MAX3224E Maxim, MAX3224E Datasheet - Page 7

• Manufacturer Part Number: MAX3224E
• Description: 15kV ESD-Protected / 1A / 1Mbps / 3.0V to 5.5V / RS-232 Transceivers with AutoShutdown Plus
• Manufacturer: Maxim

The MAX3224E–MAX3227E/MAX3244E/MAX3245E’s
internal power supply consists of a regulated dual
charge pump that provides output voltages of +5.5V
(doubling charge pump) and -5.5V (inverting charge
pump), over the +3.0V to +5.5V range. The charge
pump operates in discontinuous mode: if the output
voltages are less than 5.5V, the charge pump is
enabled; if the output voltages exceed 5.5V, the
charge-pump is disabled. Each charge pump requires
a flying capacitor (C1, C2) and a reservoir capacitor
(C3, C4) to generate the V+ and V- supplies.
±15kV ESD-Protected, 1µA, 1Mbps, 3.0V to 5.5V,
______________________________________________________________Pin Description
_______________Detailed Description
MAX3224E
MAX3225E
10, 15
12, 13
8, 17
9, 16
11
14
18
19
20
—
RS-232 Transceivers with AutoShutdown Plus
1
2
3
4
5
6
7
Dual Charge-Pump Voltage Converter
MAX3226E
MAX3227E
PIN
13
10
11
12
14
15
16
—
1
2
3
4
5
6
7
8
9
_______________________________________________________________________________________
MAX3244E
MAX3245E
15–19
12–14
9–11
4–8
28
27
24
21
23
25
26
22
20
—
1
2
3
FORCEOFF
FORCEON
R2OUTB
INVALID
READY
T_OUT
R_OUT
NAME
R_IN
GND
T_IN
C1+
C2+
V
C1-
C2-
V+
V-
CC
Ready to Transmit Output, active-high. READY is enabled high when
V- goes below -4V and the device is ready to transmit.
Positive Terminal of Voltage-Doubler Charge-Pump Capacitor
+5.5V generated by the charge pump
Negative Terminal of Voltage-Doubler Charge-Pump Capacitor
Positive Terminal of Inverting Charge-Pump Capacitor
Negative Terminal of Inverting Charge-Pump Capacitor
-5.5V generated by the charge pump
RS-232 Transmitter Outputs
RS-232 Receiver Inputs
TTL/CMOS Receiver Outputs
Valid Signal Detector Output, active low. A logic high indicates that a valid
RS-232 level is present on a receiver input.
TTL/CMOS Transmitter Inputs
Force-On Input, active high. Drive high to override AutoShutdown Plus,
keeping transmitters and receivers on (FORCEOFF must be high) (Table 1).
Ground
+3.0V to +5.5V Single Supply Voltage
Force-Off Input, active low. Drive low to shut down transmitters, receivers
(except R2OUTB), and charge pump. This overrides AutoShutdown Plus
and FORCEON (Table 1).
TTL/CMOS Noninverting Complementary Receiver Outputs. Always active.
The READY output (MAX3224E–MAX3227E) is low
when the charge pumps are disabled in shutdown
mode. The READY signal asserts high when V- goes
below -4V.
The transmitters are inverting level translators that
convert CMOS-logic levels to 5.0V EIA/TIA-232 levels.
The MAX3224E/MAX3226E/MAX3244E guarantee a
250kbps
M A X 3 2 2 5 E / M A X 3 2 2 7 E /
MAX3245E) with worst-case loads of 3kΩ in parallel with
1000pF, providing compatibility with PC-to-PC com-
LapLink is a trademark of Traveling Software.
data
FUNCTION
rate
RS-232 Transmitters
(1Mbps,
for
the
7