参数资料
| 型号： | ISL32483EIBZ-T7A |
| 厂商： | Intersil |
| 文件页数： | 2/17页 |
| 文件大小： | 0K |
| 描述： | IC TXRX RS485 FAULT PROT 14SOIC |
| 产品培训模块： | Solutions for Industrial Control Applications |
| 标准包装： | 250 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 1/1 |
| 规程： | RS422，RS485 |
| 电源电压： | 4.5 V ~ 5.5 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： | 带卷 (TR) |
ISL32483E, ISL32485E
10
FN7785.1
March 27, 2012
Application Information
RS-485 and RS-422 are differential (balanced) data
transmission standards used for long haul or noisy environments.
RS-422 is a subset of RS-485, so RS-485 transceivers are also
RS-422 compliant. RS-422 is a point-to-multipoint (multidrop)
standard, which allows only one driver and up to 10 (assuming
one-unit load devices) receivers on each bus. RS-485 is a true
multipoint standard, which allows up to 32 one-unit load devices
(any combination of drivers and receivers) on each bus. To allow
for multipoint operation, the RS-485 specification requires that
drivers must handle bus contention without sustaining any
damage.
Another important advantage of RS-485 is the extended
common mode range (CMR), which specifies that the driver
outputs and receiver inputs withstand signals that range from
+12V to -7V. RS-422 and RS-485 are intended for runs as long as
4000 feet, so the wide CMR is necessary to handle ground
potential differences, as well as voltages induced in the cable by
external fields.
The ISL3248xE is a family of ruggedized RS-485 transceivers
that improves on the RS-485 basic requirements and therefore
increases system reliability. The CMR increases to ±25V, while
the RS-485 bus pins (receiver inputs and driver outputs) include
fault protection against voltages and transients up to ±60V.
Additionally, larger-than-required differential output voltages
(VOD) increase noise immunity, while the ±16.5kV built-in ESD
protection complements the fault protection.
Receiver (Rx) Features
These devices utilize a differential input receiver for maximum
noise immunity and common mode rejection. Input sensitivity is
better than ±200mV, as required by the RS-422 and RS-485
specifications.
Receiver input (load) current surpasses the RS-422 specification
of 3mA and is four times lower than the RS-485 “Unit Load (UL)”
requirement of 1mA maximum. Thus, these products are known
as “one-quarter UL” transceivers, and there can be up to 128 of
these devices on a network while still complying with the RS-485
loading specification.
The Rx functions with common mode voltages as great as ±25V,
making them ideal for industrial or long networks where induced
voltages are a realistic concern.
All the receivers include a “full fail-safe” function that guarantees
a high-level receiver output if the receiver inputs are unconnected
(floating), shorted together, or connected to a terminated bus
with all the transmitters disabled (i.e., an idle bus).
Rx outputs feature high drive levels (typically 22mA @ VOL =1V) to
ease the design of optically coupled isolated interfaces. Except for
the ISL32485E, Rx outputs are three-statable via the active low RE
input.
The Rx includes noise filtering circuitry to reject high-frequency
signals, and typically rejects pulses narrower than 50ns
(equivalent to 20Mbps).
Driver (Tx) Features
The RS-485/RS-422 driver is a differential output device that
delivers at least 1.5V across a 54 load (RS-485) and at least
2.4V across a 100 load (RS-422). The drivers feature low
propagation delay skew to maximize bit width and to minimize
EMI, and all drivers are three-statable via the active high DE
input.
The driver outputs are slew rate limited to minimize EMI and to
minimize reflections in unterminated or improperly terminated
networks.
High Overvoltage (Fault) Protection
Increases Ruggedness
The ±60V (referenced to the IC GND) fault protection on the
RS-485 pins makes these transceivers some of the most rugged
on the market. This level of protection makes the ISL3248xE
perfect for applications where power (e.g., 24V and 48V supplies)
must be routed in the conduit with the data lines, or for outdoor
applications where large transients are likely to occur. When
power is routed with the data lines, even a momentary short
between the supply and data lines will destroy an unprotected
device. The ±60V fault levels of this family are at least five times
higher than the levels specified for standard RS-485 ICs. The
ISL3248xE protection is active whether the Tx is enabled or
disabled, and even if the IC is powered down.
If transients or voltages (including overshoots and ringing)
greater then ±60V are possible, then additional external
protection is required.
Widest Common Mode Voltage (CMV)
Tolerance Improves Operating Range
RS-485 networks operating in industrial complexes or over long
distances are susceptible to large CMV variations. Either of these
operating environments may suffer from large node-to-node
ground potential differences or CMV pickup from external
electromagnetic sources, and devices with only the minimum
required +12V to -7V CMR may malfunction. The ISL3248xE’s
extended ±25V CMR is the widest available, allowing operation in
environments that would overwhelm lesser transceivers.
Additionally, the Rx will not phase invert (erroneously change
state), even with CMVs of ±40V or differential voltages as large
as 40V.
Cable Invert (Polarity Reversal) Function
With large node count RS-485 networks, it is common for some
cable data lines to be wired backwards during installation. When
this happens, the node is unable to communicate over the
network. Once a technician finds the miswired node, he must
then rewire the connector, which is time consuming.
The ISL32483E and ISL32485E simplify this task by including
cable invert pins (INV, DINV, RINV) that allow the technician to
invert the polarity of the Rx input and/or the Tx output pins
simply by moving a jumper to change the state of the invert pins.
When the invert pin is low, the IC operates like any standard
RS-485 transceiver, and the bus pins have their normal polarity
definition of A and Y being noninverting and B and Z being
inverting. With the invert pin high, the corresponding bus pins
reverse their polarity, so B and Z are now noninverting, and A and
Y become inverting.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL32485E | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Fault Protected, Extended CMR, RS-485/RS-422 Transceivers |
| ISL32485EIBZ | 功能描述:IC TXRX RS485 FAULT PROT 8SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 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:8-DIP（0.300"，7.62mm） 供应商设备封装:8-PDIP 包装:管件 产品目录页面:1402 (CN2011-ZH PDF) |
| ISL32485EIBZ-T | 功能描述:IC TXRX RS485 FAULT PROT 8SOIC RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 类型:发射器 驱动器/接收器数:4/0 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:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
| ISL32485EIBZ-T7A | 功能描述:RS-422/RS-485 接口 IC 8LD OVP -40+85 5V PO LARITY REV 1/2 DUP 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 |
| ISL32490E | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:±60V Fault Protected, 5V, RS-485/RS-422 Transceivers with ±25V CMR |
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