3225ECPZ View Datasheet(PDF) - Intersil
Part Name
Description
Manufacturer
3225ECPZ Datasheet PDF : 20 Pages
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ICL3225E, ICL3227E, ICL3245E
TABLE 2. POWERDOWN LOGIC TRUTH TABLE
RCVR OR
XMTR
EDGE
WITHIN 30
SEC?
(NOTE 5)
FORCEOFF FORCEON TRANSMITTER RECEIVER ROUTB
INPUT
INPUT
OUTPUTS OUTPUTS OUTPUTS
RS-232
LEVEL
PRESENT
AT
RECEIVER
INPUT?
INVALID
OUTPUT
MODE OF OPERATION
ICL3225E, ICL3227E
NO
H
H
Active
Active
N.A.
No
L
Normal Operation (Enhanced
NO
H
H
Active
Active
N.A.
Yes
H
Auto Powerdown Disabled)
YES
H
L
Active
Active
N.A.
No
L
Normal Operation (Enhanced
YES
H
L
Active
Active
N.A.
Yes
H
Auto Powerdown Enabled)
NO
H
L
High-Z
Active
N.A.
No
L
Powerdown Due to Enhanced
NO
H
L
High-Z
Active
N.A.
Yes
H
Auto Powerdown Logic
X
L
X
High-Z
Active
N.A.
No
L
Manual Powerdown
X
L
X
High-Z
Active
N.A.
Yes
H
ICL322XE - INVALID DRIVING FORCEON AND FORCEOFF (EMULATES AUTOMATIC POWERDOWN)
X
NOTE 6 NOTE 6
Active
Active
N.A.
Yes
H
Normal Operation
X
NOTE 6 NOTE 6
High-Z
Active
N.A.
No
L
Forced Auto Powerdown
ICL3245E
NO
H
H
Active
Active
Active
No
L
Normal Operation (Enhanced
NO
H
H
Active
Active
Active
Yes
H
Auto Powerdown Disabled)
YES
H
L
Active
Active
Active
No
L
Normal Operation (Enhanced
YES
H
L
Active
Active
Active
Yes
H
Auto Powerdown Enabled)
NO
H
L
High-Z
Active
Active
No
L
Powerdown Due to Enhanced
NO
H
L
High-Z
Active
Active
Yes
H
Auto Powerdown Logic
X
L
X
High-Z
High-Z
Active
No
L
Manual Powerdown
X
L
X
High-Z
High-Z
Active
Yes
H
ICL3245E - INVALID DRIVING FORCEON AND FORCEOFF (EMULATES AUTOMATIC POWERDOWN)
X
NOTE 6 NOTE 6
Active
Active
Active
Yes
H
Normal Operation
X
NOTE 6 NOTE 6
High-Z
High-Z
Active
No
L
Forced Auto Powerdown
NOTES:
5. Applies only to the ICL3245E.
6. Input is connected to INVALID Output.
Powerdown Functionality
This 3V family of RS-232 interface devices requires a
nominal supply current of 0.3mA during normal operation
(not in powerdown mode). This is considerably less than the
5mA to 11mA current required of 5V RS-232 devices. The
already low current requirement drops significantly when the
device enters powerdown mode. In powerdown, supply
current drops to 1µA, because the on-chip charge pump
turns off (V+ collapses to VCC, V- collapses to GND), and
the transmitter outputs tristate. Inverting receiver outputs
may or may not disable in powerdown; refer to Table 2 for
details. This micro-power mode makes these devices ideal
for battery powered and portable applications.
Software Controlled (Manual) Powerdown
These three devices allow the user to force the IC into the
low power, standby state, and 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 enhanced automatic powerdown circuitry.
ICL3245E inverting (standard) receiver outputs also disable
when the device is in powerdown, thereby eliminating the
possible current path through a shutdown peripheral’s input
protection diode (see Figures 2 and 3).
Connecting FORCEOFF and FORCEON together disables
the enhanced automatic powerdown feature, enabling them
to function as a manual SHUTDOWN input (see Figure 4).
With any of the above control schemes, the time required to
exit powerdown, and resume transmission is only 100µs.
9
FN4900.9
February 27, 2006
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