MAX3318

SLLS687A – OCTOBER 2005 – REVISED OCTOBER 2013

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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-power-down 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-power-down plus can be disabled when

FORCEON and FORCEOFF are high. With auto-power-down 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).

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-Power-Down Plus Conditions

Normal operation,

H

H

No

No

Active

Active

L

H

auto-power-down

plus disabled

Normal operation,

H

H

No

Yes

Active

Active

H

H

auto-power-down

plus disabled

Normal operation,

L

H

Yes

No

Active

Active

L

H

auto-power-down

plus enabled

Normal operation,

L

H

Yes

Yes

Active

Active

H

H

auto-power-down

plus enabled

Power down,

L

H

No

No

Z

Active

L

L

auto-power-down

plus enabled

Power down,

L

H

No

Yes

Z

Active

H

L

auto-power-down

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-Power-Down Conditions

Power down, auto

INVALID

INVALID

X

No

Z

Active

L

L

power down

enabled

Normal operation,

INVALID

INVALID

X

Yes

Active

Active

H

H

auto power down

enabled

(1)

H = high level, L = low level, X = irrelevant, Z = high impedance

2

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