DATASHEET
ISL3330, ISL3331
FN6361
Rev 0.00
May 20, 2008
3.3V, ±15kV ESD Protected, Dual Protocol (RS-232/RS-485) Transceivers
These devices are BiCMOS interface ICs that are user
configured as either a single RS-422/RS-485 differential
transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver.
In RS-232 mode, the on-board charge pump generates
RS-232 compliant ±5V Tx output levels, from a supply as low
as 3.15V. Four small 0.1µF capacitors are required for the
charge pump. The transceivers are RS-232 compliant, with
the Rx inputs handling up to ±25V.
In RS-485 mode, the transceivers support both the RS-485
and RS-422 differential communication standards. The
RS-485 receiver features "full failsafe" operation, so the Rx
output remains in a high state if the inputs are open or
shorted together. The RS-485 transmitter supports up to
three data rates, two of which are slew rate limited for
problem free communications. The charge pump disables in
RS-485 mode, thereby saving power, minimizing noise, and
eliminating the charge pump capacitors.
Both RS-232/RS-485 modes feature loopback and shutdown
functions. The loopback mode internally connects the Tx
outputs to the corresponding Rx input, which facilitates the
implementation of board level self test functions. The outputs
remain connected to the loads during loopback, where
connection problems (e.g., shorted connectors or cables)
can be detected. The shutdown mode disables the Tx and
Rx outputs, disables the charge pump if in RS-232 mode,
and places the IC in a low current (30µA) mode.
The ISL3331 is a QFN packaged device that offers
additional functionality, including a lower speed and edge
rate option (115kbps) for EMI sensitive designs, or to allow
longer bus lengths. It also features a logic supply voltage pin
(VL) that sets the VOH level of logic outputs, and the
switching points of logic inputs, to be compatible with
another supply voltage in mixed voltage systems. The QFN's
choice of active high or low Rx enable pins increases design
flexibility, allowing Tx/Rx direction control via a single signal
by connecting DEN and RXEN together.
For a dual port version of these devices, please see the
ISL3332/ISL3333 data sheet.
Features
• User Selectable RS-232 or RS-485/RS-422 Interface Port
(Two RS-232 Transceivers or One RS-485/RS-422
Transceiver)
• Operates From a Single 3.3V Supply
• ±15kV (HBM) ESD Protected Bus Pins (RS-232 or
RS-485)
• 5V Tolerant Logic Inputs
• True Flow-Through Pinouts Simplify Board Layouts
• Pb-Free (RoHS Compliant)
• Full Failsafe (Open/Short) Rx in RS-485/RS-422 Mode
• Loopback Mode Facilitates Board Self Test Functions
• User Selectable RS-485 Data Rates . . . . . . . . . . 20Mbps
- Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps
- Slew Rate Limited (ISL3331 Only) . . . . . . . . . . 115kbps
• Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 400kbps
• Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . 30µA
• QFN Package Saves Board Space (ISL3331 Only)
• Logic Supply Pin (VL) Eases Operation in Mixed Supply
Systems (ISL3331 Only)
Applications
• Gaming Applications (e.g., Slot machines)
• Single Board Computers
• Factory Automation
• Security Networks
• Industrial/Process Control Networks
• Level Translators (e.g., RS-232 to RS-422)
• Point of Sale Equipment
Related Literature
• Application Note AN1401 “Implementing a Three Pin,
Half-Duplex, Dual Protocol Interface”
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
NO. OF
PORTS
PACKAGE OPTIONS
ISL3330
1
20 Ld SSOP
ISL3331
1
40 Ld QFN (6mmx6mm)
FN6361 Rev 0.00
May 20, 2008
RS-485 DATA
RATE (bps)
RS-232 DATA
RATE (kbps)
VL PIN?
ACTIVE H or L
Rx ENABLE?
LOW POWER
SHUTDOWN?
20M, 460k
400
No
H
Yes
20M, 460k, 115k
400
Yes
Both
Yes
Page 1 of 25
ISL3330, ISL3331
Ordering Information
PART NUMBER (NOTE)
PART MARKING
TEMP. RANGE (°C)
PACKAGE (Pb-Free)
PKG. DWG. #
ISL3330IAZ
3330 IAZ
-40 to +85
20 Ld SSOP
M20.209
ISL3330IAZ-T*
3330 IAZ
-40 to +85
20 Ld SSOP (Tape and Reel)
M20.209
ISL3331IRZ
ISL3331IRZ
-40 to +85
40 Ld 6x6 QFN
L40.6x6
ISL3331IRZ-T*
ISL3331IRZ
-40 to +85
40 Ld 6x6 QFN (Tape and Reel)
L40.6x6
*Please refer to TB347 for details on reel specifications.
NOTE: 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.
Pinouts
ISL3330
(20 LD SSOP)
TOP VIEW
C1+ 1
20 C2+
C1- 2
19 C2-
V+
3
18 VCC
A 4
17 RA
B 5
16 RB
Y 6
15 DY
Z 7
14 DZ/SLEW
13 ON
485/232 8
DEN 9
12 RXEN
GND 10
11 V-
FN6361 Rev 0.00
May 20, 2008
NC
NC
C1-
C1+
C2+
C2-
VCC
NC
NC
VL
ISL3331
(40 LD QFN)
TOP VIEW
40
39
38
37
36
35
34
33
32
31
4
27 DZ/SLEW
Z
5
26 NC
NC
6
25 NC
NC
7
24 NC
NC
8
23 NC
NC
9
22 NC
NC
10
21 ON
11
12
13
14
15
16
17
18
19
20
RXEN
Y
V-
28 DY
NC
3
RXEN
B
GND
29 RB
GND
2
SPB
A
NC
30 RA
DEN
1
485/232
V+
Page 2 of 25
ISL3330, ISL3331
TABLE 2. ISL3330 FUNCTION TABLE
RECEIVER
OUTPUTS
CHARGE
PUMPS
(Note 1)
LOOPBACK
(Note 2)
MODE
RA
RB
Y
Z
DRIVER
SPEED
(Mbps)
N/A
High-Z
High-Z
High-Z
High-Z
-
ON
OFF
RS-232
1
N/A
High-Z
High-Z
ON
ON
0.46
ON
OFF
RS-232
1
0
N/A
ON
ON
High-Z
High-Z
-
ON
OFF
RS-232
1
1
1
N/A
ON
ON
ON
ON
0.46
ON
OFF
RS-232
0
0
0
1
N/A
High-Z
High-Z
ON
High-Z
0.46
ON
OFF
RS-232
0
0
1
0
N/A
High-Z
ON
ON
High-Z
0.46
ON
OFF
RS-232
0
0
1
1
N/A
ON
ON
ON
ON
0.46
ON
ON
RS-232
X
0
0
0
X
High-Z
High-Z
High-Z
High-Z
-
OFF
OFF
Shutdown
1
1
0
0
X
High-Z
High-Z
High-Z
High-Z
-
OFF
OFF
RS-485
1
X
0
1
1/0
High-Z
High-Z
ON
ON
20/0.46
OFF
OFF
RS-485
1
X
1
0
X
ON
High-Z
High-Z
High-Z
-
OFF
OFF
RS-485
1
1
1
1
1/0
ON
High-Z
ON
ON
20/0.46
OFF
OFF
RS-485
1
0
1
1
1/0
ON
High-Z
ON
ON
20/0.46
OFF
ON
RS-485
INPUTS
485/232
ON
RXEN
0
1
0
0
0
1
0
0
1
0
DEN SLEW
DRIVER OUTPUTS
NOTES:
1. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN are high.
