,
T (temp) in
°K,
Figure 1
Figure 1
Figure 1
Figure 1
Output Pulse Low
Time
Reset Pulse Width (Note 2)
Setup Time
Start Pulse (Note 3)
Delay Time from Trigger to
Ready (Note
4)
Glitch Immunity on I/O
Input
Time-Select Pin Logic
Levels
I/O Output Voltage Low
I/O Input Voltage Low
I/O Input Voltage High
Note
Note
Note
Note
1:
2:
3:
4:
t
L1-8
t
RESET
t
SETUP
t
START
t
READY
Figure 1, T
A
= +25°C
Figure 1
See Temperature Accuracy histograms in
Typical Operating Characteristics.
Guaranteed by design. Not production tested.
Limit maximum start pulse at 1ms to avoid timing overlap.
If no reset pulse is applied.
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Maxim Integrated
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2
MAX6575L/H
SOT Temperature Sensor with
Multidrop Single-Wire Digital Interface
Typical Operating Characteristics
(V
DD
= +5V, T
A
= +25°C, unless otherwise noted.)
TEMPERATURE ACCURACY
(T
A
= +25°C)
MAX6575 toc01
TEMPERATURE ACCURACY
(T
A
= +85°C)
MAX6575 toc02
ACCURACY vs. TEMPERATURE
MAX6576 toc3a
35
PERCENTAGE OF PARTS SAMPLED (%)
30
25
20
15
10
5
0
PERCENTAGE OF PARTS SAMPLED (%)
SAMPLE SIZE = 200
40
35
30
25
20
15
10
5
0
SAMPLE SIZE = 200
1.5
1.0
ACCURACY (°C)
0.5
0
-0.5
-1.0
-5 -4
-3 -2 -1
0
1
2
3
4
5
-5 -4
-3 -2 -1
0
1
2
3
4
5
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
ACCURACY (°C)
ACCURACY (°C)
180
SUPPLY CURRENT (µA)
170
160
150
140
130
120
MAX6575 toc03b
190
SUPPLY CURRENT vs. TEMPERATURE
THERMAL STEP RESPONSE
IN PERFLUORINATED FLUID
MAX6575 toc04
THERMAL STEP RESPONSE
IN STILL AIR
MAX6575 toc05
+100°C
+100°C
+15°C/div
MOUNTED ON 0.75 in.
2
OF 2oz. COPPER
+12.5°C/div
+25°C
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
5sec/div
MOUNTED ON 0.75 in.
2
OF 2oz. COPPER
+25°C
20sec/div
Pin Configuration
PIN
1
2
3
4, 5
6
NAME
V
DD
GND
N.C.
TS0, TS1
I/O
Positive Supply Voltage
Ground
No Connect. Connect pin to GND or leave open.
Time-Select Pins. Set the time delay factor by connecting TS1 and TS0 to either V
DD
or GND. See Table 1.
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).
FUNCTION
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Maxim Integrated
│
3
MAX6575L/H
SOT Temperature Sensor with
Multidrop Single-Wire Digital Interface
Table 1. Time-Select Pin Configuration
TIME-SELECT PINS
TS1
GND
GND
VDD
VDD
TS0
GND
VDD
GND
VDD
TIMEOUT MULTIPLIERS
(μs/°K)
MAX6575L
5
20
40
80
MAX6575H
160
320
480
640
Detailed Description
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 mono-
stable, 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) per-
mit 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.
Operating the MAX6575L/H
maximum delay of 520ms, at which point it will again be
in a ready state awaiting a start pulse.
Definition of Terms:
t
RESET
: Time I/O must be externally pulled low to guar-
antee the MAX6575L/H is in a ready state await-
ing external trigger. (Part will assume a ready
state after 520ms without a reset pulse.)
t
SETUP
: Time I/O must be high prior to a start pulse.
t
START
: Trigger pulse which starts the on-chip timing
sequence on its falling edge.
t
Dx
:
Timing delay between the falling edge of the
start pulse and the falling edge initiated by
CHIP#x.
I/O pulse low time (5Tμs).
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 rep-
resented by the edgeto-edge delay of the externally trig-
gered 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 t
RESET
(16ms max). The device will automatically reset after a
t
Lx:
t
READY
: 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) = [t
Dx(μs)
/ timeout multiplier(μs/°K)] - 273.15°K
t
SETUP
APPLIED START
PULSE
CHIP# 1
RESPONSE
CHIP# 2
RESPONSE
CHIP# 3
RESPONSE
CHIP# 4
RESPONSE
t
RESET
t
START
t
D1
t
L1
t
D2
t
D3
t
L2
t
L3
t
L4
t
D4
t
READY
Figure 1. Timing Diagram
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Maxim Integrated
│
4
MAX6575L/H
SOT Temperature Sensor with
Multidrop Single-Wire Digital Interface
Table 2. Allowable Temperature Differential (°C)
TIMEOUT
MULTIPLIER
5
20
40
80
160
320
480
640
MAX6575L
5
20
>165
40
>165
95.5
80
>165
>165
132.0
160
>165
>165
>165
153.5
MAX6575H
320
>165
>165
>165
>165
>165
480
>165
>165
>165
>165
>165
70.2
640
>165
>165
>165
>165
>165
>165
37.9
Table 3. Typical Peak Noise Amplitude
PARAMETER
Timeout
Multiplier
Noise
Amplitude
(°C)
5
MAX6575L
20
40
80
160
MAX6575H
320
480
640
±0.33
±0.15
±0.15
±0.098
±0.091
±0.063
±0.043
±0.037
Time-Select Pins (TS1, TS0)
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 V
DD
to select the desired tem-
perature 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).
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) com-
bination. As long as these combinations of timeout mul-
tipliers 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.
Applications Information
Timeout Selection
Under extreme temperature conditions, it is possible for
an overlap to occur between the timeout delays of differ-
ent 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 avoid-
ed in multidrop configurations by selecting the appropriate
timeout multipliers. Table 2 illustrates the allowable tem-
perature differential between devices when the maximum
error is present on each device. Allowable temperature
differentials greater than 165°C indicate no overlap.
Noise Considerations
The accuracy of the MAX6575L/H timeout delay is sus-
ceptible 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 averag-
ing 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
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