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LTC9101-1/

LTC9102/LTC9103

Rev. 0

For more information www.analog.com

OPERATING MODES

The LTC9101-1/LTC9102/LTC9103 includes up to 48

independent ports, each of which can operate in one of

three modes: manual, semi-auto, or auto. A fourth mode,

shutdown, disables the port (see Table 5).

Table 5. Operating Modes

MODE

AUTO

OPMD

DETECT/

CLASS

POWER-UP

AUTOMATIC

THRESHOLD

ASSIGNMENT

Auto

11b

Enabled

at Reset Automatically

Yes

11b

Host

Enabled Automatically

Yes

Semi-Auto

10b

Host

Enabled

Upon

Request

Manual

01b

Once

Upon

Request

Upon

Request

Shutdown

00b

Disabled

In manual mode, the port waits for instructions from the

host system before taking any action. It runs a single

detection, or detection and classification cycle when com-

manded to by the host, and reports the result in its Port

Status register. The host system can command the port

to apply or remove power at any time.

In semi-auto mode, the port repeatedly attempts to detect

and classify any PD attached to it. It reports the status of

these attempts back to the host, and waits for a command

from the host before applying power to the port. The host

must enable detection and classification.

Auto mode operates the same as semi-auto mode except

it will automatically apply power to the port if detection

and classification are successful. Auto mode will autono-

mously set the ICUT-2P, ILIM-2P, and PCUT-4P values based

on the Class result. This operational mode may be entered

by setting AUTO high at reset or by changing the OPMD

state to Auto (11b). See AUTO pin description and the

Auto Mode Maximum PSE Power section.

APPLICATIONS INFORMATION

In shutdown mode the port is disabled and will not detect

or power a PD.

Regardless of which mode it is in, the LTC9101-1/

LTC9102/LTC9103 will remove power automatically from

any port or channel, as appropriate, that generates a fault.

It will also automatically remove power from any port/

channel that generates a disconnect event if disconnect

detection is enabled. The host controller may also com-

mand the port to remove power at any time.

Reset and the AUTO Pin

The initial LTC9101-1/LTC9102/LTC9103 configuration

depends on the state of AUTO during reset. Reset occurs

at power-up, whenever RESET is pulled low, or when the

global Reset All bit is set. Changing the state of AUTO

after power-up will not change the port behavior of the

LTC9101-1/LTC9102/LTC9103 until a reset occurs.

With AUTO high, each port will detect and classify repeat-

edly until a PD is discovered, set ICUT-2P, ILIM-2P, and

PCUT-4P according to the PSE assigned Class, apply

power to valid PDs, and remove power when a PD is

disconnected.

Table 6 and Table 7 show the ICUT-2P, ILIM-2P, and PCUT-4P

values that will be automatically set in auto mode, based

on the PSE assigned Class.

Table 6. Typical Auto Mode Power On Thresholds,

Single-Signature PD**

PSE ASSIGNED

CLASS

PER-CHANNEL

PER-PORT

ICUT-2P

ILIM-2P

PCUT-4P

94mA

425mA

4.86W

150mA

425mA

7.56W

338mA

425mA

16.2W

638mA

850mA

32.4W

581mA

850mA

48.1W

731mA

850mA

64.3W

825mA

1063mA

80.5W

975mA

1167mA

96.1W

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