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參數資料
| 型號： | DS18B20+PAR |
| 廠商： | Maxim Integrated |
| 文件頁數： | 7/19頁 |
| 文件大小： | 221K |
| 描述： | IC THERM MICROLAN PROG-RES TO-92 |
| 產品培訓模塊： | 1-Wire Communications Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 500 |
| 功能： | 溫度計，恒溫計 |
| 傳感器類型： | 內部 |
| 感應溫度： | -55°C ~ 100°C |
| 精確度： | ±2°C（最小值） |
| 拓撲： | 寄存器庫，變簽式暫存器 |
| 輸出類型： | 1-Wire? |
| 輸出警報： | 是 |
| 輸出風扇： | 無 |
| 電源電壓： | 3 V ~ 5.5 V |
| 工作溫度： | -55°C ~ 100°C |
| 安裝類型： | 通孔 |
| 封裝/外殼： | TO-226-3、TO-92-3 標準主體 |
| 供應商設備封裝： | TO-92-3 |
| 包裝： | 管件 |
| 產品目錄頁面： | 1435 (CN2011-ZH PDF) |
DS18B20-PAR
7 of 19
and then compare this value to either the ROM code CRC (for ROM reads) or to the scratchpad CRC (for
scratchpad reads). If the calculated CRC matches the read CRC, the data has been received error free. The
comparison of CRC values and the decision to continue with an operation are determined entirely by the
bus master. There is no circuitry inside the DS18B20-PAR that prevents a command sequence from
proceeding if the DS18B20-PAR CRC (ROM or scratchpad) does not match the value generated by the
bus master.
The equivalent polynomial function of the CRC (ROM or scratchpad) is: CRC = X
8
+ X
5
+ X
4
+ 1
The bus master can re-calculate the CRC and compare it to the CRC values from the DS18B20-PAR
using the polynomial generator shown in Figure 8. This circuit consists of a shift register and XOR gates,
and the shift register bits are initialized to 0. Starting with the least significant bit of the ROM code or the
least significant bit of byte 0 in the scratchpad, one bit at a time should shifted into the shift register.
After shifting in the 56
th
bit from the ROM or the most significant bit of byte 7 from the scratchpad, the
polynomial generator will contain the re-calculated CRC. Next, the 8-bit ROM code or scratchpad CRC
from the DS18B20-PAR must be shifted into the circuit. At this point, if the re-calculated CRC was
correct, the shift register will contain all 0s. Additional information about the Dallas 1-Wire cyclic
redundancy check is available in Application Note 27 entitled Understanding and Using Cyclic
Redundancy Checks with Dallas Semiconductor Touch Memory Products.
CRC GENERATOR Figure 8
1-WIRE BUS SYSTEM
The 1-Wire bus system uses a single bus master to control one or more slave devices. The DS18B20-
PAR is always a slave. When there is only one slave on the bus, the system is referred to as a single-
drop system; the system is multi-drop if there are multiple slaves on the bus.
All data and commands are transmitted least significant bit first over the 1-Wire bus.
The following discussion of the 1-Wire bus system is broken down into three topics: hardware
configuration, transaction sequence, and 1-Wire signaling (signal types and timing).
HARDWARE CONFIGURATION
The 1-Wire bus has by definition only a single data line. Each device (master or slave) interfaces to the
data line via an open drain or 3state port. This allows each device to release the data line when the
device is not transmitting data so the bus is available for use by another device. The 1-Wire port of the
DS18B20-PAR (the DQ pin) is open drain with an internal circuit equivalent to that shown in Figure 9.
The 1-Wire bus requires an external pullup resistor of approximately 5 k? thus, the idle state for the 1-
Wire bus is high. If for any reason a transaction needs to be suspended, the bus MUST be left in the idle
state if the transaction is to resume. Infinite recovery time can occur between bits so long as the 1-Wire
bus is in the inactive (high) state during the recovery period. If the bus is held low for more than 480 約,
all components on the bus will be reset. In addition, to assure that the DS18B20-PAR has sufficient
supply current during temperature conversions, it is necessary to provide a strong pullup (such as a
MOSFET) on the 1-Wire bus whenever temperature conversions or EEPROM writes are taking place (as
described in the PARASITE POWER section).
(MSB)
(LSB)
XOR
XOR
XOR
INPUT
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相關代理商/技術參數 |
參數描述 |
|---|---|
| DS18B20-PAR/T&R | 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor |
| DS18B20-PAR_07 | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:1-Wire Parasite-Power Digital Thermometer |
| DS18B20-PAR+T&R | 制造商:Maxim Integrated Products 功能描述: 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 1-WIRE 3PIN TO-92 - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC THERM MICROLAN PROG-RES TO-92 制造商:Maxim Integrated Products 功能描述:Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr |
| DS18B20-PAR+T&R | 功能描述:板上安裝溫度傳感器 Prgmble Resolution 1-Wire Parasite Pwr RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor |
| DS18B20-SL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Programmable Resolution 1-Wire Digital Thermometer |
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