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参数资料
| 型号： | MAX3291EPD |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | IC TXRX RS485/422 5-10MBPS 14DIP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 25 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 1/1 |
| 规程： | RS422，RS485 |
| 电源电压： | 4.75 V ~ 5.25 V |
| 安装类型： | 通孔 |
| 封装/外壳： | 14-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 14-PDIP |
| 包装： | 管件 |
MAX3291/MAX3292
% Jitter = (total jitter / tBAUD) 100
When the total amount of time skew becomes 10% or
more of the baud period, the data error rate can
increase sharply.
128 Transceivers on the Bus
The standard RS-485 receiver input impedance is 12k
(one unit load), and the standard driver can drive up to
32 unit loads. The MAX3291/MAX3292 transceivers have
a 1/4-unit-load receiver input impedance (48k
), allow-
ing up to 128 transceivers to be connected in parallel on
one communication line. Any combination of these
devices and/or other RS-485 transceivers with a total of
32 unit-loads or less can be connected to the line.
Low-Power Shutdown Mode
Initiate low-power shutdown mode by bringing RE high
and DE low. In shutdown the MAX3291/MAX3292 typi-
cally draw only 1A of supply current.
Simultaneously driving RE and DE is allowed; the parts
are guaranteed not to enter shutdown if RE is high and
DE is low for less than 80ns. If the inputs are in this
state for at least 300ns, the parts are guaranteed to
enter shutdown.
Enable times tZH and tZL in the Switching Characteris-
tics tables correspond to when the part is not in the low-
power shutdown state. Enable times tZH(SHDN) and
tZL(SHDN) assume the parts are shut down. It takes dri-
vers and receivers longer to activate from the low-
power shutdown mode (tZH(SHDN), tZL(SHDN)) than from
the driver/receiver disable mode (tZH, tZL).
Line Repeater
For line lengths greater than what one MAX3291/
MAX3292 can drive, use the repeater application
shown in Figure 17.
Figure 18 shows the system differential voltage for the
MAX3292 driving 4000 feet of 26AWG twisted-pair wire
into two 120
termination loads.
Line Termination
The MAX3291/MAX3292 are targeted for applications
requiring the best combination of long cable length and
lowest bit-error rate. In order to achieve this combina-
tion, the cable system must be set up with care. There
are three basic steps:
1) The cable should only have two ends (no tree configu-
ration with long branches), which are terminated with
a simple resistor termination whose value is the
cable’s characteristic impedance (ZO). Avoid termina-
tions anywhere else along the cable. This ensures that
there are no reflections at the end of the cable, and
that all transmitters (whether they are located at the
ends of the cable or somewhere along the length) see
the same impedance, equal to ZO / 2.
2) Make all branches or stubs short enough so that
twice the propagation delay along the stub (down
and back) is significantly less than one baud period
(around 15% or less). This ensures that the reflec-
tions from the end of the stub (which are unavoid-
able, since the stubs are not terminated) settle in
much less than a baud period. If the application
requires a branch much longer than this, use a
repeater (see the
Line Repeater section).
RS-485/RS-422 Transceivers with Preemphasis
for High-Speed, Long-Distance Communication
12
______________________________________________________________________________________
Figure 17. Line-Repeater Application
2
s/div
VA - VB
RO
DI
RECEIVER
INPUT
1V/div
5V/div
TYPICAL OPERATING CIRCUIT, RPSET = 1M
5V/div
120
120
DATA IN
DATA OUT
R
D
RO
RE
DE
DI
A
B
Z
Y
MAX3291
MAX3292
Figure 18. MAX3292 System Differential Voltage Driving 4000
Feet, Using Two 120
Termination Resistors
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3291EPD+ | 功能描述:RS-422/RS-485 接口 IC For Long-Distance Communication RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
| MAX3291ESD | 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
| MAX3291ESD+ | 功能描述:RS-422/RS-485 接口 IC For Long-Distance Communication RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
| MAX3291ESD+T | 功能描述:RS-422/RS-485 接口 IC For Long-Distance Communication RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
| MAX3291ESD-T | 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube |
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