DATASHEET

ISL8488E, ISL8489E, ISL8490E, ISL8491E
®
Data Sheet
July 26, 2007
±15kV ESD Protected, 5V, Low Power,
High Speed and Slew Rate Limited, Full
Duplex, RS-485/RS-422 Transceivers
FN6073.4
Features
• RS-485 I/O Pin ESD Protection . . . . . . . . . . . . . ±15kV HBM
- Class 3 ESD Level on all Other Pins . . . . . . >7kV HBM
The ISL8488E, ISL8489E, ISL8490E, ISL8491E devices are
ESD protected, BiCMOS, 5V powered, single transceivers
that meet both the RS-485 and RS-422 standards for
balanced communication. Each driver output and receiver
input is protected against ±15kV ESD strikes, without
latch-up. Unlike competitive versions, these Intersil devices
are specified for 10% tolerance supplies (4.5V to 5.5V).
• High Data Rates (ISL8490E, ISL8491E) . . up to 10Mbps
• Slew Rate Limited for Error Free Data Transmission
(ISL8488E, ISL8489E)
• Single Unit Load Allows up to 32 Devices on the Bus
(See ISL4489E, ISL4491E for 256 Devices on Bus)
• Low Quiescent Current:
- 120µA (ISL8488E)
- 140µA (ISL8489E)
- 370µA (ISL8490E, ISL8491E)
These devices are configured for full duplex (separate Rx
input and Tx output pins) applications, so they are ideal for
RS-422 networks requiring high ESD tolerance on the bus
pins. The ISL8488E, ISL8490E are 8 Ld versions without Rx
and Tx output enables. The other two versions include Rx
and Tx output enable pins in a standard 14 Ld pinout.
• -7V to +12V Common Mode Input Voltage Range
• Three-State Rx and Tx Outputs (Except ISL8488E,
ISL8490E)
The ISL8488E, ISL8489E utilize slew rate limited drivers
which reduce EMI, and minimize reflections from improperly
terminated transmission lines, or unterminated stubs in
multidrop and multipoint applications.
• Full Duplex Pinout
• Operates from a Single +5V Supply (10% Tolerance)
• Current Limiting and Thermal Shutdown for Driver
Overload Protection
Data rates up to 10Mbps are achievable by using the
ISL8490E, ISL8491E, which feature higher slew rates.
• Pb-Free Plus Anneal Available (RoHS Compliant)
The devices present a “single unit load” to the RS-485 bus,
which allows a total of 32 transmitters and receivers on the
network. For “1/8 unit load” versions (256 devices on the
bus), please refer to the ISL4489E, ISL4491E data sheet.
Applications
• Factory Automation
Receiver (Rx) inputs feature a “fail-safe if open” design,
which ensures a logic high Rx output if Rx inputs are floating.
• Security Networks
Driver (Tx) outputs are short circuit protected, even for
voltages exceeding the power supply voltage. Additionally,
on-chip thermal shutdown circuitry disables the Tx outputs to
prevent damage if power dissipation becomes excessive.
• Industrial/Process Control Networks
• Building Environmental Control Systems
• Level Translators (e.g., RS-232 to RS-422)
• RS-232 “Extension Cords”
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
HALF/FULL
DUPLEX
HIGH ESD?
NO. OF DEVICES
ALLOWED ON BUS
DATA RATE
(Mbps)
ISL8488E
Full
Yes
32
0.25
Yes
No
120
8
ISL8489E
Full
Yes
32
0.25
Yes
Yes
140
14
ISL8490E
Full
Yes
32
10
No
No
370
8
ISL8491E
Full
Yes
32
10
No
Yes
370
14
1
SLEW-RATE
RECEIVER/
QUIESCENT
PIN
LIMITED?
DRIVER ENABLE?
