ISL33354EIAZ-T [INTERSIL]
Full fail-safe (open/short) RS-485/422 port 2 Rx;
| 型号： | ISL33354EIAZ-T |
| 厂家： | 
Intersil |
| 描述： | Full fail-safe (open/short) RS-485/422 port 2 Rx |
| 文件： | 总23页 (文件大小：775K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
DATASHEET
5V, ±15kV ESD Protected, Two Port, Dual Protocol
(RS-232/RS-485) Transceivers
ISL33354E, ISL33357E
Features
The ISL33354E, ISL33357E are two port interface ICs where
port 1 is configured as a dual (2 Tx, 2 Rx) RS-232 transceiver,
and port 2 is a single RS-485/422 transceiver.
• ±15kV (HBM) ESD protected bus pins (RS-232 or RS-485)
• Operates from a single 5V supply
• Two independent ports: port 1 set for RS-232 (2 transceivers)
and port 2 for RS-485/RS-422 (1 transceiver)
An on-board charge pump generates RS-232 compliant ±5V Tx
output levels from a single V supply as low as 4.5V. The
CC
• True flow-through pinouts (Rx inputs and Tx outputs all on
the same side) simplify board layouts
transceivers are RS-232 compliant, with the Rx inputs
handling up to ±25V.
• Pb-free (RoHS compliant)
The port 2 transceiver supports both the RS-485 and RS-422
differential communication standards. The receiver features
"full fail-safe" operation, so the Rx output remains in a high
state if the inputs are open or shorted together. The
transmitter supports two data rates, one of which is slew rate
limited for problem free communication at low data rates. The
active low Rx enable pin (RE485) allows Tx/Rx direction
control, via a single signal, simply by connecting the
corresponding DE485 and RE485 pins together.
• Full fail-safe (open/short) RS-485/422 port 2 Rx
• User selectable RS-485 data rates
- Fast speed. . . . . . . . . . . . . . . . . . . . . . . . . . . . up to 20Mbps
- Slew rate limited . . . . . . . . . . . . . . . . . . . . . . up to 115kbps
• Fast RS-232 data rate . . . . . . . . . . . . . . 460kbps (Minimum)
• Small charge pump capacitors . . . . . . . . . . . . . . . . 4 x 0.1µF
• Low current shutdown mode . . . . . . . . . . . . . . . . . . . . . . 55µA
• QFN package saves board space (ISL33357E only)
The ISL33354E and ISL33357E also include a shutdown
function, which disables the Tx and Rx outputs, disables the
charge pumps and places the IC in a low current (55µA) mode.
Applications
• Gaming applications (e.g., slot machines)
The ISL33357E is a QFN packaged device for space
constrained applications.
• Single board computers
Related Literature
• For a full list of related documents, visit our website
- ISL33354E, ISL33357E product pages
• Factory automation
• Security networks
• Industrial/process control networks
• Level translators (e.g., RS-232 to RS-422)
• Point-of-sale equipment
TABLE 1. SUMMARY OF FEATURES
PORT 2
RS-485 DATA RATE
PORT 1
RS-232 DATA RATE
PORT 2
RS-485 Rx AND Tx
LOW POWER
SHUTDOWN?
PART NUMBER
ISL33354E
PACKAGE OPTION
28 Ld SSOP
20M, 115k
20M, 115k
650k
650k
YES
YES
YES
YES
ISL33357E
40 Ld QFN (6 x 6mm)
October 21, 2016
FN8775.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 |Copyright Intersil Americas LLC. 2015, 2016. 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
ISL33354E, ISL33357E
Ordering Information
PART NUMBER
(Notes 2, 3)
PART
MARKING
TEMPERATURE
RANGE (°C)
TAPE AND REEL
(UNITS)
PACKAGE
(RoHS COMPLIANT)
PKG. DWG. #
M28.209
M28.209
L40.6x6
ISL33354EIAZ
33354 EIAZ
-40 to +85
-40 to +85
-40 to +85
-40 to +85
-40 to +85
-
1k
-
28 Ld SSOP
ISL33354EIAZ-T (Note 1)
ISL33357EIRZ
33354 EIAZ
33357E IRZ
33357E IRZ
33357E IRZ
28 Ld SSOP
40 Ld QFN
40 Ld QFN
40 Ld QFN
ISL33357EIRZ-T (Note 1)
1k
250
L40.6x6
ISL33357EIRZ-T7A
(Note 1)
L40.6x6
NOTES:
1. Refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is 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.
3. For Moisture Sensitivity Level (MSL), see product information page for ISL33354E, ISL33357E. For more information on MSL, see tech brief TB363.
TABLE 2. KEY DIFFERENCES BETWEEN FAMILY OF PARTS
VCC
(V)
RS485 (bps)
DATA RATE
RS232 (bps)
DATA RATE
PART NUMBER
ISL33354E
ISL33357E
ISL33334E
ISL33337E
PKG
5
28Ld SSOP
40Ld QFN
28Ld SSOP
40Ld QFN
20M, 115k
20M, 115k
20M, 115k
20M, 115k
650k
650k
400k
400k
5
3.3
3.3
NOTE: For a full list of dual protocol transceivers, please visit our website.
Pin Configurations
ISL33354E
(28 LD SSOP)
TOP VIEW
ISL33357E
(40 LD QFN)
TOP VIEW
C1+
C1-
1
2
3
4
5
6
7
8
9
28 C2+
27 C2-
40 39 38 37 36 35 34 33 32 31
PORT 1
PORT 1
R
26 V
CC
V+
V+
R2OUT
1
2
30
29
28
27
26
25
24
23
22
21
R
25 R2OUT
24 R1OUT
23 T2IN
R1IN
R2IN
T1OUT
T2OUT
*GND
R1IN
R2IN
R1OUT
T2IN
R
R
3
D
D
22 T1IN
T1OUT
T2OUT
*GND
4
T1IN
21 SHDN
D
D
5
*V
CC
*V
20
DI
CC
6
SHDN
DI
Y 10
Z 11
19 DE485
18 RO
PORT 2
D
*V
7
CC
D
R
A 12
17 V-
8
DE485
Y
Z
B 13
16 RE485
15 GND
9
RO
SLOW485 14
R
PORT 2
EP
DNC
10
A
* NOT A SUPPLY PIN, BUT MUST BE CONNECTED TO THE
NOTED SUPPLY.
11 12 13 14 15 16 17 18 19 20
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ISL33354E, ISL33357E
Pin Descriptions
PIN #
for
PIN # for
QFN
PIN NAME SSOP
PORT/MODE
BOTH
FUNCTION
NC
-
12, 20, 32,
33, 39, 40
No Internal Connection.
DNC
-
21
25
BOTH
BOTH
Do not make any external connections to this pin.
SHDN
21
A low on SHDN disables the charge pumps, disables all the outputs and places the device in low power
shutdown. Internally pulled-high. SHDN = 1 for normal operation.
V
26
15
31, 34
15, 16
BOTH
BOTH
System power supply input (4.5V to 5.5V). Both pins 31 and 34 must connect to the V supply.
CC
CC
GND
Ground connection. QFN pins 15 and 16 must both connect to GND. This is also the potential of the
QFN’s exposed metal pad (EP).
*V
CC
9
7, 14, 26
BOTH
BOTH
For proper operation, connect this lead to the V supply. This is not a power supply lead, so no decoupling
CC
is required.
*GND
RxIN
8
6, 17
2, 3
For proper operation, connect this lead to GND. This is not a power supply lead.
4, 5
1 / RS-232 RS-232 receiver input with ±15kV ESD protection. A low on RxIN forces RxOUT high; a high on RxIN
forces RxOUT low.
RxOUT
TxIN
24, 25
22, 23
29, 30
27, 28
1 / RS-232 RS-232 receiver output.
1 / RS-232 RS-232 transmitter input. A low on TxIN drives the corresponding TxOUT high, while a high on TxIN drives
the corresponding TxOUT low.
