MAX214EWI Ver la hoja de datos (PDF) - Maxim Integrated
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MAX214EWI Datasheet PDF : 12 Pages
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Programmable DTE/DCE,
+5V RS-232 Transceiver
+5.5V
ISHDN
1µF
1µF
C1+
VCC
V+
1µF
C1-
1µF
MAX214 V-
C2+ +5V
1µF
C2- 400k
+5.5V
TIN
Tx
TOUT
ROUT
Rx
3k
RIN +5.5V
0V OR +5.5V
DRIVE
DTE/DCE
5k
+5.5V
HI-Z
+5.5V
SHDN
GND
CAPACITORS MAY BE
POLARIZED OR UNPOLARIZED
Figure 1. MAX214 Shutdown-Current Test Circuit
RS-232 Drivers
With VCC = 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,
VCC = 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 VCC 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,
S1
VCC
S3
GND
C1+ S2
C1
S4
C1-
120kHz
V+
S5
C3 IL +
RL +
S7
VCC
C2+ S6
C2
S8
C2-
C4 IL -
GND
RL -
V-
Figure 2. Charge-Pump Diagram
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