ICC (μA)
COUNT
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2004, 2007. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Pinouts
Ordering Information
ISL8488E, ISL8490E
(8 LD SOIC)
TOP VIEW
VCC 1
R
RO 2
DI 3
GND 4
D
PART
NUMBER
(Note 1)
8
A
ISL8488EIB
7
B
6
Z
5
Y
ISL8489E, ISL8491E
(14 LD SOIC)
TOP VIEW
8 Ld SOIC
M8.15
ISL8488EIBZA 8488 EIBZ
(Note 2)
-40 to +85
8 Ld SOIC
(Pb-free)
M8.15
ISL8489EIB
ISL8489EIB
-40 to +85
14 Ld SOIC M14.15
ISL8489EIBZ
(Note 2)
8489EIBZ
-40 to +85
14 Ld SOIC M14.15
(Pb-free)
ISL8490EIBZ
(Note 2)
8490E IBZ
-40 to +85
8 Ld SOIC
(Pb-free)
ISL8491EIB
ISL8491EIB
-40 to +85
14 Ld SOIC M14.15
8491EIBZ
-40 to +85
14 Ld SOIC M14.15
(Pb-free)
14 VCC
RO 2
13 NC
ISL8491EIBZ
(Note 2)
RE 3
12 A
NOTES:
DE 4
11 B
DI 5
D
9 Y
GND 7
8 NC
8488 EIB
M8.15
1. Add “-T” suffix for tape and reel. Please refer to TB347 for details
on reel specifications.
10 Z
GND 6
TEMP.
PKG.
RANGE (°C) PACKAGE DWG. #
-40 to +85
NC 1
R
PART
MARKING
2. Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and
100% matte tin plate termination finish, which are RoHS
compliant and compatible with both SnPb and Pb-free soldering
operations. Intersil Pb-free products are MSL classified at
Pb-free peak reflow temperatures that meet or exceed the
Pb-free requirements of IPC/JEDEC J STD-020.
Truth Tables (For ISL8488E, ISL8490E, only the DE = 1 and RE = 0 entries are valid)
TRANSMITTING
RECEIVING
INPUTS
OUTPUTS
INPUTS
OUTPUT
RE
DE
DI
Z
Y
RE
DE
A-B
RO
X
1
1
0
1
0
X
≥ +0.2V
1
X
1
0
1
0
0
X
≤ -0.2V
0
X
0
X
High-Z
High-Z
0
X
Inputs Open
1
1
X
X
High-Z
Pin Descriptions
PIN
FUNCTION
RO
Receiver output: If A > B by at least 0.2V, RO is high; If A < B by 0.2V or more, RO is low; RO = High if A and B are unconnected (floating).
RE
Receiver output enable. RO is enabled when RE is low; RO is high impedance when RE is high.
DE
Driver output enable. The driver outputs, Y and Z, are enabled by bringing DE high. They are high impedance when DE is low.
DI
Driver input. A low on DI forces output Y low and output Z high. Similarly, a high on DI forces output Y high and output Z low.
GND
Ground connection.
A
±15kV HBM ESD Protected, Non-inverting receiver input.
B
±15kV HBM ESD Protected, Inverting receiver input.
Y
±15kV HBM ESD Protected, Non-inverting driver output.
Z
±15kV HBM ESD Protected, Inverting driver output.
VCC
NC
System power supply input (4.5V to 5.5V).
No Connection.
2
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Typical Operating Circuit
ISL8488E, ISL8490E
+5V
+5V
+
+
0.1µF
0.1µF
1
1
VCC
2
3
RO
R
VCC
A
8
B
7
Z
6
Y
5
DI
D
RT
RT
5
Y
6
Z
7
B
8
A
GND
D
R
DI
3
RO
2
GND
4
4
ISL8489E, ISL8491E
+5V
+5V
+
RO
3
RE
4
DE
5
0.1µF
14
VCC
2
+
0.1µF
14
R
A
12
B
11
Z
10
Y
9
DI
D
GND
RT
RT
9
Y
10
Z
11
B
12
A
VCC
DI
5
DE
4
RE
3
RO
2
D
R
GND
6, 7
6, 7
3
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Absolute Maximum Ratings
Thermal Information
VCC to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltages
DI, DE, RE . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to (VCC + 0.5V)
Input/Output Voltages
A, B, Y, Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -8V to + 12.5V
RO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to (VCC + 0.5V)
Short Circuit Duration
Y, Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Thermal Resistance (Typical)
θJA (°C/W)
8 Ld SOIC Package (Note 3) . . . . . . . . . . . . . . . . . .
170
14 Ld SOIC Package (Note 3) . . . . . . . . . . . . . . . . .
128
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
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C
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.