2. Loopback is enabled when ON = 0, and DEN = RXEN = 1.
ISL3330 Truth Tables
RS-485 TRANSMITTING MODE
RS-232 TRANSMITTING MODE
INPUTS (ON = 1)
INPUTS (ON = 1)
OUTPUTS
485/232
DEN
DY
DZ
Y
Z
0
1
0
0
1
1
0
1
0
1
1
0
0
1
1
0
0
1
0
1
1
1
0
0
0
0
X
X
High-Z
High-Z
485/232
DEN
DY
SLEW
Y
Z
DATA RATE
(Mbps)
1
1
0
1
1
0
20
1
1
1
1
0
1
20
1
1
0
0
1
0
0.46
1
1
1
0
0
1
0.46
1
0
X
X
High-Z High-Z
-
RS-485 RECEIVING MODE
RS-232 RECEIVING MODE
INPUTS (ON = 1)
INPUTS (ON = 1)
OUTPUT
485/232
RXEN
A
B
RA
RB
0
1
0
0
1
1
0
1
0
1
1
0
0
1
1
0
0
1
0
1
1
1
0
0
0
1
Open
Open
1
1
0
0
X
X
High-Z
High-Z
FN6361 Rev 0.00
May 20, 2008
OUTPUTS
OUTPUT
485/232
RXEN
B-A
RA
RB
1
1
-40mV
1
High-Z
1
1
-200mV
0
High-Z
1
1
Open or Shorted together
1
High-Z
1
0
X
High-Z
High-Z
Page 3 of 25
ISL3330, ISL3331
TABLE 3. ISL3331 FUNCTION TABLE
RECEIVER
OUTPUTS
INPUTS
DRIVER
OUTPUTS
Z
DRIVER
DATA
RATE
(Mbps)
CHARGE
PUMPS
(Note 3)
MODE
485/232
ON
RXEN
AND/OR
RXEN
0
1
1 and 0
0
N/A
N/A
High-Z
High-Z
High-Z
High-Z
-
ON
RS-232
0
1
1 and 0
1
N/A
N/A
High-Z
High-Z
ON
ON
0.46
ON
RS-232
0
1
0 or 1
0
N/A
N/A
ON
ON
High-Z
High-Z
-
ON
RS-232
DEN
SLEW
SPB
RA
RB
Y
0
1
0 or 1
1
N/A
N/A
ON
ON
ON
ON
0.46
ON
RS-232
0
0
1 and 0
1
N/A
N/A
High-Z
High-Z
ON
High-Z
0.46
ON
RS-232
0
0
0 or 1
0
N/A
N/A
High-Z
ON
ON
High-Z
0.46
ON
RS-232
0
0
0 or 1
1
N/A
N/A
ON
ON
ON
ON
0.46
ON
RS-232 (Note 4)
X
0
1 and 0
0
X
X
High-Z
High-Z
High-Z
High-Z
-
OFF
Shutdown
1
1
1 and 0
0
X
X
High-Z
High-Z
High-Z
High-Z
-
OFF
RS-485
1
X
1 and 0
1
0
1/0
High-Z
High-Z
ON
ON
0.46/0.115
OFF
RS-485
1
X
1 and 0
1
1
X
High-Z
High-Z
ON
ON
20
OFF
RS-485
1
X
0 or 1
0
X
X
ON
High-Z
High-Z
High-Z
-
OFF
RS-485
1
1
0 or 1
1
0
1/0
ON
High-Z
ON
ON
0.46/0.115
OFF
RS-485
1
1
0 or 1
1
1
X
ON
High-Z
ON
ON
20
OFF
RS-485
1
0
0 or 1
1
0
1/0
ON
High-Z
ON
ON
0.46/0.115
OFF
RS-485 (Note 4)
1
0
0 or 1
1
1
X
ON
High-Z
ON
ON
20
OFF
RS-485 (Note 4)
NOTES:
3. Charge pumps are on if in RS-232 mode and ON or DEN or RXEN is high, or RXEN is low.
4. Loopback is enabled when ON = 0, and DEN = 1, and (RXEN = 1 or RXEN = 0).
ISL3331 Truth Tables
RS-485 TRANSMITTING MODE
RS-232 TRANSMITTING MODE
INPUTS (ON = 1)
INPUTS (ON = 1)
OUTPUTS
OUTPUTS
DATA
485/232
DEN
SLEW
SPB
DY
Y
Z
Mbps
485/232
DEN
DY
DZ
Y
Z
1
1
0
0
0/1
1/0
0/1
0.115
0
1
0
0
1
1
1
1
0
1
0/1
1/0
0/1
0.460
0
1
0
1
1
0
1
1
1
X
0/1
1/0
0/1
20
0
1
1
0
0
1
1
0
X
X
X
0
1
1
1
0
0
0
0
X
X
High-Z
High-Z
High-Z High-Z
RS-485 RECEIVING MODE
INPUTS (ON = 1)
RS-232 RECEIVING MODE
INPUTS (ON = 1)
485/232 RXEN and/or RXEN
485/232 RXEN and/or RXEN
OUTPUT
A
B
RA
RB
0
0 or 1
0
0
1
1
0
0 or 1
0
1
1
0
0
0 or 1
1
0
0
1
0
0 or 1
1
1
0
0
0
0 or 1
Open
Open
1
1
0
1 and 0
X
X
FN6361 Rev 0.00
May 20, 2008
-
OUTPUT
B-A
RA
RB
1
0 or 1
-40mV
1
High-Z
1
0 or 1
-200mV
0
High-Z
1
0 or 1
Open or Shorted
together
1
High-Z
1
1 and 0
X
High-Z High-Z
High-Z High-Z
Page 4 of 25
ISL3330, ISL3331
Pin Descriptions
PIN
MODE
FUNCTION
485/232
BOTH
Interface Mode Select input. High for RS-485 Mode and low for RS-232 Mode.
DEN
BOTH
Driver output enable. The driver outputs, Y and Z, are enabled by bringing DEN high. They are high impedance when DEN
is low.
GND
BOTH
Ground connection.
NC
BOTH
No Connection.
ON
BOTH
In RS-232 mode only, ON high enables the charge pumps. ON low, with DEN and RXEN low (and RXEN high if QFN), turns
off the charge pumps (in RS-232 mode), and in either mode places the device in low power shutdown. In both modes, when
ON is low, and DEN is high, and RXEN is high or RXEN is low, loopback is enabled.
RXEN
BOTH
Receiver output enable. Rx is enabled when RXEN is high; Rx is high impedance when RXEN is low and, if using the QFN
package, RXEN is high. When using the QFN and the active high Rx enable function, RXEN should be high or floating.
RXEN
BOTH
Active low receiver output enable. Rx is enabled when RXEN is low; Rx is high impedance when RXEN is high and RXEN
is low. (i.e., to use active low Rx enable function, tie RXEN to GND). For single signal Tx/Rx direction control, connect RXEN
to DEN. Internally pulled high. (QFN only)
VCC
BOTH
System power supply input (3.3V).
VL
BOTH
Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. QFN logic input pins that are externally
tied high in an application, should use the VL supply for the high voltage level. (QFN only)
A
RS-232 Receiver input with ±15kV ESD protection. A low on A forces RA high; A high on A forces RA low.
RS-485 Inverting receiver input with ±15kV ESD protection.
B
RS-232 Receiver input with ±15kV ESD protection. A low on B forces RB high; A high on B forces RB low.
RS-485 Noninverting receiver input with ±15kV ESD protection.
DY
RS-232 Driver input. A low on DY forces output Y high. Similarly, a high on DY forces output Y low.
RS-485 Driver input. A low on DY forces output Y high and output Z low. Similarly, a high on DY forces output Y low and output Z high.
DZ/SLEW RS-232 Driver input. A low on DZ forces output Z high. Similarly, a high on DZ forces output Z low.
RS-485 Slew rate control. With the SLEW pin high, the drivers run at the maximum slew rate (20Mbps). With the SLEW pin low, the
drivers run at a reduced slew rate (460kbps). The QFN version works in conjunction with SPB to select one of three RS-485
data rates. Internally pulled high in RS-485 mode.
SPB
RA
RS-485 Speed control. Works in conjunction with the SLEW pin to select the 20Mbps, 460kbps or 115kbps RS-485 data rate.
Internally pulled high. (QFN only)
RS-232 Receiver output.
RS-485 Receiver output: If B > A by at least -40mV, RA is high; If B < A by -200mV or more, RA is low; RA = High if A and B are
unconnected (floating) or shorted together (i.e., full fail-safe).
RB
RS-232 Receiver output.
RS-485 Not used. Output is high impedance, and unaffected by RXEN and RXEN.
Y
RS-232 Driver output with ±15kV ESD protection.
RS-485 Inverting driver output with ±15kV ESD protection.
Z
RS-232 Driver output with ±15kV ESD protection.
RS-485 Noninverting driver output with ±15kV ESD protection.
C1+
RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.
C1-
RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed in RS-485 Mode.
C2+
RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.
C2-
RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed in RS-485 Mode.
V+
RS-232 Internally generated positive RS-232 transmitter supply (+5.5V). C3 not needed in RS-485 Mode.
V-
RS-232 Internally generated negative RS-232 transmitter supply (-5.5V). C4 not needed in RS-485 Mode.
