DS18B20 Maxim Integrated Products, DS18B20 Datasheet - Page 6

• Manufacturer Part Number: DS18B20
• Description: IC THERM MICROLAN PROG-RES TO-92
• Manufacturer: Maxim Integrated Products

Specifications of DS18B20

• Function: Thermometer, Thermostat
• Topology: Register Bank, Scratchpad
• Sensor Type: Internal
• Sensing Temperature: -55°C ~ 125°C
• Output Type: 1-Wire®
• Output Alarm: Yes
• Output Fan: No
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -55°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: TO-92-3 (Standard Body), TO-226
• Full Temp Accuracy: +/- 2 C
• Digital Output - Bus Interface: Serial (1-Wire)
• Digital Output - Number Of Bits: 12 bit
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Figure 4. Supplying the Parasite-Powered DS18B20 During Temperature Conversions
Figure 5. Powering the DS18B20 with an External Supply
64-BIT LASERED ROM CODE
Each DS18B20 contains a unique 64–bit code (see Figure 6) stored in ROM. The least significant 8 bits
of the ROM code contain the DS18B20’s 1-Wire family code: 28h. The next 48 bits contain a unique
serial number. The most significant 8 bits contain a cyclic redundancy check (CRC) byte that is
calculated from the first 56 bits of the ROM code. A detailed explanation of the CRC bits is provided in
the CRC Generation section. The 64-bit ROM code and associated ROM function control logic allow the
DS18B20 to operate as a 1-Wire device using the protocol detailed in the 1-Wire Bus System section.
Figure 6. 64-Bit Lasered ROM Code
MSB
8-BIT CRC
µP
µP
LSB
V
PU
V
MSB
PU
4.7k
4.7k
48-BIT SERIAL NUMBER
1-Wire BUS
6 of 22
V
PU
1-Wire BUS
GND
DS18B20
DQ
LSB
V
DD
GND
DS18B20
MSB
DQ
V
8-BIT FAMILY CODE (28h)
DD
V
(EXTERNAL SUPPLY)
DD
TO OTHER
1-WIRE DEVICES
TO OTHER
1-WIRE DEVICES
DS18B20
LSB