+2.35V to +5.5V, 1µA, 2Tx/2Rx RS-232 Transceivers
with 15ꢀV ESD-ꢁrotected I/O and Logic ꢁins
For Figure 9 and Figure 10, a single transmitter was dri-
ven at 460kbps, and all transmitters were loaded with
an RS-232 receiver in parallel with 1000pF.
5V
T1IN
5V/div
0
Data Cable Applications
The MAX3380E/MAX3381Es’ 15kV ESD protection on
both the RS-232 I/Os as well as the logic I/Os makes
them ideal candidates for data cable applications. A
data cable is both an electrical connection and a level
translator, allowing ultra-miniaturization of cell phones
and other small portable devices.
5V
T1OUT
5V/div
0
-5V
5V
0
R1OUT
5V/div
Previous data cable approaches suffered from com-
plexity due to the required protection circuits on both
the logic side of the cable, as well as on the RS-232
connections. The example shown in Figure 11 shows
the ease of using the MAX3380E/MAX3381E in data
cable applications. For best performance, keep the
logic level lines short and use the RS-232 level lines to
span any distance.
1µs/div
= V = +4.2V, C1 = 0.1µF, C2 = C3 = C4 = 1µF,
V
C
CC
L
= 1000pF
LOAD
Figure 9. Loopback Test Results at 460kbps (V
= +4.2V)
CC
V
CC
2V
C5
T1IN
2V/div
0
V
V
L
CC
5V
C1+
V+
V-
C3
C4
T1OUT
5V/div
C1
0
C1-
C2+
-5V
MAX3380E
MAX3381E
2V
0
R1OUT
2V/div
C2
C2-
TIME (1µs/div)
T_ OUT
T_ IN
V
CC
= V = +2.5V, C1 = 0.1µF, C2 = C3 = C4 = 1µF,
L
C
= 1000pF
LOAD
R_ IN
R_ OUT
Figure 10. Loopback Test Results at 460kbps (V
= +2.5V)
CC
5kΩ
FORCEON
FORCEOFF
1000pF
V
CC
GND
Figure 8. Loopback Test Circuit
±- ______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
