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DS75LV
Digital Thermometer and Thermostat
www.maxim-ic.com
DESCRIPTION
This low-voltage (1.7V to 3.7V) digital thermometer
and thermostat provides 9-, 10-, 11-, or 12-bit digital
temperature readings over a -55°C to +125°C range
with
±2°C
accuracy over a -25°C to +100°C range. At
power-up, the DS75LV defaults to 9-bit resolution for
software compatibility with the LM75. Communication
with the DS75LV is achieved through a simple 2-wire
serial interface. Three address pins allow up to eight
DS75LV devices to operate on the same 2-wire bus,
which greatly simplifies distributed temperature-
sensing applications.
The DS75LV thermostat has a dedicated open-drain
output (O.S.) and programmable fault tolerance,
which allows the user to define the number of
consecutive error conditions that must occur before
O.S is activated. There are two thermostatic
operating modes that control thermostat operation
based on user-defined trip-points (T
OS
and T
HYST
).
A block diagram of the DS75LV is shown in Figure 1
and detailed pin descriptions are given in Table 1.
FEATURES
Operating Range from 1.7V to 3.7V
Temperature Measurements Require No
External Components
Measures Temperatures from -55°C to +125°C
(-67°F to +257°F)
±2°C
Accuracy Over a -25°C to +100°C Range
Thermometer Resolution is User-
Configurable from 9 (Default) to 12 Bits (0.5°C
to 0.0625°C Resolution)
9-Bit Conversion Time is 25ms (Max)
Thermostatic Settings are User-Definable
Data Read/Write Occurs Through a 2-Wire
Serial Interface (SDA and SCL Pins)
Data Lines Filtered Internally for Noise
Immunity (50ns Deglitch)
Bus Timeout Feature Prevents Lockup
Problems on 2-Wire Interface
Multidrop Capability Simplifies Distributed
Temperature-Sensing Applications
Pin/Software Compatible with the LM75
Available in 8-Pin
μSOP
(μMAX) and SO
Packages
APPLICATIONS
Personal Computers
Cellular Base Stations
Office Equipment
Any Thermally Sensitive System
ORDERING INFORMATION
PART
DS75LVS+
TEMP RANGE
-55°C to +125°C
PIN-PACKAGE
DS75LV
(150-mil) 8-SO
DS75LV
(150-mil) 8-SO,
2500 Piece
Tape-and-Reel
DS75LV
8-µSOP
(µMAX)
DS75LV
8-µSOP
(µMAX), 3000
Piece Tape-
and-Reel
PIN CONFIGURATION
SDA
SCL
O.S.
GND
1
8
DS75LVS+T&R
V
DD
A
0
A
1
A
2
DS75LVU+T&R
DS75LVU+
-55°C to +125°C
2
3
4
7
6
5
-55°C to +125°C
DS75LVS—SO (150 mils)
DS75L
-55°C to +125°C
SDA
SCL
O.S.
GND
1
8
V
DD
A
0
A
1
A
2
Ordering Information continued at the end of the data sheet.
DS75L
2
3
4
7
6
5
DS75LVU—μSOP/μMAX
1 of 13
112006
DS75LV: Digital Thermometer and Thermostat
ABSOLUTE MAXIMUM RATINGS*
Voltage on V
DD
, Relative to Ground
Voltage on Any Other Pin, Relative to Ground
Operating Temperature Range
Storage Temperature Range
Soldering Temperature
-0.3V to +4.0V
-0.3V to +6.0V
-55°C to +125°C
-55°C to +125°C
260°C for 10 seconds
These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation
sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
The Dallas Semiconductor DS75LV is built to the highest quality standards and manufactured for long-term
reliability. All Dallas Semiconductor devices are made using the same quality materials and manufacturing
methods. However, the DS75LV is not exposed to environmental stresses, such as burn-in, that some industrial
applications require. For specific reliability information on this product, please contact the factory in Dallas at (972)
371-4448.
DC ELECTRICAL CHARACTERISTICS
(-55°C to +125°C; 1.7V
≤
V
DD
≤
3.7V.)
