DS18B20

Part: DS18B20 from Maxim Integrated Products

Type: Programmable Resolution 1-Wire Digital Thermometer

Description: The DS18B20 is a digital thermometer that provides 9-bit to 12-bit Celsius temperature measurements over a 1-Wire bus, operating from 3.0V to 5.5V, with ±0.5°C accuracy from -10°C to +85°C, and supporting parasite power mode.

Operating Conditions:

• Supply voltage: +3.0V to +5.5V
• Operating temperature: -55°C to +125°C
• Resolution: 9 bits to 12 bits

Absolute Maximum Ratings:

• Max voltage on any pin relative to ground: +6.0V
• Max junction/storage temperature: +125°C

Key Specs:

• Temperature measurement range: -55°C to +125°C
• Accuracy: ±0.5°C from -10°C to +85°C
• Programmable resolution: 9 bits to 12 bits
• Standby current (I DDS): 750 nA (min) to 1000 nA (max) (up to +70°C)
• Active current (I DD): 1 mA (min) to 1.5 mA (max) (V DD = 5V)
• 12-bit temperature conversion time (t CONV): 750 ms (max)
• EEPROM writes (N EEWR): 50k writes (-55°C to +55°C)
• EEPROM data retention (t EEDR): 10 years (-55°C to +55°C)

Features:

• Unique 1-Wire interface requires only one port pin for communication
• Integrated temperature sensor and EEPROM
• No external components required
• Parasitic power mode requires only 2 pins for operation (DQ and GND)
• Simplifies distributed temperature-sensing applications with multidrop capability
• Each device has a unique 64-bit serial code stored in on-board ROM
• Flexible user-definable nonvolatile (NV) alarm settings with alarm search command

Applications:

• Thermostatic Controls
• Industrial Systems
• Consumer Products
• Thermometers
• Thermally Sensitive Systems

Package:

• 8-Pin SO (150 mils)
• 8-Pin μSOP
• 3-Pin TO-92

• Unique 1-Wire ® Interface Requires Only One Port Pin for Communication
• Reduce Component Count with Integrated Temperature Sensor and EEPROM
• Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
• ±0.5°C Accuracy from -10°C to +85°C
• Programmable Resolution from 9 Bits to 12 Bits
• No External Components Required
• Parasitic Power Mode Requires Only 2 Pins for Operation (DQ and GND)
• Simplifies Distributed Temperature-Sensing Applications with Multidrop Capability
• Each Device Has a Unique 64-Bit Serial Code Stored in On-Board ROM
• Flexible User-Definable Nonvolatile (NV) Alarm Settings with Alarm Search Command Identifies Devices with Temperatures Outside Programmed Limits
• Available in 8-Pin SO (150 mils), 8-Pin μSOP, and 3-Pin TO-92 Packages

• Thermostatic Controls
• Industrial Systems
• Consumer Products
• Thermometers
• Thermally Sensitive Systems

Ordering Information appears at end of data sheet.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

(-55°C to +125°C; V DD = 3.0V to 5.5V)

Note 1:

All voltages are referenced to ground.

Note 2: The Pullup Supply Voltage specification assumes that the pullup device is ideal, and therefore the high level of the pullup is equal to V PU . In order to meet the V IH spec of the DS18B20, the actual supply rail for the strong pullup transis- tor must include margin for the voltage drop across the transistor when it is turned on; thus: V PU_ACTUAL = V PU_IDEAL + VTRANSISTOR .

Note 3: See typical performance curve in Figure 1. Thermometer Error limits are 3-sigma values.

Note 4: Logic-low voltages are specified at a sink current of 4mA.

Note 5: To guarantee a presence pulse under low voltage parasite power conditions, V ILMAX may have to be reduced to as low as 0.5V.

Note 6: Logic-high voltages are specified at a source current of 1mA.

Note 7: Standby current specified up to +70°C. Standby current typically is 3μA at +125°C.

Note 8: To minimize I DDS , DQ should be within the following ranges: GND ≤ DQ ≤ GND + 0.3V or V DD - 0.3V ≤ DQ ≤ V DD.

Note 9: Active current refers to supply current during active temperature conversions or EEPROM writes.

Note 10: DQ line is high ('high-Z' state).

Note 11: Drift data is based on a 1000-hour stress test at +125°C with V DD = 5.5V.

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Voltage Range 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 Temperature ...............................Refer to the IPC/JEDEC

J-STD-020 Specification.

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.