SP3222EEY/TR Exar, SP3222EEY/TR Datasheet - Page 9

• Manufacturer Part Number: SP3222EEY/TR
• Description: RS-232 Interface IC RS232 Transceiver 3-5.5V 2-drvr/2-rcvr
• Manufacturer: Exar

Specifications of SP3222EEY/TR

• Product Category: RS-232 Interface IC
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-20
• Function: Transceiver
• Number Of I/os: 4

Figure 9. Loopback Test results at 120kbps
Figure 8. SP3222E/SP3232E Driver Loopback Test
Circuit
Figure 10. Loopback Test results at 235kbps
OUTPUTS
R1 OUT
R1 OUT
T1 OUT
T1 OUT
INPUTS
LOGIC
T1 IN
LOGIC
C2
T1 IN
C5
C1
1
+
+
2
1
2
3
+
3
0.1µF
0.1µF
0.1µF
Ch1
Ch3
Ch1
Ch3
5.00V Ch2 5.00V M 2.50µs Ch1
5.00V
5.00V Ch2 5.00V M 5.00µs Ch1
5.00V
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com
C1+
C2+
C2-
TxIN
C1-
RxOUT
EN*
[
[
SP3222E
SP3232E
V
V
GND
T
T
T
T
T
T
T
T
CC
CC
5kΩ
*SHDN
TxOUT
* SP3222E only
RxIN
]
]
V+
V-
0V
0V
1000pF
V
C3
C4
CC
+
+
0.1µF
0.1µF
9
Receivers
The Receivers convert EIA/TIA-232 levels
to TTL or CMOS logic output levels. The
SP3222E receivers have an inverting tri-state
output. These receiver outputs (RxOUT)
are tri-stated when the enable control EN =
HIGH. In the shutdown mode, the receivers
can be active or inactive. EN has no effect on
TxOUT. The truth table logic of the SP3222E
driver and receiver outputs can be found in
Table 2.
Since receiver input is usually from a trans-
mission line where long cable lengths and
system interference can degrade the signal,
the inputs have a typical hysteresis margin
of 300mV. This ensures that the receiver
is virtually immune to noisy transmission
lines. Should an input be left unconnected,
an internal 5kΩ pulldown resistor to ground
will commit the output of the receiver to a
HIGH state.
Table 2. SP3222E Truth Table Logic for Shutdown
and Enable Control
Charge Pump
The charge pump is an Exar-patended
design (U.S. 5,306,954) and uses a unique
approach compared to older less-efficient
designs. The charge pump still requires four
external capacitors, but uses a four-phase
voltage shifting technique to attain sym-
metrical 5.5V power supplies. The internal
power supply consists of a regulated dual
charge pump that provides output voltages
of +/-5.5V regardless of the input voltage
(Vcc) over the +3.0V to +5.5V range.
SHDN
0
0
1
1
EN
0
1
0
1
Tri-state
Tri-state
TxOUT
Active
Active
SP3222E/SP3232E_101_031413
DESCRIPTION
Tri-state
Tri-state
RxOUT
Active
Active