PARAMETER
Supply Voltage
Thermometer Error
(Note 2)
Input Logic High
Input Logic Low
SDA Output Logic Low
Voltage (Note 1)
O.S. Saturation Voltage
Input current each I/O pin
I/O Capacitance
Standby Current
Active Current
(Notes 3, 4)
SYMBOL
V
DD
T
ERR
V
IH
V
IL
V
OL1
V
OL2
V
OL
C
I/O
I
DD1
I
DD
CONDITIONS
(Note 10)
-25 to +100
-55 to +125
(Note 1)
(Note 1)
3mA sink current
6mA sink current
4mA sink current
(Notes 1, 2)
0.4 < V
I/O
< 0.9 V
DD
(Notes 3, 4)
Active Temp
Conversions
Communication only
MIN
1.7
MAX
3.7
±
2.0
±
3.0
5.5
0.3 × V
DD
0.4
V
0
0.6
0.8
-10
+10
10
2
1000
100
V
μA
pF
μA
μA
UNITS
V
°C
V
V
0.7 × V
DD
-0.5
0
AC ELECTRICAL CHARACTERISTICS
(-55°C to +125°C; 1.7V
≤
V
DD
≤
3.7V.)
PARAMETER
Resolution
SYMBOL
CONDITION
MIN
9
TYP
MAX
12
25
50
ms
11-bit conversions
12-bit conversions
SCL Frequency
Bus Free Time Between a
STOP and START
Condition
START and Repeated
START Hold Time from
f
SCL
t
BUF
t
HD:STA
(Note 5)
(Notes 5, 6)
2 of 13
1.3
600
100
200
400
KHz
μs
ns
UNITS
bits
9-bit conversions
Temperature Conversion
Time
10-bit conversions
t
CONVT
DS75LV: Digital Thermometer and Thermostat
Falling SCL
Low Period of SCL
High Period of SCL
Repeated START Condition
Setup Time to Rising SCL
Data-Out Hold Time from
Falling SCL
Data-In Setup Time to
Rising SCL
Rise Time of SDA and SCL
(Receive)
Fall Time of SDA and SCL
(Receive)
Spike Suppression Filter
Time (Deglitch Filter)
STOP Setup Time to Rising
SCL
Capacitive Load for Each
Bus Line
Input Capacitance
Serial Interface Reset Time
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:
Note
10:
t
LOW
t
HIGH
t
SU:STA
t
HD:DAT
t
SU:DAT
t
R
t
F
t
SS
t
SU:STO
C
B
C
I
t
TIMEOUT
(Note 5)
(Note 5)
(Note 5)
(Notes 5, 8)
(Note 5)
(Notes 5, 7)
(Notes 5, 7)
1.3
0.6
600
0
100
20 + 0.1C
B
20 + 0.1C
B
0
0.9
μs
μs
ns
μs
ns
300
300
50
ns
ns
ns
ns
400
5
pF
pF
ms
(Note 5)
600
SDA time low (Note 9)
75
325
All voltages are referenced to ground.
Internal heating caused by O.S. loading will cause the DS75LV to read approximately 0.5°C higher if O.S. is sinking the max rated
current.
I
DD
specified with O.S. pin open.
I
DD
specified with V
DD
at 3.0V and SDA, SCL = 3.0V, 0°C to 70°C.
See Timing Diagram in Figure 2. All timing is referenced to 0.9 x V
DD
and 0.1 x V
DD
.
After this period, the first clock pulse is generated.
For example, if C
B
= 300pF, then t
R
[min] = t
F
[min] = 50ns.
The DS75LV provides an internal hold time of at least 75ns on the SDA signal to bridge the undefined region of SCL's falling edge.
This time-out applies only when the DS75LV is holding SDA low. Other devices can hold SDA low indefinitely and the DS75LV will
not reset.
The DS75LV has a maximum operating voltage of 3.7V. Contact Dallas Semiconductor for information on the availability of a 3.7V to
5.5V version of the DS75LV.
Table 1. Detailed Pin Description
PIN
1
2
3
4
5
6
7
8
SYMBOL
SDA
SCL
O.S.
GND
A
2
A
1
A
0
V
DD
PIN DESCRIPTION
Data Input/Output.
For 2-wire serial communication port. Open-drain.
Clock Input.
2-wire serial communication port.
Thermostat Output.
Open-drain.
Ground
Address Input
Address Input
Address Input
Supply Voltage.
+1.7V to +3.7V supply pin.
3 of 13
DS75LV: Digital Thermometer and Thermostat
Figure 1. DS75LV Functional Block Diagram
PRECISION
REFERENCE
OVERSAMPLING
MODULATOR
DIGITAL
DECIMATOR
V
DD
CONFIGURATION
REGISTER
ADDRESS
AND
I/O CONTROL
SCL
SDA
A
0
A
1
A
2
TEMPERATURE
REGISTER
O.S.
T
OS
AND T
HYST
REGISTERS
THERMOSTAT
COMPARATOR
R
P
GND
Figure 2. Timing Diagram
4 of 13
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