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参数资料
| 型号： | DS275E+T&R |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 2/8页 |
| 文件大小： | 0K |
| 描述： | IC TXRX LINE-PWR RS232 14-TSSOP |
| 标准包装： | 1,000 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 1/1 |
| 规程： | RS232 |
| 电源电压： | 4.5 V ~ 5.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 14-TSSOP（0.173"，4.40mm 宽） |
| 供应商设备封装： | 14-TSSOP |
| 包装： | 带卷 (TR) |
DS275
2 of 8
DS275 BLOCK DIAGRAM Figure 1
OPERATION
Designed for the unique requirements of battery-backed systems, the DS275 provides a low-power half-
duplex interface to an RS-232 serial port. Typically, a designer must use an RS-232 device which uses
system power during both negative and positive transitions of the transmit signal to the RS-232 port. If
the connector to the RS-232 port is left connected for an appreciable time after the communication
session has ended, power will statically flow into that port, draining the battery capacity. The DS275
eliminates this static current drain by stealing current from the receive line (RXIN) of the RS-232 port
when that line is at a negative level (marking). Since most asynchronous communication over an RS-232
connection typically remains in a marking state when data is not being sent, the DS275 will not consume
system power in this condition. System power would only be used when positive-going transitions are
needed on the transmit RS-232 output (TXOUT) when data is sent. However, since synchronous
communication sessions typically exhibit a very low duty-cycle, overall system power consumption
remains low.
RECEIVER SECTION
The RXIN pin is the receive input for an RS-232 signal whose levels can range from
±±±±3 to ±±±±15 volts. A
negative data signal is called a mark while a positive data signal is called a space. These signals are
inverted and then level-shifted to normal +5-volt CMOS/TTL logic levels. The logic output associated
with RXIN is RXOUT which swings from +VCC to ground. Therefore, a mark on RXIN produces a logic 1 at
RXOUT; a space produces a logic 0.
The input threshold of RXIN is typically around 1.8 volts with 500 millivolts of hysteresis to improve
noise rejection. Therefore, an input positive-going signal must exceed 1.8 volts to cause RXOUT to switch
states. A negative-going signal must now be lower than 1.3 volts (typically) to cause RXOUT to switch
again. An open on RXIN is interpreted as a mark, producing a logic 1 at RXOUT.
TRANSMITTER SECTION
TXIN is the CMOS/TTL-compatible input for digital data from the user system. A logic 1 at TXIN
produces a mark (negative data signal) at TXOUT while a logic 0 produces a space (positive data signal).
As mentioned earlier, the transmitter section employs a unique driver design that uses the RXIN line for
swinging to negative levels. The RXIN line must be in a marking or idle state to take advantage of this
design; if RXIN is in a spacing state, TXOUT will only swing to ground. When TXOUT needs to transition to
a positive level, it uses the VDRV power pin for this level. VDRV can be a voltage supply between 5 to 12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS275N | 功能描述:RS-232接口集成电路 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
| DS275N+ | 功能描述:RS-232接口集成电路 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
| DS275S | 功能描述:RS-232接口集成电路 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
| DS275S/T&R | 制造商:Maxim Integrated Products 功能描述:IC TXRX LINE-PWR RS232 IND 8SOIC |
| DS275S/T&R | 功能描述:RS-232接口集成电路 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
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