FN6361 Rev 0.00
May 20, 2008
Page 5 of 25
ISL3330, ISL3331
/
Typical Operating Circuits
+3.3V
+
+3.3V
0.1µF
1
C1
0.1µF
+
C2
0.1µF
+
2
20
19
C1+
VCC
3
+ C3
0.1µF
V- 11
C2-
5
Y
7
Z
15
D
+
20
DZ
ON
485/232
Y
D
7
8
VCC
+
C2
0.1µF
+
A
B
2
20
19
C1+
VCC
V+
Z
3
+ C3
0.1µF
V- 11
C2-
C4
0.1µF
+
4
17
R
6
16
15
D
7
14
C2
0.1µF
+
VCC
485/232
GND
DY
DZ
13
20
19
A
4
B
5
18
VCC
V+
C1C2+
17
R
16
6
15
D
7
13
10
NOTE: PINOUT FOR SSOP
RS-485 MODE WITHOUT LOOPBACK
VCC
14
VCC
+ C3
0.1µF
C4
0.1µF
+
RA
12
RXEN
Y
3
V- 11
C2-
SLEW
GND
FN6361 Rev 0.00
May 20, 2008
ON
LB
Rx
VCC
ON
2
C1+
RB
DEN
485/232
VCC
DY
DEN
VCC
9
8
14
D
0.1µF
1
+
Z
VCC
+
C1
0.1µF
RA
12
RXEN
Y
15
RS-232 MODE WITH LOOPBACK
18
C1C2+
5
RB
NOTE: PINOUT FOR SSOP
+3.3V
1
RA
10
RS-232 MODE WITHOUT LOOPBACK
C1
0.1µF
C4
0.1µF
+
9
NOTE: PINOUT FOR SSOP
0.1µF
+ C3
0.1µF
12
RXEN
10
+
16
R
6
GND
+3.3V
17
LB
Rx
VCC
13
3
V- 11
R
5k
Z
DEN
8
V+
C2-
5
9
VCC
19
VCC
C1C2+
4
B1
DY
14
D
C2
0.1µF
2
VCC
RXEN
6
+
18
C1+
5k
RB
12
0.1µF
1
C1
0.1µF
A1
RA
16
R
5k
C4
0.1µF
+
17
R
5k
B
V+
C1C2+
4
A
+
18
VCC
RB
DY
SLEW
9
8
DEN
485/232
GND
ON
13
10
NOTE: PINOUT FOR SSOP
RS-485 MODE WITH LOOPBACK
Page 6 of 25
ISL3330, ISL3331
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
VL (QFN Only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VCC + 0.5V
Input Voltages
All Except A,B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
Input/Output Voltages
A, B (Any Mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25V to +25V
Y, Z (Any Mode, Note 5) . . . . . . . . . . . . . . . . . . . -12.5V to +12.5V
RA, RB (Non-QFN Package) . . . . . . . . . . . -0.5V to (VCC + 0.5V)
RA, RB (QFN Package) . . . . . . . . . . . . . . . . -0.5V to (VL + 0.5V)
Output Short Circuit Duration
Y, Z, RA, RB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Thermal Resistance (Typical)
JA (°C/W) JC (°C/W)
20 Ld SSOP Package (Note 6) . . . . . .
55
N/A
40 Ld QFN Package (Notes 7, 8). . . . .
31
2.5
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.
NOTES:
5. One output at a time, IOUT 100mA for 10 minutes.
6. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
7. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
Tech Brief TB379.
8. For JC, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications
PARAMETER
Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA = +25°C (Note 9)
SYMBOL
TEST CONDITIONS
TEMP
MIN
(°C) (Note 15)
TYP
MAX
(Note 15) UNITS
DC CHARACTERISTICS - RS-485 DRIVER (485/232 = VCC)
Driver Differential VOUT (no load)
VOD1
Driver Differential VOUT (with load)
VOD2
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
Full
-
-
VCC
V
R = 50 (RS-422) (Figure 1)
Full
2
2.3
-
V
R = 27 (RS-485) (Figure 1)
Full
1.5
2
5
V
VOD3
RD = 60, R = 375, VCM = -7V to 12V
(Figure 1)
Full
1.5
-
5
V
VOD
R = 27 or 50 (Figure 1)
Full
-
0.01
0.2
V
VOC
R = 27 or 50 (Figure 1)
Full
-
-
3.0
V
VOC
R = 27 or 50 (Figure 1)
Full
-
0.01
0.2
V
Full
35
-
250
mA
VOUT = 12V
Full
-
-
150
µA
VOUT = -7V
Full
-150
-
-
µA
Driver Short-Circuit Current,
VOUT = High or Low
IOS
-7V (VY or VZ) 12V (Note 11)
Driver Three-State Output Leakage
Current (Y, Z)
IOZ
Outputs Disabled,
VCC = 0V or 3.45V
DC CHARACTERISTICS - RS-232 DRIVER (485/232 = 0V)
Driver Output Voltage Swing
VO
All TOUTS Loaded with 3k to Ground
Full
±5.0
-
-
V
Driver Output Short-Circuit Current
IOS
VOUT = 0V
Full
-60
-
60
mA
2.2
-
V
DC CHARACTERISTICS - LOGIC PINS (i.e., DRIVER AND CONTROL INPUT PINS)
Input High Voltage
FN6361 Rev 0.00
May 20, 2008
VIH1
VL = VCC if QFN
Full
VIH2
2.7V VL < 3.0V (QFN Only)
Full
2
-
V
VIH3
2.3V VL < 2.7V (QFN Only)
Full
1.6
-
V
VIH4
1.6V VL < 2.3V (QFN Only)
Full
0.7*VL
-
V
VIH5
1.2V VL < 1.6V (QFN Only)
25
-
-
V
0.7*VL
Page 7 of 25
ISL3330, ISL3331
Electrical Specifications
PARAMETER
Input Low Voltage
Input Current
Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)
SYMBOL
TEST CONDITIONS
TEMP
MIN
(°C) (Note 15)
MAX
(Note 15) UNITS
TYP
VIL1
VL = VCC if QFN
Full
-
-
0.8
V
VIL2
VL 2.7V (QFN Only)
Full
-
-
0.8
V
VIL3
2.3V VL < 2.7V (QFN Only)
Full
-
-
0.7
V
-
VIL4
1.6V VL < 2.3V (QFN Only)
Full
-
0.35*VL
V
VIL5
1.3V VL < 1.6V (QFN Only)
25
0.35*VL
-
V
VIL6
1.2V VL < 1.3V (QFN Only)
25
0.25*VL
-
V
IIN1
Except SLEW, RXEN (QFN), and SPB (QFN)
Full
-2
-
2
µA
IIN2
SLEW (Note 13), RXEN (QFN), and SPB (QFN)
Full
-25
-
25
µA
-7V VCM 12V, Full Failsafe
Full
-0.2
-
-0.04
V
VCM = 0V
25
-
35
-
mV
VIN = 12V
Full
-
-
0.8
mA
VIN = -7V
Full
-0.64
-
-
mA
Full
15
-
-
k
DC CHARACTERISTICS - RS-485 RECEIVER INPUTS (485/232 = VCC)
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Input Current (A, B)
Receiver Input Resistance
VTH
VTH
IIN
RIN
VCC = 0V or 3.15V to 3.45V
-7V VCM 12V, VCC = 0 (Note 12), or
3.15V VCC 3.45V
DC CHARACTERISTICS - RS-232 RECEIVER INPUTS (485/232 = GND)
Receiver Input Voltage Range
VIN
Full
-25
-
25
V
Receiver Input Threshold
VIL
Full
-
1.1
0.8
V
VIH
Full
2.4
1.6
-
V
Receiver Input Hysteresis
VTH
25
-
0.5
-
V
Receiver Input Resistance
RIN
Full
3
5
7
k
VIN = ±15V, VCC Powered-Up (Note 12)
DC CHARACTERISTICS - RECEIVER OUTPUTS (485 OR 232 MODE)
Receiver Output High Voltage
VOH1
IO = -1.5mA (VL = VCC if QFN)
Full
VCC - 0.4
-
V
VOH2
IO = -100µA, VL 1.2V (QFN Only)
Full
VL - 0.1
-
V
VOH3
IO = -500µA, VL = 1.5V (QFN Only)
Full
1.2
-
V
VOH4
IO = -150µA, VL = 1.2V (QFN Only)
Full
1.0
-
V
Receiver Output Low Voltage
VOL
IO = 5mA
Full
-
0.2
0.4
V
Receiver Short-Circuit Current
IOSR
0V VO VCC
Full
7
-
85
mA
Receiver Three-State Output
Current
IOZR
Output Disabled, 0V VO VCC (or VL for QFN)
Full
-
-
±10
µA
ICC232
485/232 = 0V, ON = VCC
Full
-
3.7
7
mA
ICC485
485/232 = VCC, ON = VCC
Full
-
1.3
5
mA
ISHDN232 ON = DEN = RXEN = 0V
(RXEN = SPB = VL if QFN)
Full
-
10
30
µA
ISHDN485 ON = DEN = RXEN = SLEW = 0V
(RXEN = VL, SPB = 0V if QFN)
Full
-
30
60
µA
POWER SUPPLY CHARACTERISTICS
No-Load Supply Current (Note 10)
Shutdown Supply Current
ESD CHARACTERISTICS
Bus Pins (A, B, Y, Z) Any Mode
Human Body Model
25
-
±15
-
kV
All Other Pins
Human Body Model
25
-
±2.5
-
kV
Machine Model
25
-
±200
-
V
FN6361 Rev 0.00
May 20, 2008
Page 8 of 25
ISL3330, ISL3331
Electrical Specifications
PARAMETER
Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)
SYMBOL
TEST CONDITIONS
TEMP
MIN
(°C) (Note 15)
TYP
MAX
(Note 15) UNITS
RS-232 DRIVER and RECEIVER SWITCHING CHARACTERISTICS (485/232 = 0V, ALL VERSIONS AND SPEEDS)
