DS18B20

2 of 22

ORDERING INFORMATION

PART

TEMP RANGE

PIN-PACKAGE

TOP MARK

DS18B20

-55

°C to +125°C

3 TO-92

18B20

DS18B20+

-55

°C to +125°C

3 TO-92

18B20

DS18B20/T&R

-55

°C to +125°C

3 TO-92 (2000 Piece)

18B20

DS18B20+T&R

-55

°C to +125°C

3 TO-92 (2000 Piece)

18B20

DS18B20-SL/T&R

-55

°C to +125°C

3 TO-92 (2000 Piece)*

18B20

DS18B20-SL+T&R

-55

°C to +125°C

3 TO-92 (2000 Piece)*

18B20

DS18B20U

-55

°C to +125°C

8

µSOP

18B20

DS18B20U+

-55

°C to +125°C

8

µSOP

18B20

DS18B20U/T&R

-55

°C to +125°C

8

µSOP (3000 Piece)

18B20

DS18B20U+T&R

-55

°C to +125°C

8

µSOP (3000 Piece)

18B20

DS18B20Z

-55

°C to +125°C

8 SO

DS18B20

DS18B20Z+

-55

°C to +125°C

8 SO

DS18B20

DS18B20Z/T&R

-55

°C to +125°C

8 SO (2500 Piece)

DS18B20

DS18B20Z+T&R

-55

°C to +125°C

8 SO (2500 Piece)

DS18B20

+Denotes a lead-free package. A “+” will appear on the top mark of lead-free packages.

T&R = Tape and reel.

*TO-92 packages in tape and reel can be ordered with straight or formed leads. Choose “SL” for straight leads. Bulk TO-92 orders are straight

leads only.

PIN DESCRIPTION

PIN

NAME

FUNCTION

SO

µSOP

TO-92

1, 2, 6,

7, 8

2, 3, 5,

6, 7

—

N.C.

No Connection

3

8

3

parasite power mode.

4

1

2

DQ

Data Input/Output. Open-drain 1-Wire interface pin. Also

provides power to the device when used in parasite power

mode (see the Powering the DS18B20 section.)

5

4

1

GND

Ground

OVERVIEW

Figure 1 shows a block diagram of the DS18B20, and pin descriptions are given in the Pin Description

table. The 64-bit ROM stores the device’s unique serial code. The scratchpad memory contains the 2-byte

temperature register that stores the digital output from the temperature sensor. In addition, the scratchpad

configuration register. The configuration register allows the user to set the resolution of the temperature-

(EEPROM), so they will retain data when the device is powered down.

The DS18B20 uses Maxim’s exclusive 1-Wire bus protocol that implements bus communication using

one control signal. The control line requires a weak pullup resistor since all devices are linked to the bus

via a 3-state or open-drain port (the DQ pin in the case of the DS18B20). In this bus system, the

microprocessor (the master device) identifies and addresses devices on the bus using each device’s unique

64-bit code. Because each device has a unique code, the number of devices that can be addressed on one