NOTE:
3. θJA is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V; Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25°C,
(Note 4).
PARAMETER
SYMBOL
TEST CONDITIONS
TEMP
MIN
(°C) (NOTE 9)
TYP
MAX
(NOTE 9) UNITS
DC CHARACTERISTICS
Driver Differential VOUT (no load)
VOD1
Driver Differential VOUT (with load)
VOD2
Full
-
-
VCC
V
R = 50Ω (RS-422) (Figure 1)
Full
2
3
-
V
R = 27Ω (RS-485) (Figure 1)
Full
1.5
2.3
5
V
ΔVOD
R = 27Ω or 50Ω (Figure 1)
Full
-
0.01
0.2
V
VOC
R = 27Ω or 50Ω (Figure 1)
Full
-
-
3
V
ΔVOC
R = 27Ω or 50Ω (Figure 1)
Full
-
0.01
0.2
V
VIH
DE, DI, RE
Full
2
-
-
V
Logic Input Low Voltage
VIL
DE, DI, RE
Full
0.8
-
-
V
Logic Input Current
IIN1
DI
Full
-2
-
2
μA
DE, RE (Note 8)
Full
-40
-
40
μA
VIN = 12V
Full
-
-
1
mA
VIN = -7V
Change in Magnitude of Driver
Differential VOUT for Complementary
Output States
Driver Common-Mode VOUT
Change in Magnitude of Driver
Common-Mode VOUT for
Complementary Output States
Logic Input High Voltage
Input Current (A, B) (Note 7)
IIN2
DE = 0V, VCC = 0V
or 4.5V to 5.5V
Full
-0.8
-
-
mA
Driver Three-State Output Current (Y, Z)
IOZD
DE = 0V, -7V ≤ VO ≤ 12V (Note 8)
Full
-100
-
100
μA
Receiver Differential Threshold Voltage
VTH
-7V ≤ VCM ≤ 12V
Full
-0.2
-
0.2
V
70
-
mV
Receiver Input Hysteresis
ΔVTH
VCM = 0V
25
-
Receiver Output High Voltage
VOH
IO = -4mA, VID = 200mV
Full
3.5
-
-
V
Receiver Output Low Voltage
VOL
IO = 4mA, VID = 200mV
Full
-
-
0.4
V
Receiver Three-State Output Current
IOZR
RE = VCC, 0.4V ≤ VO ≤ 2.4V (Note 8)
Full
-
-
±1
μA
Receiver Input Resistance
RIN
-7V ≤ VCM ≤ 12V
Full
12
-
-
kΩ
No-Load Supply Current (Note 5)
ICC
Driver Short-Circuit Current,
VO = High or Low
IOSD1
4
ISL8488E, DI = 0V or VCC
Full
-
120
140
μA
ISL8489E, DE, DI, RE = 0V or VCC
Full
-
140
190
μA
ISL8490E/ISL8491E, DE, DI, RE = 0V or
VCC
Full
-
370
460
μA
DE = VCC, -7V ≤ VY or VZ ≤ 12V (Note 6)
Full
35
-
250
mA
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Electrical Specifications
Test Conditions: VCC = 4.5V to 5.5V; Unless Otherwise Specified. Typicals are at VCC = 5V, TA = +25°C,
(Note 4). (Continued)
PARAMETER
SYMBOL
Receiver Short-Circuit Current
IOSR
TEST CONDITIONS
0V ≤ VO ≤ VCC
TEMP
MIN
(°C) (NOTE 9)
TYP
MAX
(NOTE 9) UNITS
Full
7
-
85
mA
tPLH, tPHL RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
250
400
2000
ns
tSKEW
RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
-
160
800
ns
tR, tF
SWITCHING CHARACTERISTICS (ISL8488E, ISL8489E)
Driver Input to Output Delay
Driver Output Skew
RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
250
600
2000
ns
Driver Enable to Output High
tZH
CL = 100pF, SW = GND (Figure 3, Note 8)
Full
250
1000
2000
ns
Driver Enable to Output Low
tZL
CL = 100pF, SW = VCC (Figure 3, Note 8)
Full
250
860
2000
ns
Driver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 3, Note 8)
Full
300
660
3000
ns
tLZ
CL = 15pF, SW = VCC (Figure 3, Note 8)
Driver Differential Rise or Fall Time
Driver Disable from Output Low
Full
300
640
3000
ns
Full
250
500
2000
ns
(Figure 4)
25
-
60
-
ns
tZH
CL = 15pF, SW = GND (Figure 5, Note 8)
Full
-
10
50
ns
tPLH, tPHL (Figure 4)
Receiver Input to Output Delay
Receiver Skew | tPLH - tPHL |
tSKD
Receiver Enable to Output High
Receiver Enable to Output Low
tZL
CL = 15pF, SW = VCC (Figure 5, Note 8)
Full
-
10
50
ns
Receiver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 5, Note 8)
Full
-
10
50
ns
