ISL8483EIBZ-T Intersil, ISL8483EIBZ-T Datasheet - Page 8

• Manufacturer Part Number: ISL8483EIBZ-T
• Description: TRANSCEIVER RS-485/422 ESD 8SOIC
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ISL8483EIBZ-T

• Number Of Drivers/receivers: 1/1
• Protocol: RS422, RS485
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Test Circuits and Waveforms
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 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.
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
4kΩ, and meets the RS-485 “Unit Load” requirement of 12kΩ
minimum.
(SHDN) FOR ISL8483E ONLY
SIGNAL
GENERATOR
t
t
ZH(SHDN)
ZL(SHDN)
PARAMETER
t
t
ZH
ZL
(Note 6)
(Note 6)
t
t
HZ
LZ
(Note 9)
(Note 9)
FIGURE 5A. TEST CIRCUIT
RE
A
B
DE
0
0
0
0
0
0
R
8
RO
+1.5V
+1.5V
+1.5V
-1.5V
-1.5V
-1.5V
A
FIGURE 5. RECEIVER ENABLE AND DISABLE TIMES
(Continued)
15pF
1kΩ
SW
ISL8483E, ISL8485E
GND
GND
GND
V
V
V
SW
CC
CC
CC
GND
V
CC
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.
ISL8483E, ISL8485E receiver outputs are three-stat-able via
the active low RE input.
Driver Features
The RS485, RS-422 driver is a differential output device that
delivers at least 1.5V across a 54Ω load (RS-485), and at
least 2V across a 100Ω load (RS-422). The drivers feature
low propagation delay skew to maximize bit width, and to
minimize EMI.
Drivers of the ISL8483E, ISL8485E are tri-stateable via the
active high DE input.
The ISL8483E driver outputs are slew rate limited to
minimize EMI, and to minimize reflections in un-terminated
or improperly terminated networks. Data rate on these slew
rate limited versions is a maximum of 250kbps. Outputs of
the ISL8485E driver are not limited, so faster output
transition times allow data rates of at least 10Mbps.
t
t
ZH
ZL
NOTE 7
RE
RO
NOTE 7
RO
, t
, t
ZH(SHDN)
ZL(SHDN)
NOTE 7
FIGURE 5B. MEASUREMENT POINTS
1.5V
OUTPUT HIGH
1.5V
1.5V
OUTPUT LOW
t
t
HZ
1.5V
LZ
V
V
OH
OL
September 9, 2008
+ 0.5V
- 0.5V
3V
0V
FN6048.9
V
V
V
0V
OH
CC
OL