MAX200–MAX209/
MAX211/MAX213
+5V, RS-232 Transceivers
with 0.1μF External Capacitors
Detailed Description
I
SHDN
+5.5V
0.1µF
C1+
0.1µF
C1-
C2+
0.1µF
C2-
V
CC
0.1µF
The MAX200–MAX209/MAX211/MAX213 consist of three
sections: charge-pump voltage converters, drivers (trans-
mitters), and receivers. Each section is described in detail.
V+
MAX200
MAX205
MAX206
MAX211
MAX213
+5.5V
+5V to ±10V Dual Charge-Pump
Voltage Converter
0.1µF
V-
400kΩ
+5.5V
T
IN
T1 T0 T5
T
OUT
3kΩ
R
OUT
0V OR +5.5V
DRIVE
+5.5V (0)
EN
(EN)
SHDN
(SHDN)
GND
R1 T0 R5
R
IN
5kΩ
The +5V to ±10V conversion is performed by two charge-
pump voltage converters (Figure 4). The first uses capaci-
tor C1 to double +5V to +10V, storing +10V on the V+
output filter capacitor, C3. The second chargepump volt-
age converter uses capacitor C2 to invert +10V to -10V,
storing -10V on the V- output filter capacitor, C4.
The MAX201 and MAX209 include only the V+ to Vcharge
pump, and are intended for applications that have a V
CC
= +5V supply and a V+ supply in the +9V to +13.2V range.
In shutdown mode, V+ is internally connected to V
CC
by
a 1kΩ pulldown resistor and V- is internally connected to
ground by a 1kΩ pullup resistor.
+5.5V
RS-232 Drivers
NOTE 1:
( ) ARE FOR MAX213.
NOTE 2:
CAPACITORS CAN BE POLARIZED OR UNPOLARIZED.
Figure 1. Shutdown Current Test Circuit
EN
INPUT +3V
0V
OUTPUT ENABLE TIME
+3.5V
RECEIVER
OUTPUT
C
L
= 150pF
+0.8V
+3V
When V
CC
= +5V, the typical driver output-voltage swing
is ±8V when loaded with a nominal 5kΩ RS-232 receiver.
The output swing is guaranteed to meet the EIA/TIA-232E
and V.28 specifications, which call for ±5V minimum out-
put levels under worst-case conditions. These include
a minimum 3kΩ load, V
CC
= +4.5V, and the maximum
operating temperature. 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 since
400kΩ pullup resistors to V
CC
are included onchip. Since
all drivers invert, the pullup resistors force the outputs of
unused drivers low. The input pullup resistors typically
source 15μA; therefore, the driver inputs should be driven
high or open circuited to minimize power-supply current
in shutdown mode.
When in low-power shutdown mode, the driver outputs
are turned off and their leakage current is less than 1mA,
even if the transmitter output is backdriven between 0V
and (V
CC
+ 6V). Below -0.5V, the transmitter output is
diode clamped to ground with a 1kΩ series impedance.
The transmitter output is also zener clamped to approxi-
mately (V
CC
+ 6V), with a 1kΩ series impedance.
EN
INPUT
0V
OUTPUT ENABLE TIME
V
OH
V
OL
V
OH
- 0.1V
R
L
= 1kΩ
V
OL
+ 0.1V
RECEIVER
OUTPUTS
+ 2.5V
NOTE:
POLARITY OF
EN
IS REVERSED FOR THE MAX213.
Figure 2. Receiver Output Enable and Disable Timing
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