MAX338 Datasheet, PDF (8/12 Pages) Maxim Integrated Products – ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver

±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3kΩ in parallel with 2500pF.
The transmitter outputs display no ringing or undesir-
able 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 MAX3385E maintains the RS-232 ±5.0V minimum
transmitter output voltage even at high data rates.
Figure 6 shows a transmitter loopback test circuit.
Figure 7 shows a loopback test result at 120kbps, and
Figure 8 shows the same test at 250kbps. For Figure 7,
all transmitters were driven simultaneously at 120kbps
into RS-232 loads in parallel with 1000pF. For Figure 8,
a single transmitter was driven at 250kbps, and all
transmitters were loaded with an RS-232 receiver in
parallel with 1000pF.
Interconnection with 3V and 5V Logic
The MAX3385E can directly interface with various 5V
logic families, including ACT and HCT CMOS. See
Table 3 for more information on possible combinations
of interconnections.
V_CC
0.1µF
C1+
C1
C1-
V_CC
V+
C2+
MAX3385E
V-
C2
C2-
T_ IN
T_ OUT
R_ OUT
R_ IN
5k
V_CC
SHDN
GND
Figure 6. Loopback Test Circuit
C3
C4
1000pF
T1IN
5V/div
T1OUT
5V/div
R1OUT
V_CC = 3.3V
C1–C4 = 0.1µF
2µs/div
5V/div
Figure 7. MAX3385E Loopback Test Result at 120kbps
T1IN
T1OUT
5V/div
5V/div
R1OUT
V_CC = 3.3V
C1–C4 = 0.1µF
2µs/div
5V/div
Figure 8. MAX3385E Loopback Test Result at 250kbps
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