DS1721S

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P17

DS1721

13 of 17

SAMPLE COMMAND SEQUENCE Table 6

Example: Bus master programs the DS1721 for 11-bit conversions in the continuous mode with an active

low state for the thermostat output. It then programs TH=50°C and TL=45°C and starts temperature

conversions.

BUS MASTER

MODE

DS1721

MODE

DATA (MSB

FIRST)

COMMENTS

TX RX START Bus Master initiates a START condition

TX RX <address, 0>

Bus Master sends DS1721 address; R/ W = 0

RX TX ACK DS1721 generates acknowledge bit

TX RX ACh Bus Master sends access configuration protocol

RX TX ACK DS1721 generates acknowledge bit

TX RX 08h Bus Master programs configuration register as

described above. This will also clear thermostat

flags

RX TX ACK DS1721 generates acknowledge bit

TX RX START Bus Master Initiates a REPEATED START

condition

TX RX <address, 0>

Bus Master sends DS1721 address; R/ W = 0

RX TX ACK DS1721 generates acknowledge bit

TX RX A1h Bus Master sends access TH protocol

RX TX ACK DS1721 generates acknowledge bit

TX RX 32h Bus Master writes MSB of TH (50°C)

RX TX ACK DS1721 generates acknowledge bit

TX RX 00h Bus Master writes LSB of TH (50°C)

RX TX ACK DS1721 generates acknowledge bit

TX RX START Bus Master initiates a REPEATED START

condition

TX RX <address, 0>

Bus Master sends DS1721 address; R/ W = 0

RX TX ACK DS1721 generates acknowledge bit

TX RX A2h Bus Master sends access TL protocol

RX TX ACK DS1721 generates acknowledge bit

TX RX 2Dh Bus Master writes MSB of TL (45°C)

RX TX ACK DS1721 generates acknowledge bit

TX RX 00h Bus Master writes LSB of TL (45°C)

RX TX ACK DS1721 generates acknowledge bit

TX RX START Bus Master initiates a REPEATED START

condition

TX RX <address, 0>

Bus Master sends DS1721 address; R/ W = 0

RX TX ACK DS1721 generates acknowledge bit

TX RX 51h Bus Master sends start convert protocol

RX TX ACK DS1721 generates acknowledge bit

TX RX STOP Bus Master initiates STOP condition

DS1721

14 of 17

ABSOLUTE MAXIMUM RATINGS*

Voltage on VDD, Relative to Ground -0.3V to +6.0V

Voltage on any other pin, Related to Ground -0.3V to +6.0V

Operating Temperature -55°C to +125°C

Storage Temperature -55°C to +125°C

Soldering Temperature 260°C for 10 seconds

* This is a stress rating 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.

RECOMMENDED DC OPERATING CONDITIONS

(-55°C to +125°C; 2.7V £ V

DD

£ 5.5V)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

Supply Voltage V

DD

2.7 5.5 V 1

DC ELECTRICAL CHARACTERISTICS (-55°C to +125°C; 2.7V £ V

DD

£ 5.5V)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

Input Logic High V

IH

0.7

V

DD

V

DD

+0.3

V 1

Input Logic Low V

IL

-0.5

0.3

V

DD

V 1

V

OL1

3 mA sink

current

0 0.4 V 1

SDA Output Logic

Low Voltage

V

OL2

6 mA sink

current

0 0.6 V 1

V

OH

1 mA source

current

2.4 V 1

T

OUT

Output Logic

Voltage

V

OL

4 mA sink

current

0.4 V 1

Input Current Each

I/O Pin

0.4V £ V

I/O

£ 0.9 V

DD

-10 +10 µA 2

I/O Capacitance C

I/O

10 pF

Standby Current I

DD1

0.8 µA 3, 4

Temperature

Conversions,

-55°C to +85°C

+85°C to +125°C

1000

1250

µA 3, 4

Communication

only

110 µA 3, 4

Active Current I

DD

EEPROM Write 400 µA 3,4

DS1721

15 of 17

DC ELECTRICAL CHARACTERISTICS:

DIGITAL THERMOMETER (-55°C to +125°C; 2.7V £ V

DD

£ 5.5V)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

-10°C to +85°C,

3.0V≤V

DD

≤5.5V

±1.0 °C

-10°C to +85°C,

2.7V≤V

DD

<3.0V

±1.5 °C

DS1721

Thermometer Error

T

ERR

-55°C to +125°C ±2.0 °C

Resolution 9 12 bits

9-bit

Conversions

93.75

10-bit

Conversions

187.5

11-bit

Conversions

375

Conversion Time t

CONVT

12-bit

Conversions

750

ms

AC ELECTRICAL CHARACTERISTICS:

2-WIRE INTERFACE (-55°C to +125°C; V

DD

=2.7V to 5.5V)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

SCL Clock

Frequency

f

SCL

Fast Mode

Standard Mode

0

0

400

100

KHz

Bus Free Time

Between a STOP

and START

Condition

t

BUF

Fast Mode

Standard Mode

1.3

4.7

µs

Hold Time

(Repeated) START

Condition

t

HD:STA

Fast Mode

Standard Mode

0.6

4.0

µs 5

Low Period of

SCL Clock

t

LOW

Fast Mode

Standard Mode

1.3

4.7

µs

High Period of

SCL Clock

t

HIGH

Fast Mode

Standard Mode

0.6

4.0

µs

Setup Time for a

Repeated START

Condition

t

SU:STA

Fast Mode

Standard Mode

0.6

4.7

µs

Data Hold Time t

HD:DAT

Fast Mode

Standard Mode

0

0

0.9 µs 6

Data Set-up Time t

SU:DAT

Fast Mode

Standard Mode

100

250

ns 7

Rise Time of both

SDA and SCL

Signals

t

R

Fast Mode

Standard Mode

20+0.1

C

B

300

1000

ns 7

Fall Time of both

SDA and SCL

Signals

t

F

Fast Mode

Standard Mode

20+0.1

C

B

300

1000

ns 8

Set-up time for

STOP Condition

t

SU:STO

Fast Mode

Standard Mode

0.6

4.0

µs

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P17

DS1721S

Mfr. #:

Manufacturer:

Description:

SENSOR DIGITAL -55C-125C 8SOIC

Lifecycle:

New from this manufacturer.

Delivery:

DHL FedEx Ups TNT EMS

Payment:

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