MAX3222EC/D MAXIM [Maxim Integrated Products], MAX3222EC/D Datasheet - Page 13

• Manufacturer Part Number: MAX3222EC/D
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 3 shows two transmitter outputs recovering from
shutdown mode. As they become active, the two trans-
mitter outputs are shown going to opposite RS-232 levels
(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
Figure 7. Loopback Test Circuit
Figure 8. MAX3241E Loopback Test Result at 120kbps
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
R1OUT
T1OUT
T1IN
C1
C2
V
CC
0.1µF
Transmitter Outputs Recovering
C1+
C1-
C2+
C2-
T_ IN
R_ OUT
V
C1–C4 = 0.1µF
CC
= 3.3V
______________________________________________________________________________________
MAX3222E
MAX3232E
MAX3237E
MAX3241E
MAX3246E
GND
2µs/div
V
CC
Up to 1Mbps, True RS-232 Transceivers
T_ OUT
5kΩ
R_ IN
V+
V-
from Shutdown
C3
C4
1000pF
5V/div
5V/div
5V/div
the transmitters are enabled only when the magnitude
of V- exceeds approximately -3.0V.
The MAX3241E is designed to power serial mice while
operating from low-voltage power supplies. It has
been tested with leading mouse brands from manu-
facturers such as Microsoft and Logitech. The
MAX3241E successfully drove all serial mice tested
and met their current and voltage requirements.
Figure 9. MAX3241E Loopback Test Result at 250kbps
Figure 10. MAX3237E Loopback Test Result at 1000kbps
(MBAUD = V
R1OUT
T1OUT
+5V
+5V
+5V
-5V
T1IN
0
0
0
V
CC
CC
V
C1–C4 = 0.1µF
= 3.3V, C1–C4 = 0.1µF
CC
)
= 3.3V
400ns/div
2µs/div
Mouse Drivability
T_IN
T_OUT
5kΩ + 250pF
R_OUT
5V/div
5V/div
5V/div
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