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PDF ISL32485E Data sheet ( Hoja de datos )
| Número de pieza | ISL32485E | |
| Descripción | (ISL32483E / ISL32485E) RS-485/RS-422 Transceivers | |
| Fabricantes | Intersil | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de ISL32485E (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
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Fault Protected, Extended CMR, RS-485/RS-422
Transceivers with Cable Invert and ±16.5kV ESD
ISL32483E, ISL32485E
The ISL3248xE are fault protected, 5V powered differential
transceivers that exceed the RS-485 and RS-422 standards for
balanced communication. The RS-485 transceiver pins (driver
outputs and receiver inputs) are fault protected up to ±60V and
are protected against ±16.5kV ESD strikes without latch-up.
Additionally, the extended common mode range allows these
transceivers to operate in environments with common mode
voltages up to ±25V (>2X the RS-485 requirement), making this
fault-protected RS-485 family one of the most robust on the
market.
Transmitters (Tx) deliver an exceptional 2.5V (typical) differential
output voltage into the RS-485 specified 54Ω load. This yields
better noise immunity than standard RS-485 ICs or allows up to
six 120Ω terminations in star network topologies.
Receiver (Rx) inputs feature a “Full Fail-Safe” design, which
ensures a logic high Rx output if Rx inputs are floating, shorted,
or on a terminated but undriven (idle) bus.
The ISL32483E and ISL32485E include cable invert functions
that reverse the polarity of the Rx and/or Tx bus pins in case the
cable is misconnected. Unlike competing devices, Rx full fail-safe
operation is maintained even when the Rx input polarity is
switched.
For fault protected RS-485 transceivers without the cable invert
function, please see the ISL32470E and ISL32490E data sheets.
Features
• Fault Protected RS-485 Bus Pins . . . . . . . . . . . . . . Up to ±60V
• Extended Common Mode Range . . . . . . . . . . . . . . . . . . . ±25V
More Than Twice the Range Required for RS-485
• ±16.5kV HBM ESD Protection on RS-485 Bus Pins
• Cable Invert Pins
Corrects for Reversed Cable Connections While Maintaining Rx
Full Fail-Safe Functionality
• Full Fail-Safe (Open, Short, Terminated) RS-485 Receivers
• 1/4 Unit Load (UL) for Up to 128 Devices on the Bus
• High Rx IOL for Opto-Couplers in Isolated Designs
• Hot Plug Circuitry: Tx and Rx Outputs Remain Three-State
During Power-up/Power-down
• Slew Rate Limited RS-485 Data Rate . . . . . . . . . . . . . 1Mbps
• Low Quiescent Supply Current . . . . . . . . . . . . . . . . . . . 2.3mA
• Ultra Low Shutdown Supply Current . . . . . . . . . . . . . . . 10µA
Applications
• Utility Meters/Automated Meter Reading Systems
• High Node Count RS-485 Systems
• PROFIBUS® and RS-485 Based Field Bus Networks, and
Factory Automation
• Security Camera Networks
• Building Lighting and Environmental Control Systems
• Industrial/Process Control Networks
30
B
25
A
20
VID = ±1V
15
10
5
RO
0
-5
TIME (400ns/DIV)
FIGURE 1. EXCEPTIONAL Rx OPERATES AT 1Mbps EVEN WITH
±25V COMMON MODE VOLTAGE
25
12
0
-7
-12
-20
-25
STANDARD RS-485
CLOSEST
TRANSCEIVER
COMPETITOR
ISL3248XE
FIGURE 2. TRANSCEIVERS DELIVER SUPERIOR COMMON MODE
RANGE vs STANDARD RS-485 DEVICES
January 18, 2011
FN7785.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 |Copyright Intersil Americas Inc. 2011. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
Free Datasheet http://www.datasheet4u.com/
1 page  
ISL32483E, ISL32485E
Absolute Maximum Ratings
VCC to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltages
DI, INV, RINV, DINV, DE, RE. . . . . . . . . . . . . . . . . . . . -0.3V to (VCC + 0.3V)
Input/Output Voltages
A/Y, B/Z, A, B, Y, Z. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±60V
A/Y, B/Z, A, B, Y, Z
(Transient Pulse Through 100Ω, see Note 15). . . . . . . . . . . . . . . . . ±80V
RO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to (VCC +0.3V)
Short Circuit Duration
Y, Z. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite
ESD Rating . . . . . . . . . . . . . . . . . . . . see “ESD PERFORMANCE” on page 6
Latch-up (Tested per JESD78, Level 2, Class A). . . . . . . . . . . . . . . . +125°C
Thermal Information
Thermal Resistance (Typical)
θJA (°C/W) θJC (°C/W)