TxOUT
C1+
C1-
C2+
C2-
V+
V-
6, 7
1
4, 5
37
38
36
35
1
1 / RS-232 RS-232 transmitter output with ±15kV ESD protection.
1 / RS-232 External charge pump capacitor is connected to this lead.
1 / RS-232 External charge pump capacitor is connected to this lead.
1 / RS-232 External charge pump capacitor is connected to this lead.
1 / RS-232 External charge pump capacitor is connected to this lead.
1 / RS-232 Internally generated positive RS-232 transmitter supply (+6V).
1 / RS-232 Internally generated negative RS-232 transmitter supply (-7V).
2 / RS-485 RS-485 noninverting receiver input with ±15kV ESD protection.
2 / RS-485 RS-485 inverting receiver input with ±15kV ESD protection.
2/ RS-485 RS-485 noninverting driver output with ±15kV ESD protection.
2/ RS-485 RS-485 inverting driver output with ±15kV ESD protection.
2 / RS-485 RS-485 driver input. A low on DI forces output Y low and output Z high.
2
28
27
3
17
12
13
10
11
20
18
19
10
11
8
A
B
Y
Z
9
DI
24
22
RO
2 / RS-485 RS-485 receiver output: If A > B by at least -40mV, RO is high; If A < B by -200mV or more, RO is low;
RO = High if A and B are unconnected (floating) or shorted together (i.e., full fail-safe).
SLOW48
5
14
16
19
-
13
18
23
EP
2 / RS-485 RS-485 data rate control. A low on SLOW485 selects the 115kbps RS-485 data rate (slew rate limited
output transitions); a high selects the 20Mbps data rate (full speed transitions). Internally pulled-high.
RE485
DE485
EP
2/ RS-485 RS-485 active low receiver output enable. RO is enabled when RE485 is low; RO is high impedance
when RE485 is high. Internally pulled low.
2/ RS-485 RS-485 driver output enable (DE). The driver outputs, Y and Z, are enabled by driving DE485 high. They
are high impedance when DE485 is low. Internally pulled high.
BOTH
QFN exposed thermal pad (EPAD). Connect to GND.
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ISL33354E, ISL33357E
Typical Operating Circuits
+5V
+
+
+
0.1µF
9, 26
1
C
1
0.1µF
C1+
V
3
CC
C
0.1µF
3
+
V+
V-
2
C1-
28
C
2
C2+
17
0.1µF
C
4
27
C2-
0.1µF
+
4
24
25
R1OUT
R2OUT
R1IN
R2IN
R
5kΩ
5
R
5kΩ
7
6
23
22
T2OUT
T1OUT
D
D
T2IN
T1IN
13
12
B
A
18
16
R
RO
RE485
11
10
Z
Y
20
DI
D
19
V
CC
DE485
21
V
CC
SHDN
14
SLOW485
GND
8, 15
NOTE: PINOUT FOR SSOP
FIGURE 1. 1 PORT IN RS-232 MODE AND 1 PORT IN RS-485 MODE
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ISL33354E, ISL33357E
TABLE 3. ISL33354E AND ISL33357E FUNCTION TABLE
INPUTS
RECEIVER OUTPUTS
DRIVER OUTPUTS
DRIVER
DATA
RATE
R1OUT
AND
CHARGE
PUMPS
(Note 4)
T1OUT AND
PORT
SHDN
RE485
DE485 SLOW485
RO
N.A.
ON
R2OUT
Y AND Z
N.A.
T2OUT
(bps)
MODE
RS-232
1
2
2
1
1
1
N.A.
0
N.A.
0
N.A.
0
ON
ON
ON
ON
ON
460k
115k
115k
N.A.
High-Z
ON
N.A.
N.A.
RS-485 Rx
0
1
0
ON
N.A.
RS-485 Tx
and Rx
2
2
2
1
1
1
1
0
0
1
0
1
0
1
1
High-Z
ON
N.A.
N.A.
N.A.
ON
High-Z
ON
N.A.
N.A.
N.A.
ON
ON
ON
115k
20M
20M
RS-485 Tx
RS-485 Rx
ON
RS-485 Tx
and Rx
2
1
0
1
X
1
X
1
X
High-Z
High-Z
N.A.
ON
N.A.
ON
20M
N.A.
RS-485 Tx
Shutdown
1 and 2
High-Z
High-Z
High-Z
OFF
NOTE:
4. Charge pumps are off if SHDN = 0. If SHDN = 1, the charge pumps are on.
RS-485 TRANSMITTING (PORT 2)
INPUTS OUTPUTS
Truth Tables
RS-232 TRANSMITTING (PORT 1)
SHDN DE485
DI
0
1
0
1
X
SLOW485
Y
0
1
0
1
Z
1
0
1
0
DATA RATE (bps)
115k
INPUTS
OUTPUTS
1
1
1
1
1
0
1
1
1
1
0
X
0
0
1
1
X
X
SHDN
T1IN
0
T2IN
0
T1OUT
T2OUT
115k
1
1
1
1
0
1
1
20M
0
1
1
0
0
1
20M
1
0
High-Z High-Z
High-Z High-Z
N.A.
1
1
0
0
X
N.A.
X
X
High-Z
High-Z
RS-485 RECEIVING (PORT 2)
INPUTS
RS-232 RECEIVING (PORT 1)
INPUTS
OUTPUT
OUTPUTS
SHDN
RE485
A-B
RO
1
SHDN
R1IN
R2IN
R1OUT
R2OUT
1
1
1
1
0
0
0
0
1
X
≥-40mV
≤-200mV
1
1
1
1
1
0
0
0
0
1
1
1
0
1
0
Open or shorted together
1
1
0
0
0
1
0
X
X
High-Z
High-Z
1
1
Open
X
Open
X
1
1
High-Z
High-Z
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ISL33354E, ISL33357E
Absolute Maximum Ratings (T = +25°C)
Thermal Information
A
V
to Ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Thermal Resistance (Typical)
28 Ld SSOP Package (Notes 7, 9). . . . . . . .
40 Ld QFN Package (Notes 6, 8) . . . . . . . . .
Maximum Junction Temperature (Plastic Package) . . . . . . . . . . . +150°C
Maximum Storage Temperature Range . . . . . . . . . . . . . -65°C to +150°C
Pb-Free Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB493
JA (°C/W) JC (°C/W)
CC
Input Voltages
60
36
All Except A, B, RxIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
Input/Output Voltages
32
2.5
A, B, RxIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25V to +25V
Y, Z, TxOUT (Note 5). . . . . . . . . . . . . . . . . . . . . . . . . . . . . -12.5V to +12.5V
RO, RxOUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to (V + 0.5V)
CC
Output Short-Circuit Duration
Recommended Operating Conditions
Y, Z, TxOUT, RxOUT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . See Specification Table on page 7
Latch-Up (per JESD78, Level 2, Class A). . . . . . . . . . . . . . . . . . . . . . . +85°C
Supply Voltage (V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5V
CC
Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C
RS-485 Tx Load . . . . . . . . . . . . . . . . . . . . . . One or two 120Ω Terminations
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:
5. One output at a time, I
OUT
≤ 100mA for ≤10 mins.
6. is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
JA
Brief TB379.
7. is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
JA
8. For , the “case temp” location is the center of the exposed metal pad on the package underside.
JC
9. For , the “case temp” location is taken at the package top center.
JC
Electrical Specifications Test Conditions: V = 4.5V to 5.5V, C - C = 0.1µF, unless otherwise specified. Typicals are at V = 5V,
CC
1
4
CC
T
= +25°C (Note 10). Boldface limits apply across the operating temperature range, -40°C to +85°C.
