Datasheet

TRS3318E
SLLS805B –APRIL 2007–REVISED OCTOBER 2013 www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
DETAILED DESCRIPTION
Flexible control options for power management are featured when the serial port and driver inputs are inactive.
The auto-powerdown plus feature functions when FORCEON is low and FORCEOFF is high. During this mode of
operation, if the device does not sense valid signal transitions on all receiver and driver inputs for approximately
30 s, the built-in charge pump and drivers are powered down, reducing the supply current to 1 µA. By
disconnecting the serial port or placing the peripheral drivers off, auto-powerdown plus can be disabled when
FORCEON and FORCEOFF are high. With auto-powerdown plus enabled, the device activates automatically
when a valid signal is applied to any receiver or driver input. INVALID is high (valid data) if any receiver input
voltage is greater than 2.7 V or less than –2.7 V, or has been between –0.3 V and 0.3 V for less than 30 µs
(typical number). INVALID is low (invalid data) if all receiver input voltage are between –0.3 V and 0.3 V for more
than 30 µs (typical number).
FUNCTION TABLE
(1)
INPUT CONDITIONS OUTPUT STATES
VALID
RECEIVER
OPERATING
RS-232
OR DRIVER
MODE
FORCEON FORCEOFF LEVEL DRIVER RECEIVER INVALID READY
EDGE
PRESENT AT
WITHIN 30 s
RECEIVER
Auto-Powerdown Plus Conditions
Normal operation,
H H No No Active Active L H auto-powerdown
plus disabled
Normal operation,
H H No Yes Active Active H H auto-powerdown
plus disabled
Normal operation,
L H Yes No Active Active L H auto-powerdown
plus enabled
Normal operation,
L H Yes Yes Active Active H H auto-powerdown
plus enabled
Power down,
L H No No Z Active L L auto-powerdown
plus enabled
Power down,
L H No Yes Z Active H L auto-powerdown
plus enabled
Manual power
X L X No Z Active L L
down
Manual power
X L X Yes Z Active H L
down
Auto-Powerdown Conditions
Power down,
INVALID INVALID X No Z Active L L auto-powerdown
enabled
Normal operation,
INVALID INVALID X Yes Active Active H H auto-powerdown
enabled
(1) H = high level, L = low level, X = irrelevant, Z = high impedance
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