Datasheet

MAX3322E/MAX3323E
Power-Supply Decoupling
In most circumstances, a 0.1µF bypass capacitor is ade-
quate. In applications sensitive to power-supply noise,
decouple V
CC
to ground with a capacitor of the same
value as charge-pump capacitor C1. Connect bypass
capacitors as close to the IC as possible.
High Data Rates
The MAX3322E/MAX3323E maintain the RS-232 ±5.0V
minimum transmitter output voltage even at high data
rates. Figure 10 shows a transmitter loopback test cir-
cuit. Figure 11 shows a loopback test result at
125kbps, and Figure 12 shows the same test at
250kbps. For Figure 11, all transmitters were driven
simultaneously at 125kbps into RS-232 loads in parallel
with 1000pF. For Figure 12, a single transmitter was dri-
ven at 250kbps, and all transmitters were loaded with
an RS-232 receiver in parallel with 1000pF.
Interconnection with 3V and 5V Logic
The MAX3322E/MAX3323E can directly interface with
various 5V logic families, including ACT and HCT
CMOS. The logic voltage power-supply pin V
L
sets the
output voltage level of the receivers and the input
thresholds of the transmitters.
±15kV ESD-Protected, RS-232 Transceivers for
Multidrop Applications
10 ______________________________________________________________________________________
MAX3323E
R_OUT
GND
T_IN
C2-
5
C2+
4
C1-
3
C1+
1
R_IN
5kΩ
T_OUT
V-
6
V+
2
V
CC
SHDN
C4
0.1µF
1000pF
C3
0.1µF
C1
0.1µF
0.1µF
C2
0.1µF
+3.3V
Figure 10. Loopback Test Circuit
MAX3322E fig11
2µs/div
T1IN
5V/div
T1OUT
5V/div
R1OUT
5V/div
V
CC
= 3.3V
Figure 11. Loopback Test Results at 125kbps
MAX3322E fig12
1µs/div
T1IN
5V/div
T1OUT
5V/div
R1OUT
5V/div
V
CC
= 3.3V
Figure 12. Loopback Test Results at 250kbps