A
TEMP
(°C) (Note 15)
MIN
MAX
(Note 15) UNIT
PARAMETER
SYMBOL
TEST CONDITIONS
TYP
DC CHARACTERISTICS - RS-485 DRIVER (Port 2)
Driver Differential V
Driver Differential V
(No Load)
V
V
Full
Full
Full
-
2.5
2.2
2
-
V
V
V
V
V
V
OUT
OD1
CC
(with Load)
R = 50Ω (RS-422) (Figure 2)
R = 27Ω (RS-485) (Figure 2)
3.1
2.7
2.7
0.01
-
OUT
OD2
5
5
V
R
= 60Ω, R = 375Ω, V = -7V to 12V (Figure 2) Full
D CM
OD3
Change in Magnitude of Driver
Differential V for
V
R = 27Ω or 50Ω (Figure 2)
Full
-
0.2
OD
OUT
Complementary Output States
Driver Common-Mode V
OUT
V
R = 27Ω or 50Ω (Figure 2) (Note 14)
R = 27Ω or 50Ω (Figure 2) (Note 14)
Full
Full
-
-
-
3.1
0.2
V
V
OC
Change in Magnitude of Driver
Common-Mode V for
V
OC
0.01
OUT
Complementary Output States
Driver Short-Circuit Current,
I
-7V ≤ (V or V ) ≤ 12V (Note 12)
Full
35
-
250
mA
OS
Y
Z
V
= High or Low
OUT
Driver Three-State Output Leakage
Current (Y, Z)
I
Outputs disabled,
= 0V or 5.5V
V
V
= 12V
= -7V
Full
Full
-
-
-
500
µA
µA
OZ
OUT
V
CC
-200
-
OUT
DC CHARACTERISTICS - RS-232 DRIVER (PORT 1)
Driver Output Voltage Swing
V
All T
loaded with 3kΩ to ground
= 0V
OUT
Full
Full
±5
+6/-7
-
V
O
OUTS
Driver Output Short-Circuit Current
I
V
-60
25/-35
60
mA
OS
DC CHARACTERISTICS - LOGIC PINS (i.e., DRIVER AND CONTROL INPUT PINS)
Input High Voltage
Input Low Voltage
V
Full
Full
2
1.6
1.4
-
V
V
IH
V
-
0.8
IL
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ISL33354E, ISL33357E
Electrical Specifications Test Conditions: V = 4.5V to 5.5V, C - C = 0.1µF, unless otherwise specified. Typicals are at V = 5V,
CC
1
4
CC
T
= +25°C (Note 10). (Continued) Boldface limits apply across the operating temperature range, -40°C to +85°C. (Continued)
A
TEMP
(°C) (Note 15)
MIN
MAX
(Note 15) UNIT
PARAMETER
Input Current
SYMBOL
TEST CONDITIONS
Pins without pull-ups or pull-downs
SLOW485, DE485, RE485, SHDN
TYP
I
Full
Full
-2
-
-
2
µA
µA
IN1
IN2
I
-25
25
DC CHARACTERISTICS - RS-485 RECEIVER INPUTS (PORT 2)
Receiver Differential Threshold
Voltage
V
-7V ≤ V ≤ 12V, full fail-safe
CM
Full
-0.2
-
-0.04
V
TH
Receiver Input Hysteresis
V
V
V
= 0V
25
Full
Full
Full
-
-
35
-
mV
mA
mA
kΩ
TH
CM
Receiver Input Current (A, B)
I
= 0V or 4.5 to 5.5V
V
V
= 12V
= -7V
-
-
-
0.8
IN
CC
IN
IN
-0.64
15
-
-
Receiver Input Resistance
R
-7V ≤ V ≤ 12V, V = 0 (Note 13) or
CM CC
IN
4.5V ≤ V ≤ 5.5V
CC
DC CHARACTERISTICS - RS-232 RECEIVER INPUTS (PORT 1)
Receiver Input Voltage Range
Receiver Input Threshold
V
Full
Full
Full
25
-25
-
25
V
V
IN
V
-
2.4
-
1.4
1.9
0.5
5
0.8
IL
V
-
-
V
IH
Receiver Input Hysteresis
Receiver Input Resistance
V
V
TH
IN
R
V
= ±15V, V powered up (Note 13)
CC
Full
3
7
kΩ
IN
DC CHARACTERISTICS - RECEIVER OUTPUTS (PORTS 1 and 2)
Receiver Output High Voltage
Receiver Output Low Voltage
Receiver Short-Circuit Current
Receiver Three-State Output Current
POWER SUPPLY CHARACTERISTICS
No-Load Supply Current, (Note 11)
Shutdown Supply Current
V
I
I
= -2mA
= 3mA
Full
Full
Full
Full
3.5
4.6
-
V
V
OH
O
O
V
-
7
-
0.1
0.4
85
OL
I
0V ≤ V ≤ V
CC
-
-
mA
µA
OSR
O
I
Output disabled, 0V ≤ V ≤ V
CC
±10
OZR
O
I
SHDN = V
CC
Full
Full
-
-
3.7
55
7
mA
µA
CC
I
SHDN = SLOW485 = GND, RE485 = V
,
CC
160
SHDN
DE485 = GND
ESD CHARACTERISTICS
Bus Pins (A, B, Y, Z, RxIN, TxOUT)
All Other Pins
Human body model, Bus pin to GND
Human body model (per JEDEC)
Machine model (per JEDEC)
25
25
25
-
-
-
±15
±4
-
-
-
kV
kV
V
±200
RS-232 DRIVER AND RECEIVER SWITCHING CHARACTERISTICS (PORT 1)
Driver Output Transition Region
Slew Rate
SR
R
= 3kΩ, measured from
C ≥15pF
Full
Full
Full
Full
Full
Full
25
-
18
12
30
V/µs
V/µs
µs
L
L
3V to -3V or -3V to 3V
C ≤2500pF
4
-
L
Driver Output Transition Time
Driver Propagation Delay
t , t
R
R
= 3kΩ, C = 2500pF, 10% - 90%
0.22
1.2
1
3.1
r
f
L
L
L
t
= 3kΩ C = 1000pF (Figure 7)
-
2
µs
DPHL
L
t
-
1.2
240
20
2
µs
DPLH
Driver Propagation Delay Skew
Driver Enable Time from Shutdown
Driver Maximum Data Rate
t
t
- t
(Figure 7)
= ±3.0V, C = 1000pF
-
-
400
ns
DSKEW
DPHL DPLH
t
V
-
-
µs
DENSD
DR
OUT
L
R
= 3kΩ, C = 1000pF, one transmitter
Full
460
650
kbps
D
L
L
switching
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ISL33354E, ISL33357E
Electrical Specifications Test Conditions: V = 4.5V to 5.5V, C - C = 0.1µF, unless otherwise specified. Typicals are at V = 5V,
CC
1
4
CC
T
= +25°C (Note 10). (Continued) Boldface limits apply across the operating temperature range, -40°C to +85°C. (Continued)
A
TEMP
(°C) (Note 15)
MIN
MAX
(Note 15) UNIT
PARAMETER
SYMBOL
TEST CONDITIONS
C = 15pF (Figure 8)
TYP
50
40
10
2
Receiver Propagation Delay
t
t
Full
Full
Full
Full
-
120
120
40
-
ns
ns
RPHL
RPLH
L
-
-
Receiver Propagation Delay Skew
Receiver Maximum Data Rate
t
t
- t
RPHL RPLH
(Figure 8)
ns
RSKEW
DR
C = 15pF
0.46
Mbps
R
L
RS-485 DRIVER SWITCHING CHARACTERISTICS (FAST DATA RATE (20Mbps), PORT 2, (SLOW485 = V ))
CC
Driver Differential Input to Output
Delay
t
, t
DLH DHL
R
= 54Ω, C = 100pF (Figure 3)
Full
15
30
50
ns
DIFF
L
Driver Output Skew
t
R
R
= 54Ω, C = 100pF (Figure 3)
Full
Full
Full
Full
Full
Full
Full
-
3
-
3
10
20
ns
ns
ns
ns
ns
ns
ns
SKEW
DIFF
DIFF
L
Driver Differential Rise or Fall Time
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable from Output Low
Driver Disable from Output High
t , t
= 54Ω, C = 100pF, (Figure 3)
11
27
24
31
24
65
R
F
L
t
C
C
C
C
= 100pF, SW = V (Figure 4)
CC
