Dallas Semiconductor DS1731U-T-R, DS1731U, DS1631U, DS1631AU-T-R, DS1631AU Datasheet

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FEATURES

§ DS1631 and DS1631A Provide ±0.5°C

Accuracy over a 0°C to +70°C Range

§ DS1731 Provides ±1°C Accuracy over a

-10°C to +85°C Range

§ DS1631A Automatically Begins Taking

Temperature Measurements at Power-Up

§ Operating Temperature Range: -55°C to

+125°C (-67°F to +257°F)

§ Temperature Measurements Require No

External Components

§ Output Resolution is User-Selectable to 9,

10, 11, or 12 Bits

§ Wide Power-Supply Range (+2.7V to +5.5V)

§ Converts Temperature-to-Digital Word in

750ms (max)

§ Multidrop Capability Simplifies Distributed

Temperature-Sensing Applications

§ Thermostatic Settings are User-Definable

and Nonvolatile (NV)

§ Data is Read/Written Through 2-Wire Serial

Interface (SDA and SCL Pins)

§ All Three Devices are Available in 8-Pin

mSOP Packages and the DS1631 is Also
Available in a 150mil SO package—see
Table 1 for Ordering Information

PIN CONFIGURATIONS

DESCRIPTION

The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature
readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C
from 0°C to +70°C with 3.0V £ V

DD

£ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with

3.0V £ V

DD

£ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip

points (T

H

and TL). The TH and TL registers and thermometer configuration settings are stored in NV
EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically
begins taking temperature measurements at power-up, which allows it to function as a stand-alone
thermostat. Communication with the DS1631/DS1631A/DS1731 is achieved through a 2-wire serial
interface, and three address pins allow up to eight devices to be multidropped on the same 2-wire bus.

Pin descriptions for the DS1631/DS1631A/DS1731 are provided in Table 2 and user-accessible registers
are summarized in Table 3. A functional diagram is shown in Figure 1.

DS1631/DS1631A/DS1731

High-Precision Digital

Thermometer and Thermostat

www.maxim-ic.com

SO (150mil)

(DS1631Z)

SC

L

V

DD

A

0

A

1

A

2

GND

T

OUT

SDA

6

875

3

1

2

4

m

SOP

(DS1631U, DS1631AU, DS1731U)

SC

L

V

DD

A

0

A

1

A

2

GND

T

OUT

SDA

6

875

3

1

2

4

See Table 2 for Pin Descriptions

APPLICATIONS

§ Network Routers and Switches

§ Cellular Base Stations

§ Portable Products

§ Any Space-Constrained Thermally Sensitive

Product

DS1631/DS1631A/DS1731

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Table 1. ORDERING INFORMATION

ORDERING

NUMBER

PACKAGE
MARKING

DESCRIPTION

DS1631U D1631

DS1631 in 8-Pin mSOP

DS1631U/T&R D1631

DS1631 in 8-Pin mSOP, 3000-Piece Tape-and-Reel
DS1631Z DS1631Z DS1631 in 150mil 8-Pin SO
DS1631Z/T&R DS1631Z DS1631 in 150mil 8-Pin SO, 2500-Piece Tape-and-Reel
DS1631AU 1631A

DS1631A in 8-Pin mSOP
DS1631AU/T&R 1631A

DS1631A in 8-Pin mSOP, 3000-Piece Tape-and-Reel
DS1731U D1731

DS1731 in 8-Pin mSOP
DS1731U/T&R D1731

DS1731 in 8-Pin mSOP, 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.
3T

OUT

Thermostat Output Pin. Push-Pull.
4 GND Ground Pin
5A2Address Input Pin
6A1Address Input Pin
7A0Address Input Pin
8VDDSupply Voltage Pin. +2.7V to +5.5V Power-Supply Pin.

Figure 1. FUNCTIONAL DIAGRAM

CONFIGURATION REGISTER

A

ND CONTROL LOGIC

ADDRESS

AND

I/O CONTROL

A1A2A

0

SCL

SD

A

DIGITAL

COMPARATOR/LOGIC

T

H

REGISTER

TL REGISTER

T

OU

T

TEMPERATURE SENSOR

and DS ADC

TEMPERATURE REGISTER

V

DD

GND

DS1631/DS1631A/DS1731

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ABSOLUTE MAXIMUM RATINGS*

Voltage on any Pin Relative to Ground -0.5V to +6.0V
Operating Temperature Range -55°C to +125°C
Storage Temperature Range -55°C to +125°C
Solder Dip Temperature (10s) See IPC/JEDEC J-STD-020A Specification
Reflow Oven Temperature +220°C

* 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

(V

DD

= 2.7V to 5.5V; TA = -55°C to +125°C.)

