ICL3221E INTERSIL [Intersil Corporation], ICL3221E Datasheet - Page 15

• Manufacturer Part Number: ICL3221E
• Manufacturer: INTERSIL [Intersil Corporation]

.
Mouse Driveability
The ICL3241E and ICL3243E have been specifically
designed to power a serial mouse while operating from low
voltage supplies. Figure 9 shows the transmitter output
voltages under increasing load current. The on-chip
switching regulator ensures the transmitters will supply at
least
V+ transmitters, 7.3mA for single V- transmitter). The
Automatic Powerdown feature does not work with a mouse,
so FORCEOFF and FORCEON should be connected to V
High Data Rates
The ICL32xxE maintain the RS-232
transmitter output voltages even at high data rates.
Figure 10 details a transmitter loopback test circuit, and
Figure 11 illustrates the loopback test result at 120kbps. For
this test, all transmitters were simultaneously driving RS-232
loads in parallel with 1000pF, at 120kbps. Figure 12 shows
the loopback results for a single transmitter driving 1000pF
and an RS-232 load at 250kbps. The static transmitters were
also loaded with an RS-232 receiver.
5V/DIV
2V/DIV
FIGURE 9. TRANSMITTER OUTPUT VOLTAGE vs LOAD
FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING
-1
-2
-3
-4
-5
-6
±
6
5
4
3
2
1
0
5V during worst case conditions (15mA for paralleled
0
V
C1 - C4 = 0.1µF
V
CC
CC
1
= +3.3V
POWERDOWN
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
ICL3221E, ICL3222E, ICL3223E, ICL3232E, ICL3241E, ICL3243E
3
ICL3241E, ICL3243E
V
V
OUT
OUT
TIME (20µs/DIV)
4
+
-
15
5
±
6
5V minimum
7
OUT+
V
V
OUT
OUT
8
CURRENT)
+
-
T1
T2
9
CC
10
.
.
5V/DIV
R1
5V/DIV
R1
T1
T1
FIGURE 10. TRANSMITTER LOOPBACK TEST CIRCUIT
T1
T1
OUT
OUT
OUT
OUT
IN
IN
V
V
C
C
CC
CC
1
2
V
C1 - C4 = 0.1µF
V
C1 - C4 = 0.1µF
+
+
FIGURE 11. LOOPBACK TEST AT 120kbps
FIGURE 12. LOOPBACK TEST AT 250kbps
CC
CC
= +3.3V
= +3.3V
0.1µF
C1+
C1-
C2+
C2-
T
R
EN
SHDN OR
FORCEOFF
IN
OUT
+
ICL32xxE
V
CC
2µs/DIV
5µs/DIV
T
OUT
R
5K
V+
V-
IN
June 22, 2007
+
+
C
C
1000pF
FN4910.19
3
4