1
SP385ADS/05
SP385A Line Driver/Receiver
Copyright 2000 Sipex Corporation
SP385A
+3V to +5V RS-232 Line Driver/Receiver
s
Operates from 3.3V or 5V Power Supply
s
Meets All EIA-232D and V.28 Specifica-
tions at 5V
s
Meets EIA-562 Specifications at 3.3V
s
Two Drivers and Receivers
s
Operates with 0.1
F to 10
F Capacitors
s
High Data Rate -- 120kbps Under Load
s
Low Power Shutdown
1
A
s
3-State TTL/CMOS Receiver Outputs
s
Low Power CMOS -- 5mA Operation
DESCRIPTION...
The Sipex SP385A is an enhanced version of the Sipex SP200 family of RS232 line drivers/
receivers. The SP385A offers +3.3V operation for EIA-562 and EIA-232 applications. The
SP385A maintains the same performance features offered in its predecessors. The SP385A is
available in plastic SOIC or SSOP packages operating over the commercial and industrial
temperature ranges. The SP385A is pin compatible to the LTC1385 EIA-562 transceiver, except
the drivers in the SP385A can only be disabled with the ON/OFF pin.
R
2
R
1
T
2
T
1
TTL/CMOS INPUTS
RS232 OUTPUTS
TTL/CMOS OUTPUTS
RS232 INPUTS
CHARGE
PUMP
SP385ADS/05
SP385A Line Driver/Receiver
Copyright 2000 Sipex Corporation
2
ABSOLUTE MAXIMUM RATINGS
This is a stress rating only and functional operation of the device at
these or any other conditions above those indicated in the operation
sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods of time may affect
reliability.
V
cc
.................................................................................................................................................................
+6V
V
+
....................................................................................................................
(Vcc-0.3V) to +13.2V
V
-
..............................................................................................................................................................
13.2V
Input Voltages
T
IN
.........................................................................................................................
-0.3 to (Vcc +0.3V)
R
IN
............................................................................................................................................................
15V
Output Voltages
T
OUT
....................................................................................................
(V+, +0.3V) to (V-, -0.3V)
R
OUT
................................................................................................................
-0.3V to (Vcc +0.3V)
Short Circuit Duration
T
OUT
.........................................................................................................................................
Continuous
Power Dissipation
CERDIP .............................................................................. 675mW
(derate 9.5mW/
C above +70
C)
Plastic DIP .......................................................................... 375mW
(derate 7mW/
C above +70
C)
Small Outline ...................................................................... 375mW
(derate 7mW/
C above +70
C)
SPECIFICATIONS
V
CC
=+3.3V
10%; 0.1
F charge pump capacitors; T
MIN
to T
MAX
unless otherwise noted.
PARAMETERS
MIN.
TYP.
MAX.
UNITS
CONDITIONS
TTL INPUT
Logic Threshold
Low
0.8
Volts
T
IN
; ON/OFF Vcc = 3.3V
High
2.0
Volts
T
IN
; ON/OFF Vcc = 3.3V
Logic Pullup Current
15
200
A
T
IN
= 0V
Maximum Data Rate
120
kbps
C
L
= 2500pF, R
L
= 3k
TTL OUTPUT
TTL/CMOS Output
Voltage, Low
0.5
Volts
I
OUT
= 3.2mA; Vcc = 3.3V
Voltage, High
2.4
Volts
I
OUT
= -1.0mA
Leakage Current; T
A
= +25
C
0.05
10
A
ON/OFF=0V, 0V
V
OUT
V
CC
EIA-562 OUTPUT
Output Voltage Swing
3.7
4.2
Volts
All transmitter outputs loaded
with 3k
to ground
Power-Off Output Resistance
300
V
CC
= 0V; V
OUT
=
2V
Output Short Circuit Current
10
mA
Infinite duration
EIA-562 INPUT
Voltage Range
-15
+15
Volts
Voltage Threshold
Low
0.8
1.2
Volts
V
CC
= 3.3V, T
A
= +25
C
High
1.7
2.4
Volts
V
CC
= 3.3V, T
A
= +25
C
Hysteresis
0.2
0.5
1.0
Volts
V
CC
= 3.3V, T
A
= +25
C
Resistance
3
5
7
k
V
IN
= 15V to 15V
DYNAMIC CHARACTERISTICS
Driver Propagation Delay
4.0
s
TTL to RS-562
Receiver Propagation Delay
1.5
s
RS-562 to TTL
Instantaneous Slew Rate
30
V/
s
C
L
= 10pF, R
L
= 3k
- 7k
;
T
A
= +25
C
Transition Region Slew Rate
10
V/
s
C
L
= 2500pF, R
L
= 3k
;
measured from +2V to -2V
or -2V to +2V
Output Enable Time
300
ns
Output Disable Time
1000
ns
POWER REQUIREMENTS
V
CC
Power Supply Current
3
6
mA
No load, T
A
= +25
C; V
CC
= 3.3V
8
mA
All transmitters R
L
= 3k
T
A
= +25
C
Shutdown Supply Current
0.010
5
A
V
CC
= 3.3V, T
A
= +25
C
3
SP385ADS/05
SP385A Line Driver/Receiver
Copyright 2000 Sipex Corporation
PERFORMANCE CURVES
-55
-40
0
25
70
85
125
Temperature (C)
0
5
10
15
20
25
30
VCC = 6V
VCC = 5V
VCC = 4V
VCC = 3V
I CC
(mA)
4.5
4.75
5.0
5.25
5.5
VCC (Volts)
6.8
7.4
7.6
7.8
8.0
8.2
8.4
Load current = 0mA
T
A
= 25C
V
OH
(Volts)
7.0
7.2
0
5
10
15
20
Load Current (mA)
0
6
8
10
12
V+ (Volts)
2
4
VCC = 5V
VCC = 4V
VCC = 6V
25
30
35
40
0
2
4
6
8
10
12
14
Load Current (mA)
V Voltage (Volts)
-3
-4
-5
-6
-7
-8
-9
-10
-11
VCC = 6V
VCC = 5V
VCC = 4V
SPECIFICATIONS
V
CC
=+5V
10%; 0.1
F charge pump capacitors; T
MIN
to T
MAX
unless otherwise noted.