Receiver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 5, Note 8)
Full
-
10
50
ns
Full
250
-
-
kbps
tPLH, tPHL RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
13
24
50
ns
tSKEW
RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
-
3
10
ns
tR, tF
RDIFF = 54Ω, CL = 100pF (Figure 2)
Full
5
12
25
ns
Maximum Data Rate
fMAX
SWITCHING CHARACTERISTICS (ISL8490E, ISL8491E)
Driver Input to Output Delay
Driver Output Skew
Driver Differential Rise or Fall Time
Driver Enable to Output High
tZH
CL = 100pF, SW = GND (Figure 3, Note 8)
Full
-
14
70
ns
Driver Enable to Output Low
tZL
CL = 100pF, SW = VCC (Figure 3, Note 8)
Full
-
14
70
ns
Driver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 3, Note 8)
Full
-
44
70
ns
Driver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 3, Note 8)
Full
-
21
70
ns
tPLH, tPHL (Figure 4)
Receiver Input to Output Delay
Receiver Skew | tPLH - tPHL |
tSKD
Full
30
90
150
ns
(Figure 4)
25
-
5
-
ns
Receiver Enable to Output High
tZH
CL = 15pF, SW = GND (Figure 5, Note 8)
Full
-
9
50
ns
Receiver Enable to Output Low
tZL
CL = 15pF, SW = VCC (Figure 5, Note 8)
Full
-
9
50
ns
Receiver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 5, Note 8)
Full
-
9
50
ns
Receiver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 5, Note 8)
Full
-
9
50
ns
Full
10
-
-
Mbps
25
-
±15
-
kV
25
-
>±7
-
kV
Maximum Data Rate
fMAX
ESD PERFORMANCE
RS-485 Pins (A, B, Y, Z)
Human Body Model
All Other Pins
NOTES:
4. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless
otherwise specified.
5. Supply current specification is valid for loaded drivers when DE = 0V.
6. Applies to peak current. See “Typical Performance Curves” on page 9 for more information.
7. Devices meeting these limits are denoted as “single unit load (1 UL)” transceivers. The RS-485 standard allows up to 32 Unit Loads on the bus.
8. Not applicable to the ISL8488E, ISL8490E.
9. Parts are 100% tested at +25°C. Over-temperature limits established by characterization and are not production tested.
5
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Test Circuits and Waveforms
R
VCC
DE
Z
DI
VOD
D
Y
R
VOC
FIGURE 1. DRIVER VOD AND VOC
3V
DI
1.5V
1.5V
0V
tPLH
VCC
tPHL
CL = 100pF
DE
VOH
50%
OUT (Y)
50%
Z
DI
VOL
RDIFF
D
Y
tPLH
tPHL
CL = 100pF
VOH
SIGNAL
GENERATOR
OUT (Z)
50%
50%
VOL
90%
DIFF OUT (Y - Z)
10%
tR
+VOD
90%
10%
-VOD
tF
SKEW = |tPLH (Y or Z) - tPHL (Z or Y)|
FIGURE 2A. TEST CIRCUIT
FIGURE 2B. MEASUREMENT POINTS
FIGURE 2. DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
6
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Test Circuits and Waveforms (Continued)
DE
Z
DI
500Ω
VCC
D
SIGNAL
GENERATOR
SW
Y
3V
DE
1.5V
1.5V
GND
0V
CL
tZH
tHZ
OUTPUT HIGH
OUT (Y, Z)
PARAMETER OUTPUT
RE
DI
SW
CL (pF)
tHZ
Y/Z
X
1/0
GND
15
tLZ
Y/Z
X
0/1
VCC
15
2.3V
0V
tZL
tLZ
VCC
OUT (Y, Z)
tZH
Y/Z
X
1/0
GND
100
tZL
Y/Z
X
0/1
VCC
100
VOH - 0.5V VOH
2.3V
VOL + 0.5V V
OL
OUTPUT LOW
FIGURE 3A. TEST CIRCUIT
FIGURE 3B. MEASUREMENT POINTS
FIGURE 3. DRIVER ENABLE AND DISABLE TIMES (EXCLUDING ISL8488E, ISL8490E)
RE
3V
15pF
B
+1.5V
R
A
A
1.5V
1.5V
RO
0V
tPHL
tPLH
VCC
SIGNAL
GENERATOR
50%
RO
50%
0V
FIGURE 4B. MEASUREMENT POINTS
FIGURE 4A. TEST CIRCUIT
FIGURE 4. RECEIVER PROPAGATION DELAY
RE
3V
B
R
SIGNAL
GENERATOR
1kΩ
RO
VCC
SW
A
RE
1.5V
1.5V
0V
GND
15pF
tZH
OUTPUT HIGH
RO
PARAMETER
DE
A
SW
tHZ
X
+1.5V
GND
tLZ
X
-1.5V
VCC
tZH
X
+1.5V
GND
tZL
X
-1.5V
VCC
FIGURE 5A. TEST CIRCUIT
tHZ
VOH - 0.5V VOH
