SP3223EBCA-L/TR Exar Corporation, SP3223EBCA-L/TR Datasheet - Page 12

• 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

ONLINE pin is HIGH, the AUTO ON-LINE
mode is disabled.
The AUTO ON-LINE
stages:
The first stage, shown in Figure 22, detects
an inactive input. A logic HIGH is asserted
on R
or the external transmitters are disabled.
Otherwise, R
This circuit is duplicated for each of the other
receivers.
The second stage of the AUTO ON-LINE
circuitry, shown in Figure 23, processes all
the receiver's R
cumulated delay that disables the device
to a µA supply current. The STATUS pin
goes to a logic LOW when the cable is
disconnected, the external transmitters
are disabled, or the SHUTDOWN pin is
invoked. The typical accumulated delay
is around 20µs. When the SP3223 driv-
ers or internal charge pump are disabled,
the supply current is reduced to µA.
This can commonly occur in handheld
Figure 6. AUTO ON-LINE
X
INACT if the cable is disconnected
) Inactive Detection
2) Accumulated Delay
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-707 • www.exar.com
X
INACT will be at a logic LOW.
X
RS-232 OUTPUT
INACT signals with an ac-
RS-232 INPUT
VOLTAGES
RECEIVER
VOLTAGES
STATUS
®
DRIVER
Timing Waveforms
®
circuit has two
+2.7V
-2.7V
+5V
V
-5V
CC
0V
0V
0V
t
STSL
®
®
2
t
ONLINE
t
STSH
or portable applications where the RS-232
cable is disconnected or the RS-232 drivers
of the connected peripheral are turned off.
The AUTO ON-LINE
by the SHUTDOWN pin. If this pin is a logic
LOW, the AUTO ON-LINE
operate regardless of the logic state of the
ONLINE pin. Table 3 summarizes the logic
of the AUTO ON-LINE
The truth table logic of the SP3223 driver and
receiver outputs can be found in Table 2.
The STATUS pin outputs a logic LOW signal
if the device is shutdown. This pin goes to
a logic HIGH when the external transmitters
are enabled and the cable is connected.
When the SP3223 devices are shutdown,
the charge pumps are turned off. V+ charge
pump output decays to V
decays to GND. The decay time will depend
on the size of capacitors used for the charge
pump. Once in shutdown, the time required
to exit the shut down state and have valid
V+ and V- levels is typically 200µs.
For easy programming, the STATUS can
be used to indicate DTR or a Ring Indicator
signal. Tying ONLINE and SHUTDOWN
together will bypass the AUTO ON-LINE
circuitry so this connection acts like a shut-
down input pin
W
H
U
D
O
N
S
T
®
mode can be disabled
®
SP3223E/EB/EU_00_20
operating modes.
®
CC
function will not
,the V- output
®