Driver Output Transition Region
Slew Rate
Driver Output Transition Time
Driver Propagation Delay
SR
tr, tf
tDPHL
CL 15pF
Full
-
20
30
V/µs
CL 2500pF
Full
4
12
-
V/µs
RL = 3k, CL = 2500pF, 10% to 90%
Full
0.22
1.2
3.1
µs
RL = 3kCL = 1000pF (Figure 6)
Full
-
1
2
µs
Full
-
1.2
2
µs
tDPHL - tDPLH (Figure 6)
Full
-
300
450
ns
25
-
1200
-
ns
RL = 5kMeasured at VOUT = ±3V
25
-
500
-
ns
VOUT = ±3.0V (Note 14)
25
-
25
-
µs
RL = 3kMeasured From 3V
to -3V or -3V to 3V
tDPLH
Driver Propagation Delay Skew
tDSKEW
Driver Enable Time
tDEN
Driver Disable Time
tDDIS
Driver Enable Time from Shutdown
tDENSD
Driver Maximum Data Rate
DRD
RL = 3kCL = 1000pF, One Transmitter
Switching
Full
250
400
-
kbps
Receiver Propagation Delay
tRPHL
CL = 15pF (Figure 7)
Full
-
40
120
ns
Full
-
60
120
ns
tRPLH
tRPHL - tRPLH (Figure 7)
Full
-
20
40
ns
CL = 15pF
Full
0.46
2
-
Mbps
tZL
CL = 15pF, SW = VCC (Figure 5)
Full
-
18
-
ns
tZH
CL = 15pF, SW = GND (Figure 5)
Full
-
18
-
ns
Receiver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 5)
Full
-
22
-
ns
Receiver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 5)
Full
-
22
-
ns
Receiver Propagation Delay Skew
tRSKEW
Receiver Maximum Data Rate
DRR
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Enable from Shutdown to
Output Low
tZLSHDN CL = 15pF, SW = VCC (Figure 5, Note 14)
25
-
60
-
ns
Receiver Enable from Shutdown to
Output High
tZHSHDN CL = 15pF, SW = GND (Figure 5, Note 14)
25
-
20
-
ns
RS-485 DRIVER SWITCHING CHARACTERISTICS (FAST DATA RATE (20Mbps), 485/232 = VCC, SLEW = VCC, ALL VERSIONS)
Driver Differential Input to Output
Delay
Driver Output Skew
Driver Differential Rise or Fall Time
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2)
Full
10
20
35
ns
tSKEW
RDIFF = 54, CL = 100pF (Figure 2)
Full
-
2
10
ns
tR, tF
RDIFF = 54, CL = 100pF (Figure 2)
Full
3
20
30
ns
Driver Enable to Output Low
tZL
CL = 100pF, SW = VCC (Figure 3)
Full
-
28
60
ns
Driver Enable to Output High
tZH
CL = 100pF, SW = GND (Figure 3)
Full
-
39
60
ns
Driver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 3)
Full
-
30
60
ns
Driver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 3)
Full
-
25
60
ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC
(Figure 3, Note 14)
Full
-
100
250
ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND
(Figure 3, Note 14)
Full
-
290
375
ns
Full
20
35
-
Mbps
Driver Maximum Data Rate
fMAX
RDIFF = 54, CL = 100pF (Figure 2)
RS-485 DRIVER SWITCHING CHARACTERISTICS (MEDIUM DATA RATE (460kbps), 485/232 = VCC, SLEW = 0V, SPB (QFN Only) = VCC, ALL
VERSIONS)
Driver Differential Input to Output
Delay
Driver Output Skew
Driver Differential Rise or Fall Time
FN6361 Rev 0.00
May 20, 2008
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2)
Full
200
500
1000
ns
tSKEW
RDIFF = 54, CL = 100pF (Figure 2)
Full
-
10
150
ns
tR, tF
RDIFF = 54, CL = 100pF (Figure 2)
Full
300
660
1100
ns
Page 9 of 25
ISL3330, ISL3331
Electrical Specifications
PARAMETER
Test Conditions: VCC = 3.15V to 3.45V, C1 to C4 = 0.1µF, VL = VCC (for QFN only), Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA = +25°C (Note 9) (Continued)
SYMBOL
TEST CONDITIONS
TEMP
MIN
(°C) (Note 15)
TYP
MAX
(Note 15) UNITS
Driver Enable to Output Low
tZL
CL = 100pF, SW = VCC (Figure 3)
Full
-
42
100
ns
Driver Enable to Output High
tZH
CL = 100pF, SW = GND (Figure 3)
Full
-
350
450
ns
Driver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 3)
Full
-
30
60
ns
tHZ
CL = 15pF, SW = GND (Figure 3)
Full
-
25
60
ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC
(Figure 3, Note 14)
Full
-
-
500
ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND
(Figure 3, Note 14)
Full
-
-
750
ns
Full
460
2000
-
kbps
Driver Disable from Output High
Driver Maximum Data Rate
fMAX
RDIFF = 54, CL = 100pF (Figure 2)
RS-485 DRIVER SWITCHING CHARACTERISTICS (SLOW DATA RATE (115kbps, QFN ONLY), 485/232 = VCC, SLEW = SPB = GND)
Driver Differential Input to Output
Delay
Driver Output Skew
Driver Differential Rise or Fall Time
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2)
Full
800
1600
2500
ns
tSKEW
RDIFF = 54, CL = 100pF (Figure 2)
Full
-
250
500
ns
tR, tF
RDIFF = 54, CL = 100pF (Figure 2)
Full
1000
1700
3100
ns
Driver Enable to Output Low
tZL
CL = 100pF, SW = VCC (Figure 3)
Full
-
45
100
ns
Driver Enable to Output High
tZH
CL = 100pF, SW = GND (Figure 3)
Full
-
910
1200
ns
Driver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 3)
Full
-
35
60
ns
Driver Disable from Output High
tHZ
CL = 15pF, SW = GND (Figure 3)
Full
-
29
60
ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC
(Figure 3, Note 14)
Full
-
-
800
ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND
(Figure 3, Note 14)
Full
-
-
1500
ns
Full
115
800
-
kbps
Full
20
45
70
ns
Full
-
3
10
ns
Driver Maximum Data Rate
fMAX
RDIFF = 54, CL = 100pF (Figure 2)
RS-485 RECEIVER SWITCHING CHARACTERISTICS (485/232 = VCC, ALL VERSIONS AND SPEEDS)
Receiver Input to Output Delay
tPLH, tPHL (Figure 4)
Receiver Skew | tPLH - tPHL |
tSKEW
(Figure 4)
Receiver Maximum Data Rate
fMAX
Full
20
40
-
Mbps
Receiver Enable to Output Low
tZL
CL = 15pF, SW = VCC (Figure 5)
Full
-
15
60
ns
Receiver Enable to Output High
tZH
CL = 15pF, SW = GND (Figure 5)
Full
-
15
60
ns
Receiver Disable from Output Low
tLZ
CL = 15pF, SW = VCC (Figure 5)
Full
-
20
60
ns
tHZ
CL = 15pF, SW = GND (Figure 5)
Full
-
20
60
ns
Receiver Enable from Shutdown to
Output Low
tZLSHDN CL = 15pF, SW = VCC (Figure 5, Note 14)
Full
-
500
900
ns
Receiver Enable from Shutdown to
Output High
tZHSHDN CL = 15pF, SW = GND (Figure 5, Note 14)
Full
-
500
900
ns
Receiver Disable from Output High
NOTES:
9. 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.
10. Supply current specification is valid for loaded drivers when DEN = 0V.
11. Applies to peak current. See “Typical Performance Curves” beginning on page 19 for more information.
12. RIN defaults to RS-485 mode (>15k) when the device is unpowered (VCC = 0V), or in SHDN, regardless of the state of the 485/232 pin.
13. The Slew pin has a pull-up resistor that enables only when in RS-485 mode (485/232 = VCC).
14. ON, RXEN, and DEN all simultaneously switched Low-to-High.
15. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization
and are not production tested.