PARAMETER SYMBOL CONDITION MIN MAX UNITS NOTES

Supply Voltage V

DD

2.7 5.5 V 1

0°C to +70°C,

3.0V £ V

DD

£ 5.5V

±0.5

0°C to +70°C,

2.7V £ V

DD

< 3.0V

±1

DS1631, DS1631A
Thermometer Error

T

ERR

-55°C to +125°C ±2

°C 2

-10°C to +85°C,

3.0V £ V

DD

£ 5.5V

±1

-10°C to +85°C,

2.7V £ V

DD

< 3.0V

±1.5

DS1731
Thermometer Error

T

ERR

-55°C to +125°C ±2

°C 2

Low-Level Input
Voltage

V

IL

-0.5 0.3 x V

DD

V

High-Level Input
Voltage

V

IH

0.7 x
V

DD

VDD + 0.3 V

V

OL1

3mA sink current 0 0.4

SDA Low-Level
Output Voltage

V

OL2

6mA sink current 0 0.6

V

Input Current Each
I/O Pin

0.4 < V

I/O

< 0.9V

DD

-10 +10 µA

Temperature
conversion

-55°C to +85°C

1

Temperature
conversion
+85°C to +125°C

1.25

mA

E2 write 400

Active Supply
Current

I

DD

Communication only 110

µA

3

Standby Supply
Current

I

STBY

0°C to +70°C 800 nA 4

V

OH

1mA source current 2.4 V 1

T

OUT

Output Logic

Voltage

V

OL

4mA sink current 0.4 V 1

DS1631/DS1631A/DS1731

4 of 14

AC ELECTRICAL CHARACTERISTICS

(V

DD

= 2.7V to 5.5V; TA = -55°C to +125°C.)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

9-bit resolution 93.75
10-bit
resolution

187.5

11-bit
resolution

375

Temperature
Conversion Time

t

TC

12-bit
resolution

750

ms

SCL Frequency f

SCL

0 400 kHz
Bus Free Time
Between a STOP and
START Condition

t

BUF

1.3 µs 5

START and Repeated
START Hold Time
from Falling SCL

t

HD:STA

0.6 µs 5, 6

Low Period of SCL t

LOW

1.3 µs 5

High Period of SCL t

HIGH

0.6 µs 5
Repeated START
Condition Setup Time
to Rising SCL

t

SU:STA

0.6 µs 5

Data-Out Hold Time
from Falling SCL

t

HD:DAT

0

0.9 µs 5

Data-In Setup Time to
Rising SCL

t

SU:DAT

100 ns 5

Rise Time of SDA and
SCL

t

R

20 + 0.1C

B

1000 ns 5, 7

Fall Time of SDA and
SCL

t

F

20 + 0.1C

B

300 ns 5, 7

STOP Setup Time to
Rising SCL

t

SU:STO

0.6 µs 5

Capacitive Load for
Each Bus Line

C

B

400 pF

I/O Capacitance C

I/O

10 pF

Input Capacitance C

I

5pF
Spike Pulse Width that
can be Suppressed by
Input Filter

t

SP

050ns

NOTES:

1) All voltages are referenced to GND.

2) See Figure 2 for Typical Operating Curves.

3) Specified with T

OUT

pin open; A0, A1, A2 = 0V or VDD; and f

SCL

³ 2Hz.

4) Specified with temperature conversions stopped; T

OUT

pin open; SDA = VDD; SCL = VDD; and A0, A1,

A2 = 0V or VDD.

5) See Timing Diagram in Figure 3. 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.

DS1631/DS1631A/DS1731

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EEPROM AC ELECTRICAL CHARACTERISTICS

(V

DD

= 2.7V to 5.5V; TA = -55°C to +125°C.)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

EEPROM Write Cycle Time t

wr

410ms

EEPROM Writes N

EEWR

-55°C to +55°C 50k Writes

EEPROM Data Retention t

EEDR

-55°C to +55°C 10 Years

Figure 2. TYPICAL OPERATING CURVES

Figure 3. TIMING DIAGRAM

All timing is referenced to 0.9 x VDD and 0.1 x VDD.

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 10203040 506070

+3

s

-3

s

Mean

REFERENCE TEMPERATURE (°C)

ERROR (°C)

DS1631/DS1631A

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

-10 0 10 20 30 40 50 60 70 80

+3

s

-3

s

Mean

REFERENCE TEMPERATURE (°C)

ERROR (°C)

DS1731