Datasheet

MAX214
Programmable DTE/DCE,
+5V RS-232 Transceiver
_______________________________________________________________________________________ 7
RS-232 Drivers
With V
CC
= 5V, the typical driver output voltage swing
is ±8V when loaded with a nominal 5kΩ RS-232
receiver. Under worst-case operating conditions
(including 116kbps data rate, 3kΩ  2500pF load,
V
CC
= 4.5V, maximum rated temperature) the output
swing is guaranteed to meet the ±5V minimum speci-
fied by EIA/TIA-232 and V.28. The open-circuit output
voltage swing ranges from (V+ - 0.6V) to V-.
Input thresholds are both CMOS and TTL compatible.
The inputs of unused drivers can be left unconnected
because 400kΩ pull-up resistors to V
CC
are included
on-chip. Since all drivers invert, the pull-up resistors
force the outputs of unused drivers low. The input
pull-up resistors typically source 10µA; in shutdown
mode, they are disconnected to reduce supply current.
When in low-power shutdown mode, the driver outputs
are turned off and their leakage current is less than
1µA, even if the transmitter output is back-driven with
voltages up to ±15V.
RS-232 Receivers
The receivers convert the RS-232 signals to
CMOS-logic levels. They invert, to match the inversion
of RS-232 drivers. The guaranteed receiver input
thresholds are significantly tighter than the ±3V
thresholds required by the EIA/TIA-232E specification,
V+
GND
MAX214
1µF
V
CC
1µF
Rx
Tx
1µF
C1+
C1-
C2+
C2-
+5V
+5.5V
T
OUT
R
OUT
400k
5k
I
SHDN
0V OR +5.5V
DRIVE
1µF
1µF
3k
+5.5V
R
IN
T
IN
CAPACITORS MAY BE 
POLARIZED OR UNPOLARIZED
DTE/DCE
+5.5V
V-
+5.5V
+5.5V
SHDN
HI-Z
Figure 1. MAX214 Shutdown-Current Test Circuit
C1-
I
L
- R
L
-
V+
S1
V -
S2 S5 S6
C1 C3 C2
I
L
+ R
L
+
S3 S4 S7 S8
C4
C1+
GND
GND
V
CC
V
CC
C2-
C2+
120kHz
Figure 2. Charge-Pump Diagram