FN6361 Rev 0.00
May 20, 2008
Page 10 of 25
ISL3330, ISL3331
Test Circuits and Waveforms
R
DEN
VCC
Y
DY
RD
D
VOD
Z
+
-
VCM
VOC
R
FIGURE 1. RS-485 DRIVER VOD AND VOC TEST CIRCUIT
3V
DY
1.5V
1.5V
0V
VCC
CL = 100pF
DEN
tPHL
VOH
Y
DY
tPLH
RDIFF
D
50%
OUT (Z)
Z
50%
VOL
CL = 100pF
tPLH
tPHL
SIGNAL
GENERATOR
VOH
OUT (Y)
50%
50%
VOL
tDLH
tDHL
90%
DIFF OUT (Z - Y)
0V
10%
+VOD
90%
0V
10%
tR
-VOD
tF
SKEW = |tPLH (Y OR Z) - tPHL (Z OR Y)|
FIGURE 2B. MEASUREMENT POINTS
FIGURE 2A. TEST CIRCUIT
FIGURE 2. RS-485 DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
DEN
DY
SIGNAL
GENERATOR
Y
500
D
Z
VCC
SW
GND
CL
ENABLED
DEN
1.5V
0V
tZH
tZH(SHDN)
FOR SHDN TESTS, SWITCH ON AND DEN L- H SIMULTANEOUSLY
PARAMETER OUTPUT
RXEN
DY
SW
CL (pF)
tHZ
Y/Z
X
0/1
GND
15
tLZ
Y/Z
X
1/0
VCC
15
tZH
Y/Z
X
0/1
GND
100
tZL
Y/Z
X
1/0
VCC
100
tZH(SHDN)
Y/Z
0
0/1
GND
100
tZL(SHDN)
Y/Z
0
1/0
VCC
100
FIGURE 3A. TEST CIRCUIT
3V
1.5V
OUT (Y, Z)
OUTPUT HIGH
tHZ
VOH - 0.5V VOH
2.3V
0V
tZL
tZL(SHDN)
OUT (Y, Z)
tLZ
VCC
2.3V
OUTPUT LOW
VOL + 0.5V V
OL
FIGURE 3B. MEASUREMENT POINTS
FIGURE 3. RS-485 DRIVER ENABLE AND DISABLE TIMES
FN6361 Rev 0.00
May 20, 2008
Page 11 of 25
ISL3330, ISL3331
Test Circuits and Waveforms (Continued)
RXEN
VCC
0V
+1.5V
15pF
A
R
B
B
RA
0V
0V
-1.5V
tPLH
tPHL
VCC
SIGNAL
GENERATOR
RA
1.5V
1.5V
0V
FIGURE 4B. MEASUREMENT POINTS
FIGURE 4A. TEST CIRCUIT
FIGURE 4. RS-485 RECEIVER PROPAGATION DELAY
RXEN
A
R
SIGNAL
GENERATOR
1k
RA
VCC
SW
B
GND
ENABLED
RXEN
1.5V
3V
1.5V
0V
15pF
tZH
tZH(SHDN)
FOR SHDN TESTS, SWITCH ON AND RXEN L- H SIMULTANEOUSLY
OUTPUT HIGH
RA
tHZ
VOH - 0.5V VOH
1.5V
0V
PARAMETER
DEN
B (V)
SW
tHZ
X
+1.5
GND
tLZ
X
-1.5
VCC
tZL
tZL(SHDN)
tZH
X
+1.5
GND
tZL
X
-1.5
VCC
RA
tZH(SHDN)
0
+1.5
GND
tZL(SHDN)
0
-1.5
VCC
tLZ
VCC
1.5V
VOL + 0.5V V
OUTPUT LOW
OL
FIGURE 5B. MEASUREMENT POINTS
FIGURE 5A. TEST CIRCUIT
FIGURE 5. RS-485 RECEIVER ENABLE AND DISABLE TIMES
VCC
3V
DEN
DY,Z
DY,Z
D
1.5V
1.5V
CL
Y, Z
0V
tDPHL
RL
SIGNAL
GENERATOR
tDPLH
VO+
OUT (Y,Z)
0V
0V
VO-
SKEW = |tDPHL - tDPLH|
FIGURE 6B. MEASUREMENT POINTS
FIGURE 6A. TEST CIRCUIT
FIGURE 6. RS-232 DRIVER PROPAGATION DELAY
VCC
3V
RXEN
A, B
A, B
R
50%
50%
CL = 15pF
RA, RB
0V
tRPLH
tRPHL
SIGNAL
GENERATOR
VOH
RA, RB
50%
50%
VOL
SKEW = |tRPHL - tRPLH|
FIGURE 7A. TEST CIRCUIT
FIGURE 7B. MEASUREMENT POINTS
FIGURE 7. RS-232 RECEIVER PROPAGATION DELAY
FN6361 Rev 0.00
May 20, 2008
Page 12 of 25
ISL3330, ISL3331
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 9. The Tx and Rx enables aren’t required,
so connect RXEN and DEN to VCC through a 1k resistor.
Detailed Description
The ISL333x port supports dual protocols: RS-485/RS-422,
and RS-232. 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 signalling, 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/RS-422
maximum distance of 4000’ (1220m). It is important to note
that the ISL333x don’t follow the RS-485 convention
whereby the inverting I/O is labeled “B/Z”, and the non
inverting I/O is “A/Y”. Thus, in the application diagrams,
see Figures 8 and 9, the 333x A/Y (B/Z) pins connect to
the B/Z (A/Y) pins of the generic RS-485/RS-422 ICs.
Conversely, RS-485 is a true multipoint standard, which
allows up to 32 devices (any combination of drivers that 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 8. A port set to RS-485/RS-422 mode
includes one Rx and one Tx. See Application Note AN1401
for details about implementing a three pin, selectable
RS-232/half-duplex RS-485 port.
RS-232 is a point-to-point, singled ended (signal voltages
referenced to GND) communication protocol targeting fairly
short (< 150’, 46m) and low data rate (250kbps
• Lower Tx and Rx Skews - Wider, consistent bit widths
• Lower ICC - Max ICC is 2x to -4x lower than competition
• Flow-Thru 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
RX FEATURES
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 (20ns) so the receivers
contribute negligibly to bit width distortion. Inputs include the
standards required 3k to 7k 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.
Rx outputs are short circuit protected, and are tri-statable via
the active high RXEN pin, when the IC is shutdown (SHDN;
see Tables 2 and 3, and the “Low Power Shutdown (SHDN)
Mode” on page 16), or via the active low RXEN pin available
on the QFN package option (see “ISL3331 (QFN Package)
Special Features” on page 17).
TX FEATURES
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 400kbps, and
with loads of 1000pF. The drivers are designed for low skew
(typically 12% of the 400kbps bit width), and are compliant to
the RS-232 slew rate specification (4V to 30V/µs) for a wide
range of load capacitances. Tx inputs float if left
unconnected and may cause ICC increases. For the best
results, connect unused inputs to GND.
Tx outputs are short circuit protected, and incorporate a
thermal SHDN feature to protect the IC in situations of
severe power dissipation. See the “RS-485 Mode” on
page 14 for more details. Drivers disable via the active high
FN6361 Rev 0.00
May 20, 2008
DEN pin, in SHDN (see Tables 2 and 3, and the “Low Power
Shutdown (SHDN) Mode” on page 16), or when the 3.3V
power supply is off. Because RS-232 is a point-to-point (only
one Tx allowed on the bus) standard, the main use for this
DEN disable function is to reduce power by eliminating the
load current (approximately 1mA per Tx output) through the
5k resistor in the Rx at the cable’s far end.
CHARGE PUMPS
The on-chip charge pumps create the RS-232 transmitter
power supplies (typically +5.7/-5.3V) from a single supply as
low as 3.15V, and are enabled only if the port is configured
for RS-232 operation, and not in SHDN. 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 to RS-232
mode ICC is reduced significantly. Unlike competing devices
that require the charge pump in RS-485 mode, disabling the
charge pump saves power, and minimizes noise. If the
application is a dedicated RS-485 port, then the charge
pump capacitors aren’t even required.
DATA RATES AND CABLING
Drivers operate at data rates up to 400kbps, and are
guaranteed for data rates up to 250kbps. The charge pumps
and drivers are designed such that one driver can be
operated at the rated load, and at 250kbps (see Figure 33).
Figure 33 also shows that drivers can easily drive several
thousands of picofarads at data rates up to 250kbps, while
still delivering compliant ±5V output levels.
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.
Figures 36 and 37 illustrate driver and receiver waveforms at
250kbps, and 400kbps, respectively. For these graphs, one
driver drives the specified capacitive load, and a receiver.
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 ISL333x RS-232 port uses a five
conductor cable for interconnection. Bus terminations are
not required, nor allowed, by the RS-232 standard.
RS-485 Mode
RX 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 as great as +12V and
-7V, regardless of supply voltage, making them ideal for long
networks where induced voltages are a realistic concern.
Page 14 of 25
ISL3330, ISL3331
Each RS-485/422 port includes a single receiver (RA), and
the unused Rx output (RB) is disabled.
Drivers are also tri-stated when the IC is in SHDN, or when
the 3.3V power supply is off.
Worst case receiver input currents are 20% lower than the
1 “unit load” (1mA) RS-485 limit, which translates to a 15k
minimum input resistance.
SPEED OPTIONS
These receivers include 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). Failsafe 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.
All the Rx outputs are short circuit protected, and are
tri-statable via the active high RXEN pin, or when the IC is
shutdown (see Tables 2 and 3, and the “Low Power
Shutdown (SHDN) Mode” on page 16). ISL3331 (QFN)
receiver outputs are also tri-statable via an active low RXEN
input (see “ISL3331 (QFN Package) Special Features” on
page 17).
