MAX3222EEAP+ Maxim Integrated Products, MAX3222EEAP+ Datasheet - Page 10

• Manufacturer Part Number: MAX3222EEAP+
• Description: IC TXRX RS-232 LP 20-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3222EEAP+

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Propagation Delay Time Ns: 0.15 us
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 0.3 mA
• Operating Temperature Range: - 40 C to + 85 C
• Data Rate: 250 Kbps
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The complementary outputs on the MAX3237E/
MAX3241E (R_OUTB) are always active, regardless of the
state of EN or SHDN. This allows the device to be used
for ring indicator applications without forward biasing
other devices connected to the receiver outputs. This is
ideal for systems where V
to accommodate peripherals such as UARTs (Figure 2).
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
Figure 2. Detection of RS-232 Activity when the UART and
Interface are Shut Down; Comparison of MAX3237E/MAX3241E
(b) with Previous Transceivers (a)
10
b) NEW MAX3237E/MAX3241E: EN SHUTS DOWN RECEIVER OUTPUTS
B (EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO UART IN SHUTDOWN.
B B OUTPUTS INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH.
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM
A A ACTIVE RECEIVER OUTPUT IN SHUTDOWN.
V
V
CC
CC
______________________________________________________________________________________
UART
UART
GND
GND
PROTECTION
PROTECTION
TO
μP
DIODE
DIODE
TRANSITION
DETECTOR
LOGIC
Rx
Tx
Rx
Tx
SHDN = GND
THREE-STATED
V
SHDN = GND
CC
V
EN = V
R1OUTB
CC
R1OUT
CC
T1IN
CC
drops to zero in shutdown
MAX3237E/MAX3241E
PREVIOUS
RS-232
5kΩ
5kΩ
R1IN
T1OUT
Supply current falls to less than 1µA in shutdown mode
(SHDN = low). The MAX3237E’s supply current falls
to10nA (typ) when all receiver inputs are in the invalid
range (-0.3V < R_IN < +0.3V). When shut down, the
device’s charge pumps are shut off, V+ is pulled down
to V
puts are disabled (high impedance). The time required
to recover from shutdown is typically 100µs, as shown
in Figure 3. Connect SHDN to V
not used. SHDN has no effect on R_OUT or R_OUTB
(MAX3237E/MAX3241E).
As with all Maxim devices, ESD-protection structures
are incorporated to protect against electrostatic dis-
charges encountered during handling and assembly.
The driver outputs and receiver inputs of the
MAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E
have extra protection against static electricity. Maxim’s
engineers have developed state-of-the-art structures to
protect these pins against ESD of ±15kV without damage.
The ESD structures withstand high ESD in all states:
normal operation, shutdown, and powered down. After
an ESD event, Maxim’s E versions keep working without
latchup, whereas competing RS-232 products can latch
and must be powered down to remove latchup.
Furthermore, the MAX3237E logic I/O pins also have
±15kV ESD protection. Protecting the logic I/O pins to
±15kV makes the MAX3237E ideal for data cable
applications.
Figure 3. Transmitter Outputs Recovering from Shutdown or
Powering Up
5V/div
2V/div
CC
0
0
, V- is pulled to ground, and the transmitter out-
V
C1–C4 = 0.1μF
CC
= 3.3V
MAX3222E/MAX3237E/MAX3241E/
MAX3246E Shutdown Mode
40μs/div
±15kV ESD Protection
CC
if shutdown mode is
T2OUT
SHDN
T1OUT