MAX3224 Maxim, MAX3224 Datasheet - Page 13

• Manufacturer Part Number: MAX3224
• Description: 1A Supply Current / 1Mbps / 3.0V to 5.5V / RS-232 Transceivers with AutoShutdown Plus
• Manufacturer: Maxim

simultaneously at 120kbps into RS-232 loads in parallel
with 1000pF. For Figure 9, a single transmitter was dri-
ven at 250kbps, and all transmitters were loaded with
an RS-232 receiver in parallel with 250pF.
The MAX3225/MAX3227/MAX3245 maintain the RS-232
±5.0V minimum transmitter output voltage at data rates
up to 1Mbps (MegaBaud). Figure 10 shows a loopback
test result with a single transmitter driven at 1Mbps and
all transmitters loaded with an RS-232 receiver in paral-
lel with 250pF.
Figure 8. MAX3224/MAX3226/MAX3244 Loopback Test Result
at 120kbps
Figure 9. MAX3224/MAX3226/MAX3244 Loopback Test Result
at 250kbps
R1OUT
R1OUT
T1OUT
T1OUT
T1IN
T1IN
RS-232 Transceivers with AutoShutdown Plus
V
V
CC
CC
= 3.3V
= 3.3V
1µA Supply Current, 1Mbps, 3.0V to 5.5V,
______________________________________________________________________________________
2 s/div
2 s/div
5V/div
5V/div
5V/div
5V/div
5V/div
5V/div
The MAX3244/MAX3245 are specifically designed to
power serial mice while operating from low-voltage
power supplies. They have been tested with leading
mouse brands from manufacturers such as Microsoft
and Logitech. The MAX3244/MAX3245 successfully
drove all serial mice tested and met their respective
current and voltage requirements. The MAX3244/
MAX3245 dual charge pump ensures the transmitters
will supply at least ±5V during worst-case conditions.
Figure 11a shows the transmitter output voltages under
increasing load current. Figure 11b shows a typical
mouse connection.
Figure 10. MAX3225/MAX3227/MAX3245 Loopback Test
Result at 1Mbps
Figure 11a. MAX324_ Transmitter Output Voltage vs. Load
Current per Transmitter
R1OUT
T1OUT
T1IN
-1
-2
-3
-4
-5
-6
V
6
5
4
3
2
1
0
CC
= 3.3V
0
V
V
CC
CC
1
LOAD CURRENT PER TRANSMITTER (mA)
= 3.0V
2
3
200ns/div
4
5
Mouse Driveability
V
V
6
OUT+
OUT-
7
8
V
V
OUT+
OUT-
9
10
5V/div
5V/div
5V/div
13