60
ZL
L
L
L
L
t
= 100pF, SW = GND (Figure 4)
-
60
ZH
t
= 15pF, SW = V (Figure 4)
CC
-
60
LZ
t
= 15pF, SW = GND (Figure 4)
-
60
HZ
Driver Enable from Shutdown to
Output Low
t
R
R
R
= 500Ω, C = 100pF, SW = V (Figure 4)
CC
-
250
ZL(SHDN)
L
L
Driver Enable from Shutdown to
Output High
t
= 500Ω, C = 100pF, SW = GND (Figure 4)
Full
Full
-
-
152
30
250
ns
ZH(SHDN)
L
L
Driver Maximum Data Rate
f
= 54Ω, C = 100pF (Figure 3)
-
Mbps
MAX
DIFF
L
RS-485 DRIVER SWITCHING CHARACTERISTICS (SLOW DATA RATE (115kbps), PORT 2, (SLOW485 = GND))
Driver Differential Input to Output
Delay
t
, t
DLH DHL
R
= 54Ω, C = 100pF (Figure 3)
Full
800
1500
2500
ns
DIFF
L
Driver Output Skew
t
R
R
= 54Ω, C = 100pF (Figure 3)
Full
Full
Full
Full
Full
Full
Full
-
350
2000
32
1250
3100
600
600
60
ns
ns
ns
ns
ns
ns
ns
SKEW
DIFF
DIFF
L
Driver Differential Rise or Fall Time
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable from Output Low
Driver Disable from Output High
t , t
= 54Ω, C = 100pF (Figure 3)
1000
R
F
L
t
C
C
C
C
= 100pF, SW = V (Figure 4)
CC
-
-
-
-
-
ZL
L
L
L
L
t
= 100pF, SW = GND (Figure 4)
300
31
ZH
t
= 15pF, SW = V (Figure 4)
CC
LZ
t
= 15pF, SW = GND (Figure 4)
24
60
HZ
Driver Enable from Shutdown to
Output Low
t
R
R
R
= 500Ω, C = 100pF, SW = V (Figure 4)
CC
65
800
ZL(SHDN)
L
L
Driver Enable from Shutdown to
Output High
t
= 500Ω, C = 100pF, SW = GND (Figure 4)
Full
Full
-
-
420
800
800
ns
ZH(SHDN)
L
L
Driver Maximum Data Rate
f
= 54Ω, C = 100pF (Figure 3)
-
kbps
MAX
DIFF
L
RS-485 RECEIVER SWITCHING CHARACTERISTICS (PORT 2, ALL SPEEDS)
Receiver Input to Output Delay
Receiver Skew | t - t
t
, t
PLH PHL
(Figure 5)
(Figure 5)
Full
Full
Full
Full
Full
Full
Full
20
50
0.1
40
22
23
24
25
90
10
-
ns
ns
|
t
-
-
-
-
-
-
PLH PHL
SKEW
Receiver Maximum Data Rate
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Output Low
Receiver Disable from Output High
f
Mbps
ns
MAX
t
C
C
C
C
= 15pF, SW = V (Figure 6)
CC
60
60
60
60
ZL
L
L
L
L
t
= 15pF, SW = GND (Figure 6)
ns
ZH
t
= 15pF, SW = V (Figure 6)
CC
ns
LZ
t
= 15pF, SW = GND (Figure 6)
ns
HZ
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ISL33354E, ISL33357E
Electrical Specifications Test Conditions: V = 4.5V to 5.5V, C - C = 0.1µF, unless otherwise specified. Typicals are at V = 5V,
CC
1
4
CC
T
= +25°C (Note 10). (Continued) Boldface limits apply across the operating temperature range, -40°C to +85°C. (Continued)
A
TEMP
(°C) (Note 15)
MIN
MAX
(Note 15) UNIT
PARAMETER
SYMBOL
TEST CONDITIONS
TYP
260
Receiver Enable from Shutdown to
Output Low
t
C
C
= 15pF, SW = V (Figure 6)
CC
Full
Full
-
-
700
ns
ZLSHDN
L
L
Receiver Enable from Shutdown to
Output High
t
= 15pF, SW = GND (Figure 6)
260
700
ns
ZHSHDN
NOTES:
10. 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.
11. Supply current specification is valid for loaded RS-485 (port 2) drivers when DE485 = 0V.
12. Applies to peak current. See “Typical Performance Curves” on page 12 for more information.
13. A, B, RxIN defaults to RS-485 mode (>15kΩ) when the device is unpowered (V = 0V), or in SHDN.
CC
14. V ≤ 5.25V.
CC
15. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
Test Circuits and Waveforms
R
DE485
V
CC
Z
Y
DI
R
V
OD
D
D
V
R
OC
FIGURE 2. RS-485 DRIVER V AND V TEST CIRCUIT
OD OC
3V
0V
DI
50%
50%
PHL
t
t
PLH
V
OH
50%
50%
50%
50%
OUT (Y)
OUT (Z)
V
OL
t
t
PHL
PLH
V
OH
C
= 100pF
= 100pF
L
DE485
DI
V
OL
V
CC
t
t
DLH
DHL
Z
Y
R
+V
DIFF
D
OD
90%
10%
90%
10%
DIFF OUT (Y - Z)
0V
0V
C
L
-V
OD
SIGNAL
GENERATOR
t
t
F
R
SKEW = |t
PLH
(Y or Z) - t
PHL
(Z or Y)|
FIGURE 3B. MEASUREMENT POINTS
FIGURE 3A. TEST CIRCUIT
FIGURE 3. RS-485 DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
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ISL33354E, ISL33357E
Test Circuits and Waveforms(Continued)
DE485
DI
ENABLED
50%
Z
Y
500Ω
V
3V
0V
CC
DE485
(SHDN FOR SHDN)
D
50%
GND
SW
SIGNAL
GENERATOR
C
L
t
ZH
ZH(SHDN)
t
HZ
t
OUTPUT HIGH
2.3V
V
OH
V
- 0.5V
OH
FOR SHDN TESTS, SWITCH SHDN RATHER THAN DE485
OUT (Y, Z)
0V
PARAMETER SHDN/DE485 OUTPUT
DI
SW
C
(pF)
L
t
1/-
1/-
1/-
1/-
-/1
-/1
Y/Z
Y/Z
Y/Z
Y/Z
Y/Z
Y/Z
1/0
0/1
1/0
0/1
1/0
0/1
GND
15
t
t
HZ
ZL
LZ
t
ZL(SHDN)
t
t
V
15
V
LZ
CC
CC
GND
100
100
100
100
OUT (Y, Z)
ZH
2.3V
V
+ 0.5V
V
OL
t
V
OL
ZL
CC
OUTPUT LOW
t
GND
ZH(SHDN)
t
V
CC
ZL(SHDN)
FIGURE 4A. TEST CIRCUIT
FIGURE 4B. MEASUREMENT POINTS
FIGURE 4. RS-485 DRIVER ENABLE AND DISABLE TIMES
RE485
R
+1.5V
-1.5V
15pF
A
B
A
0V
0V
0V
RO
t
PLH
t
PHL
V
CC
SIGNAL
GENERATOR
RO
1.5V
1.5V
0V
FIGURE 5B. MEASUREMENT POINTS
FIGURE 5A. TEST CIRCUIT
FIGURE 5. RS-485 RECEIVER PROPAGATION DELAY
RE485
B
1kΩ
V
3V
RO
CC
R
SHDN
1.5V
ENABLED
1.5V
GND
(FOR SHDN TESTS)
SW
SIGNAL
A
0V
3V
GENERATOR
15pF
RE485
1.5V
HZ
FOR SHDN TESTS, SWITCH SHDN RATHER THAN RE485
0V
t
ZH
t
PARAMETER
SHDN/RE485
A
SW
GND
t
ZH(SHDN)
OUTPUT HIGH
V
t
1/-
1/-
1/-
1/-
-/0
-/0
+1.5V
-1.5V
+1.5V
-1.5V
+1.5V
-1.5V
OH
V
- 0.5V
HZ
OH
RO
1.5V
t
V
CC
GND
LZ
0V
t
ZH
t
V
t
t
ZL
ZL
CC
LZ
t
ZL(SHDN)
t
GND
V
ZH(SHDN)
CC
OL
RO
t
V
1.5V
ZL(SHDN)
CC
V
+ 0.5V
OL
V
OUTPUT LOW
FIGURE 6B. MEASUREMENT POINTS
FIGURE 6. RS-485 RECEIVER ENABLE AND DISABLE TIMES
FIGURE 6A. TEST CIRCUIT
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ISL33354E, ISL33357E
Test Circuits and Waveforms(Continued)
3V
SHDN
TxIN
V
1.5V
1.5V
CC
C
L
0V
TxOUT
TxIN
D
t
t
DPHL
DPLH
V
R
O+
L
SIGNAL
GENERATOR
TxOUT
