SP230ACP SIPEX [Sipex Corporation], SP230ACP Datasheet - Page 8

• Manufacturer Part Number: SP230ACP
• Description: +5V Powered Multi-Channel RS-232 Drivers/Receivers
• Manufacturer: SIPEX [Sipex Corporation]

Table 2. Wake–Up Truth Table
output impedance of V
degrade V
as low as 1.0 F.
Shutdown (SD)
The SP230A, SP235A/B, SP236A/B,
SP240A/B and SP241A/B all feature a control
input which will disable the part and reduce V
current typically to less than 5 A, which is
especially useful to designers of battery–pow-
ered systems. In the “power–off” mode the
receiver and transmitter will both be tri-stated.
V
to ground.
For complete shutdown to occur and the 10 A
current drain to be realized, the following con-
ditions must be met:
Please note that for proper operation, the SD
input pin must never be left floating.
Figure 2. Charge Pump Voltage Inverter
SP30A/234A/235A/236A/237A/238A/239A/
SP241A/235B/236B/240A/240B/241A/241B
VOLTAGE DOUBLER
+
SD
• +5.00V must be applied to the SD pin;
• ENABLE must either 0V, +5.0V or not connected;
• the transmitter inputs must be either +5.0V or not
• V
• Receiver inputs must be >0V and <+5V
will discharge to V
0
0
1
1
connected;
CC
FROM
OSCILLATOR
GND
must be +5V;
INTERNAL
V+
EN
OH
0
1
0
1
and V
S1
S2
Up/Down
OL
Power
Down
Down
. Capacitor values can be
Up
Up
CC
+
, and V
+
C2
and V
S3
S4
-
will discharge
-
Receiver
+5V Powered Multi-Channel RS-232 Drivers/Receivers
, which will
Outputs
Tri–state
Tri–state
+
Enable
Enable
C4
GND
V- = -(V+)
CC
8
ENABLE Input (EN)
The SP235A/B, SP236A/B, SP239A, SP240A/
B, and SP241A/B all feature an enable input
(EN), which allows the receiver outputs to be
either tri–stated or enabled. The enable input is
active low; 0V applied to EN will enable the
receiver outputs. This can be especially useful
when the receiver is tied directly to a micropro-
cessor data bus.
Protection From Shorts to > 15V
The driver outputs are protected against shorts
to ground, other driver outputs, and V
For protection against voltages exceeding 15V,
two back–to–back zener diodes connected to
clamp the outputs to an acceptable voltage level
are recommended. (Refer to Figure 3.)
Improved Drive Capability for Mouse
Applications
Each of the devices in this data sheet have
improved drive capability for non-standard ap-
plications. Although the EIA RS-232D stan-
dards specify the maximum loading to be 3k
and 2500pF, the SP230A, SP234A, SP235A/B,
SP236A/B, SP237A, SP238A, SP239, SP240A/
B, and SP241A/B can typically drive loads as
low as 1k and still maintain 5V outputs. This
feature is especially useful when the serial port
is intended to be used for a “self-powered”
mouse. In this case the voltage necessary to
operate the circuits in the mouse can be derived
from the RS-232 driver output as long as the
loading is 1k (refer to Figure 4). For applica-
tions which even exceed this requirement, driv-
ers can be connected in parallel, increasing the
drive capability to 750 , while maintaining the
Figure 3. High Voltage Short Circuit Protection
5V V
OH
T IN
T IN
1
2
and V
OL
levels (refer to Figure 5).
© Copyright 2000 Sipex Corporation
15V ZENER
15V ZENER
T OUT
T OUT
1
2
+
or V
-
.