参数资料
型号: MAX3086CSD+
厂商: Maxim Integrated Products
文件页数: 7/21页
文件大小: 0K
描述: IC TXRX RS485/RS422 10MBPS14SOIC
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 50
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: 表面贴装
封装/外壳: 14-SOIC(0.154",3.90mm 宽)
供应商设备封装: 14-SOIC
包装: 管件
产品目录页面: 1404 (CN2011-ZH PDF)
Fail-Safe
The MAX3080 family guarantees a logic-high receiver
output when the receiver inputs are shorted or open, or
when they are connected to a terminated transmission
line with all drivers disabled. This is done by setting the
receiver threshold between -50mV and -200mV. If the
differential receiver input voltage (A-B) is greater than
or equal to -50mV, RO is logic high. If A-B is less than
or equal to -200mV, RO is logic low. In the case of a
terminated bus with all transmitters disabled, the
receiver’s differential input voltage is pulled to 0V by
the termination. With the receiver thresholds of the
MAX3080 family, this results in a logic high with a 50mV
minimum noise margin. Unlike previous fail-safe
devices, the -50mV to -200mV threshold complies with
the ±200mV EIA/TIA-485 standard.
MAX3089 Programming
The MAX3089 has several programmable operating
modes. Transmitter rise and fall times are programma-
ble between 2500ns, 750ns, and 25ns, resulting in
maximum data rates of 115kbps, 500kbps, and
10Mbps, respectively. To select the desired data rate,
drive SRL to one of three possible states by using a
three-state driver, by connecting it to VCC or GND, or
by leaving it unconnected. For 115kbps operation, set
the three-state device in high-impedance mode or
leave SRL unconnected. For 500kbps operation, drive
SRL high or connect it to VCC. For 10Mbps operation,
drive SRL low or connect it to GND. SRL can be
changed during operation without interrupting data
communications.
Occasionally, twisted-pair lines are connected back-
ward from normal orientation. The MAX3089 has two
pins that invert the phase of the driver and the receiver
to correct for this problem. For normal operation, drive
TXP and RXP low, connect them to ground, or leave
them unconnected (internal pulldown). To invert the dri-
ver phase, drive TXP high or connect it to VCC. To
invert the receiver phase, drive RXP high or connect it
to VCC. Note that the receiver threshold is positive
when RXP is high.
The MAX3089 can operate in full- or half-duplex mode.
Drive the H/F pin low, leave it unconnected (internal
pulldown), or connect it to GND for full-duplex opera-
tion, and drive it high for half-duplex operation. In full-
duplex mode, the pin configuration of the driver and
receiver is the same as that of a MAX3080 (Figure 4). In
half-duplex mode, the receiver inputs are switched to
the driver outputs, connecting outputs Y and Z to inputs
A and B, respectively. In half-duplex mode, the internal
full-duplex receiver input resistors are still connected to
pins 11 and 12.
Applications Information
256 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 MAX3080 family of transceivers have
a 1/8-unit-load receiver input impedance (96k
), allow-
ing up to 256 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.
Reduced EMI and Reflections
The MAX3080–MAX3085, and MAX3089 with SRL = VCC
or unconnected, are slew-rate limited, minimizing EMI
and reducing reflections caused by improperly termi-
nated cables. Figure 14 shows the driver output wave-
form and its Fourier analysis of a 20kHz signal
transmitted by a MAX3086/MAX3087/MAX3088, and
MAX3089 with SRL = GND. High-frequency harmonic
Fail-Safe, High-Speed (10Mbps),
Slew-Rate-Limited RS-485/RS-422 Transceivers
R
Y
Z
VOD
VOC
Figure 5. Driver DC Test Load
RECEIVER
OUTPUT
TEST POINT
1k
1k
S1
S2
VCC
CRL
15pF
Figure 6. Receiver Enable/Disable Timing Test Load
Maxim Integrated
15
MAX3080–MAX3089
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MAX3086CSD+ 功能描述:RS-422/RS-485 接口 IC Fail-Safe 10Mbps RS-485/RS-422 Tcvr 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
MAX3086CSD+T 功能描述:RS-422/RS-485 接口 IC Fail-Safe 10Mbps RS-485/RS-422 Tcvr 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
MAX3086CSD-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
MAX3086ECPD 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
MAX3086ECPD+ 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