0V
0V
V
O-
SKEW = |t
- t |
DPHL DPLH
FIGURE 7B. MEASUREMENT POINTS
FIGURE 7A. TEST CIRCUIT
FIGURE 7. RS-232 DRIVER PROPAGATION DELAY AND TRANSITION TIMES
3V
SHDN
RxIN
V
RxIN
50%
CC
50%
C
= 15pF
L
0V
t
RxOUT
R
t
RPLH
RPHL
V
OH
SIGNAL
GENERATOR
RxOUT
50%
50%
V
OL
SKEW = |t
- t |
RPHL RPLH
FIGURE 8B. MEASUREMENT POINTS
FIGURE 8. RS-232 RECEIVER PROPAGATION DELAY AND TRANSITION TIMES
FIGURE 8A. TEST CIRCUIT
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ISL33354E, ISL33357E
Typical Performance Curves
V
= 5V, T = +25°C, unless otherwise specified
A
CC
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
V
, +25°C
OL
V
, +85°C
OL
V
, +25°C
OH
V
, +85°C
OH
0
1
2
3
4
5
0
1
2
3
4
5
RECEIVER OUTPUT VOLTAGE (V)
DIFFERENTIAL OUTPUT VOLTAGE (V)
FIGURE 9. RECEIVER OUTPUT CURRENT vs RECEIVER OUTPUT
VOLTAGE
FIGURE 10. RS-485, DRIVER OUTPUT CURRENT vs DIFFERENTIAL
OUTPUT VOLTAGE
150
3.6
3.5
Y OR Z = LOW
FULL TEMP RANGE
100
50
R
= 100Ω
DIFF
3.4
3.3
3.2
3.1
3.0
0
Y OR Z = HIGH
-50
-100
-150
+25°C
+85°C
R
= 54Ω
DIFF
-40°C
-4 -2
-40
0
50
85
-25
25
75
-7 -6
0
2
4
6
8
10
12
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
FIGURE 11. RS-485, DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs
TEMPERATURE
FIGURE 12. RS-485, DRIVER OUTPUT CURRENT vs SHORT-CIRCUIT
VOLTAGE
4.0
SHDN = V
CC
3.5
3.0
2.5
2.0
1.5
1.0
-40
0
50
85
-25
25
TEMPERATURE (°C)
75
FIGURE 13. SUPPLY CURRENT vs TEMPERATURE
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ISL33354E, ISL33357E
Typical Performance Curves
V
= 5V, T = +25°C, unless otherwise specified (Continued)
A
CC
400
350
300
250
200
150
100
50
1700
1650
1600
1550
1500
1450
1400
R
= 54Ω, C = 100pF
L
R
= 54Ω, C = 100pF
L
DIFF
DIFF
|t
- t |
PHLZ PLHY
|t
- t |
PLHZ PHLY
t
DHL
t
DLH
t
DHL
|t
- t
|
DLH DHL
-40
0
50
85
-40
0
50
85
-25
25
TEMPERATURE (°C)
75
-25
25
75
TEMPERATURE (°C)
FIGURE 14. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (SLOW DATA RATE)
FIGURE 15. RS-485, DRIVER SKEW vs TEMPERATURE
(SLOW DATA RATE)
40
2.5
R
= 54Ω, C = 100pF
L
R
= 54Ω, C = 100pF
L
DIFF
DIFF
2.0
1.5
1.0
0.5
0
35
30
25
20
|t |
- t
DLH DHL
t
DHL
t
DLH
|t
- t
|
PLHZ PHLY
|t
- t
|
PHLZ PLHY
-40
0
50
85
-25
25
75
-40
0
50
85
-25
25
75
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 16. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (FAST DATA RATE)
FIGURE 17. RS-485, DRIVER SKEW vs TEMPERATURE
(FAST DATA RATE)
R
= 60Ω, C = 100pF
L
R
= 60Ω, C = 100pF
L
DIFF
DIFF
5
0
5
DI
DI
0
5
0
5
0
RO
RO
5
5
4
3
2
1
0
4
3
2
1
0
Y
Z
Y
Z
TIME (400ns/DIV)
TIME (400ns/DIV)
FIGURE 18. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (SLOW DATA RATE)
FIGURE 19. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (SLOW DATA RATE)
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ISL33354E, ISL33357E
Typical Performance Curves
V
= 5V, T = +25°C, unless otherwise specified (Continued)
CC A
R
= 60Ω, C = 100pF
L
R
= 60Ω, C = 100pF
L
DIFF
DIFF
5
0
5
0
DI
DI
5
0
5
0
RO
RO
5
5
4
3
2
1
0
4
3
2
1
0
Y
Z
Y
Z
TIME (200ns/DIV)
TIME (10ns/DIV)
FIGURE 21. RS-485, DRIVER AND RECEIVER WAVEFORMS,
FIGURE 20. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (FAST DATA RATE)
HIGH TO LOW (FAST DATA RATE)
7.5
7.5
250kbps
500kbps
V
+
5.0
2.5
0
OUT
5.0
2.5
0
V
+
OUT
OUTPUTS STATIC
BOTH T LOADED WITH 3kΩ TO GND
BOTH T
OUTS
LOADED WITH 3kΩ TO GND
OUTS
2 TRANSMITTERS AT 250kbps OR 500kbps
-2.5
-5.0
-2.5
-5.0
-7.5
500kbps
250kbps
V
-
V
-
OUT
OUT
-7.5
0
1000
2000
3000
4000
5000
-40
-25
0
25
50
75 85
LOAD CAPACITANCE (pF)
TEMPERATURE (°C)
FIGURE 22. RS-232, TRANSMITTER OUTPUT VOLTAGE vs LOAD
CAPACITANCE
FIGURE 23. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
TEMPERATURE
40
C
= 3500pF, 2 CHANNELS SWITCHING
L
30
5V
0
Y or Z = LOW
TxIN
20
10
5V
0
V
SHORTED TO GND
OUT
TxOUT/RxIN
0
-10
-20
-30
-40
-5V
5V
Y or Z = HIGH
RxOUT
0
-40
0
50
85
-25
25
75
TEMPERATURE (°C)
2µs/DIV
FIGURE 24. RS-232, TRANSMITTER SHORT-CIRCUIT CURRENT vs
TEMPERATURE
FIGURE 25. RS-232, TRANSMITTER AND RECEIVER WAVEFORMS AT
250kbps
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ISL33354E, ISL33357E
Typical Performance Curves
V
= 5V, T = +25°C, unless otherwise specified (Continued)
A
CC
60
58
56
54
52
50
48
V
= 5V
IN
FULL TEMP RANGE
C
= 1000pF, 2 CHANNELS SWITCHING
L
5V
0
TxIN
5V
0
TxOUT/RxIN
SR IN = 15V/µs
-5V
5V
SR IN = 100V/µs
RxOUT
0
50
500
1000
DATA RATE (kbps)
1500
2000
1µs/DIV
FIGURE 26. RS-232, TRANSMITTER AND RECEIVER WAVEFORMS AT
500kbps
FIGURE 27. RS-232, RECEIVER OUTPUT + DUTY CYCLE vs DATA RATE
7.5
1100
V
OUT ±4V
1000
900
800
700
600
500
400
300
200
100
BOTH T
OUTS
LOADED WITH 5kΩ TO GND
V
+
5.0
2.5
OUT
+25°C
+85°C
2 TRANSMITTERS SWITCHING
2 TRANSMITTERS AT +25°C
0
BOTH T
OUTS
LOADED WITH 5kΩ TO GND, C = 1000pF
L
1 TRANSMITTER AT +25°C
-2.5
+85°C
+25°C
-5.0
-7.5
1 TRANSMITTER AT +85°C
2 TRANSMITTERS AT +85°C
2000 3000 4000
LOAD CAPACITANCE (pF)
V
-
OUT
0
100
200
300
400
500
600
700
800
100
1000
5000
DATA RATE (kbps)
FIGURE 28. RS-232, TRANSMITTER MAXIMUM DATA RATE vs LOAD
CAPACITANCE
FIGURE 29. RS-232, TRANSMITTER OUTPUT VOLTAGE vs DATA RATE
Die Characteristics
450
SUBSTRATE AND QFN PAD POTENTIAL
(POWERED UP):
2 TRANSMITTERS SWITCHING
BOTH T
OUTS
LOADED WITH 3kΩ TO GND, C = 1000pF
L
400
350
300
250
200
150
GND
PROCESS:
+85°C
BiCMOS
+25°C
50
150
250
350
450
550
650
750
DATA RATE (kbps)
