MAX3248EEAI-T Maxim Integrated, MAX3248EEAI-T Datasheet - Page 11

• Manufacturer Part Number: MAX3248EEAI-T
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX3238E, MAX3248Er

Figure 7 shows two transmitter outputs when recovering
from shutdown mode. As they become active, the out-
Figure 7. Transmitter Outputs when Recovering from Shutdown
or Powering Up
Figure 8. Loopback Test Circuit
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
5V/div
2V/div
*C3 CAN BE RETURNED TO V
C1
C2
V
V
V
CC
CC
CC
= 3.3V, C1–C4 = 0.1µF, R
with ±15kV ESD-Protected I/O and Logic Pins
FORCEON
FORCEOFF
C1+
C1-
C2+
C2-
T_ IN
R_ OUT
______________________________________________________________________________________
Recovering from Shutdown
CC
Transmitter Outputs when
OR GND.
4µs/div
MAX3238E
MAX3248E
LOAD
GND
V
= 3kΩ, C
CC
LOAD
T_ OUT
5kΩ
R_ IN
= 2500pF
V+
V-
T2OUT
T1OUT
FORCEON =
FORCEOFF
C3*
C4
1000pF
puts are shown going to opposite RS-232 levels (one
transmitter input is high, the other is low). Each trans-
mitter is loaded with 3kΩ in parallel with 2500pF. The
transmitter 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 MAX3238E/MAX3248E maintain the RS-232 ±5.0V
minimum transmitter output voltage even at high data
rates. Figure 8 shows a transmitter loopback test cir-
cuit. Figure 9 shows a loopback test result at 120kbps,
Figure 9. Loopback Test Result at 120kbps
Figure 10. Loopback Test Result at 250kbps
R1OUT
T1OUT
R1OUT
T1OUT
T1IN
T1IN
V
V
CC
CC
= 3.3V, C1–C4 = 0.1µF, C
= 3.3V, C1–C4 = 0.1µF, C
2µs/div
2µs/div
LOAD
LOAD
= 1000pF
= 1000pF
High Data Rates
+5V
+5V
+5V
+5V
+5V
+5V
-5V
-5V
0
0
0
0
0
0
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