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參數(shù)資料
| 型號： | MC1489A |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | Quad Line EIA-232D Receivers(RS-232四線接收器) |
| 中文描述： | 四線環(huán)評- 232D接收器（RS - 232接口四線接收器） |
| 文件頁數(shù)： | 6/10頁 |
| 文件大小： | 98K |
| 代理商： | MC1489A |
MC1489, MC1489A
http://onsemi.com
6
APPLICATIONS INFORMATION
General Information
The Electronic Industries Association (EIA) has released
the EIA232D specification detailing the requirements for
the interface between data processing equipment and data
communications equipment. This standard specifies not
only the number and type of interface leads, but also the
voltage levels to be used. The MC1488 quad driver and its
companion circuit, the MC1489 quad receiver, provide a
complete interface system between DTL or TTL logic levels
and the EIA232D defined levels. The EIA232D
requirements as applied to receivers are discussed herein.
The required input impedance is defined as between
3000
and 7000
for input voltages between 3.0 and 25 V
in magnitude; and any voltage on the receiver input in an
open circuit condition must be less than 2.0 V in magnitude.
The MC1489 circuits meet these requirements with a
maximum open circuit voltage of one V
BE
.
The receiver shall detect a voltage between 3.0 and
25 V as a Logic “1” and inputs between 3.0 and 25 V as a
Logic “0.” On some interchange leads, an open circuit of
power “OFF” condition (300 or more to ground) shall be
decoded as an “OFF” condition or Logic “1.” For this
reason, the input hysteresis thresholds of the MC1489
circuits are all above ground. Thus an open or grounded
input will cause the same output as a negative or Logic “1”
input.
Device Characteristics
The MC1489 interface receivers have internal feedback
from the second stage to the input stage providing input
hysteresis for noise rejection. The MC1489 input has typical
turnon voltage of 1.25 V and turnoff of 1.0 V for a typical
hysteresis of 250 mV. The MC1489A has typical turnon of
1.95 V and turnoff of 0.8 V for typically 1.15 V of
hysteresis.
Each receiver section has an external response control
node in addition to the input and output pins, thereby
allowing the designer to vary the input threshold voltage
levels. A resistor can be connected between this node and an
external power supply. Figures 4, 6 and 7 illustrate the input
threshold voltage shift possible through this technique.
This response node can also be used for the filtering of
high frequency, high energy noise pulses. Figures 10 and 11
show typical noise pulse rejection for external capacitors of
various sizes.
These two operations on the response node can be
combined or used individually for many combinations of
interfacing applications. The MC1489 circuits are
particularly useful for interfacing between MOS circuits and
MDTL/MTTL logic systems. In this application, the input
threshold voltages are adjusted (with the appropriate supply
and resistor values) to fall in the center of the MOS voltage
logic levels (see Figure 12).
The response node may also be used as the receiver input
as long as the designer realizes that he may not drive this
node with a low impedance source to a voltage greater than
one diode above ground or less than one diode below
ground. This feature is demonstrated in Figure 13 where two
receivers are slaved to the same line that must still meet the
EIA232D impedance requirement.
PW, INPUT PULSE WIDTH (ns)
500 pF
MC1489
6
5
4
3
2
1
10,000
1000
100
10
300 pF
100 pF
10 pF
E
i
Figure 10. Typical Turn On Threshold versus
Capacitance from Response Control Pin to GND
MC1489A
PW, INPUT PULSE WIDTH (ns)
12 pF
500 pF
100 pF
300 pF
6
5
4
3
2
1
10,000
1000
100
10
E
i
Figure 11. Typical Turn On Threshold versus
Capacitance from Response Control Pin to GND
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MC1489AD | 功能描述:RS-232接口集成電路 Quad Line EIA-232D RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: |
| MC1489AD1 | 功能描述:緩沖器和線路驅(qū)動器 Quad Line Receiver RoHS:否 制造商:Micrel 輸入線路數(shù)量:1 輸出線路數(shù)量:2 極性:Non-Inverting 電源電壓-最大:+/- 5.5 V 電源電壓-最小:+/- 2.37 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Reel |
| MC1489AD1013TR | 功能描述:總線接收器 Quad Line Receiver RoHS:否 制造商:Texas Instruments 接收機數(shù)量:4 接收機信號類型:Differential 接口類型:EIA/TIA-422-B, V.11 工作電源電壓:3.3 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:TSSOP-16 封裝:Reel |
| MC1489ADG | 功能描述:RS-232接口集成電路 Quad Line EIA-232D Receiver RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: |
| MC1489ADR2 | 功能描述:RS-232接口集成電路 Quad Line EIA-232D RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: |
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