For the ISL3331 (QFN), when using the active high RXEN
function, the RXEN pin may be left floating (internally pulled
high), or should be connected to VCC through a 1k resistor.
If using the active low RXEN, then the RXEN pin must be
connected to GND.
TX FEATURES
The RS-485/RS-422 driver is a differential output device that
delivers at least 1.5V across a 54 load (RS-485), and at
least 2V across a 100 load (RS-422). The drivers feature
low propagation delay skew to maximize bit widths, and to
minimize EMI.
To allow multiple drivers on a bus, the RS-485 specification
requires that drivers survive worst case bus contentions
undamaged. The ISL333x 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°C. If the
contention persists, the thermal shutdown/re-enable cycle
repeats until the fault is cleared. Receivers stay operational
during thermal shutdown.
The RS-485 multi-driver operation also requires drivers to
include tri-state functionality, where the port has a DEN 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
DEN pin should connect to VCC through a 1k resistor.
FN6361 Rev 0.00
May 20, 2008
The ISL3330 (SSOP) features two speed options that are
user selectable via the SLEW pin: a high slew rate setting
optimized for 20Mbps data rates (Fast), and a slew rate
limited option for operation up to 460kbps (Med). The
ISL3331 (QFN) offers an additional, more slew rate limited,
option for data rates up to 115kbps (Slow). See the “Data
Rate“ and “RS-485 Slew Rate Limited Data Rates” on
page 17 for more information.
Receiver performance is the same for all three speed
options.
DATA RATE, CABLES, AND TERMINATIONS
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 lengths of 20’ to
30’ (6m to 9m), while devices operating at or below 115kbps
can operate at the maximum length of 4000’ (1220m).
Higher data rates require faster edges, so both the ISL333x
versions offer an edge rate capable of 20Mbps data rates.
They both have a second option for 460kbps, but the
ISL3331 also offers another, very slew rate limited, edge rate
to minimize problems at slow 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” on
page 17 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.
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.
TABLE 4. RECOMMENDED STUB LENGTHS
SPEED OPTION
MAXIMUM STUB LENGTH
ft. (m)
SLOW
350 to 500 (107 to 152)
MED
100 to 150 (30.5 to 46)
FAST
1 to 3 (0.3 to 0.9)
Page 15 of 25
ISL3330, ISL3331
In point-to-point, or point-to-multipoint (RS-422) networks,
the main cable should be terminated in its characteristic
impedance (typically 120) 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, 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 (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.
High ESD
All pins on the ISL333x include ESD protection structures
rated at ±2.5kV (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. ISL333x 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 robustness of any board level scheme.
Small Packages
Competing 3.3V dual protocol ICs are available only in a
20 Ld or 24 Ld SSOP. The ISL3331’s tiny 6mmx6mm QFN
footprint is 36% to 44% smaller than the competing SSOPs.
Flow-Through Pinouts
Even the ISL333x pinouts are features, in that the
“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 on the
other side for easy connection to a UART, avoids costly and
problematic crossovers. Figure 10 illustrates the
flow-through nature of the pinout.
Low Power Shutdown (SHDN) Mode
The ISL333x enter the SHDN mode when ON = 0, and the
Tx and Rx are disabled (DEN = 0, RXEN = 0, and
RXEN = 1) and the already low supply current drops to as
low as 10µA. SHDN disables the Tx and Rx outputs, and
FN6361 Rev 0.00
May 20, 2008
disables the charge pumps if the port is in RS-232 mode, so
V+ collapses to VCC, and V- collapses to GND.
All but 10µA of SHDN ICC current is due to control input
(SPB, SLEW) pull-up resistors (~10µA/resistor), so SHDN
ICC varies depending on the ISL333x configuration. The
specification tables indicate the worst case values, but
careful selection of the configuration yields lower currents.
For example, in RS-232 mode the SPB pin isn’t used, so
floating it or tying it high minimizes SHDN ICC.
ISL3330
CONNECTOR
Proper termination is imperative to minimize reflections
when using the 20Mbps speed option. Short networks using
the medium and slow speed options need not be terminated,
but terminations are recommended unless power dissipation
is an overriding concern. Note that the RS-485 specification
allows a maximum of two terminations on a network,
otherwise the Tx output voltage may not meet the required
VOD.
A
B
Y
Z
R
RA
D
DY
UART
OR
ASIC
OR
µCONTROLLER
FIGURE 10. ILLUSTRATION OF FLOW-THROUGH PINOUT
When enabling from SHDN in RS-232 mode, allow at least
25µs for the charge pumps to stabilize before transmitting
data. If fast enables are required, and ICC isn’t the greatest
concern, disable the drivers with the DEN pin to keep the
charge pumps active. The charge pumps aren’t used in
RS-485 mode, thus the transceiver is ready to send or
receive data in less than 2µs, which is much faster than
competing devices that require the charge pump for all
modes of operation.
Internal Loopback Mode
Setting ON = 0, DEN = 1, and RXEN = 1 or RXEN = 0 (QFN
only), places the port in the loopback mode, a mode that
facilitates implementing board level self test functions. In
loopback, internal switches disconnect the Rx inputs from
the Rx outputs, and feed back the Tx outputs to the
appropriate Rx output. This way the data driven at the Tx
input appears at the corresponding Rx output (refer to
“Typical Operating Circuits” on page 6). The Tx outputs
remain connected to their terminals, so the external loads
are reflected in the loopback performance. This allows the
loopback function to potentially detect some common bus
faults such as one or both driver outputs shorted to GND, or
outputs shorted together.
Note that the loopback mode uses an additional set of
receivers, as shown in the “Typical Operating Circuits” on
page 6. These loopback receivers are not standards
compliant, so the loopback mode can’t be used to implement
a half-duplex RS-485 transceiver. See Application Note
AN1401 for specific details on implementing a 3-pin, half
duplex, dual protocol port.
Page 16 of 25
ISL3330, ISL3331
ISL3331 (QFN Package) Special Features
Logic Supply (VL Pin)
The ISL3331 (QFN) includes a VL pin that powers the logic
inputs (Tx inputs and control pins) and Rx outputs. These
pins interface with “logic” devices such as UARTs, ASICs,
and µcontrollers, and today many of these devices use
power supplies significantly lower than 3.3V. Thus, a 3.3V
output level from a 3.3V powered dual protocol IC might
seriously overdrive and damage the logic device input.
Similarly, the logic device’s low VOH might not exceed the
VIH of a 3.3V powered dual protocol input. Connecting the
VL pin to the power supply of the logic device (as shown in
Figure 11) limits the ISL3331’s Rx output VOH to VL (see
Figure 14) and reduces the Tx and control input switching
points to values compatible with the logic device output
levels. Tailoring the logic pin input switching points and
output levels to the supply voltage of the UART, ASIC, or
µcontroller eliminates the need for a level shifter/translator
between the two ICs.
VCC = +3.3V
RA
DY
GND
VCC = +2V
VOH = 3.3V
RXD
VIH 2
VOH 2
ISL3330
ESD
DIODE
TXD
GND
UART/PROCESSOR
VCC = +3.3V
VCC = +2V
VL
RA
DY
GND
VOH = 2V
RXD
VIH = 1.4V
VOH 2
ESD
DIODE
TXD
GND
.
TABLE 5. VIH AND VIL vs VL FOR VCC = 3.3V
VL (V)
VIH (V)
VIL (V)
1.2
0.85
0.26
1.5
0.9
0.5
1.8
0.9
0.73
2.3
1.2
1.0
2.7
1.4
1.3
3.3
1.8
1.7
Note: With VL 1.6V, the ISL3331 may not operate at the full
data rate unless the logic signal VIL is at least 0.2V below
the typical value listed in Table 5.
The VL supply current (IL) is typically less than 35µA, as
shown in Figures 19 and 20. All of the DC VL current is due
to inputs with internal pull-up resistors (SPB, SLEW, RXEN)
being driven to the low input state. The worst case IL current
occurs when all three of the inputs are low (see Figure 19),
due to the IL through the pull-up resistors. IIL through an
input pull-up resistor is ~10µA, so the IL in Figure 19 drops
by about 18µA (at VL = 3.3V) when the SPB is high and 232
mode disables the SLEW pin pull-up (middle vs top curve).
When all three inputs are driven high, IL drops to ~10nA.
Thus, to minimize power dissipation, drive these inputs high
when unneeded (e.g., SPB isn’t used in RS-232 mode, so
drive it high).
QFN logic input pins that are externally tied high in an
application, should use the VL supply for the high voltage
level.