8 Ld SOIC Package (Notes 4, 5). . . . . . . . . . 116
47
14 Ld SOIC Package (Notes 4, 5) . . . . . . . .
88
39
Maximum Junction Temperature (Plastic Package) . . . . . . . . . . . . +150°C
Maximum Storage Temperature Range . . . . . . . . . . . . . . -65°C to +150°C
Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
Supply Voltage (VCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V
Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C
Bus Pin Common Mode Voltage Range . . . . . . . . . . . . . . . . . -25V to +25V
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
5. For θJC, the “case temp” location is taken at the package top center.
Electrical Specifications Test Conditions: VCC = 4.5V to 5.5V; Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25°C (Note 6).
Boldface limits apply over the operating temperature range, -40°C to +85°C.
PARAMETER
SYMBOL
TEST CONDITIONS
TEMP
MIN
MAX
(°C) (Note 14) TYP (Note 14) UNITS
DC CHARACTERISTICS
Driver Differential VOUT
(No load)
VOD1
Full -
- VCC V
Driver Differential VOUT
(Loaded, Figure 3A)
VOD2
RL = 100Ω (RS-422)
RL = 54Ω (RS-485)
Full 2.4 3.2
-
Full 1.5 2.5 VCC
RL = 54Ω (PROFIBUS, VCC ≥ 5V)
Full 2.0 2.5
-
RL = 21Ω (Six 120Ω terminations for Star
Full
0.8
1.3
Configurations, VCC ≥ 4.75V)
-
Change in Magnitude of Driver
Differential VOUT for
Complementary Output
States
ΔVOD
RL = 54Ω or 100Ω (Figure 3A)
Full -
- 0.2
V
V
V
V
V
Driver Differential VOUT with
VOD3
RL = 60Ω, -7V ≤ VCM ≤ 12V
Full 1.5 2.1 VCC
Common Mode Load
(Figure 3B)
RL = 60Ω, -25V ≤ VCM ≤ 25V (VCC ≥ 4.75V)
Full
1.7
2.3
RL = 21Ω, -15V ≤ VCM ≤ 15V (VCC ≥ 4.75V)
Full
0.8
1.1
-
Driver Common-Mode VOUT
(Figure 3)
VOC RL = 54Ω or 100Ω
RL = 60Ω or 100Ω, -20V ≤ VCM ≤ 20V
Full -1
Full -2.5
-
-
3
5
Change in Magnitude of Driver
Common-Mode VOUT for
Complementary Output
States
DVOC
RL = 54Ω or 100Ω (Figure 3A)
Full -
- 0.2
V
V
V
V
V
V
Driver Short-Circuit Current
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
IOSD
IOSD1
IOSD2
VIH
VIL
IIN1
DE = VCC, -25V ≤ VO ≤ 25V (Note 8)
At First Fold-back, 22V ≤ VO ≤ -22V
At Second Fold-back, 35V ≤ VO ≤ -35V
DE, DI, RE, INV, RINV, DINV
DE, DI, RE, INV, RINV, DINV
DI
DE, RE, INV, RINV, DINV
Full -250 - 250 mA
Full -83
83 mA
Full -13
13 mA
Full 2.5
-
-
V
Full -
- 0.8 V
Full -1 - 1 µA
Full -15 6 15 µA
5 FN7785.0
January 18, 2011
Free Datasheet http://www.datasheet4u.com/
5 Page 
ISL32483E, ISL32485E
Intersil’s unique cable invert function is superior to that found on
competing devices, because the Rx full fail-safe function is
maintained, even when the Rx polarity is reversed. Competitor
devices implement the Rx invert function simply by inverting the
Rx output. This means that with the Rx inputs floating or shorted
together, the Rx appropriately delivers a logic 1 in normal
polarity, but outputs a logic low when the IC is operated in the
inverted mode. Intersil’s innovative Rx design guarantees that,
with the Rx inputs floating or shorted together (VID=0V), the Rx
output remains high, regardless of the state of the invert pins.
