MAX3238CAI+T Maxim Integrated Products, MAX3238CAI+T Datasheet - Page 9

• Manufacturer Part Number: MAX3238CAI+T
• Description: IC TXRX RS-232 TRUE 28-SSOP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of MAX3238CAI+T

• Number Of Drivers/receivers: 5/3
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

In applications that are sensitive to power-supply noise,
decouple V
value as capacitors C2, C3, and C4. Connect the
bypass capacitor as close to the IC as possible.
Figure 5 shows two transmitter outputs when exiting
shutdown mode. As they become active, the outputs
are shown going to opposite RS-232 levels (one trans-
mitter input is high, the other is low). Each transmitter is
loaded with 3k
outputs display no ringing or undesirable transients as
they come out of shutdown. Note that the transmitters
are enabled only when the magnitude of V- exceeds
approximately 3V.
The MAX3238 maintains the RS-232 ±5.0V minimum
transmitter output voltage even at high data rates.
Figure 6 shows a transmitter loopback test circuit.
Figure 7 shows a loopback test result at 120kbps, and
Figure 8 shows the same test at 250kbps. For Figure 7,
all transmitters were driven simultaneously at 120kbps
into RS-232 loads in parallel with 1000pF. For Figure 8,
a single transmitter was driven at 250kbps, and all
transmitters were loaded with an RS-232 receiver in
parallel with 1000pF.
Figure 5. Transmitter Outputs when Exiting Shutdown or
Powering Up
2V/div
2V/div
V
C1 - C4 = 0.1 F
CC
RS-232 Transceiver with AutoShutdown Plus
= 3.3V
CC
to ground with a capacitor of the same
in parallel with 2500pF. The transmitter
+3.0V to +5.5V, 1µA, up to 250kbps, True
_______________________________________________________________________________________
Transmitter Outputs when
Power-Supply Decoupling
5 s/div
Exiting Shutdown
High Data Rates
FORCEON =
FORCEOFF
T2OUT
T1OUT
The MAX3238 can directly interface with various 5V-
logic families, including ACT and HCT CMOS. See
Table 4 for more information on possible combinations
of interconnections.
Table 4. Logic Family Compatibility with
Various Supply Voltages
Figure 6. Loopback Test Circuit
VOLTAGE
SYSTEM
POWER-
SUPPLY
*C3 CAN BE RETURNED TO V
3.3
(V)
5
5
C1
C2
V
V
CC
CC
VOLTAGE
SUPPLY
V
FORCEOFF
T_ IN
R_ OUT
FORCEON
(V)
3.3
3.3
C1+
C1-
C2+
C2-
CC
5
CC
OR GND.
Compatible with all CMOS families.
Compatible with all TTL and CMOS
families.
Compatible with ACT and HCT
CMOS, and with AC, HC, or
CD4000 CMOS.
MAX3238
GND
V
CC
with 3V and 5V Logic
COMPATIBILITY
T_ OUT
5k
Interconnection
R_ IN
V+
V-
C3*
C4
1000pF
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