ISL4221EIRZ Intersil, ISL4221EIRZ Datasheet - Page 10

• Manufacturer Part Number: ISL4221EIRZ
• Description: IC TXRX 1TX/1RX 3V RS-232 16-QFN
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ISL4221EIRZ

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 2.7 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-VQFN Exposed Pad, 16-HVQFN, 16-SQFN, 16-DHVQFN
• Package: 16QFN EP
• Data Transmission Topology: Point-to-Point
• Interface Standards: ElA/TIA-232|RS-232|V.24|V.28
• Data Rate: 0.5 Mbps
• Function: Line Transmitter/Receiver
• Number Of Transmitters: 1
• Transmitter Signal Type: Single-Ended
• Transmitter Communication Type: RS-232
• Driving Mode: 3-State
• Typical Single Supply Voltage: 3.3|5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Power Supply Decoupling
In most circumstances a 0.1µF bypass capacitor is
adequate. In applications that are particularly sensitive to
power supply noise, decouple V
capacitor of the same value as the charge-pump capacitor C
Connect the bypass capacitor as close as possible to the IC.
Transmitter Outputs when Exiting
Power-down
Figure 8 shows the response of two transmitter outputs
when exiting power-down mode. As they activate, the two
transmitter outputs properly go to opposite RS-232 levels,
with no glitching, ringing, nor undesirable transients. Each
transmitter is loaded with 3kΩ in parallel with 2500pF.
Note that the transmitters enable only when the magnitude
of the supplies exceed approximately 3V.
Operation Down to 2.7V
ISL4221E, ISL4223E and ISL3232E transmitter outputs
meet RS-562 levels (±3.7V), at the full data rate, with V
as low as 2.7V. RS-562 levels typically ensure inter
operability with RS-232 devices.
High Data Rates
The ISL4221E, ISL4223E and ISL3232E maintain the RS-
232 ±5V minimum transmitter output voltages even at high
data rates. Figure 9 details a transmitter loopback test
circuit, and Figure 10 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 11 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 8. TRANSMITTER OUTPUTS WHEN EXITING
V
C1 - C4 = 0.1µF
CC
= +3.3V
FORCEOFF
POWER-DOWN
TIME (20µs/DIV)
10
CC
to ground with a
ISL3232E, ISL4221E, ISL4223E
T1
T2
CC
1
.
5V/DIV
R1
5V/DIV
R1
T1
T1
T1
T1
OUT
OUT
OUT
OUT
FIGURE 9. TRANSMITTER LOOPBACK TEST CIRCUIT
IN
IN
V
V
C
CC
C
CC
1
2
V
C1 - C4 = 0.1µF
V
C1 - C4 = 0.1µF
FIGURE 10. LOOPBACK TEST AT 120kbps
FIGURE 11. LOOPBACK TEST AT 250kbps
CC
+
+
CC
= +3.3V
= +3.3V
0.1µF
C1+
C1-
C2+
C2-
T
R
FORCEON
FORCEOFF
IN
OUT
ISL4221E, ISL4223E
+
TIME (5µs/DIV)
TIME (2µs/DIV)
V
CC
T
OUT
5k
R
V+
V-
IN
+
+
May 13, 2010
1000pF
C
C
3
4
FN6045.6