PARAMETERS
MIN.
TYP.
MAX.
UNITS
CONDITIONS
TTL INPUT
Logic Threshold
Low
0.8
Volts
T
IN
; ON/OFF
High
2.0
Volts
T
IN
; ON/OFF
Logic Pullup Current
15
200
A
T
IN
= 0V
Maximum Data Rate
120
kbps
C
L
= 2500pF, R
L
= 3k
TTL OUTPUT
TTL/CMOS Output
Voltage, Low
0.4
Volts
I
OUT
= 3.2mA; Vcc = +5V
Voltage, High
3.5
Volts
I
OUT
= -1.0mA
Leakage Current; T
A
= +25
C
0.05
10
A
ON/OFF = O, 0V
V
OUT
V
CC
EIA-232 OUTPUT
Output Voltage Swing
5
9
Volts
All transmitter outputs loaded
with 3k
to ground
Power-Off Output Resistance
300
V
CC
= 0V; V
OUT
=
2V
Output Short Circuit Current
18
mA
Infinite duration
EIA-232 INPUT
Voltage Range
-15
+15
Volts
Voltage Threshold
Low
0.8
1.2
Volts
V
CC
= 5V, T
A
= +25
C
High
1.7
2.4
Volts
V
CC
= 5V, T
A
= +25
C
Hysteresis
0.2
0.5
1.0
Volts
V
CC
= 5V, T
A
= +25
C
Resistance
3
5
7
k
V
IN
= 15V to 15V
DYNAMIC CHARACTERISTICS
Driver Propagation Delay
4.0
s
TTL to RS-232
Receiver Propagation Delay
1.5
s
RS-232 to TTL
Instantaneous Slew Rate
30
V/
s
C
L
= 10pF, R
L
= 3k
- 7k
;
T
A
=+25
C
Transition Region Slew Rate
10
V/
s
C
L
= 2500pF, R
L
= 3k
;
measured from +3V to -3V
or -3V to +3V
Output Enable Time
400
ns
Output Disable Time
250
ns
POWER REQUIREMENTS
V
CC
Power Supply Current
10
15
mA
No load, T
A
= +25
C; V
CC
= 5V
25
mA
All transmitters R
L
= 3k
;
T
A
= +25
C
Shutdown Supply Current
1
10
A
V
CC
= 5V, T
A
= +25
C
SP385ADS/05
SP385A Line Driver/Receiver
Copyright 2000 Sipex Corporation
4
PINOUT...
TYPICAL OPERATING CIRCUIT...
ON/OFF
V
GND
T OUT
R IN
R OUT
T IN
T IN
R OUT
N/C
C +
V+
C -
C +
C -
V-
T OUT
R IN
2
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
1
1
CC
2
2
SP385A
2
1
2
2
1
1
1
ON/OFF
V
GND
T OUT
R IN
R OUT
T IN
T IN
R OUT
N/C
N/C
C +
V+
C -
C +
C -
V-
T OUT
R IN
N/C
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
1
1
CC
2
2
SP385A
2
1
2
2
1
1
1
2
R
2
10
9
R IN
R OUT
2
R
1
13
14
R IN
R OUT
1
T
2
11
8
T IN
2
T OUT
2
T
1
12
15
T IN
1
T OUT
1
16
GND
400K
400K
TTL/CMOS INPUTS
RS232 OUTPUTS
4
2
C +
C -
1
1
7
17
V
CC
V+
+
+
0.1 F
6.3V
+5V to +10V
Voltage Doubler
+5V INPUT
3
V-
TTL/CMOS OUTPUTS
RS232 INPUTS
2
1
5K
0.1 F
16V
5K
6
5
C +
C -
2
2
+
0.1 F
16V
+10V to -10V
Voltage Inverter
0.1 F
SP311A
+
18
ON/OFF
+
0.1 F
16V
SOIC Package
R
2
12
9
R IN
R OUT
2
R
1
15
16
R IN
R OUT
1
T
2
13
8
T IN
2
T OUT
2
T
1
14
17
T IN
1
T OUT
1
18
GND
400K
400K
TTL/CMOS INPUTS
RS232 OUTPUTS
4
2
C +
C -
1
1
7
19
V
CC
V+
+
+
0.1 F
6.3V
+5V to +10V
Voltage Doubler
+5V INPUT
3
V-
TTL/CMOS OUTPUTS
RS232 INPUTS
2
1
5K
0.1 F
16V
5K
6
5
C +
C -
2
2
+
0.1 F
16V
+10V to -10V
Voltage Inverter
0.1 F
SP311A
+
20
ON/OFF
+
0.1 F
16V
SSOP Package
SP385A
SP385A
5
SP385ADS/05
SP385A Line Driver/Receiver
Copyright 2000 Sipex Corporation
FEATURES...
