Datasheet

MAX3233E/MAX3235E
±15kV ESD-Protected, 1µA, 250kbps, 3.3V/5V, Dual
RS-232 Transceivers with Internal Capacitors
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Each transmitter is loaded with 3kΩ in parallel with
1000pF. The transmitter outputs display no ringing or
undesirable transients as they come out of shutdown.
Note that the transmitters are enabled only when the
magnitude of V- exceeds approximately -3V.
High Data Rates
The MAX3233E/MAX3235E maintain the RS-232 ±5.0V
minimum transmitter output voltage even at high data
rates. Figure 8 shows a transmitter loopback test cir-
cuit. Figure 9 shows a loopback test result at 120kbps,
and Figure 10 shows the same test at 250kbps. For
Figure 9, all transmitters were driven simultaneously at
120kbps into RS-232 loads in parallel with 1000pF. For
Figure 10, a single transmitter was driven at 250kbps,
and all transmitters were loaded with an RS-232 receiv-
er in parallel with 250pF.
Interconnection with 3V and 5V Logic
The MAX3233E/MAX3235E can directly interface with
various 5V logic families, including ACT and HCT
CMOS. See Table 3 for more information on possible
combinations of interconnections.
Figure 9. Loopback Test Result at 120kbps
2µs/div
T1IN
T1OUT
R1OUT
5V/div
5V/div
5V/div
V
CC
= 3.3V (MAX3233E), V
CC
= 5.0V (MAX3235E)
Figure 10. Loopback Test Result at 250kbps
2µs/div
T1IN
T1OUT
R1OUT
5V/div
5V/div
5V/div
V
CC
= 3.3V (MAX3233E), V
CC
= 5.0V (MAX3235E)
COMPATIBILITY
Compatible with all CMOS families
Compatible with ACT and HCT CMOS, and
with AC, HC, or CD4000 CMOS
Compatible with all TTL and CMOS families
DEVICE
V
CC
SUPPLY VOLTAGE
(V)
MAX3233E 3.3
MAX3233E 3.3
LOGIC POWER-SUPPLY
VOLTAGE
(V)
3.3
5
MAX3235E 53.3/5
Table 3. Logic Family Compatibility with Various Supply Voltages