Board Mount Temperature Sensors IC THERMOMETER ECONO DIG

DS1822+

Manufacturer Part NumberDS1822+
DescriptionBoard Mount Temperature Sensors IC THERMOMETER ECONO DIG
ManufacturerMaxim Integrated Products
DS1822+ datasheet
 

Specifications of DS1822+

Temperature ThresholdProgrammableFull Temp Accuracy+/- 2 C
Package / CaseTO-92Digital Output - Bus Interface1-Wire
Digital Output - Number Of Bits9 bit to 12 bitSupply Voltage (max)5.5 V
Supply Voltage (min)3 VMaximum Operating Temperature+ 125 C
Minimum Operating Temperature- 55 COutput TypeDigital
Supply Current1.5 mAIc Output TypeDigital
Sensing Accuracy Range± 2°CSupply Voltage Range3V To 5.5V
Resolution (bits)12bitSensor Case StyleTO-92
No. Of Pins3Accuracy %2°C
Rohs CompliantYesLead Free Status / RoHS StatusLead free / RoHS Compliant
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FEATURES
®
Unique 1-Wire
interface requires only one
port pin for communication.
Each device has a unique 64-bit serial code
stored in an on-board ROM.
Multidrop capability simplifies distributed
temperature-sensing applications.
Requires no external components.
Can be powered from data line. Power supply
range is 3.0V to 5.5V.
Measures temperatures from -55°C to +125°C
(-67°F to +257°F).
±2.0°C accuracy from -10°C to +85°C.
Thermometer resolution is user-selectable
from 9 to 12 bits.
Converts temperature to 12-bit digital word in
750ms (max.)
User-definable
nonvolatile
settings.
Alarm
search
command
addresses devices whose temperature is
outside of programmed limits (temperature
alarm condition).
Software compatible with the DS18B20.
Applications include thermostatic controls,
industrial
systems,
consumer
thermometers, or any thermally sensitive
system.
DESCRIPTION
The DS1822 digital thermometer provides 9- to 12-bit centigrade temperature measurements and has an
alarm function with NV user-programmable upper and lower trigger points. The DS1822 communicates
over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a
central microprocessor. It has an operating temperature range of –55°C to +125°C and is accurate to
±2.0°C over the range of –10°C to +85°C. In addition, the DS1822 can derive power directly from the
data line (“parasite power”), eliminating the need for an external power supply.
Each DS1822 has a unique 64-bit serial code, which allows multiple DS1822s to function on the 1-Wire
bus; thus, it is simple to use one microprocessor to control many DS1822s distributed over a large area.
Applications that can benefit from this feature include HVAC environmental controls, temperature
monitoring systems inside buildings, equipment or machinery, and process monitoring and control
systems.
1-Wire is a registered trademark of Dallas Semiconductor.
PIN ASSIGNMENT
DALLAS
1822
1 2 3
1
2 3
(NV)
alarm
(BOTTOM VIEW)
identifies
and
TO-92
(DS1822)
PIN DESCRIPTION
GND - Ground
products,
DQ
- Data In/Out
V
- Power Supply Voltage
DD
NC
- No Connect
1 of 21
DS1822
Econo 1-Wire Digital
Thermometer
NC
NC
8
1
NC
NC
2
7
V
NC
3
6
DD
DQ
GND
4
5
8-Pin 150mil SO
(DS1822Z)
101107

DS1822+ Summary of contents

  • Page 1

    FEATURES ® Unique 1-Wire interface requires only one port pin for communication. Each device has a unique 64-bit serial code stored in an on-board ROM. Multidrop capability simplifies distributed temperature-sensing applications. Requires no external components. Can be powered from ...

  • Page 2

    ... ORDER INFORMATION ORDERING PACKAGE NUMBER MARKING DS1822 1822 DS1822/T&R 1822 DS1822+ 1822 (See Note) DS1822+T&R 1822 (See Note) DS1822Z DS1822 DS1822Z/T&R DS1822 DS1822Z+ DS1822 (See Note) DS1822Z+T&R DS1822 (See Note) Note: A “+” symbol will also be marked on the package. DETAILED PIN DESCRIPTIONS Table 1 ...

  • Page 3

    DS1822 BLOCK DIAGRAM Figure PARASITE POWER 4.7K CIRCUIT DQ INTERNAL V GND 64-BIT ROM DD AND 1-wire PORT POWER SUPPLY SENSE DS1822 MEMORY CONTROL LOGIC TEMPERATURE SENSOR ALARM HIGH TRIGGER ...