The Sipex SP385A is a +3V to +5V EIA-232/EIA-
562 line transceiver. It is a pin-for-pin alternative for
the SP310A and will operate in the same socket with
capacitors ranging from 0.1
F to 10
F, either polar-
ized or nonpolarized, in +3V supplies. The SP385A
offers the same features such as 120kbps guaranteed
transmission rate, increased drive current for longer
and more flexible cable configurations, low power
dissipation and overall ruggedized construction for
commercial and industrial environments.
The SP385A also includes a shutdown feature that
tri-states the drivers and the receivers.
The SP385A includes a charge pump voltage con-
verter which allows it to operate from a single +3.3V
or +5V supply. These converters double the V
CC
voltage input in order to generate the EIA-232 or EIA-
562 output levels. For +5V operation, the SP385A
driver outputs adhere to all EIA-232D and CCITT
V.28 specifications. While at +3.3V operation, the
outputs adhere to EIA-562 specifications. Due to
Sipex's efficient charge pump design, the charge
pump levels and the driver outputs are less noisy
than other 3V EIA-232 transceivers.
The SP385A has a single control line which simul-
taneously shuts down the internal DC/DC con-
verter and puts all transmitter and receiver outputs
into a high impedance state.
The SP385A is available in 18-pin plastic SOIC
and 20-pin plastic SSOP packages for operation
over commercial and industrial temperature
ranges. Please consult the factory for surface-
mount packaged parts supplied on tape-on-reel
as well as parts screened to MIL-M-38510.
The SP385A is ideal for +3.3V battery applica-
tions requiring low power operation. The charge
pump strength allows the drivers to provide
4.0V signals, plenty for typical EIA-232
applications since the EIA-232 receivers have
input sensitivity levels of less than
3V.
THEORY OF OPERATION
The SP385A device is made up of three
basic circuit blocks -- 1) a driver/transmitter,
2) a receiver and 3) a charge pump.
Driver/Transmitter
The drivers are inverting transmitters, which
accept TTL or CMOS inputs and output the
RS-232 signals with an inverted sense relative to
the input logic levels. Typically the RS-232 output
voltage swing is
9V for 5V supply and
4.2V
for 3.3V supply. Even under worst case loading
conditions of 3k
and 2500pF, the output is guar-
anteed to be
5V for a 5V supply and
3.7V for
a 3.3V supply which adheres to EIA-232 and EIA-
562 specifications, respecitively. The transmitter
outputs are protected against infinite short-circuits
to ground without degradation in reliability.
The instantaneous slew rate of the transmitter
output is internally limited to a maximum of 30V/
s in order to meet the standards [EIA 232-D 2.1.7,
Paragraph (5)]. However, the transition region
slew rate of these enhanced products is typically
10V/
s. The smooth transition of the loaded output
from V
OL
to V
OH
clearly meets the monotonicity
requirements of the standard [EIA 232-D 2.1.7,
Paragraphs (1) & (2)].
Receivers
The receivers convert RS-232 input signals to
inverted TTL signals. Since the input is usually
from a transmission line, where long cable lengths
and system interference can degrade the signal, the
inputs have a typical hysteresis margin of 500mV.
This ensures that the receiver is virtually immune
to noisy transmission lines.
The input thresholds are 0.8V minimum and 2.4V
maximum, again well within the
3V RS-232
requirements. The receiver inputs are also pro-
tected against voltages up to
15V. Should an
input be left unconnected, a 5k
pull-down resis-
tor to ground will commit the output of the receiver
to a high state.
In actual system applications, it is quite possible
for signals to be applied to the receiver inputs
before power is applied to the receiver circuitry.
This occurs for example when a PC user attempts
to print only to realize the printer wasn't turned on.
In this case an RS-232 signal from the PC will
appear on the receiver input at the printer. When
the printer power is turned on, the receiver will
operate normally. All of these enhanced devices
are fully protected.
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