ISL4244EIR-T Intersil, ISL4244EIR-T Datasheet - Page 13

• Manufacturer Part Number: ISL4244EIR-T
• Description: IC 3DRVR/5RCVR RS232 3V 32-QFN
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ISL4244EIR-T

• Number Of Drivers/receivers: 3/5
• Protocol: RS232
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Mouse Driveability
The ISL424XE are specifically designed to power a serial
mouse while operating from low voltage supplies. Figure 11
shows the transmitter output voltages under increasing load
current. The on-chip switching regulator ensures the
transmitters will supply at least ±5V during worst case
conditions (15mA for paralleled V+ transmitters, 7.3mA for
single V- transmitter).
High Data Rates
The ISL4238E, ISL4244E, ISL4245 maintain the RS-232
±5V minimum transmitter output voltages even at high data
rates. Figure 12 details a transmitter loopback test circuit,
and Figure 13 illustrates the ISL4238E/ISL4244E loopback
test result at 120kbps. For this test, all transmitters were
simultaneously driving RS-232 loads in parallel with 1000pF,
at 120kbps. Figure 14 shows the ISL4238E/ISL4244E
loopback results for a single transmitter driving 1000pF and
an RS-232 load at 250kbps. Figure 15 illustrates the
ISL4245E loopback test result at 250kbps. For this test, all
transmitters were simultaneously driving RS-232 loads in
parallel with 1000pF, at 250kbps. Figure 16 shows the
5V/DIV
2V/DIV
FIGURE 10. TRANSMITTER OUTPUTS WHEN EXITING
FIGURE 11. TRANSMITTER OUTPUT VOLTAGE vs LOAD
-1
-2
-3
-4
-5
-6
6
5
4
3
2
1
0
0
V
C1 to C4 = 0.1µF
V
CC
CC
1
= +3.3V
POWER-DOWN
CURRENT (PER TRANSMITTER, i.e., DOUBLE
CURRENT AXIS FOR TOTAL V
FORCEOFF
LOAD CURRENT PER TRANSMITTER (mA)
V
T1
T2
T3
CC
2
= 3.0V
3
ISL424XE
V
V
OUT
OUT
TIME (20µs/DIV)
4
+
-
13
5
6
7
OUT+
ISL4238E, ISL4244E, ISL4245E
V
V
OUT
OUT
8
CURRENT)
+
-
T2
T1
9
10
ISL4245E loopback results for a single transmitter driving
250pF and an RS-232 load at 1Mbps. The static transmitters
were also loaded with an RS-232 receiver.
FIGURE 13. ISL4238E/ISL4244E LOOPBACK TEST AT 120kbps
5V/DIV.
5V/DIV.
R1
FIGURE 14. ISL4238E/ISL4244E LOOPBACK TEST AT
T1
R1
T1
T1
FIGURE 12. TRANSMITTER LOOPBACK TEST CIRCUIT
OUT
OUT
T1
OUT
OUT
IN
IN
V
V
C
C
CC
CC
1
2
V
C1 to C4 = 0.1µF
V
C1 - C4 = 0.1µF
+
+
CC
CC
= +3.3V
= +3.3V
250kbps (C
0.1µF
C1+
C1-
C2+
C2-
T
R
FORCEON
FORCEOFF
IN
OUT
+
L
= 1000pF)
ISL4238E
ISL4244E
ISL4245
V
CC
5µs/DIV
2µs/DIV.
T
OUT
R
V+
5k
V-
IN
May 13, 2010
+
+
C
C
C
3
4
L
FN8038.5