MAX3243ECWI Maxim, MAX3243ECWI Datasheet - Page 8

• Manufacturer Part Number: MAX3243ECWI
• Description: 15kV ESD-Protected / 1A / 3.0V to 5.5V / 250kbps / RS-232 Transceivers with AutoShutdown
• Manufacturer: Maxim

±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps,
RS-232 Transceivers with AutoShutdown
Table 1. Output Control Truth Table
8
X = Don’t Care
Figure 3a. MAX32_ _E Entering 1µA Supply Mode via
AutoShutdown
The MAX3221E/MAX3223E/MAX3243E feature an
INVALID output that is enabled low when no valid RS-232
signal levels have been detected on all receiver inputs.
INVALID is functional in any mode (Figures 3 and 5).
The MAX3221E/MAX3223E/MAX3243E achieve a 1µA
supply current with Maxim’s new AutoShutdown fea-
ture, which operates when FORCEON is low and
FORCEOFF is high. When these devices sense no valid
+0.3V
-0.3V
R_IN
Shutdown
(Forced Off)
Normal Operation
(Forced On)
Normal Operation
(AutoShutdown)
Shutdown
(AutoShutdown)
* TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1 A IF
_______________________________________________________________________________________
ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30 s.
OPERATION
STATUS
FORCEON
X
X
1
1
0
0
0
0
FORCEOFF
COUNTER
0
0
1
1
1
1
1
1
30µs
AutoShutdown
R
AND TRANSMITTERS
POWER SUPPLY
(MAX3221E/
INVALID
MAX3223E)
TO MAX32_ _E
EN
0
1
0
1
0
1
0
1
RECEIVER
LEVEL
VALID
Yes
Yes
signal levels on all receiver inputs for 30µs, the on-
board charge pump and drivers are shut off, reducing
supply current to 1µA. This occurs if the RS-232 cable
is disconnected or the connected peripheral transmit-
ters are turned off. The device turns on again when a
valid level is applied to any RS-232 receiver input. As a
result, the system saves power without changes to the
existing BIOS or operating system.
Figure 3b. MAX32__E with Transmitters Enabled Using
AutoShutdown
No
No
X
X
X
X
+2.7V
-2.7V
R_IN
* TRANSMITTERS ARE ENABLED IF:
ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V.
ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30 s.
T_OUT
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
(MAX3221E/
MAX3223E)
R_OUT
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
(MAX3243E)
R_OUT
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
COUNTER
30µs
R
(MAX3243E)
POWER SUPPLY
INVALID
R2OUTB
TO MAX32_ _E
Active
Active
Active
Active
Active
Active
Active
Active