  • Page 4

    OPERATION—MEASURING TEMPERATURE The core functionality of the DS1822 is its direct-to-digital temperature sensor. The resolution of the temperature sensor is user-configurable to 9, 10, 11 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively. The default ...

  • Page 5

    OPERATION—ALARM SIGNALING After the DS1822 performs a temperature conversion, the temperature value is compared to the user- defined two’s complement alarm trigger values stored in the 1-byte T The sign bit (S) indicates if the value is positive or negative: ...

  • Page 6

    The use of parasite power is not recommended for temperatures above 100°C since the DS1822 may not be able to sustain communications due to the higher leakage currents that can exist at these temperatures. For applications in which such temperatures ...

  • Page 7

    MEMORY The DS1822’s memory is organized as shown in Figure 7. The memory consists of an SRAM scratchpad with NV EEPROM storage for the high and low alarm trigger registers (T register. Note that if the DS1822 alarm function is ...

  • Page 8

    CONFIGURATION REGISTER Byte 4 of the scratchpad memory contains the configuration register, which is organized as illustrated in Figure 8. The user can set the conversion resolution of the DS1822 using the R0 and R1 bits in this register as ...

  • Page 9

    Application Note 27 entitled Understanding and Using Cyclic Redundancy Checks with Dallas Semiconductor Touch Memory Products. CRC GENERATOR Figure 9 (MSB) 1-WIRE BUS SYSTEM The 1-Wire bus system uses a single bus master to control one or ...

  • Page 10

    TRANSACTION SEQUENCE The transaction sequence for accessing the DS1822 is as follows: Step 1. Initialization Step 2. ROM Command (followed by any required data exchange) Step 3. DS1822 Function Command (followed by any required data exchange very important ...

  • Page 11

    SKIP ROM [CCh] The master can use this command to address all devices on the bus simultaneously without sending out any ROM code information. For example, the master can make all DS1822s on the bus perform simultaneous temperature conversions by ...

  • Page 12

    POWERING THE DS1822 section. 2 RECALL E [B8h] This command recalls the alarm trigger values (T places the data in ...

  • Page 13

    ROM COMMANDS FLOW CHART Figure 11 Initialization Sequence 33h N READ ROM COMMAND Y DS1822 T X FAMILY CODE 1 BYTE DS1822 T X SERIAL NUMBER 6 BYTES DS1822 T X CRC BYTE MASTER T X RESET PULSE DS1822 T ...

  • Page 14

    DS1822 FUNCTION COMMANDS FLOW CHART Figure 12 44h MASTER T CONVERT X FUNCTION TEMPERATURE COMMAND ? Y N PARASITE POWER ? DS1822 BEGINS CONVERSION DEVICE N CONVERTING TEMPERATURE ? Y MASTER MASTER R “0s” R “1s” B4h N ...

  • Page 15

    SIGNALING The DS1822 uses a strict 1-Wire communication protocol to insure data integrity. Several signal types are defined by this protocol: reset pulse, presence pulse, write 0, write 1, read 0, and read 1. All of these signals, with ...

  • Page 16

    The DS1822 samples the 1-Wire bus during a window that lasts from 15μs to 60μs after the master initiates the write time slot. If the bus is high during the sampling window written to the DS1822. If ...

  • Page 17

    DS1822 is valid for 15μs after the falling edge that initiated the read time slot. Therefore, the master must release the bus and then sample the bus state within 15μs from the start of the slot. Figure ...

  • Page 18

    DS1822 OPERATION EXAMPLE 1 In this example there are multiple DS1822s on the bus and they are using parasite power. The bus master initiates a temperature conversion in a specific DS1822 and then reads its scratchpad and recalculates the CRC ...

  • Page 19

    ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Range Storage Temperature Range Solder Dip Temperature Reflow Oven Temperature *These are stress ratings only and functional operation of the device at these or any other conditions above ...

  • Page 20

    AC ELECTRICAL CHARACTERISTICS: NV MEMORY PARAMETER NV Write Cycle Time EEPROM Writes EEPROM Data Retention AC ELECTRICAL CHARACTERISTICS PARAMETER Temperature Conversion Time Time to Strong Pullup On Time Slot Recovery Time Write 0 Low Time Write 1 Low Time Read ...

  • Page 21

    TIMING DIAGRAMS Figure DS1822 ...