The full duplex ISL32483E includes two invert pins that allow for
separate control of the Rx and Tx polarities. If only the Rx cable is
miswired, then only the RINV pin need be driven to a logic 1. If
the Tx cable is miswired, then DINV must be connected to a logic
high. The half-duplex version has only one logic pin (INV) that,
when high, switches the polarity of both the Tx and the Rx blocks.
High VOD Improves Noise Immunity and
Flexibility
The ISL3248xE driver design delivers larger differential output
voltages (VOD) than the RS-485 standard requires or than most
RS-485 transmitters can deliver. The typical ±2.5V VOD provides
more noise immunity than networks built using many other
transceivers.
Another advantage of the large VOD is the ability to drive more
than two bus terminations, which allows for utilizing the
ISL3248xE in “star” and other multi-terminated, nonstandard
network topologies.
Figure 10 details the transmitter’s VOD versus IOUT characteristic,
and includes load lines for four (30Ω) and six (20Ω) 120Ω
terminations. The figure shows that the driver typically delivers
±1.3V into six terminations, and the “Electrical Specifications” on
page 5 guarantee a VOD of ±0.8V at 21Ω over the full
temperature range. The RS-485 standard requires a minimum
1.5V VOD into two terminations, but the ISL3248xE delivers
RS-485 voltage levels with 2x to 3x the number of terminations.
Hot Plug Function
When a piece of equipment powers up, there is a period of time
in which the processor or ASIC driving the RS-485 control lines
(DE, RE) is unable to ensure that the RS-485 Tx and Rx outputs
are kept disabled. If the equipment is connected to a bus, a
driver activating prematurely during power-up may crash the bus.
To avoid this scenario, the ISL3248xE devices incorporate a “Hot
Plug” function. Circuitry monitoring VCC ensures that, during
power-up and power-down, the Tx and Rx outputs remain disabled,
regardless of the state of DE and RE, if VCC is less than ≈3.5V. This
gives the processor or ASIC a chance to stabilize and drive the
RS-485 control lines to the proper states. Figure 9 illustrates the
power-up and power-down performance of the ISL3248xE
compared to an RS-485 IC without the Hot Plug feature.
VCC
3.5V
2.8V
5.0
2.5
A/Y
0
ISL83088E
ISL3248XE
RO ISL3248XE
DE, DI = VCC
RE = GND
5.0
2.5
0
RL = 1kΩ
RL = 1kΩ
5.0
2.5
0
TIME (40µs/DIV)
FIGURE 9. HOT PLUG PERFORMANCE (ISL3248XE) vs ISL83088E
WITHOUT HOT PLUG CIRCUITRY
ESD Protection
All pins on the ISL3248xE devices include Class 3 (>8kV)
Human Body Model (HBM) ESD protection structures that are
good enough to survive ESD events commonly seen during
manufacturing. Even so, the RS-485 pins (driver outputs and
receiver inputs) incorporate more advanced structures that
allow them to survive ESD events in excess of ±16.5kV HBM
(±15kV for full-duplex version). The RS-485 pins are particularly
vulnerable to ESD strikes, because they typically connect to an
exposed port on the exterior of the finished product. Simply
touching the port pins or connecting a cable can cause an ESD
event that might destroy unprotected ICs. The new ESD
structures protect the device whether or not it is powered up,
and without interfering with the exceptional ±25V CMR. This
built-in ESD protection minimizes the need for board-level
protection structures (e.g., transient suppression diodes) and
the associated, undesirable capacitive load they present.
Data Rate, Cables, and Terminations
RS-485/RS-422 are intended for network lengths up to 4000 feet,
but the maximum system data rate decreases as the transmission
length increases. These 1Mbps versions can operate at full data
rates with lengths up to 800 feet (244m). Jitter is the limiting
parameter at this data rate, so employing encoded data streams
(e.g., Manchester coded or Return-to-Zero) may allow increased
transmission distances.
Twisted pair is the cable of choice for RS-485/RS-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.
11 FN7785.0
January 18, 2011
Free Datasheet http://www.datasheet4u.com/
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet ISL32485E.PDF ] | |
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| Número de pieza | Descripción | Fabricantes |
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