Active Low Rx Enable (RXEN)
In many RS-485 applications, especially half duplex
configurations, users like to accomplish “echo cancellation”
by disabling the corresponding receiver while its driver is
transmitting data. This function is available on the QFN
package via an active low RXEN pin. The active low function
also simplifies direction control by allowing a single Tx/Rx
direction control line. If the active high RXEN were used,
either two valuable I/O pins would be used for direction
control, or an external inverter is required between DEN and
RXEN. Figure 12 details the advantage of using the RXEN
pin. When using RXEN, ensure that RXEN is tied to GND.
RS-485 Slew Rate Limited Data Rates
ISL3331
UART/PROCESSOR
FIGURE 11. USING VL PIN TO ADJUST LOGIC LEVELS
VL can be anywhere from VCC down to 1.2V, but the input
switching points may not provide enough noise margin when
VL < 1.5V. Table 5 indicates typical VIH and VIL values for
various VL voltages so the user can ascertain whether or not
a particular VL voltage meets his needs.
FN6361 Rev 0.00
May 20, 2008
The ISL333x FAST speed option (SLEW = High) utilizes Tx
output transitions optimized for a 20Mbps data rate. These
fast edges may increase EMI and reflection issues, even
though fast transitions aren’t required at the lower data rates
used by many applications. With the SLEW pin low, both
product types switch to a moderately slew rate limited output
transition targeted for 460kbps (MED) data rates. The
ISL3331 (QFN version), offers an additional slew rate limited
data rate that is optimized for 115kbps (SLOW), and is
selected when SLEW = 0 and SPB = 0 (see Table 3). The
Page 17 of 25
ISL3330, ISL3331
slew limited edges permit longer unterminated networks, or
longer stubs off terminated busses, and help minimize EMI
and reflections. Nevertheless, for the best jitter performance
when driving long cables, the faster speed options 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 preferable
to go with the slow speed option for data rates of 115kbps or
less to minimize fast edge effects. Likewise, the medium
speed option is a good choice for data rates between
115kbps and 460kbps. For higher data rates, or when the
absolute best jitter is required, use the high speed option.
1k
OR NC
An evaluation board, part number ISL3331EVAL1Z, is
available to assist in assessing the dual protocol IC’s
performance. The evaluation board contains a QFN
packaged device, but because the same die is used in all
packages, the board is also useful for evaluating the
functionality of the other versions. The board’s design allows
for evaluation of all standard features, plus the QFN specific
features. Refer to the evaluation board application note for
details, and contact your sales representative for ordering
information.
ISL3331 +3.3V
+
RXEN *
VCC
RA
0.1µF
B
R
A
RXEN
Tx/Rx
Evaluation Board
DEN
Y
DY
Z
D
GND
ACTIVE HIGH RX ENABLE
ISL3331 +3.3V
+
VCC
RXEN
RA
R
0.1µF
B
RXEN *
A
DEN
Y
Tx/Rx
DY
D
Z
GND
* QFN ONLY
ACTIVE LOW RX ENABLE
FIGURE 12. USING ACTIVE LOW vs ACTIVE HIGH RX
ENABLE
FN6361 Rev 0.00
May 20, 2008
Page 18 of 25
ISL3330, ISL3331
Typical Performance Curves
VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified
3.5
30
3.0
VOH, +25°C
25
20
HIGH OUTPUT VOLTAGE (V)
RECEIVER OUTPUT CURRENT (mA)
VOL, +25°C
VOL, +85°C
VOH, +85°C
15
10
5
0
0.0
1.0
2.0
RECEIVER OUTPUT VOLTAGE (V)
IOH = -0.5mA
1.5 IOH = -1mA
0.5
DIFFERENTIAL OUTPUT VOLTAGE (V)
60
50
40
30
20
10
1.0
1.5
2.0
1.0
1.5
2.5
3.3
3.0
2.5
3.0
2.30
2.25
RDIFF = 100
2.20
2.15
2.10
2.05
RDIFF = 54
2.00
1.95
1.90
-40
3.5
-25
DIFFERENTIAL OUTPUT VOLTAGE (V)
250
75
85
4.5
+25°C
+85°C
0
25
50
TEMPERATURE (°C)
FIGURE 16. RS-485, DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs TEMPERATURE
FIGURE 15. RS-485, DRIVER OUTPUT CURRENT vs
DIFFERENTIAL OUTPUT VOLTAGE
200
4.0
RS-232, RXEN, RXEN, ON = X, DEN = VCC
-40°C
150
3.5
100
ICC (mA)
OUTPUT CURRENT (mA)
2.0
FIGURE 14. RECEIVER HIGH OUTPUT VOLTAGE vs LOGIC
SUPPLY VOLTAGE (VL) (QFN ONLY)
70
0.5
IOH = -2mA
VL (V)
80
0
IOH = -6mA
1.0
3.0 3.3
90
DRIVER OUTPUT CURRENT (mA)
2.0
0
FIGURE 13. RECEIVER OUTPUT CURRENT vs RECEIVER
OUTPUT VOLTAGE
0
2.5
50
Y OR Z = LOW
0
Y OR Z = HIGH
-50
1.5
-100
-150
RS-232, RXEN, RXEN = X, ON = VCC, DEN = GND
2.5
2.0
+25°C
+85°C
3.0
RS-485, HALF DUPLEX, DEN = VCC, RXEN, RXEN, ON = X
RS-485, FULL DUPLEX, DEN = VCC, RXEN, RXEN, ON = X
RS-485, DEN = GND, RXEN, RXEN = X, ON = VCC
-40°C
-7 -6
-4
-2
0
2
4
6
OUTPUT VOLTAGE (V)
8
10
12
FIGURE 17. RS-485, DRIVER OUTPUT CURRENT vs SHORT
CIRCUIT VOLTAGE
FN6361 Rev 0.00
May 20, 2008
1.0
-40
-25
0
50
25
75
TEMPERATURE (°C)
FIGURE 18. SUPPLY CURRENT vs TEMPERATURE
Page 19 of 25
85
ISL3330, ISL3331
Typical Performance Curves
50
30
NO LOAD
VIN = VL or GND
DEN, RXEN, ON = GND
45
40
VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
VL VCC
25
RXEN = VL
ICC AND IL (µA)
35
IL(µA)
30
RS-485, SLEW, SPB, RXEN = GND
25
20
RS-232, RXEN = GND, SPB = VL
15
10
RS-485, SLEW, SPB, RXEN = VL
1.0
1.5
2.0
2.5
3.0
3.5
SPB = GND
RS-485 IL
20
15
RS-232/RS-485 ICC
10
SPB = VL
RS-485 IL
5
RS-232, SPB, RXEN = VL OR
5
0
DEN, RXEN, DY, DZ/SLEW, ON = GND
NO LOAD
VIN = VL OR GND
VL VCC
0
4.0
1.0
1.5
2.0
2.5
VL (V)
VL (V)
FIGURE 19. RS-232, VL SUPPLY CURRENT vs VL VOLTAGE
(QFN ONLY)
1640
SPB = VL
RS-232 IL
3.0
3.5
4.0
FIGURE 20. VCC and VL SHDN SUPPLY CURRENTS vs VL
VOLTAGE (QFN ONLY)
300
RDIFF = 54, CL = 100pF
RDIFF = 54, CL = 100pF
|tPLHZ - tPHLY|
1630
1620
|tPHLZ - tPLHY|
200
1610
tDHL
1600
1590
SKEW (ns)
PROPAGATION DELAY (ns)
250
tDLH
100
1580
1570
150
tDHL
50
1560
|tDLH - tDHL|
1550
-40
0
25
TEMPERATURE (°C)
-25
50
75
85
FIGURE 21. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (SLOW DATA RATE, QFN ONLY)
550
0
-40
16
25
TEMPERATURE (°C)
50
75
85
RDIFF = 54, CL = 100pF
14
545
|tPLHZ - tPHLY|
12
540
535
SKEW (ns)
PROPAGATION DELAY (ns)
0
FIGURE 22. RS-485, DRIVER SKEW vs TEMPERATURE
(SLOW DATA RATE, QFN ONLY)
RDIFF = 54, CL = 100pF
tDHL
530
tDLH
525
tDHL
10
8
|tPHLZ - tPLHY|
6
4
|tDLH - tDHL|
520
515
-40
-25
2
-25
0
25
50
75
TEMPERATURE (°C)
FIGURE 23. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (MEDIUM DATA RATE)
FN6361 Rev 0.00
May 20, 2008
85
0
-40
-25
0
25
50
75
TEMPERATURE (°C)
FIGURE 24. RS-485, DRIVER SKEW vs TEMPERATURE
(MEDIUM DATA RATE)
Page 20 of 25
85
ISL3330, ISL3331
