MAX202E–MAX213E, MAX232E/MAX241E
±±15kV ESD-Potected,V+1kVRED232VTPansceivePsV
k+VandVkDVasV-owePVEupplies
A small amount oꢁ power can be drawn ꢁrom V+ and V-,
__________ApplicationsVInfoPꢁation
CapacitoPVEelection
The capacitor type used ꢁor C1ꢃC4 is not critical ꢁor
proper operation. The MAX202E, MAX206ꢃMAX208E,
MAX211E, and MAX213E require 0.1ꢄµ capacitors,
and the MAX232E and MAX241E require 1ꢄµ
capacitors, although in all cases capacitors up to 10ꢄµ
can be used without harm. Ceramic, aluminum-
electrolytic, or tantalum capacitors are suggested ꢁor
the 1ꢄµ capacitors, and ceramic dielectrics are
suggested ꢁor the 0.1ꢄµ capacitors. When using the
minimum recommended capacitor values, make sure
the capacitance value does not degrade excessively
as the operating temperature varies. Iꢁ in doubt, use
capacitors with a larger (e.g., 2x) nominal value. The
capacitors’ eꢁꢁective series resistance (ESR), which
usually rises at low temperatures, inꢁluences the
amount oꢁ ripple on V+ and V-.
although this will reduce both driver output swing and
noise margins. Increasing the value oꢁ the charge-pump
capacitors (up to 10ꢄµ) helps maintain perꢁormance
when power is drawn ꢁrom V+ or V-.
SPivingVMultipleVReceivePs
Each transmitter is designed to drive a single receiver.
Transmitters can be paralleled to drive multiple
receivers.
SPivePVOutputsVwhenV xitingVEhutdown
The driver outputs display no ringing or undesirable
transients as they come out oꢁ shutdown.
HighVSataVRates
These transceivers maintain the RS-232 5.0V
minimum driver output voltages at data rates oꢁ over
120kbps. µor data rates above 120kbps, reꢁer to the
Transmitter Output Voltage vs. Load Capacitance
graphs in the Typical Operating Characteristics.
Communication at these high rates is easier iꢁ the
capacitive loads on the transmitters are smallꢂ i.e.,
short cables are best.
Use larger capacitors (up to 10ꢄµ) to reduce the output
impedance at V+ and V-. This can be useꢁul when
“stealing” power ꢁrom V+ or ꢁrom V-. The MAX203E and
MAX205E have internal charge-pump capacitors.
Bypass V
to ground with at least 0.1ꢄµ. In
CC
applications sensitive to power-supply noise generated
by the charge pumps, decouple V to ground with a
CC
capacitor the same size as (or larger than) the charge-
pump capacitors (C1ꢃC4).
Table 2. Summary of EIA/TIA-232E, V.28 Specifications
EIA/TIA-232E, V.28
SPECIFICATIONS
PARAMETER
CONDITIONS
0 Level
3kΩ to 7kΩ load
+5V to +15V
Driver Output Voltage
1 Level
3kΩ to 7kΩ load
-5V to -15V
25V
Driver Output Level, Max
Data Rate
No load
3kΩ ≤ R ≤ 7kΩ, C ≤ 2500pµ
Up to 20kbps
+3V to +15V
-3V to -15V
25V
L
L
0 Level
1 Level
Receiver Input Voltage
Receiver Input Level
Instantaneous Slew Rate, Max
3kΩ ≤ R ≤ 7kΩ, C ≤ 2500pµ
30V/ꢄs
L
L
Driver Output Short-Circuit Current, Max
100mA
V.28
EIA/TIA-232E
-2V < V < +2V
1ms or 3ꢀ oꢁ the period
4ꢀ oꢁ the period
300Ω
Transition Rate on Driver Output
Driver Output Resistance
OUT
Maxim Integrated
13
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