FIGURE 30. RS-232, TRANSMITTER SKEW vs DATA RATE
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ISL33354E, ISL33357E
Detailed Description
Typical Application
Each of the ISL3335XE parts supports dual protocols:
RS-485/422 (port 2), and RS-232 (port 1). RS-485 and RS-422
are differential (balanced) data transmission standards for use
in high speed (up to 20Mbps) networks, or long haul and noisy
environments. The differential signaling, coupled with RS-485’s
requirement for an extended Common-Mode Range (CMR) of
+12V to -7V make these transceivers extremely tolerant of
ground potential differences, as well as voltages induced in the
cable by external fields. Both of these effects are real concerns
when communicating over the RS-485/422 maximum distance
of 4000’ (1220m).
RS-232 to RS-485 Converter
The ISL33354E, ISL33357E are ideal for implementing a single
IC 2-wire (Tx Data, Rx Data) protocol converter, because each
port is programmed for a different protocol. Figure 31 illustrates
the simple connections to create a single transceiver RS-232 to
RS-422 converter. Depending on the RS-232 data rate, using an
RS-422 bus as an RS-232 “extension cord” can extend the
transmission distance up to 4000’ (1220m). A similar circuit on
the other end of the cable completes the conversion to/from
RS-232.
+5V
+
RS-422 is typically a point-to-point (one driver talking to one
receiver on a bus), or a point-to-multireceiver (multidrop)
standard that allows only one driver and up to 10 receivers on
each bus. Because of the one driver per bus limitation, RS-422
networks use a two bus, full duplex structure for bidirectional
communication, and the Rx inputs and Tx outputs (no tri-state
required) connect to different busses, as shown in Figure 33 on
page 17.
0.1µF
9, 26
1
C
0.1µF
C1+
V
3
1
CC
C
0.1µF
+
+
3
V+
2
C1-
28
C2+
C
2
0.1µF
+
17
24
V-
27
4
C2-
C
0.1µF
4
+
R1OUT
R1IN
NC
NC
R
R
5kΩ
R2IN
TxD
RS-232 IN
R2OUT
5
25
Conversely, RS-485 is a true multipoint standard, which allows
up to 32 devices (any combination of drivers - must be
tri-statable - and receivers) on each bus. Now, bidirectional
communication takes place on a single bus, so the Rx inputs
and Tx outputs of a port connect to the same bus lines, as
shown in Figure 32. Port 2 is set to RS-485/422 mode and
includes one Rx and one Tx.
5kΩ
6 T1OUT
T1IN
22
23
NC
D
RxD
T2IN
7
T2OUT
RS-232 OUT
D
RS-232 is a point-to-point, single ended (signal voltages
referenced to GND) communication protocol targeting fairly
short (<150’, 46m) and low data rate (<1Mbps) applications.
Port 1 contains two RS-232 transceivers (2 Tx and 2 Rx).
13
12
B
A
RO
18
RS-422 IN
R
16
RE485
11
10
Z
Y
DI
20
19
RS-422 OUT
D
DE485
V
CC
GND
8, 15
NOTE: PINOUT FOR SSOP
FIGURE 31. SINGLE IC RS-232 TO RS-485 CONVERTER
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ISL33354E, ISL33357E
GENERIC 1/2 DUPLEX RS-485 XCVR
RO RE
DE
DI
GENERIC 1/2 DUPLEX RS-485 XCVR
+5V
+5V
0.1µF
+5V
ISL3335XE
R
+
D
+
0.1µF
R
0.1µF
V
CC
V
CC
GND
V
CC
RO
RE
RO
A
B
R
B/Z
RE485
Tx/Rx
A/Y
DE
DI
DE485
DI
Z
B/Z
A/Y
D
D
Y
R
T
GND
GND
R
T
FIGURE 32. TYPICAL HALF DUPLEX RS-485 NETWORK
GENERIC RS-422 Rx (SLAVE)
RO RE
GENERIC FULL DUPLEX RS-422 XCVR (SLAVE)
+5V
0.1µF
+5V
R
+
+
ISL3335XE (MASTER)
1kΩ
0.1µF
0.1µF
GND
V
+5V
CC
A
B
V
V
CC
R
CC
T
RO
DI
Y
A
B
D
R
DI
Z
DE485
Z
Y
R
B
T
R
D
A
RO
GND
GND
RE485
FIGURE 33. TYPICAL RS-422 NETWORK
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ISL33354E, ISL33357E
ISL3335XE Advantages
Charge Pumps
These dual protocol ICs offer many parametric improvements
vs those offered on competing dual protocol devices. Some of
the major improvements are:
The on-chip charge pumps create the RS-232 transmitter
power supplies (typically +6/-7V) from a single supply as low
as 4.5V, and are enabled all the time unless in SHDN via the
SHDN pin. The efficient design requires only four small 0.1µF
capacitors for the voltage doubler and inverter functions. By
operating discontinuously (i.e., turning off as soon as V+ and V-
pump up to the nominal values), the charge pump contribution
• 15kV Bus Pin ESD - Eases board level requirements
• Full Fail-Safe RS-485 Rx - Eliminates bus biasing
• Selectable RS-485 Data Rate - Up to 20Mbps, or slew rate
limited for low EMI and fewer termination issues
to I reduces significantly.
CC
• High RS-232 Data Rate - >460kbps
Data Rates and Cabling
Drivers operate at data rates up to 650kbps and are
• Lower Tx and Rx Skews - Wider, consistent bit widths
guaranteed for data rates up to 460kbps. The charge pumps
and drivers are designed such that both drivers in port 1 can
be operated at the rated load, and at 460kbps (see Figure 22
on page 14). Figure 22 also shows that drivers can easily drive
several thousand picofarads at data rates up to 250kbps,
while still delivering compliant ±5V output levels.
• Lower I - Max I is 2x to 4x lower than competition
CC CC
• Flow-Through Pinouts - Tx, Rx bus pins on one side, logic pins
on the other, for easy routing to connector/UART
• Packaging - Smaller (QFN) and Pb-free
RS-232 Mode (Port 1)
Rx Features
Receivers operate at data rates up to 2Mbps. They are
designed for a higher data rate to facilitate faster factory
downloading of software into the final product, thereby
improving the user’s manufacturing throughput.
