MAXIM DS75 User Manual
SC
SDA
SC
SDA
www.maxim-ic.com
FEATURES
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 Nine (Default) to 12 Bits
(0.5°C to 0.0625°C Resolution)
9-Bit Conversion Time is 150ms (Max)
Thermostatic Settings are User-Definable
Data is Read/Written Via 2-Wire Serial
(Interface (SDA and SCL Pins)
Multidrop Capability Simplifies Distributed
Temperature-Sensing Applications
Wide Power-Supply Range (+2.7V to
+5.5V).
Pin/software Compatible with the LM75
Available in 8-Pin μMAX® and SO
Packages. See Table 1 for Ordering
Information
Applications Include Personal Computers,
Cellular Base Stations, Office Equipment, or
Any Thermally Sensitive System
Digital Thermometer and Thermostat
PIN ASSIGNMENT
L
O.S.
GND
DS75S+ (8-Pin SO — 150mil)
DS75
2
3
VDD
A
7
0
A
6
1
A
2
V
L
O.S.
GND
DS75U+ (μMAX)
DS75
2
3
7
6
DD
A
0
A
1
A
2
PIN DESCRIPTION
SDA – Open-Drain Data I/O
SCL – Clock Input
GND – Ground
O.S. – Open-Drain Thermostat Output
A0 – Address Input
A1 – Address Input
– Address Input
A
2
V
– Power Supply
DD
DS75
DESCRIPTION
The DS75 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
DS75 defaults to 9-bit resolution for software compatibility with the LM75. Communication with the
DS75 is achieved via a simple 2–wire serial interface. Three address pins allow up to eight DS75 devices
to operate on the same 2–wire bus, which greatly simplifies distributed temperature sensing applications.
The DS75 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 userdefined trip-points (T
OS
and T
HYST
).
A block diagram of the DS75 is shown in Figure 1 and detailed pin descriptions are given in Table 2.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
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Table 1. ORDERING INFORMATION
ORDERING
NUMBER
DS75S+ DS75 (see note) DS75 in Lead-Free 150mil 8-Pin SO
DS75S+T&R DS75 (see note) DS75 in Lead-Free 150mil 8-Pin SO, 2500-Piece Tape-and-Reel
DS75U+ DS75 (see note)
DS75U+T&R DS75 (see note)
DS75S DS75 DS75 in 150mil 8-Pin SO
DS75S/T&R DS75 DS75 in 150mil 8-Pin SO, 2500-Piece Tape-and-Reel
DS75U DS75
DS75U/T&R DS75
Note: A "+" symbol will also be marked on the package near the Pin 1 indicator
PACKAGE
MARKING
DESCRIPTION
DS75 in Lead-Free 8-Pin μMAX
DS75 in Lead-Free 8-Pin μMAX, 3000-Piece Tape-and-Reel
DS75 in 8-Pin μMAX
DS75 in 8-Pin μMAX, 3000-Piece Tape-and-Reel
Table 2. DETAILED PIN DESCRIPTION
PIN SYMBOL DESCRIPTION
1 SDA Data input/output pin for 2-wire serial communication port. Open drain.
2 SCL Clock input pin for 2-wire serial communication port.
3 O.S. Thermostat output. Open drain.
4 GND
5 A2
6 A1
7 A0
8 VDD Supply Voltage. +2.7V to +5.5V supply pin.
Ground pin.
Address input pin.
Address input pin.
Address input pin.
DS75
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Figure 1. DS75 FUNCTIONAL BLOCK DIAGRAM
GIS
S
GIS
GIS
ODU
C
C
A
A
A
0
A
CO
DS75
VDD
SCL
SD
GND
PRECISION
REFEREN
E
OVERSAMPLING
M
LATOR
DIGITAL
IMATOR
DE
CONFIGURATION
RE
1
2
ADDRESS
AND
I/O CONTROL
TEMPERATURE
RE
TOS AND T
RE
TER
TER
TER
HYST
RP
O.S.
THERMOSTAT
MPARATOR
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DS75
ABSOLUTE MAXIMUM RATINGS*
Voltage on VDD, Relative to Ground –0.3V to +7.0V
Voltage on any other pin, Relative to Ground –0.3V to (V DD + 0.3V)
Operating Temperature –55°C to +125°C
Storage Temperature –55°C to +125°C
Soldering Temperature +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.
DC ELECTRICAL CHARACTERISTICS (-55°C to +125°C; 2.7V ≤ VDD ≤ 5.5V)
PARAMETER SYMBOL CONDITION MIN MAX UNITS NOTES
Supply Voltage VDD 2.7 5.5 V
Thermometer Error T
ERR
-25 to +100
-55 to +125
Input Logic High VIH 0.7VDD VDD+0.5 V 1
Input Logic Low VIL -0.5 0.3VDD V 1
SDA Output Logic Low
Voltage
V
V
OL1
OL2
O.S. Saturation Voltage VOL
Input current each I/O
pin
I/O Capacitance C
Standby Current I
I/O
DD1
Active Current IDD
10 pF
1 µA 3, 4
3 mA sink
current
6 mA sink
current
4 mA sink
current
0.4 < V
I/O
<
0.9 VDD
Active Temp.
Conversions
Communica-
tion only
0 0.4
0 0.6
0.8 V 1, 2
-10 +10
1000
100
± 2.0
± 3.0
°C
2
V 1
μA
µA 3, 4
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DS75
AC ELECTRICAL CHARACTERISTICS (-55°C to +125°C; 2.7V ≤ VDD ≤ 5.5V)
PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES
Resolution
Temperature
t
CONVT
Conversion Time
9-bit
conversions
10-bit
9 12 bits
150
ms
300
conversions
11-bit
600
conversions
12-bit
1200
conversions
SCL Frequency f
Bus Free Time
Between a STOP and
SCL
t
BUF
400 KHz
1.3
μs
5
START Condition
START and Repeated
START Hold Time
t
HD:STA
0.6
μs
5, 6
from Falling SCL
Low Period of SCL t
High Period of SCL t
Repeated START
Condition Setup Time
LOW
HIGH
t
SU:STA
1.3
0.6
0.6
μs
μs
μs
5
5
5
to Rising SCL
Data-Out Hold Time
from Falling SCL
Data-In Setup Time to
Rising SCL
Rise Time of SDA and
SCL
Fall Time of SDA and
t
HD:DAT
t
SU:DAT
tR 20 + 0.1CB
tF 20 + 0.1CB 300 ns 5, 7
0
0.9
100
ns 5
1000
μs
5
ns 5, 7
SCL
STOP Setup Time to
Rising SCL
Capacitive Load for
t
SU:STO
0.6
μs
5
CB 400 pF
Each Bus Line
Input Capacitance CI 5 pF
NOTES:
1. All voltages are referenced to ground.
2. Internal heating caused by O.S. loading will cause the DS75 to read approximately 0.5°C higher if
O.S. is sinking the max rated current.
3. I
specified with O.S. pin open.
DD
4. IDD specified with VDD at 5.0V and SDA, SCL = 5.0V, 0°C to 70°C.
5. See Timing Diagram in Figure 2. All timing is referenced to 0.9 x VDD and 0.1 x VDD.
6. After this period, the first clock pulse is generated.
7. For example, if CB = 300pF, then tR[min] = tF[min] = 50ns.
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