参数资料
型号: DS2450
英文描述: 1-Wire Quad A/D Converter
中文描述: 四路、1-Wire A/D转换器
文件页数: 11/24页
文件大小: 523K
代理商: DS2450
DS2450
11 of 24
102199
With V
CC
power supply the bus master may either send a reset pulse to exit the Convert command or
continuously generate read data time slots. As long as the DS2450 is busy with conversions the bus
master will read 0’s. After the conversion is completed the bus master will receive 1’s instead. Since in a
open-drain environment a single 0 overwrites multiple 1’s the bus master can monitor multiple devices
converting simultaneously and immediately knows when the last one is ready. As in the parasitically
powered scenario the bus master finally has to exit the Convert command by issuing a rest pulse.
1-WIRE BUS SYSTEM
The 1-Wire bus is a system which has a single bus master and one or more slaves. In all instances the
DS2450 is a slave device. The discussion of this bus system is broken down into three topics: hardware
configuration, transaction sequence, and 1-Wire signaling (signal types and timing). A 1-Wire protocol
defines bus transactions in terms of the bus state during specific time slots that are initiated on the falling
edge of sync pulses from the bus master. For a more detailed protocol description, refer to Chapter 4 of
the Book of DS19xx iButton Standards.
HARDWARE CONFIGURATION
The 1-Wire bus has only a single line by definition; it is important that each device on the bus be able to
drive it at the appropriate time. To facilitate this, each device
attached to the 1-Wire bus must have open
drain or 3-state outputs. The 1-Wire port of the DS2450 is open drain with an internal circuit equivalent
to that shown in Figure 8. A multidrop bus consists of a 1-Wire bus with multiple slaves attached. At
regular speed the 1-Wire bus has a maximum data rate of 16.3k bits per second. The speed can be
boosted to 142k bits per second by activating the Overdrive Mode. The 1-Wire bus requires a pullup
resistor of approximately 5k
at regular speed or maximum 2.2k
at Overdrive speed for
communication. During A/D conversions the bus master must provide a strong pullup to 5V to supply
sufficient energy if the DS2450 is powered entirely from the 1-Wire bus.
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. If this does not occur and the bus is left low
for more than 16
μ
s (Overdrive Speed) or more than 120
μ
s (regular speed), one or more devices on the
bus may be reset.
HARDWARE CONFIGURATION
Figure 8
SEE TEXT
相关PDF资料
PDF描述
DS2450S 1-Wire Quad A/D Converter
DS2480 Serial 1.Wire Line Driver
DS2480S Serial 1.Wire Line Driver
DS2490 USB to 1-Wire Bridge Chip
DS2490S USB to 1-Wire Bridge Chip
相关代理商/技术参数
参数描述
DS2450S 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
DS2450S/T&R 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
DS2450S+ 功能描述:模数转换器 - ADC Quad 1-Wire RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32
DS2450S+ 制造商:Maxim Integrated Products 功能描述:SEMICONDUCTOR ((NW))
DS2450S+T&R 制造商:Maxim Integrated Products 功能描述:IC CONVERTER A/D QUAD 1-W 8-SOIC