1.5V
0V
tZL
tLZ
VCC
RO
1.5V
VOL + 0.5V V
OUTPUT LOW
OL
FIGURE 5B. MEASUREMENT POINTS
FIGURE 5. RECEIVER ENABLE AND DISABLE TIMES (EXCLUDING ISL8488E, ISL8490E)
7
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Application Information
Data Rate, Cables, and Terminations
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.
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.
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 RS-422 and
RS-485 specifications.
Receiver input resistance surpasses the RS-422
specification of 4kΩ, and meets the RS-485 “Unit Load”
requirement of 12kΩ 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 rate supported by the
corresponding driver. ISL8489E/ISL8491E receiver outputs
are three-statable via the active low RE input.
Driver Features
The RS-485/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. ISL8489E/ISL8491E driver outputs are threestatable via the active high DE input.
The ISL8488E/ISL8489E driver outputs are slew rate limited
to further reduce EMI, and to minimize reflections in
unterminated or improperly terminated networks. Data rates
on these slew rate limited versions are a maximum of
250kbps. Outputs of ISL8490E/ISL8491E drivers are not
limited, so faster output transition times allow data rates of at
least 10Mbps.
8
RS-485/RS-422 are intended for network lengths up to
4000’, but the maximum system data rate decreases as the
transmission length increases. Devices operating at 10Mbps
are limited to lengths of a few hundred feet, while the
250kbps versions can operate at full data rates with lengths
in excess of 1000’.
Proper termination is imperative, when using the 10Mbps
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. In point-to-point, or point-to-multipoint (single driver
on bus) networks, the main cable should be terminated in its
characteristic impedance (typically 120Ω) at the end farthest
from the driver. In multi-receiver applications, stubs
connecting receivers to the main cable should be kept as
short as possible. Multipoint (multi-driver) systems require
that the main cable be terminated in its characteristic
impedance at both ends. Stubs connecting a transceiver to
the main cable should be kept as short as possible.
Built-In Driver Overload Protection
As stated previously, the RS-485 specification requires that
drivers survive worst case bus contentions undamaged. The
ISL84xxE devices meet this requirement via driver output
short circuit current limits, and on-chip thermal shutdown
circuitry.
The driver output stages incorporate short circuit current
limiting circuitry which ensures that the output current never
exceeds the RS-485 specification, even at the common
mode voltage range extremes. Additionally, these devices
utilize a foldback circuit which reduces the short circuit
current, and thus the power dissipation, whenever the
contending voltage exceeds either supply.
In the event of a major short circuit condition, ISL84xxE
devices also include a thermal shutdown feature that
disables the drivers whenever the die temperature becomes
excessive. This eliminates the power dissipation, allowing
the die to cool. The drivers automatically reenable after the
die temperature drops about 15°. If the contention persists,
the thermal shutdown/reenable cycle repeats until the fault is
cleared. Receivers stay operational during thermal
shutdown.
