SP3238E
Intelligent +3.0V to +5.5V RS-232 Transceiver
FEATURES
■ Meets true EIA/TIA-232-F Standards
from a +3.0V to +5.5V power supply
■ Interoperable with EIA/TIA-232 and
adheres to EIA/TIA-562 down to a +2.7V
power source
■
AUTO ON-LINE
®
circuitry automatically
wakes up from a 1µA shutdown
■ Minimum 250Kbps data rate under load
■ Regulated Charge Pump Yields Stable
RS-232 Outputs Regardless of V
CC
Variations
■ Enhanced ESD Specifications:
+15kV Human Body Model
+15kV IEC61000-4-2 Air Discharge
+8kV IEC61000-4-2 Contact Discharge
C2+ 1
GND 2
C2- 3
V- 4
T1OUT 5
T2OUT
T3 OUT
R1IN
R 2IN
6
7
8
9
SP3238E
28 C1+
27 V+
26 V
CC
25
C1-
24 T1 IN
23 T2 IN
22 T3 IN
21 R1OUT
20 R2OUT
19 T4IN
18
17
16
R3 OUT
T5 IN
R1OUT
T4OUT 10
R3 IN 11
T5 OUT 12
ONLINE 13
SHUTDOWN 14
15 STATUS
Now Available in Lead Free Packaging
The SP3238E device is an RS-232 transceiver solution intended for portable or hand-held applications
such as notebook and palmtop computers. The SP3238E uses an internal high-efficiency, charge-pump
power supply that requires only 0.1µF capacitors in 3.3V operation. This charge pump and Exar's driver
architecture allow the SP3238E device to deliver compliant RS-232 performance from a single power
supply ranging from +3.0V to +5.5V. The SP3238E is a 5-driver / 3-receiver device that is ideal for laptop
/ notebook computer and PDA applications. The SP3238E includes one complementary receiver that
remains alert to monitor an external device's Ring Indicate signal while the device is shutdown.
The
AUTO ON-LINE
®
feature allows the device to automatically "wake-up" during a shutdown state
when an RS-232 cable is connected and a connected peripheral is turned on. Otherwise, the device
automatically shuts itself down drawing less than 1µA.
DESCRIPTION
Device
Power
Supplies
+3.0V to +5.5V
+3.0V to +5.5V
+3.0V to +5.5V
+3.0V to +5.5V
RS-232
Drivers
1
2
3
5
RS-232
Receivers
1
2
5
3
External
Components
4 Capacitors
4 Capacitors
4 Capacitors
4 Capacitors
Auto
On-Line
Circuitry
No
Yes
Yes
Yes
SELECTION TABLE
TTL 3-State
# of
Pins
16
20
28
28
SP3220E
SP3223E
SP3243E
SP3238E
Yes
Yes
Yes
Yes
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
SP3238E_100_020111
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation
of the device at these ratings or any other above those
indicated in the operation sections of the specifications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may
affect reliability and cause permanent damage to the
device.
V
CC
.......................................................-0.3V to +6.0V
V+ (NOTE 1).......................................-0.3V to +7.0V
V- (NOTE 1)........................................+0.3V to -7.0V
V+ + |V-| (NOTE 1)...........................................+13V
I
CC
(DC V
CC
or GND current).........................+100mA
Input Voltages
TxIN, ONLINE, SHUTDOWN, ....-0.3V to Vcc + 0.3V
RxIN...................................................................+25V
Output Voltages
TxOUT.............................................................+13.2V
RxOUT, STATUS.......................-0.3V to (V
CC
+0.3V)
Short-Circuit Duration
TxOUT....................................................Continuous
Storage Temperature......................-65°C to +150°C
NOTE 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Power Dissipation per package
28-pin SSOP (derate 11.2mW/
o
C above +70
o
C)..........900mW
28-pin TSSOP (derate 13.2mW/
o
C above +70
o
C)......1100mW
ELECTRICAL CHARACTERISTICS
V
CC
= +3.0V to +5.5V, C1 - C4 = 0.1µF (tested at 3.3V +/-5%), C1 - C4 = 0.22µF (tested at 3.3V +/-10%),
C1 = 0.047µF and C2 - C4 = 0.33µF (tested at 5.0V +/-10%), T
AMB
= T
MIN
to T
MAX
,
unless otherwise noted. Typical
values are at T
A
= 25
o
C
PARAMETER
DC CHARACTERISTICS
Supply Current, AUTO ON-
LINE®
Supply Current, Shutdown
Supply Current
AUTO ON-LINE® Disabled
Input Logic Threshold
LOW
HIGH
Input Leakage Current
Output Leakage Current
Output Voltage LOW
Output Voltage HIGH
DRIVER OUTPUTS
Output Voltage Swing
+5.0
+5.4
V
All driver outputs loaded with 3KΩ to
GND
V
CC
-0.6
V
CC
-0.1
1.0
10
µA
All RxIN open, ONLINE = GND,
SHUTDOWN = V
CC
, TxIN = GND or
V
CC
SHUTDOWN = GND, TxIN = Vcc or
GND
ONLINE = SHUTDOWN = Vcc,
no load, TxIN = GND or V
CC
V
CC
= +3.3V or +5.0V, TxIN
ONLINE, SHUTDOWN
TxIN, ONLINE, SHUTDOWN,
T
AMB
= +25
o
C
Receivers disabled
I
OUT
= 1.6mA
I
OUT
= -1.0mA
MIN.
TYP.
MAX.
