Rainbow Electronics DS75LV User Manual

V

SC

SDA

SC

SDA

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 temperature­sensing 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

A block diagram of the DS75LV is shown in Figure 1
and detailed pin descriptions are given in Table 2.

OS

and T

HYST

).

APPLICATIONS

Personal Computers
Cellular Base Stations
Office Equipment
Any Thermally Sensitive System

PIN CONFIGURATION

L

O.S.

GND

DS75LVS—SO (150 mils)

L

O.S.

GND

DS75LVU—mSOP/mMAX

DS75L

2

3

DS75L

2

3

VDD

A

7

6

7

6

0

A

1

A

2

V

DD

A

0

A

1

A

2

DS75L

Digital Thermometer and Thermostat

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 mSOP (mMAX) and SO

Packages

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS75LVS+ -55°C to +125°C

DS75LVS+T&R -55°C to +125°C

DS75LVU+ -55°C to +125°C

DS75LVU+T&R -55°C to +125°C

Ordering Information continued at the end of the data sheet.

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 Tape­and-Reel

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DS75LV: Digital Thermometer and Thermostat

ABSOLUTE MAXIMUM RATINGS*

Voltage on VDD, Relative to Ground -0.3V to +4.0V
Voltage 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 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 £ VDD £ 3.7V.)

PARAMETER SYMBOL CONDITIONS MIN MAX UNITS

Supply Voltage VDD (Note 10) 1.7 3.7 V
Thermometer Error

(Note 2)

T

ERR

Input Logic High VIH (Note 1) 0.7 × VDD 5.5 V
Input Logic Low VIL (Note 1) -0.5 0.3 × VDD V

V

OL1

SDA Output Logic Low
Voltage (Note 1)

V

OL2

O.S. Saturation Voltage VOL

Input current each I/O pin 0.4 < V
I/O Capacitance C
Standby Current I

Active Current
(Notes 3, 4)

DD1

I

DD

I/O

AC ELECTRICAL CHARACTERISTICS

(-55°C to +125°C; 1.7V £ V

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

Resolution

£ 3.7V.)

DD

-25 to +100

-55 to +125

± 2.0
± 3.0

°C

3mA sink current 0 0.4

V

6mA sink current 0 0.6

4mA sink current
(Notes 1, 2)

< 0.9 VDD -10 +10

I/O

0.8 V

mA
10 pF
(Notes 3, 4) 2

Active Temp
Conversions

1000

mA

mA

Communication only 100

9 12 bits

9-bit conversions 25

Temperature Conversion
Time

t

CONVT

10-bit conversions 50

11-bit conversions 100

12-bit conversions 200

SCL Frequency f
Bus Free Time Between a

STOP and START
Condition
START and Repeated
START Hold Time from

400 KHz

SCL

t

(Note 5)

BUF

t

HD:STA

(Notes 5, 6)

1.3

600

ns

2 of 13

ms

ms

DS75LV: Digital Thermometer and Thermostat
Falling SCL
Low Period of SCL t
High Period of SCL t
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

(Note 5) 1.3

LOW

(Note 5) 0.6

HIGH

t

SU:STA

t

HD:DAT

t

SU:DAT

t

R

t

F

t

SS

t

SU:STO

C

B

(Note 5) 600 ns

(Notes 5, 8)

(Note 5)

(Notes 5, 7) 20 + 0.1CB

0

100

0.9

ns

300

(Notes 5, 7) 20 + 0.1CB 300 ns

0 50 ns

(Note 5) 600 ns

400 pF

ms
ms

ms

ns

Input Capacitance CI 5 pF
Serial Interface Reset Time t

SDA time low (Note 9) 75 325 ms

TIMEOUT

Note 1:
Note 2:

Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:

Note
10:

Table 1. Detailed Pin Description

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.

specified with O.S. pin open.

I

DD

specified with VDD at 3.0V and SDA, SCL = 3.0V, 0°C to 70°C.

I

DD

See Timing Diagram in Figure 2. All timing is referenced to 0.9 x V
After this period, the first clock pulse is generated.
For example, if C
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.

= 300pF, then tR[min] = tF[min] = 50ns.

B

and 0.1 x VDD.

DD

PIN SYMBOL PIN DESCRIPTION

1 SDA
2 SCL
3 O.S.
4 GND
5 A2
6 A1
7 A0
8 VDD

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.

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Figure 1. DS75LV Functional Block Diagram

GIS

S

GIS

GIS

ODU

C

C

A

A

A

0

A

CO

PRECISION

REFEREN

E

OVERSAMPLING

M

LATOR

V

SCL

SD

ADDRESS

AND

I/O CONTROL

2

CONFIGURATION

RE

TER

TEMPERATURE

RE

TER

TOS AND T

RE

TER

HYST

GND

Figure 2. Timing Diagram

DS75LV: Digital Thermometer and Thermostat

DIGITAL

IMATOR

DE

O.S.

THERMOSTAT

MPARATOR

RP

SDA

t

SCL

F

t

LOW

t

HD;S TA

S

t

R

t

HD;DAT

t

SU;DAT

t

F

t

SU;STA

t

HD;S TA

Sr P S

t

SP

t

SU;STO

t

R

t

BUF

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