ESD Protection
All pins on these devices include class 3 Human Body Model
(HBM) ESD protection structures, but the RS-485 pins
(driver outputs and receiver inputs) incorporate advanced
structures allowing them to survive ESD events in excess of
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
±15kV HBM. The RS-485 pins are particularly vulnerable to
ESD damage 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. These new ESD
structures protect the device whether or not it is powered up,
Typical Performance Curves
protect without allowing any latch-up mechanism to activate,
and without degrading the RS-485 common mode range of
-7V to +12V. This built-in ESD protection eliminates the need
for board level protection structures (e.g., transient
suppression diodes), and the associated, undesirable
capacitive load they present.
VCC = 5V, TA = +25°C; Unless Otherwise Specified.
3.6
DIFFERENTIAL OUTPUT VOLTAGE (V)
90
DRIVER OUTPUT CURRENT (mA)
80
70
60
50
40
30
20
10
0
0
1
2
3
4
3.4
3.2
RDIFF = 100Ω
3.0
2.8
2.6
2.4
RDIFF = 54Ω
2.2
2.0
-40
5
-25
DIFFERENTIAL OUTPUT VOLTAGE (V)
25
50
75
85
TEMPERATURE (°C)
FIGURE 6. DRIVER OUTPUT CURRENT vs DIFFERENTIAL
OUTPUT VOLTAGE
FIGURE 7. DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs
TEMPERATURE
400
160
140
ISL8490E/ISL8491E
120
ISL8490E/ISL8491E, DE = X, RE = X
350
Y OR Z = LOW
100
80
300
ISL8488E/ISL8489E
60
40
ICC (µA)
OUTPUT CURRENT (mA)
0
20
0
-20
Y OR Z = HIGH
-40
250
200
ISL8489E, DE = X, RE = X
150
-60
ISL8490E/ISL8491E
-80 ISL8488E/ISL8489E
-100
-120
-7 -6
-4
-2
0
2
4
6
OUTPUT VOLTAGE (V)
100
8
10
12
FIGURE 8. DRIVER OUTPUT CURRENT vs SHORT CIRCUIT
VOLTAGE
9
50
ISL8488E
-40
-25
0
25
TEMPERATURE (°C)
50
75
85
FIGURE 9. SUPPLY CURRENT vs TEMPERATURE
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Typical Performance Curves
VCC = 5V, TA = +25°C; Unless Otherwise Specified.
250
750
200
tPLHY
tPLHZ
650
|tPLHY - tPHLZ|
SKEW (ns)
PROPAGATION DELAY (ns)
700
600
tPHLY
150
|tPHLY - tPLHZ|
100
550
tPHLZ
50
500
|CROSS PT. OF Y↑ AND Z↓ TO CROSS PT. OF Y↓ AND Z↑|
450
-40
-25
0
25
TEMPERATURE (°C)
50
0
-40
85
75
FIGURE 10. DRIVER PROPAGATION DELAY vs
TEMPERATURE (ISL8488E/ISL8489E)
-25
0
25
TEMPERATURE (°C)
50
85
75
FIGURE 11. DRIVER SKEW vs TEMPERATURE
(ISL8488E/ISL8489E)
30
5
4
|tPHLY - tPLHZ|
26
24
tPLHY
22
tPHLZ
tPLHZ
3
SKEW (ns)
|tPLHY - tPHLZ|
2
20
1
18
|CROSS PT. OF Y↑ AND Z↓ TO CROSS PT. OF Y↓ AND Z↑|
tPHLY
16
-40
-25
0
25
50
0
-40
85
75
-25
TEMPERATURE (°C)
DRIVER OUTPUT (V)
0
4
Z
3
2
RECEIVER OUTPUT (V)
0
DRIVER INPUT (V)
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
5
RO
Y
1
0
TIME (400ns/DIV)
FIGURE 14. DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (ISL8488E/ISL8489E)
10
50
85
75
FIGURE 13. DRIVER SKEW vs TEMPERATURE
(ISL8490E/ISL8491E)
RDIFF = 54Ω, CL = 100pF
5
25
TEMPERATURE (°C)
FIGURE 12. DRIVER PROPAGATION DELAY vs
TEMPERATURE (ISL8490E/ISL8491E)
DI
0
RDIFF = 54Ω, CL = 100pF
5
DI
0
5
RO
DRIVER INPUT (V)
PROPAGATION DELAY (ns)
28
0
4
3
2
Y
Z
1
0
TIME (400ns/DIV)
FIGURE 15. DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (ISL8488E/ISL8489E)
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
DI
0
5
RO
0
4
Z
3
2
Y
1
0
TIME (20ns/DIV)
FIGURE 16. DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (ISL8490E/ISL8491E)
RDIFF = 54Ω, CL = 100pF
5
DI
0
5
RO
DRIVER INPUT (V)
5
RECEIVER OUTPUT (V)
RDIFF = 54Ω, CL = 100pF
DRIVER INPUT (V)
VCC = 5V, TA = +25°C; Unless Otherwise Specified.