UNITS
CONDITIONS
1.0
0.3
10
1.0
µA
mA
LOGIC INPUTS AND RECEIVER OUTPUTS
0.8
+0.01
+0.05
+1.0
+10
0.4
V
V
µA
µA
V
V
2.4
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
SP3238E_100_020111
2
V
CC
= +3.0V to +5.5V, C1 - C4 = 0.1µF (tested at 3.3V +/-5%), C1 - C4 = 0.22µF (tested at 3.3V +/-10%),
C1 = 0.047µF and C2 - C4 = 0.33µF (tested at 5.0V +/-10%), T
AMB
= T
MIN
to T
MAX
,
unless otherwise noted. Typical
values are at T
A
= 25
o
C
PARAMETER
DRIVER OUTPUTS (continued)
Output Resistance
Output Short-Circuit Current
RECEIVER INPUTS
Input Voltage Range
Input Threshold LOW
Input Threshold LOW
Input Threshold HIGH
Input Threshold HIGH
Input Hysteresis
Input Resistance
STATUS Output Voltage LOW
STATUS Output Voltage HIGH
Receiver Threshold to Drivers
Enabled (t
ONLINE
)
Receiver Positive or Negative
Threshold to STATUS HIGH (t
STSH
)
Receiver Positive or Negative
Threshold to STATUS LOW (t
STSL
)
TIMING CHARACTERISTICS
Maximum Data Rate
Receiver Propagation Delay
t
PHL
t
PLH
Receiver Output Enable Time
Receiver Output Disable Time
Driver Skew
Receiver Skew
Transition-Region Slew Rate
250
kbps
R
L
= 3KΩ, C
L
= 1000pF, one
driver switching
Receiver input to Receiver out-
put, C
L
= 150pF
Normal operation
Normal operation
| t
PHL
- t
PLH
|, T
AMB
= 25°C
| t
PHL
- t
PLH
|
Vcc = 3.3V, R
L
= 3kΩ, T
AMB
=
25°C, measurements taken from
-3.0V to +3.0V or +3.0V to -3.0V
V
CC
-0.6
200
0.5
20
3
-25
0.6
0.8
1.2
1.5
1.5
1.8
0.5
5
7
0.4
2.4
2.4
25
V
V
V
V
V
V
kΩ
V
V
µs
µs
µs
I
OUT
= 1.6mA
I
OUT
= -1.0mA
Figure 10
Figure 10
Figure 10
Vcc = 3.3V
Vcc = 5.0V
Vcc = 3.3V
Vcc = 5.0V
300
+35
+60
Ω
mA
V
CC
= V+ = V- = 0V, V
OUT
=+2V
V
OUT
= 0V
MIN.
TYP.
MAX.
UNITS
CONDITIONS
ELECTRICAL CHARACTERISTICS
AUTO ON-LINE® CIRCUITRY CHARACTERISTICS (ONLINE = GND, SHUTDOWN = VCC)
0.15
0.15
200
200
100
50
30
µs
ns
ns
ns
ns
V/µs
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
SP3238E_100_020111
3
TYPICAL PERFORMANCE CHARACTERISTICS
Unless otherwise noted, the following performance characteristics apply for V
CC
= +3.3V, 250kbps data rate, all
drivers loaded with 3kΩ, 0.1µF charge pump capacitors, and T
AMB
= +25°C.
25
20
V /u S
6
4
V o lt
15
10
5
0
0
1000
2000
pF
3000
4000
5000
POS. SR
NE G S R
2
0
-2 0
-4
-6
pF
1000
2000
3000
4000
5000
VOH
VOL
Figure 1. Transmitter Output Voltage VS. Load
Capacitance
Figure 2. Slew Rate VS. Load Capacitance
60
50
40
mA
250K bps
30
20
10
0
0
1000
2000
pF
3000
4000
5000
120K bps
20K bps
Figure 3. Supply Current VS. Load Capacitance
when Transmitting Data
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
SP3238E_100_020111
4
NAME
C2+
GND
C2-
V-
T
1
OUT
T
2
OUT
T
3
OUT
R
1
IN
R
2
IN
T
4
OUT
R
3
IN
T
5
OUT
ONLINE
SHUTDOWN
STATUS
R
1
OUT
T
5
IN
R
3
OUT
T
4
IN
R
2
OUT
R
1
OUT
T
3
IN
T
2
IN
T
1
IN
C1-
Vcc
V+
C1+
FUNCTION
Positive terminal of the symmetrical charge-pump capacitor C2.
Ground.
Negative terminal of the symmetrical charge-pump capacitor C2.
Regulated -5.5V output generated by the charge pump.
RS-232 Driver Output.
RS-232 Driver Output.
RS-232 Driver Output.
RS-232 receiver input.
RS-232 receiver input.
RS-232 Driver Output.
RS-232 receiver input.
RS-232 Driver Output.
Apply logic HIGH to override
AUTO ON-LINE®
circuitry keeping drivers
active (SHUTDOWN must also be logic HIGH, refer to Table 2).
Apply logic LOW to shut down drivers and charge pump.
This overrides all
AUTO ON-LINE®
circuitry and ONLINE (Refer to table 2).
TTL/CMOS Output indicating if a RS-232 signal is present on any receiver
input.
Non-Inverting receiver - 1 output, active in shutdown.
TTL/CMOS driver input.
TTL/CMOS receiver output.
TTL/CMOS driver input.
TTL/CMOS receiver output.
TTL/CMOS receiver output.
TTL/CMOS driver input.
TTL/CMOS driver input.
TTL/CMOS driver input.
Negative terminal of the symmetrical charge-pump capacitor C1.
+3.0V to +5.5V supply voltage.
Regulated +5.5V output generated by the charge pump.
Positive terminal of the symmetrical charge-pump capacitor C1.
PIN NUMBER
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Table 1. Device Pin Description
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
SP3238E_100_020111
5
Microcontroller MCU
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