SP3223EBCA-L/TR Exar Corporation, SP3223EBCA-L/TR Datasheet - Page 10

• Manufacturer Part Number: SP3223EBCA-L/TR
• Description: Intelligent +3.0V To +5.5V RS-232 Transceivers
• Manufacturer: Exar Corporation
• Type: Transceiverr

Specifications of SP3223EBCA-L/TR

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.200", 5.30mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Receivers
The receivers convert ±5.0V EIA/TIA-232
levels to TTL or CMOS logic output levels.
Receivers have an inverting output that can
be disabled by using the EN pin.
Receivers are active when the AUTO ON-
LINE® circuitry is enabled or when in shut-
down. During the shutdown, the receivers will
continue to be active. If there is no activity
present at the receivers for a period longer
than 00µs or when SHUTDOWN is enabled,
the device goes into a standby mode where
the circuit draws µA. Driving EN to a logic
HIGH forces the outputs of the receivers into
high-impedance. The truth table logic of the
SP3223 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 pull-down resistor to ground
will commit the output of the receiver to a
HIGH state.
Table 2. SHUTDOWN and EN Truth Tables
Note: In AUTO ON-LINE
and SHUTDOWN = V
there is no activity present at the Receiver inputs.
SHUTDOWN
0
0


Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-707 • www.exar.com
Device: SP3223
EN
0

0

CC
®
, the device will shut down if
Mode where ONLINE = GND
T
High Z
High Z
Active
Active
X
OUT
R
High Z
High Z
Active
Active
X
OUT
0
Charge Pump
The charge pump is a patented 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 symmetrical
5.5V power supplies. The internal power
supply consists of a regulated dual charge
Figure 4. Loopback Test Circuit for RS-232 Driver
Data Transmission Rates
Figure 5. Loopback Test Circuit result at 250Kbps
(All Drivers Fully Loaded)
SP3223E/EB/EU_00_20