RS-232 receivers invert and convert RS-232 input levels (±3V
to ±25V) to the standard TTL/CMOS levels required by a UART,
ASIC, or µcontroller serial port. Receivers are designed to
operate at faster data rates than the drivers, and they feature
very low skews (10ns) so the receivers contribute negligibly to
bit width distortion. Inputs include the standards required 3kΩ
to 7kΩ pull-down resistor, so unused inputs may be left
unconnected. Rx inputs also have built-in hysteresis to
increase noise immunity and to decrease erroneous triggering
due to slowly transitioning input signals.
Figures 25 and 26 illustrate driver and receiver waveforms at
250kbps, and 500kbps, respectively. For these graphs, both
drivers of port 1 drive the specified capacitive load and a
receiver in the port.
RS-232 doesn’t require anything special for cabling; just a
single bus wire per transmitter and receiver, and another wire
for GND. So an ISL3335XE RS-232 port uses a five conductor
cable for interconnection. Bus terminations are not required,
nor allowed, by the RS-232 standard.
Rx outputs are short-circuit protected, and are only tri-statable
when the entire IC is shutdown via the SHDN pin (see Table 3
on page 5 and “Low Power Shutdown (SHDN) Mode” on
page 20 for more details).
RS-485 Mode (Port 2)
Rx Features
Tx Features
RS-485 receivers convert differential input signals as small as
200mV, as required by the RS-485 and RS-422 standards, to
TTL/CMOS output levels. The differential Rx provides
maximum sensitivity, noise immunity and common-mode
rejection. Per the RS-485 standard, receiver inputs function
with common-mode voltages from +12V to -7V, regardless of
supply voltage, making them ideal for long networks where
induced voltages are a realistic concern. The RS-485/RS-422
port includes a single receiver (RO).
RS-232 drivers invert and convert the standard TTL/CMOS
levels from a UART, or µcontroller serial port to RS-232
compliant levels (±5V minimum). The Tx delivers these
compliant output levels even at data rates of 650kbps, with
loads of 1000pF. The drivers are designed for low skew
(typically 12% of the 500kbps bit width), and are compliant to
the RS-232 slew rate spec (4 to 30V/µs) for a wide range of
load capacitances. Tx inputs float if left unconnected and may
cause I increases. For the best results, connect unused
CC
Worst case receiver input currents are 20% lower than the 1
“unit load” (1mA) RS-485 limit, which translates to a 15kΩ
minimum input resistance.
inputs to GND.
Tx outputs are short-circuit protected, and incorporate a
thermal shutdown feature to protect the IC in situations of
severe power dissipation - see the RS-485 “Tx Features” on
page 19 section for more details. Both Tx outputs disable
when the IC enters thermal shutdown.
This receiver includes a “full fail-safe” function that guarantees
a high level receiver output if the receiver inputs are
unconnected (floating), shorted together, or if the bus is
terminated but undriven (i.e., differential voltage collapses to
near zero due to termination). Fail-safe with shorted, or
terminated and undriven inputs is accomplished by setting the
Rx upper switching point at -40mV, thereby ensuring that the
Rx recognizes a 0V differential as a high level.
Drivers also tri-state in SHDN mode (SHDN = 0), or when the
5V power supply is off (see Table 3 and “Low Power Shutdown
(SHDN) Mode” on page 20 for more details). SHDN is a global
function - affecting both ports - so it is useful for disabling the
RS-232 outputs only if both ports will always be disabled
together, and if it is acceptable for the Rx to be disabled as well.
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ISL33354E, ISL33357E
The Rx output is short-circuit protected and is tri-stated when
the RE485 input is driven low or when the IC is forced into
SHDN via a logic low on the SHDN pin.
Nevertheless, for the best jitter performance when driving long
cables, the faster speed option may be preferable, even at
lower data rates. The faster output transitions deliver less
variability (jitter) when loaded with the large capacitance
associated with long cables. Of course, faster transitions
require more attention to ensuring short stub lengths and
quality terminations, so there are trade-offs to be made.
Assuming a jitter budget of 10%, it is likely better to go with
the slow speed option for data rates of 115kbps or less, to
minimize fast edge effects. For higher data rates, or when the
absolute best jitter is required, use the high speed option. The
data rate selection pertains to only port 2.
Tx Features
The RS-485/RS-422 driver is a differential output device that
delivers at least 2.2V across a 54Ω load (RS-485), and at least
2.5V across a 100Ω load (RS-422). Both levels significantly
exceed the standards’ requirements, and these exceptional
output voltages increase system noise immunity, and/or allow
for transmission over longer distances. The drivers feature low
propagation delay skew to maximize bit widths and to
minimize EMI.
Data Rate, Cables and Terminations
To allow multiple drivers on a bus, the RS-485 specification
requires that drivers survive worst case bus contentions
undamaged. The ISL3335XE drivers meet this requirement via
driver output short-circuit current limits and on-chip thermal
shutdown circuitry. The output stages incorporate current
limiting circuitry that ensures that the output current never
exceeds the RS-485 specification, even at the common-mode
voltage range extremes of 12V and -7V. In the event of a major
short-circuit condition, 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 re-enable
after the die temperature drops about 15 degrees. If the
contention persists, the thermal shutdown/re-enable cycle
repeats until the fault is cleared. Receivers stay operational
during thermal shutdown.
RS-485/RS-422 are intended for network lengths up to 4000’
(1220m), but the maximum system data rate decreases as the
transmission length increases. Devices operating at the
maximum data rate of 20Mbps are limited to maximum
lengths of 20-100’ (6-31m), while devices operating at or
below 115kbps can operate at the maximum length of 4000’
(1220m).
Higher data rates require faster edges, so both of the
ISL3335XE versions offer an edge rate capable of 20Mbps
data rates. These ICs also offer a slew rate limited option to
minimize problems at slower data rates. Nevertheless, for the
best jitter performance when driving long cables, the faster
speed settings may be preferable, even at low data rates. See
the “RS-485 Slew Rate Limited Data Rates” section for details.
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.
RS-485 multidriver operation also requires drivers to include
tri-state functionality, so port 2 has a DE485 pin to control this
function. If the driver is used in an RS-422 network, such that
driver tri-state isn’t required, then the DE485 pin should be
connected to V , through a 1kΩ resistor, to keep the Tx in the
CC
The preferred cable connection technique is “daisy-chaining”,
where the cable runs from the connector of one device directly
to the connector of the next device, such that cable stub
lengths are negligible. A “backbone” structure, where stubs
run from the main backbone cable to each device’s connector,
is the next best choice, but care must be taken to ensure that
each stub is electrically “short”. See Table 4 for recommended
maximum stub lengths for each speed option.
enabled state. Drivers are also tri-stated when the IC is in
SHDN, or when the 5V power supply is off.
Speed Options
The ISL3335XE offer two RS-485 speed options selectable via
the SLOW485 pin (see Table 3); “Fast” mode selects high slew
rate driver outputs optimized for 20Mbps data rates while
“Slow” mode uses slew rate limiting designed for 115kbps
operation. See the “RS-485 Slew Rate Limited Data Rates”
and “Data Rate, Cables and Terminations” sections for more
information.
TABLE 4. RECOMMENDED STUB LENGTHS
MAXIMUM STUB LENGTH
SPEED OPTION
SLOW
ft (m)
Receiver performance is the same for both speed options.
350-500 (107-152)
1-3 (0.3 - 0.9)
FAST
RS-485 Slew Rate Limited Data Rates
This IC allows the user to select fast Tx output transitions
optimized for a 20Mbps data rate, or slew rate limited
transitions optimized for a data rate of 115kbps. The 20Mbps
fast edges may increase EMI and reflection issues, even
though fast transitions aren’t required at the lower data rates
used by many applications. Choosing the slew limited edges
for lower data rates permits longer unterminated networks, or
longer stubs off terminated busses, and helps minimize EMI
and reflections.
