MAX3232CSE Maxim Integrated Products, MAX3232CSE Datasheet - Page 8

• Manufacturer Part Number: MAX3232CSE
• Description: IC TXRX RS232 1MBPS LP 16-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3232CSE

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Case: SOP
• Dc: 00+
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Q1175588

3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232
Transceivers Using Four 0.1µF External Capacitors
Figure 2. Detection of RS-232 Activity when the UART and
Interface are Shut Down; Comparison of MAX3237/MAX3241
(b) with Previous Transceivers (a).
8
b) NEW MAX3237/MAX3241: EN SHUTS DOWN RECEIVER OUTPUTS (EXCEPT FOR
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM
B OUTPUTS), SO NO CURRENT FLOWS TO UART IN SHUTDOWN. B OUTPUTS
INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH.
ACTIVE RECEIVER OUTPUT IN SHUTDOWN.
_______________________________________________________________________________________
V
V
PROTECTION
PROTECTION
CC
CC
UART
UART
GND
GND
DIODE
DIODE
µP
TO
Rx
Rx
Tx
Tx
TRANSITION
DETECTOR
LOGIC
SHDN = GND
V
SHDN = GND
CC
V
EN = V
R1OUTB
CC
R1OUT
T1IN
CC
PREVIOUS
MAX3237
MAX3241
RS-232
5kΩ
5kΩ
R1IN
T1OUT
The receivers convert RS-232 signals to CMOS-logic out-
put levels. The MAX3222/MAX3237/MAX3241 receivers
have inverting three-state outputs. In shutdown, the
receivers can be active or inactive (Table 1).
The complementary outputs on the MAX3237 (R1OUTB)
and the MAX3241 (R1OUTB, R2OUTB) are always active,
regardless of the state of EN or SHDN. This allows for
Ring Indicator applications without forward biasing other
devices connected to the receiver outputs. This is ideal
for systems where V
accommodate peripherals, such as UARTs (Figure 2).
Supply current falls to less than 1µA in shutdown mode
(SHDN = low). When shut down, the device’s charge
pumps are turned off, V+ is pulled down to V
pulled to ground, and the transmitter outputs are dis-
abled (high impedance). The time required to exit shut-
down is typically 100µs, as shown in Figure 3. Connect
SHDN to V
has no effect on R_OUT or R_OUTB.
The inverting receiver outputs (R_OUT) are put into a
high-impedance state when EN is high. The complemen-
tary outputs R1OUTB and R2OUTB are always active,
regardless of the state of EN and SHDN (Table 1). EN
has no effect on T_OUT.
The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. The charge pump requires 0.1µF capaci-
tors for 3.3V operation. For other supply voltages, refer to
Table 2 for required capacitor values. Do not use values
lower than those listed in Table 2. Increasing the capaci-
tor values (e.g., by a factor of 2) reduces ripple on the
transmitter outputs and slightly reduces power consump-
tion. C2, C3, and C4 can be increased without changing
C1’s value. However, do not increase C1 without also
increasing the values of C2, C3, and C4, to maintain the
proper ratios (C1 to the other capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade exces-
sively with temperature. If in doubt, use capacitors with a
higher nominal value. The capacitor’s equivalent series
resistance (ESR), which usually rises at low tempera-
tures, influences the amount of ripple on V+ and V-.
__________Applications Information
CC
if the shutdown mode is not used. SHDN
MAX3222/MAX3237/MAX3241
MAX3222/MAX3237/MAX3241
CC
is set to 0V in shutdown to
Capacitor Selection
RS-232 Receivers
Shutdown Mode
Enable Control
CC
, V- is