MAXIM DS75LX Technical data
SC
SDA
μ
SC
SDA
www.maxim-ic.com
GENERAL 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 DS75LX defaults to 9-bit resolution for
software compatibility with the LM75. Communication
with the DS75LX is achieved through a simple 2-wire
serial interface. Three tri-state address pins allow up
to 27 DS75LX devices to operate on the same 2-wire
bus, which greatly simplifies distributed temperaturesensing applications.
The DS75LX thermostat has a dedicated open-drain
output (O.S.) and programmable fault tolerance,
which allow 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
).
APPLICATIONS
Any Thermally Sensitive System
Cellular Base Stations
Telecom Switches and Routers
Servers
PIN CONFIGURATIONS
V
DD
A
7
0
A
6
1
A
2
L
O.S.
GND
LX
2
3
SO (150 mils)
DS75
V
DD
7
A
0
6
A
1
A
2
L
O.S.
GND
DS75
LX
2
3
SOP/μMAX
DS75LX
Digital Thermometer and Thermostat
with Extended Addressing
FEATURES
1.7V to 3.7V Operating Range
Tri-State Address Pins Allow Up to 27 Unique
Bus Addresses
Temperature Measurements Require No
External Components
Measures Temperatures from -55°C to +125°C
(-67°F to +257°F)
±2°C Accuracy from -25°C to +100°C
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 is Read/Written Through 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
Packages
ORDERING INFORMATION
PART TEMP RANGE
DS75LXS+ -55°C to +125°C
DS75LXS+T&R -55°C to +125°C
DS75LXU+ -55°C to +125°C
DS75LXU+T&R -55°C to +125°C
+ Denotes lead-free package.
T&R denotes tape-and-reel.
Note: A “+” symbol will also be marked on the package near the pin 1 indicator.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
®
) and SO
PIN
PACKAGE
8 SO
(150 mils)
8 SO
(150 mils),
2500 Piece
8 µSOP
(µMAX)
8 µSOP
(µMAX),
3000 Piece
1 of 13 050307
DS1386/DS1386P
ABSOLUTE MAXIMUM RATINGS
Voltage Range on VDD, Relative to Ground -0.3V to +4.0V
Voltage Range on Any Other Pin, Relative to Ground -0.3V to +6.0V
Operating Temperature Range -55°C to +125°C
Storage Temperature Range -55°C to +125°C
Soldering Temperature See IPC/JEDEC J-STD-020
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 DS75LX 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 DS75LX is not exposed to environmental stresses, such as burn-in, that some industrial
applications require. For specific reliability information on this product, contact the factory in Dallas at (972) 371-
4448.
DC ELECTRICAL CHARACTERISTICS
(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C.)
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
Supply Voltage V
Thermometer Error
(Note 2)
Input Logic-High SDA,
SCL
Input Logic-Low SDA,
SCL
SDA Output Logic-Low
Voltage (Note 3)
O.S. Saturation Voltage V
DD
T
ERR
V
IH
V
IL
V
OL1
V
OL2
OL
Input Current SDA, SCL 0.4 < V
I/O Capacitance C
Address Input Sink
Current
Address Input Source
Current
Address Voltage High V
Address Voltage Low V
Standby Current I
(Notes 1, 4, 5)
I
LAH
I
LAL
DD1
I
I/O
AH
AL
DD
(Note 1) 1.7 3.7 V
-25°C to +100°C
-55°C to +125°C
(Note 3) 0.7 x V
V
DD
- 0.3 0.3 x V
SS
±2.0
±3.0
V
+ 0.3 V
DD
DD
°C
V
3mA sink current 0 0.4
6mA sink current 0 0.6
4mA sink current
(Notes 2, 3)
< 0.9V
I/O
DD
0.8 V
-10 +10 µA
V
10 pF
A0, A1, or A2 tied to V
(Notes 4, 5)
A0, A1, or A2 tied to GND
(Notes 4, 5)
(Note 6) V
(Note 6) V
DD
0.2 3.5 µA
0.2 3.5 µA
- .04 V
DD
+ .04 V
SS
(Notes 4, 5) 13 µA
Active temp conversions 1000 Active Current