Proper termination is imperative to minimize reflections when
using the 20Mbps speed option. Short networks using the slow
speed option need not be terminated, but terminations are
recommended unless power dissipation is an overriding
concern. Note that the RS-485 spec allows a maximum of two
terminations on a network, otherwise the Tx output voltage
may not meet the required V
.
OD
In point-to-point, or point-to-multireceiver (RS-422) networks,
the main cable should be terminated in its characteristic
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ISL33354E, ISL33357E
impedance (typically 120Ω) at the end farthest from the driver.
Flow-Through Pinouts
In multireceiver applications, stubs connecting receivers to the
main cable should be kept as short as possible, but definitely
shorter than the limits shown in Table 4. Multipoint (RS-485)
systems require that the main cable be terminated in its
characteristic impedance at both ends. Again, keep stubs
connecting a transceiver to the main cable as short as possible
and refer to Table 4. Avoid “star” and other configurations,
where there are many “ends” which would require more than
the two allowed terminations to prevent reflections.
Even the ISL3335XE pinouts are features, in that the true
flow-through design simplifies board layout. Having the bus
pins all on one side of the package for easy routing to a cable
connector, and the Rx outputs and Tx inputs (logic pins) on the
other side for easy connection to a UART, avoids costly and
problematic crossovers. Competing “flow-through” pinouts mix
logic and bus pin inputs on one side of the package, and logic
and bus pin outputs on the other side. This forces the designer
to route four traces from the right side of the IC around the IC
to the cable connector. Figure 35 illustrates the flow-through
nature of the ISL3335XE’s pinout.
Active Low Rx Enable (RE485)
In many RS-485 applications, especially half duplex
configurations, users like to implement “echo suppression” by
disabling the corresponding receiver while its driver is
transmitting data. This function is available on the ISL3335XE
parts via an active low RE485 pin for port 2. The active low
function simplifies direction control, by allowing a single GPIO
line to provide a Tx/Rx direction control signal. Figure 34
details the advantage of using the RE485 pin.
ISL33354E
R2OUT
R1OUT
T2IN
R1IN
R2IN
T1OUT
UART
OR
ASIC
T2OUT
T1IN
Y
Z
OR
DI
+5V
D
µCONTROLLER
ISL3335XE
+
RO
0.1µF
A
B
R
V
CC
RO
A
B
R
FIGURE 35. ILLUSTRATION OF FLOW-THROUGH PINOUT
RE485
Tx/Rx
DE485
DI
Z
Y
Low Power Shutdown (SHDN) Mode
The SHDN pin is driven low to place the IC (both ports) in the
SHDN mode, and the already low supply current drops to as
low as 55µA. If this functionality isn’t desired, the SHDN pin
D
GND
should be connected to V through a 1kΩ resistor. SHDN
CC
disables the Tx and Rx outputs, and disables the charge
FIGURE 34. USING ACTIVE LOW RX ENABLE
pumps, so V+ collapses to V , and V- collapses to GND.
CC
All but 5µA of SHDN supply current is due to control input
(SHDN, SLOW485, DE485) pull-up resistors (~17µA/resistor
when the input = 0V), so SHDN supply current varies
depending on the ISL3335XE configuration. For example, the
RS-485 drivers are disabled in SHDN, so driving the DE485 pin
high during this time reduces the SHDN supply current. The
Additional Features
High ESD
All pins on the ISL3335XE include ESD protection structures
rated at ±4kV (HBM), which is good enough to survive ESD
events commonly seen during manufacturing. But the bus pins
(Tx outputs and Rx inputs) are particularly vulnerable to ESD
events because they connect to an exposed port on the
exterior of the finished product. Simply touching the port pins,
or connecting a cable, can destroy an unprotected port.
ISL3335XE bus pins are fitted with advanced structures that
deliver ESD protection in excess of ±15kV (HBM), without
interfering with any signal in the RS-485 or the RS-232 range.
This high level of protection may eliminate the need for board
level protection, or at the very least will increase the
spec table indicates the SHDN I for the worst case
CC
configuration.
When enabling from SHDN, allow at least 20µs for the charge
pumps to stabilize before transmitting RS-232 data. The
charge pumps aren’t used by the RS-485 port, so the
transceiver is ready to send or receive data in less than 1µs,
which is much faster than competing devices that require the
charge pump for all modes of operation.
robustness of any board level scheme.
Small Packages
Many competing dual protocol devices are only available in
monstrously large 24 to 28 Ld SOIC packages. The ISL33354’s
28 Ld SSOP is 50% smaller than even a 24 Ld SOIC, and the
ISL33357E’s small 6x6mm QFN footprint is 80% smaller than
a 28 Ld SOIC.
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ISL33354E, ISL33357E
Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted.
Please visit our website to make sure you have the latest revision.
DATE
REVISION
FN8775.1
CHANGE
October 21, 2016
Added Related Literature section on page 1.
Added Table 2 on page 2.
Added Tape and Reel column to Ordering information table.
October 5, 2015
FN8775.0
Initial Release
About Intersil
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For the most updated datasheet, application notes, related documentation, and related parts, please see the respective product
information page found at www.intersil.com.
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in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
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 notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be
accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third
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ISL33354E, ISL33357E
For the most recent package outline drawing, see L40.6x6.
Package Outline Drawing
L40.6x6
40 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
Rev 3, 10/06
4X
4.5
6.00
0.50
36X
A
6
B
31
40
PIN #1 INDEX AREA
6
30
1
PIN 1
INDEX AREA
4 . 10 ± 0 . 15
21
10
0.15
(4X)
11
20
0.10 M C A B
TOP VIEW
40X 0 . 4 ± 0 . 1
4
0 . 23 +0 . 07 / -0 . 05
BOTTOM VIEW
SEE DETAIL "X"
C
0.10
C
0 . 90 ± 0 . 1
BASE PLANE
( 5 . 8 TYP )
(
SEATING PLANE
0.08 C
SIDE VIEW
4 . 10 )
( 36X 0 . 5 )
5
C
0 . 2 REF
( 40X 0 . 23 )
0 . 00 MIN.
0 . 05 MAX.
( 40X 0 . 6 )
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3.
Unless otherwise specified, tolerance : Decimal ± 0.05
4. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
Tiebar shown (if present) is a non-functional feature.
5.
6.
The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 indentifier may be
either a mold or mark feature.
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ISL33354E, ISL33357E
Shrink Small Outline Plastic Packages (SSOP)
M28.209 (JEDEC MO-150-AH ISSUE B)
28 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE
N
INDEX
AREA
0.25(0.010)
M
B M
H
E
INCHES MILLIMETERS
GAUGE
PLANE
SYMBOL
MIN
MAX
0.078
-
MIN
-
MAX
2.00
-
NOTES
-B-
A
A1
A2
B
-
-
1
2
3
0.002
0.065
0.009
0.004
0.390
0.197
0.05
1.65
0.22
0.09
9.90
5.00
-
L
0.072
0.014
0.009
0.413
0.220
1.85
0.38
0.25
10.50
5.60
-
0.25
0.010
SEATING PLANE
A
9
-A-
D
C
D
E
-
3
-C-
4
A2
e
e
0.026 BSC
0.65 BSC
-
A1
C
H
L
0.292
0.022
0.322
0.037
7.40
0.55
8.20
0.95
-
B
0.10(0.004)
6
0.25(0.010) M
C
A M B S
N
28
28
7
NOTES:
0°
8°
0°
8°
-
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2
of Publication Number 95.
Rev. 2 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
0.20mm (0.0078 inch) per side.
4. Dimension “E” does not include interlead flash or protrusions.
Interlead flash and protrusions shall not exceed 0.20mm (0.0078
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. Dimension “B” does not include dambar protrusion. Allowable
dambar protrusion shall be 0.13mm (0.005 inch) total in excess of
“B” dimension at maximum material condition.
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
Submit Document Feedback
For the most recent package outline drawing, see M28.209.
FN8775.1
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23
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