Typical Performance Curves
24
VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
3.0
RDIFF = 54, CL = 100pF
RDIFF = 54, CL = 100pF
|tDLH - tDHL|
2.5
22
21
2.0
tDLH
SKEW (ns)
20
19
tDHL
18
1.5
|tPHLZ - tPLHY|
1.0
17
0.5
|tPLHZ - tPHLY|
16
-40
-25
0
25
50
75
0
-40
85
-25
TEMPERATURE (°C)
5
0
0
DRIVER OUTPUT (V)
RA
4
3
Y
2
1
RECEIVER OUTPUT (V)
5
Z
0
RDIFF = 54, CL = 100pF
DY
RA
0
4
3
Z
2
1
Y
0
TIME (400ns/DIV)
RA
0
4
3
Y
2
1
Z
0
TIME (200ns/DIV)
FIGURE 29. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (MEDIUM DATA RATE)
FN6361 Rev 0.00
May 20, 2008
RECEIVER OUTPUT (V)
0
DRIVER INPUT (V)
5
5
FIGURE 28. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (SLOW DATA RATE, QFN ONLY)
DRIVER OUTPUT (V)
DRIVER OUTPUT (V)
RECEIVER OUTPUT (V)
FIGURE 27. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (SLOW DATA RATE, QFN ONLY)
RDIFF = 54, CL = 100pF
5
0
5
TIME (400ns/DIV)
DY
85
75
FIGURE 26. RS-485, DRIVER SKEW vs TEMPERATURE
(FAST DATA RATE)
DRIVER INPUT (V)
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
DY
50
25
TEMPERATURE (°C)
FIGURE 25. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (FAST DATA RATE)
RDIFF = 54, CL = 100pF
0
DRIVER INPUT (V)
15
RDIFF = 54, CL = 100pF
DY
5
5
0
RA
0
DRIVER INPUT (V)
PROPAGATION DELAY (ns)
23
4
3
Z
2
1
Y
0
TIME (200ns/DIV)
FIGURE 30. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (MEDIUM DATA RATE)
Page 21 of 25
ISL3330, ISL3331
DY
0
5
RA
0
4
Y
3
2
Z
1
RDIFF = 54, CL = 100pF
DY
0
RA
0
4
Z
3
2
Y
1
0
TIME (10ns/DIV)
FIGURE 31. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (FAST DATA RATE)
FIGURE 32. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (FAST DATA RATE)
RS-232 REGION OF NONCOMPLIANCE
250kbps
VOUT+
5.0
2.5
400kbps
ALL TOUTS LOADED WITH 3k TO GND
0
1 TRANSMITTER AT 250kbps or 400kbps,
OTHER TRANSMITTER AT 30kbps
-2.5
400kbps
-5.0
250kbps
VOUT 0
1000
2000
3000
4000
5000
TRANSMITTER OUTPUT VOLTAGE (V)
7.5
7.5
TRANSMITTER OUTPUT VOLTAGE (V)
0
5
TIME (10ns/DIV)
-7.5
5
5.0
VOUT+
2.5
OUTPUTS STATIC
ALL TOUTS LOADED WITH 3k TO GND
AND AT V+ OR V-
0
-2.5
-5.0
VOUT -7.5
-40
LOAD CAPACITANCE (pF)
FIGURE 33. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
LOAD CAPACITANCE
-25
0
50
25
TEMPERATURE (°C)
75
40
5
Y OR Z = LOW
30
0
20
CL = 4000pF, 1 CHANNEL SWITCHING
DY
5
VOUT SHORTED TO GND
10
0
0
-5
Y/A
5
-10
RA
Y OR Z = HIGH
0
-20
-30
-40
-25
0
25
50
75
85
2µs/DIV
TEMPERATURE (°C)
FIGURE 35. RS-232, TRANSMITTER SHORT CIRCUIT
CURRENT vs TEMPERATURE
FN6361 Rev 0.00
May 20, 2008
85
FIGURE 34. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
TEMPERATURE
50
TRANSMITTER OUTPUT CURRENT (mA)
DRIVER INPUT (V)
5
RECEIVER OUTPUT (V)
RDIFF = 54, CL = 100pF
DRIVER INPUT (V)
VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
DRIVER OUTPUT (V)
DRIVER OUTPUT (V)
RECEIVER OUTPUT (V)
Typical Performance Curves
FIGURE 36. RS-232, TRANSMITTER AND RECEIVER
WAVEFORMS AT 250kbps
Page 22 of 25
ISL3330, ISL3331
Typical Performance Curves
VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
58
CL = 1000pF, 1 CHANNEL SWITCHING
DY
5
0
Y/A
-5
5
RA
FULL TEMP RANGE
56
55
SR IN = 15V/µs
54
53
52
51
SR IN = 100V/µs
50
0
49
0
500
VOUT ±4V AND DUTY CYCLE BETWEEN 40% AND 60%
500
ALL TOUTS LOADED WITH 5k TO GND
DATA RATE (kbps)
450
2 TRANSMITTERS AT +25°C
400
1 TRANSMITTER AT +25°C
350
300
250
1 TRANSMITTER AT +85°C
200
2 TRANSMITTERS AT +85°C
150
100
0
1000
1500
2000
2000
3000
4000
LOAD CAPACITANCE (pF)
5000
FIGURE 39. RS-232, TRANSMITTER MAXIMUM DATA RATE vs
LOAD CAPACITANCE
FIGURE 38. RS-232, RECEIVER OUTPUT + DUTY CYCLE vs
DATA RATE
7.5
TRANSMITTER OUTPUT VOLTAGE (V)
FIGURE 37. RS-232, TRANSMITTER AND RECEIVER
WAVEFORMS AT 400kbps
550
1000
DATA RATE (kbps)
2µs/DIV
+25°C
VOUT+
5.0
+85°C
2.5
1 TRANSMITTER SWITCHING
0
ALL TOUTS LOADED WITH 5k TO GND, CL = 1000pF
-2.5
+85°C
-5.0
+25°C
VOUT -7.5
0
100
200
300
400
DATA RATE (kbps)
500
600
FIGURE 40. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
DATA RATE
Die Characteristics
650
2 TRANSMITTERS SWITCHING
600 ALL TOUTS LOADED WITH 3k TO GND, CL = 1000pF
SKEW (ns)
550
+85°C
GND
TRANSISTOR COUNT:
500
2490
450
PROCESS:
400
+25°C
350
BiCMOS
-40°C
300
250
SUBSTRATE AND QFN PAD POTENTIAL
(POWERED UP):
0
50
200
400
600 650
DATA RATE (kbps)
FIGURE 41. RS-232, TRANSMITTER SKEW vs DATA RATE
FN6361 Rev 0.00
May 20, 2008
Page 23 of 25
RS-232 REGION OF NONCOMPLIANCE
0
VIN = ±5
57
RECEIVER + DUTY CYCLE (%)
5
ISL3330, ISL3331
Package Outline Drawing
L40.6x6
40 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
Rev 3, 10/06
4X 4.5
6.00
36X 0.50
A
B
6
PIN 1
INDEX AREA
6
PIN #1 INDEX AREA
40
31
30
1
6.00
4 . 10 ± 0 . 15
21
10
0.15
(4X)
11
20
TOP VIEW
0.10 M C A B
40X 0 . 4 ± 0 . 1
4 0 . 23 +0 . 07 / -0 . 05
BOTTOM VIEW
SEE DETAIL "X"
0.10 C
0 . 90 ± 0 . 1
(
C
BASE PLANE
( 5 . 8 TYP )
SEATING PLANE
0.08 C
SIDE VIEW
4 . 10 )
( 36X 0 . 5 )
C
0 . 2 REF
5
( 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.
5. Tiebar shown (if present) is a non-functional feature.
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.
FN6361 Rev 0.00
May 20, 2008
Page 24 of 25
ISL3330, ISL3331
Shrink Small Outline Plastic Packages (SSOP)
N
M20.209 (JEDEC MO-150-AE ISSUE B)
INDEX
AREA
H
0.25(0.010) M
E
2
3
0.25
0.010
SEATING PLANE
-A-
INCHES
GAUGE
PLANE
-B1
20 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE
B M
A
D
-C-
e
A2
A1
B
0.25(0.010) M
L
C
0.10(0.004)
C A M
B S
SYMBOL
MIN
MAX
MIN
MAX
A
0.068
0.078
1.73
1.99
A1
0.002
0.008’
0.05
0.21
A2
0.066
0.070’
1.68
1.78
NOTES
B
0.010’
0.015
0.25
0.38
C
0.004
0.008
0.09
0.20’
D
0.278
0.289
7.07
7.33
3
E
0.205
0.212
5.20’
5.38
4
e
0.026 BSC
H
0.301
L
0.025
N
NOTES:
MILLIMETERS
0.65 BSC
0.311
7.65
0.037
0.63
20
0 deg.
9
7.90’
0.95
6
20
8 deg.
0 deg.
1. Symbols are defined in the “MO Series Symbol List” in Section
2.2 of Publication Number 95.
7
8 deg.
Rev. 3 11/02
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.
© Copyright Intersil Americas LLC 2008. All Rights Reserved.
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For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such
modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets 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 parties which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN6361 Rev 0.00
May 20, 2008
Page 25 of 25
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