DRIVER OUTPUT (V)
DRIVER OUTPUT (V)
RECEIVER OUTPUT (V)
Typical Performance Curves
0
4
3
2
Y
Z
1
0
TIME (20ns/DIV)
FIGURE 17. DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (ISL8490E/ISL8491E)
Die Characteristics
SUBSTRATE POTENTIAL (POWERED UP):
GND
TRANSISTOR COUNT:
518
PROCESS:
Si Gate BiCMOS
11
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Small Outline Plastic Packages (SOIC)
M8.15 (JEDEC MS-012-AA ISSUE C)
N
8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE
INDEX
AREA
H
0.25(0.010) M
B M
INCHES
E
SYMBOL
-B-
1
2
3
L
SEATING PLANE
-A-
A
D
h x 45°
-C-
e
A1
B
0.25(0.010) M
C
0.10(0.004)
C A M
MIN
MAX
MIN
MAX
NOTES
A
0.0532
0.0688
1.35
1.75
-
A1
0.0040
0.0098
0.10
0.25
-
B
0.013
0.020
0.33
0.51
9
C
0.0075
0.0098
0.19
0.25
-
D
0.1890
0.1968
4.80
5.00
3
E
0.1497
0.1574
3.80
4.00
4
e
α
B S
0.050 BSC
-
0.2284
0.2440
5.80
6.20
-
h
0.0099
0.0196
0.25
0.50
5
L
0.016
0.050
0.40
1.27
6
α
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.
1.27 BSC
H
N
NOTES:
MILLIMETERS
8
0°
8
8°
0°
7
8°
Rev. 1 6/05
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per
side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater
above the seating plane, shall not exceed a maximum value of
0.61mm (0.024 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
12
FN6073.4
July 26, 2007
ISL8488E, ISL8489E, ISL8490E, ISL8491E
Small Outline Plastic Packages (SOIC)
M14.15 (JEDEC MS-012-AB ISSUE C)
N
INDEX
AREA
0.25(0.010) M
H
14 LEAD NARROW BODY SMALL OUTLINE PLASTIC
PACKAGE
B M
E
INCHES
-B-
1
2
3
L
SEATING PLANE
-A-
h x 45o
A
D
-C-
µα
e
A1
B
0.25(0.010) M
C A M
SYMBOL
MIN
MAX
MIN
MAX
NOTES
A
0.0532
0.0688
1.35
1.75
-
A1
0.0040
0.0098
0.10
0.25
-
B
0.013
0.020
0.33
0.51
9
C
0.0075
0.0098
0.19
0.25
-
D
0.3367
0.3444
8.55
8.75
3
E
0.1497
0.1574
3.80
4.00
4
e
C
0.10(0.004)
B S
0.050 BSC
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.
1.27 BSC
-
H
0.2284
0.2440
5.80
6.20
-
h
0.0099
0.0196
0.25
0.50
5
L
0.016
0.050
0.40
N
NOTES:
MILLIMETERS
α
14
0o
1.27
14
8o
0o
6
7
8o
Rev. 0 12/93
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
4. Dimension “E” does not include interlead flash or protrusions. Interlead
flash and protrusions shall not exceed 0.25mm (0.010 inch) per side.
5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater
above the seating plane, shall not exceed a maximum value of
0.61mm (0.024 inch).
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
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Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
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13
FN6073.4
July 26, 2007