ICL3232ECBN Intersil, ICL3232ECBN Datasheet - Page 18

• Manufacturer Part Number: ICL3232ECBN
• Description: IC TXRX RS-232 3-5.5V ESD 16SOIC
• Manufacturer: Intersil
• Type: Transceiverr

Specifications of ICL3232ECBN

• Number Of Drivers/receivers: 2/2
• Protocol: RS232
• Voltage - Supply: 3 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Devices with the automatic power-down feature include
an INVALID output signal, which switches low to indicate
that invalid levels have persisted on all of the receiver
inputs for more than 30µs (see Figure 7). INVALID
switches high 1µs after detecting a valid RS-232 level on
a receiver input. INVALID operates in all modes (forced
or automatic power-down, or forced on), so it is also
useful for systems employing manual power-down
circuitry. When automatic power-down is utilized,
INVALID = 0 indicates that the ICL32xxE is in
power-down mode.
The time to recover from automatic power-down mode is
typically 100µs.
Receiver ENABLE Control
(ICL3221E, ICL3222E, ICL3223E, ICL3241E
Only)
Several devices also feature an EN input to control the
receiver outputs. Driving EN high disables all the
inverting (standard) receiver outputs placing them in a
high impedance state. This is useful to eliminate supply
current, due to a receiver output forward biasing the
protection diode, when driving the input of a powered
down (V
input has no effect on transmitter nor monitor (R
outputs.
Capacitor Selection
The charge pumps require 0.1µF capacitors for 3.3V
operation. For other supply voltages refer to Table 3 for
capacitor values. Do not use values smaller than those
listed in Table 3. Increasing the capacitor values (by a
factor of 2) reduces ripple on the transmitter outputs and
slightly reduces power consumption. C
be increased without increasing C
not increase C
maintain the proper ratios (C
When using minimum required capacitor values, make
sure that capacitor values do not degrade excessively
with temperature. If in doubt, use capacitors with a
FIGURE 7. AUTOMATIC POWER-DOWN AND
TRANSMITTER
OUTPUT
INVALID
RECEIVER
OUTPUTS
INPUTS
CC
ICL3221E, ICL3222E, ICL3223E, ICL3232E, ICL3241E, ICL3243E
V
V
CC
CC
V+
= GND) peripheral (see Figure 2). The enable
V-
0
INVALID TIMING DIAGRAMS
0
1
AUTOPWDN
without also increasing C
t
INVL
18
1
to the other capacitors).
1
’s value, however, do
t
INVH
2
, C
2
, C
3
, and C
3
PWR UP
, and C
}
INVALID
REGION
OUTB
4
can
4
)
to
larger nominal value. The capacitor’s equivalent series
resistance (ESR) usually rises at low temperatures and it
influences the amount of ripple on V+ and V-.
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
possible to the IC.
Operation Down to 2.7V
ICL32xxE transmitter outputs meet RS-562 levels
(±3.7V), at full data rate, with V
RS-562 levels typically ensure interoperability with
RS-232 devices.
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..
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
FIGURE 8. TRANSMITTER OUTPUTS WHEN EXITING
5V/DIV
2V/DIV
3.0 to 3.6
4.5 to 5.5
3.0 to 5.5
TABLE 3. REQUIRED CAPACITOR VALUES
V
(V)
V
C1 - C4 = 0.1µF
CC
CC
1
. Connect the bypass capacitor as close as
= +3.3V
POWER-DOWN
FORCEOFF
TIME (20µs/DIV)
0.047
(µF)
0.1
0.1
C
1
CC
CC
as low as 2.7V.
to ground with a
C
2
February 22, 2010
, C
(µF)
0.33
0.47
0.1
3
T1
T2
, C
FN4910.21
4