DS1822+ Maxim Integrated Products, DS1822+ Datasheet
DS1822+
Specifications of DS1822+
Related parts for DS1822+
DS1822+ Summary of contents
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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 ...
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... 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 ...
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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 ...
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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 ...
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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: ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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POWERING THE DS1822 section. 2 RECALL E [B8h] This command recalls the alarm trigger values (T places the data in ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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TIMING DIAGRAMS Figure DS1822 ...