Datasheet > DS275E+

DS275E+

更新时间： 2023-08-15 00:00:00

品牌	Logo	应用领域
罗彻斯特 - ROCHESTER		光电二极管
页数	文件大小	规格书
11页	878K
描述
LINE TRANSCEIVER, PDSO14, ROHS COMPLIANT, TSSOP-14

阅读下载

获取价格

如果您发现信息不准确，欢迎纠错

DS275E+ 数据手册

DS275

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 (RX^IN) 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 (TX^OUT) 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 RX^INis RXOUT which swings from +VCC to ground. Therefore, a mark on RXIN produces a logic 1 at

RX^OUT; a space produces a logic 0.

The input threshold of RX^INis 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 RX^OUTto 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 RX^INline for

swinging to negative levels. The RXIN line must be in a marking or idle state to take advantage of this

design; if RX^INis in a spacing state, TXOUT will only swing to ground. When TXOUT needs to transition to

a positive level, it uses the V^DRVpower pin for this level. VDRV can be a voltage supply between 5 to 12

2 of 8

1 234 5 6 7...11

下载PDF

型号	品牌	描述	获取价格	数据表
DS275EN	MAXIM	Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDSO14, TSSOP-14	获取价格
DS275N	MAXIM	Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDIP8, 0.300 INCH, PLASTIC, DIP-8	获取价格
DS275N+	MAXIM	Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDIP8, 0.300 INCH, ROHS COMPLIANT, PLAST	获取价格
DS275S	DALLAS	Line-Powered RS-232 Transceiver Chip	获取价格
DS275S	MAXIM	Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDSO8, 0.150 INCH, SOIC-8	获取价格
DS275S+	MAXIM	Line Transceiver, 1 Func, 1 Driver, 1 Rcvr, CMOS, PDSO8, 0.150 INCH, ROHS COMPLIANT, SOIC-	获取价格