Communication only 100
µA
AC ELECTRICAL CHARACTERISTICS
(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Resolution
9 12 Bits
Temperature Conversion
Time
t
CONVT
9-bit conversions 25
10-bit conversions 50
ms
11-bit conversions 100
12-bit conversions 200
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DS75LX: Digital Thermometer and Thermostat with Extended Addressing
SCL Frequency f
SCL
400 kHz
AC ELECTRICAL CHARACTERISTICS (continued)
(1.7V ≤ VDD ≤ 3.7V, TA = -55°C to +125°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Bus Free Time Between
a STOP and START
Condition
START and Repeated
START Hold Time from
Falling SCL
Low Period of SCL t
High Period of SCL t
t
BUF
t
HD:STA
LOW
HIGH
(Note 7)
(Notes 7, 8)
(Note 7) 1.3 µs
(Note 7) 0.6 µs
1.3
600
µs
ns
Repeated START
Condition Setup Time to
t
SU:STA
(Note 7) 600 ns
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)
t
HD:DAT
t
SU:DAT
t
R
t
F
(Notes 7, 9) 0 0.9 µs
(Note 7)
(Notes 7, 10)
(Notes 7, 10)
100
20 +
0.1C
20 +
0.1C
B
B
B
B
ns
300 ns
300 ns
Spike Suppression
Filter Time (Deglitch
t
SS
0 50 ns
Filter)
STOP Setup Time to
Rising SCL
Capacitive Load for Each
Bus Line
Input Capacitance C
Serial Interface Reset
Time
Note 1: VDD must be decoupled with a high-quality 0.1µF bypass capacitor. X5R or X7R ceramic surface-mount capacitors are Note 2: Note 3: All voltages are referenced to ground.
Note 4: I Note 5: Note 6: Address pins A0, A1, A2 are directly connected to V Note 7: See the timing diagram (Figure 1). All timing is referenced to 0.9 x VDD and 0.1 x VDD. Note 8: After this period, the first clock pulse is generated. Note 9: The DS75LX provides an internal hold time of at least 75ns on the SDA signal to bridge the undefined region of SCL's falling
Note 10: For example, if C Note 11: This timeout applies only when the DS75LX is holding SDA low. Other devices can hold SDA low indefinitely and the DS75LX
Note 12: The DS75LX is available with timeout feature disabled upon special order. Contact Factory.
recommended.
Internal heating caused by O.S. loading causes the DS75LX to read approximately 0.5°C higher if O.S. is sinking the max
rated current.
specified with O.S. pin open and A0–A2 pins grounded.
DD
and address leakage specified with VDD at 3.0V and SDA, SCL = 3.0V at 0°C to +70°C.
I
DD
edge.
B
will not reset.
t
SU:STO
B 400 pF
C
B
I
t
TIMEOUT
= 300pF, then tR[min] = tF[min] = 50ns.
(Note 7) 600 ns
5 pF
SDA time low
(Notes 11, 12)
, VSS, or floating with less than 50pF capacitive load.
DD
75 325 ms
PIN DESCRIPTION
PIN NAME FUNCTION
1 SDA Data Input/Output for 2-Wire Serial Communication Port (Open Drain)
2 SCL Clock Input for 2-Wire Serial Communication Port
3 O.S. Thermostat Output Open Drain
4 GND Ground
5 A
6 A
7 A
8 V
2
1
0
DD
Address Input
Address Input
Address Input
Supply Voltage. +1.7V to +3.7V supply pin. VDD must have an external bypass
capacitor to GND. 0.1µF X5R or X7R ceramic SMT caps recommended.
3 of 13
BLOCK DIAGRAM
GIS
S
GIS
GIS
ODU
C
C
A1A
A
0
A
CO
PRECISION
REFEREN
E
V
DD
SCL
SD
ADDRESS
AND
I/O CONTROL
2
GND
Figure 1. Timing Diagram
DS75LX: Digital Thermometer and Thermostat with Extended Addressing
OVERSAMPLING
RE
RE
RE
LATOR
TER
TER
HYST
TER
M
CONFIGURATION
TEMPERATURE
TOS AND T
DIGITAL
IMATOR
DE
THERMOSTAT
MPARATOR
O.S.
R
P
4 of 13
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