參數資料
| 型號： | ISL8485CP |
| 廠商： | Intersil |
| 文件頁數： | 16/16頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC TXRX RS485/422 5V ESD 8-DIP |
| 標準包裝： | 50 |
| 類型： | 收發(fā)器 |
| 驅動器/接收器數： | 1/1 |
| 規(guī)程： | RS422，RS485 |
| 電源電壓： | 4.5 V ~ 5.5 V |
| 安裝類型： | 通孔 |
| 封裝/外殼： | 8-DIP（0.300"，7.62mm） |
| 供應商設備封裝： | 8-PDIP |
| 包裝： | 管件 |
9
FN6046.8
February 28, 2006
Application Information
RS-485 and RS-422 are differential (balanced) data
transmission standards for use in 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 spec 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’, so the wide CMR is necessary to handle
ground potential differences, as well as voltages induced in
the cable by external fields.
Receiver Features
These devices utilize a differential input receiver for maximum
noise immunity and common mode rejection. Input sensitivity
is
±200mV, as required by the RS422 and RS-485
specifications.
Receiver input impedance surpasses the RS-422 spec of
4k
, and meets the RS-485 “Unit Load” requirement of
12k
minimum.
Receiver inputs function with common mode voltages as
great as
±7V outside the power supplies (i.e., +12V and
-7V), making them ideal for long networks where induced
voltages are a realistic concern.
All the receivers include a “fail-safe if open” function that
guarantees a high level receiver output if the receiver inputs
are unconnected (floating).
Receivers easily meet the data rates supported by the
corresponding driver.
ISL8483/85/89/91 receiver outputs are three-statable via the
active low RE input.
Driver Features
The RS-485/422 driver is a differential output device that
delivers at least 1.5Vacross a 54
load (RS-485), and at
least 2V across a 100
load (RS-422). The drivers feature
low propagation delay skew to maximize bit width, and to
minimize EMI.
Drivers of the ISL8483/85/89/91 are three-statable via the
active high DE input.
The ISL8483/88/89 driver outputs are slew rate limited to
minimize EMI, and to minimize reflections in unterminated or
improperly terminated networks. Data rate on these slew
rate limited versions is a maximum of 250kbps. Outputs of
ISL8485/90/91 drivers are not limited, so faster output
transition times allow data rates of at least 5Mbps.
Data Rate, Cables, and Terminations
RS-485/422 are intended for network lengths up to 4000’,
but the maximum system data rate decreases as the
transmission length increases. Devices operating at 5Mbps
are limited to lengths less than 100’, while the 250kbps
versions can operate at full data rates with lengths in excess
of 1000’.
Twisted pair is the cable of choice for RS-485/422 networks.
Twisted pair cables tend to pick up noise and other
electromagnetically induced voltages as common mode
signals, which are effectively rejected by the differential
receivers in these ICs.
Proper termination is imperative, when using the 5Mbps
devices, to minimize reflections. Short networks using the
250kbps versions need not be terminated, but, terminations
are recommended unless power dissipation is an overriding
concern.
FIGURE 5A. TEST CIRCUIT
FIGURE 5B. MEASUREMENT POINTS
FIGURE 5. RECEIVER ENABLE AND DISABLE TIMES (EXCLUDING ISL8488, ISL8490)
Test Circuits and Waveforms (Continued)
1k
VCC
GND
SW
(SHDN) for ISL8483 only.
PARAMETER
DE
A
SW
tHZ
0
+1.5V
GND
tLZ
0-1.5V
VCC
tZH (Note 6)
0
+1.5V
GND
tZL (Note 6)
0
-1.5V
VCC
tZH(SHDN) (Note 9)
0
+1.5V
GND
tZL(SHDN) (Note 9)
0
-1.5V
VCC
SIGNAL
GENERATOR
R
RO
RE
A
B
15pF
RO
3V
0V
1.5V
VOH
0V
1.5V
VOH - 0.5V
tHZ
RO
VCC
VOL
1.5V
VOL + 0.5V
tLZ
RE
OUTPUT HIGH
OUTPUT LOW
tZL, tZL(SHDN)
tZH, tZH(SHDN)
NOTE 7
ISL8483, ISL8485, ISL8488, ISL8489, ISL8490, ISL8491
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| ISL8485CPZ | 功能描述:IC TXRX RS485/422 5V ESD 8-DIP RoHS:是 類別:集成電路 (IC) >> 接口 - 驅動器，接收器，收發(fā)器 系列:- 標準包裝:250 系列:- 類型:收發(fā)器 驅動器/接收器數:2/2 規(guī)程:RS232 電源電壓:3 V ~ 5.5 V 安裝類型:表面貼裝 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應商設備封裝:16-TSSOP 包裝:帶卷 (TR) |
| ISL8485E | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:ESD Protected to 【15kV, 5V, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers |
| ISL8485EABZ | 功能描述:IC TXRX RS485/422 5V ESD 8-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 驅動器，接收器，收發(fā)器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 類型:發(fā)射器 驅動器/接收器數:4/0 規(guī)程:RS422，RS485 電源電壓:4.75 V ~ 5.25 V 安裝類型:表面貼裝 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應商設備封裝:16-SOIC 包裝:帶卷 (TR) |
| ISL8485EABZ-T | 功能描述:IC TXRX RS485/422 5V ESD 8-SOIC RoHS:是 類別:集成電路 (IC) >> 接口 - 驅動器，接收器，收發(fā)器 系列:- 標準包裝:250 系列:- 類型:收發(fā)器 驅動器/接收器數:2/2 規(guī)程:RS232 電源電壓:3 V ~ 5.5 V 安裝類型:表面貼裝 封裝/外殼:16-TSSOP（0.173"，4.40mm 寬） 供應商設備封裝:16-TSSOP 包裝:帶卷 (TR) |
| ISL8485ECB | 功能描述:IC TXRX RS485/422 5V ESD 8-SOIC RoHS:否 類別:集成電路 (IC) >> 接口 - 驅動器，接收器，收發(fā)器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:25 系列:- 類型:收發(fā)器 驅動器/接收器數:2/2 規(guī)程:RS232 電源電壓:4.5 V ~ 5.5 V 安裝類型:通孔 封裝/外殼:16-DIP（0.300"，7.62mm） 供應商設備封裝:16-PDIP 包裝:管件 |
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