MAX241E Maxim Integrated Products, MAX241E Datasheet - Page 13

• Manufacturer Part Number: MAX241E
• Description: +5V RS-232 Transceivers
• Manufacturer: Maxim Integrated Products

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Table 2. Summary of EIA/TIA-232E, V.28 Specifications
The capacitor type used for C1–C4 is not critical for
proper operation. The MAX202E, MAX206–MAX208E,
MAX211E, and MAX213E require 0.1µF capacitors,
and the MAX232E and MAX241E require 1µF
capacitors, although in all cases capacitors up to 10µF
can be used without harm. Ceramic, aluminum-
electrolytic, or tantalum capacitors are suggested for
the 1µF capacitors, and ceramic dielectrics are
suggested for the 0.1µF capacitors. When using the
minimum recommended capacitor values, make sure
the capacitance value does not degrade excessively
as the operating temperature varies. If in doubt, use
capacitors with a larger (e.g., 2x) nominal value. The
capacitors’ effective series resistance (ESR), which
usually rises at low temperatures, influences the
amount of ripple on V+ and V-.
Use larger capacitors (up to 10µF) to reduce the output
impedance at V+ and V-. This can be useful when
“stealing” power from V+ or from V-. The MAX203E and
MAX205E have internal charge-pump capacitors.
Bypass V
applications sensitive to power-supply noise generated
by the charge pumps, decouple V
capacitor the same size as (or larger than) the charge-
pump capacitors (C1–C4).
__________Applications Information
Driver Output Voltage
Driver Output Level, Max
Data Rate
Receiver Input Voltage
Receiver Input Level
Instantaneous Slew Rate, Max
Driver Output Short-Circuit Current, Max
Transition Rate on Driver Output
Driver Output Resistance
±15kV ESD-Protected, +5V RS-232 Transceivers
CC
to ground with at least 0.1µF. In
______________________________________________________________________________________
PARAMETER
0 Level
1 Level
0 Level
1 Level
Capacitor Selection
CC
to ground with a
3kΩ to 7kΩ load
3kΩ to 7kΩ load
No load
3kΩ ≤ R
3kΩ ≤ R
V.28
EIA/TIA-232E
-2V < V
OUT
L
L
CONDITIONS
≤ 7kΩ, C
A small amount of power can be drawn from V+ and V-,
although this will reduce both driver output swing and
noise margins. Increasing the value of the charge-pump
capacitors (up to 10µF) helps maintain performance
when power is drawn from V+ or V-.
Each transmitter is designed to drive a single receiver.
Transmitters can be paralleled to drive multiple
receivers.
The driver outputs display no ringing or undesirable
transients as they come out of shutdown.
These transceivers maintain the RS-232 ±5.0V
minimum driver output voltages at data rates of over
120kbps. For data rates above 120kbps, refer to the
Transmitter Output Voltage vs. Load Capacitance
graphs in the Typical Operating Characteristics.
Communication at these high rates is easier if the
capacitive loads on the transmitters are small; i.e.,
short cables are best.
≤ 7kΩ, C
< +2V
Driver Outputs when Exiting Shutdown
L
L
≤ 2500pF
≤ 2500pF
V+ and V- as Power Supplies
Driving Multiple Receivers
+5V to +15V
-5V to -15V
±25V
Up to 20kbps
+3V to +15V
-3V to -15V
±25V
30V/µs
100mA
1ms or 3% of the period
4% of the period
300Ω
EIA/TIA-232E, V.28
SPECIFICATIONS
High Data Rates
13