ICL3222 Intersil Corporation, ICL3222 Datasheet - Page 11

• Manufacturer Part Number: ICL3222
• Description: 1?a Supply-current, +3v To +5.5v, 250kbps, Rs-232 Transmitters/receivers
• Manufacturer: Intersil Corporation

Software Controlled (Manual) Powerdown
Most devices in the ICL32XX family provide pins that allow
the user to force the IC into the low power, standby state.
On the ICL3222 and ICL3241, the powerdown control is via
a simple shutdown (SHDN) pin. Driving this pin high enables
normal operation, while driving it low forces the IC into its
powerdown state. Connect SHDN to V
function isn’t needed. Note that all the receiver outputs
remain enabled during shutdown (See Table 2). For the
lowest power consumption during powerdown, the receivers
should also be disabled by driving the EN input high (See
next section, and Figures 2 and 3).
NOTE:
ICL3222, ICL3241
ICL3221, ICL3223
ICL3243
4. Applies only to the ICL3241 and ICL3243.
RECEIVER
PRESENT
SIGNAL
INPUT?
RS-232
N.A.
N.A.
N.A.
N.A.
Yes
Yes
Yes
Yes
Yes
Yes
AT
No
No
No
No
No
No
No
No
No
FORCEOFF
OR SHDN
INPUT
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
ICL3221, ICL3222, ICL3223, ICL3232, ICL3241, ICL3243
FORCEON
INPUT
11
N.A.
N.A.
N.A.
N.A.
H
H
X
X
X
X
H
X
X
L
L
L
L
L
L
TABLE 2. POWERDOWN AND ENABLE LOGIC TRUTH TABLE
INPUT
CC
N.A.
N.A.
N.A.
N.A.
N.A.
EN
H
H
H
H
H
H
H
L
L
L
L
L
L
L
if the powerdown
TRANSMITTER
OUTPUTS
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
Active
Active
Active
Active
RECEIVER
OUTPUTS
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
High-Z
Active
Active
Active
Active
Active
Active
Active
Active
Active
Active
The ICL3221, ICL3223, and ICL3243 utilize a two pin
approach where the FORCEON and FORCEOFF inputs
determine the IC’s mode. For always enabled operation,
FORCEON and FORCEOFF are both strapped high. To
switch between active and powerdown modes, under logic
or software control, only the FORCEOFF input need be
driven. The FORCEON state isn’t critical, as FORCEOFF
dominates over FORCEON. Nevertheless, if strictly manual
control over powerdown is desired, the user must strap
FORCEON high to disable the automatic powerdown
circuitry. ICL3243 inverting (standard) receiver outputs also
disable when the device is in manual powerdown, thereby
eliminating the possible current path through a shutdown
peripheral’s input protection diode (See Figures 2 and 3).
OUTPUTS
(NOTE 4)
R
Active
Active
Active
Active
Active
Active
Active
Active
Active
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
OUTB
OUTPUT
INVALID
N.A.
N.A.
N.A.
N.A.
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
Manual Powerdown
Manual Powerdown w/Rcvr. Disabled
Normal Operation
Normal Operation w/Rcvr. Disabled
Normal Operation
(Auto Powerdown Disabled)
Normal Operation
(Auto Powerdown Enabled)
Powerdown Due to Auto Powerdown
Logic
Manual Powerdown
Manual Powerdown w/Rcvr. Disabled
Manual Powerdown
Manual Powerdown w/Rcvr. Disabled
Normal Operation
(Auto Powerdown Disabled)
Normal Operation
(Auto Powerdown Enabled)
Powerdown Due to Auto Powerdown
Logic
Manual Powerdown
Manual Powerdown
MODE OF OPERATION
March 1, 2006
FN4805.21