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PDF ISL32478E Data sheet ( Hoja de datos )
| Número de pieza | ISL32478E | |
| Descripción | Fault Protected - Extended Common Mode Range RS-485/RS-422 Transceivers | |
| Fabricantes | Intersil | |
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Fault Protected, Extended Common Mode Range,
RS-485/RS-422 Transceivers with ±16.5kV ESD
ISL32470E, ISL32472E, ISL32475E, ISL32478E
The ISL32470E, ISL32472E, ISL32475E, ISL32478E are
fault-protected, extended common mode range differential
transceivers that exceed the RS-485 and RS-422 standards for
balanced communication. The RS-485 bus pins (driver outputs
and receiver inputs) are fault protected against overvoltages up to
±60V and are protected against ±16.5kV ESD strikes without
latch-up. Additionally, these transceivers operate in environments
with common mode voltages up to ±15V (exceeds the RS-485
requirement), making this fault-protected RS-485 family one of
the more 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 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. Rx outputs feature high
drive levels; typically, 15mA @ VOL = 1V (to ease the design of
opto-coupled isolated interfaces).
Half duplex (Rx inputs and Tx outputs multiplexed together) and
full duplex pinouts are available. See Table 1 on page 2 for key
features and configurations by device number.
For a fault-protected RS-485 transceiver with a ±25V extended
common mode range, please see the ISL32490E and ISL32483E
data sheets.
Features
• Fault-Protected RS-485 Bus Pins . . . . . . . . . . . . . . Up to ±60V
• Extended Common Mode Range . . . . . . . . . . . . . . . . . . . ±15V
Larger Than Required for RS-485
• 1/4 Unit Load for Up to 128 Devices on the Bus
• ±16.5kV HBM ESD Protection on RS-485 Bus Pins
• High Transient Over-Voltage Tolerance . . . . . . . . . . . . . . .±80V
• Full Fail-Safe (Open, Short, Terminated) RS-485 Receivers
• High Rx IOL for Opto-Couplers in Isolated Designs
• Hot Plug Circuitry: Tx and Rx Outputs Remain Three-State
During Power-Up/Power-Down
• Choice of RS-485 Data Rates . . . . . . . . . . . .250kbps to 15Mbps
• 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
20
B
15
A
10
VID = ±1V
5
RO
0
-5
www.DataSheet4U.com
TIME (20ns/DIV)
FIGURE 1. EXCEPTIONAL Rx OPERATES AT >15Mbps EVEN WITH
±15V COMMON MODE VOLTAGE
15
12
0
-7
-15
STANDARD RS-485
TRANSCEIVER
ISL3247xE
FIGURE 2. TRANSCEIVERS DELIVER SUPERIOR COMMON MODE
RANGE vs STANDARD RS-485 DEVICES
January 21, 2011
FN7784.0
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.
1 page  
ISL32470E, ISL32472E, ISL32475E, ISL32478E
Absolute Maximum Ratings
VCC to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltages
DI, 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, 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 (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. . . . . . . . . . . . . . . . . . -15V to +15V
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 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
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, -15V ≤ VCM ≤ 15V (VCC ≥ 4.75V) Full 1.7 2.3
-
Driver Common-Mode VOUT (Figure
3A)
VOC RL = 54Ω or 100Ω
Full -1 - 3
V
V
V
Change in Magnitude of Driver
Common-Mode VOUT for
Complementary Output States
ΔVOC RL = 54Ω or 100Ω (Figure 3A)
Full -
- 0.2 V
Driver Short-Circuit Current
wwwL.DogaictaInSphueteHt4igUh.Vcoolmtage
Logic Input Low Voltage
Logic Input Current
IOSD
IOSD1
IOSD2
VIH
VIL
IIN1
DE = VCC, -15V ≤ VO ≤ 15V (Note 8)
At First Foldback, 22V ≤ VO ≤ -22V
At Second Foldback, 35V ≤ VO ≤ -35V
DE, DI, RE
DE, DI, RE
DI
DE, RE
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 FN7784.0
January 21, 2011
5 Page 
ISL32470E, ISL32472E, ISL32475E, ISL32478E
Test Circuits and Waveforms (Continued)
RE
B
A
R RO
15pF
SIGNAL
GENERATOR
VCM
SIGNAL
GENERATOR
B
A
RO
0V
tPLH
50%
750mV
0V
-750mV
tPHL
50%
VCC
0V
FIGURE 7A. TEST CIRCUIT
FIGURE 7B. MEASUREMENT POINTS
FIGURE 7. RECEIVER PROPAGATION DELAY AND DATA RATE
SIGNAL
GENERATOR
RE
B
A
R RO
1kΩ
15pF
VCC
SW GND
RE
(Note 11)
1.5V
1.5V
3V
0V
PARAMETER
tHZ
tLZ
tZH (Note 10)
tZL (Note 10)
tZH(SHDN) (Note 13)
tZL(SHDN) (Note 13)
DE A
0 +1.5V
0 -1.5V
0 +1.5V
0 -1.5V
0 +1.5V
0 -1.5V
SW
GND
VCC
GND
VCC
GND
VCC
tZH, tZH(SHDN)
(Note 11)
RO
tZL, tZL(SHDN)
(Note 11)
RO
tHZ
OUTPUT HIGH
1.5V
VOH - 0.5V
VOH
0V
tLZ
1.5V
OUTPUT LOW
VOL + 0.5V
VCC
VOL
FIGURE 8A. TEST CIRCUIT
FIGURE 8B. MEASUREMENT POINTS
FIGURE 8. RECEIVER ENABLE AND DISABLE TIMES
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; thus,
wwwth.DeawtiadSehCeMetR4Uis.nceocmessary to handle ground potential differences, as
well as voltages induced in the cable by external fields.
The ISL32470E, ISL32472E, ISL32475E, ISL32478E 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 ±15V, 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 ±15V,
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.
11 FN7784.0
January 21, 2011
11 Page | ||
| Páginas | Total 19 Páginas | |
| PDF Descargar | [ Datasheet ISL32478E.PDF ] | |
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