MAX3224EEUP+ Maxim Integrated Products, MAX3224EEUP+ Datasheet - Page 8

• Manufacturer Part Number: MAX3224EEUP+
• Description: IC TXRX RS-232 W/SHTDWN 20-TSSOP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3224EEUP+

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1µA Supply Current, 1Mbps, 3.0V to 5.5V,
RS-232 Transceivers with AutoShutdown Plus
The transmitters are inverting level translators that
convert CMOS-logic levels to 5.0V EIA/TIA-232 levels.
The MAX3224/MAX3226/MAX3244 guarantee a
250kbps data rate (1Mbps for the MAX3225/MAX3227/
MAX3245) with worst-case loads of 3kΩ in parallel with
1000pF, providing compatibility with PC-to-PC com-
munication software (such as LapLink
can be paralleled to drive multiple receivers. Figure 1
shows a complete system connection.
When FORCEOFF is driven to ground or when the Auto-
Shutdown Plus circuitry senses that all receiver and
transmitter inputs are inactive for more than 30sec, the
transmitters are disabled and the outputs go into a high-
impedance state. When powered off or shut down, the
outputs can be driven to ±12V. The transmitter inputs
do not have pull-up resistors. Connect unused inputs to
GND or V
Figure 1. Interface Under Control of PMU
LapLink is a registered trademark of Laplink Software, Inc.
8
POWER-
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
CPU
_______________________________________________________________________________________
CC
.
WITH
UART
CHIP
INVALID
FORCEOFF
FORCEON
I/O
RS-232 Transmitters
MAX3244
MAX3245
®
). Transmitters
RS-232
Figure 2. The MAX3244/MAX3245 detect RS-232 activity when
the UART and interface are shut down.
b)
a)
OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE
RECEIVER OUTPUT IN SHUTDOWN.
EXTERNAL DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT
PATH THROUGH THE UART’S PROTECTION DIODE.
V
NEW MAX3244/MAX3245: IN SHUTDOWN, R2OUTB IS USED TO MONITOR
V
CC
CC
UART
GND
GND
UART
TO
μP
PROTECTION
DIODE
PROTECTION
DIODE
Rx
Rx
Tx
Tx
TRANSITION
DETECTOR
LOGIC
SHDN = GND
FORCEOFF = GND
THREE-STATED
V
CC
I
V
R2OUTB
CC
R2OUT
T1IN
I
PREVIOUS
MAX3244
MAX3245
RS-232
5kΩ
5kΩ
R2IN
T1OUT