MC34653EFSLASHR2 datasheet(9/24 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

34653

FUNCTIONAL DESCRIPTION

FUNCTIONAL PIN DESCRIPTION

POWER GOOD OUTPUT (ACTIVE LOW) PG

The PG pin is the active low power good output signal that

is used to enable or disable a load. This signal goes active

after a successful power-up sequence and stays active as

long as the device is in normal operation and is not

experiencing any faults.

The signal is deactivated under the following conditions:

• Power is turned off.

• The device is disabled for more than 1.0 ms.

• The device exceeded its thermal shutdown threshold for

more than 12

µs.

• The device is in overvoltage or undervoltage mode for

more than 1.0 ms.

• Load current exceeded the overcurrent limit for more than

3.0 ms.

This pin is referenced to VIN.

OUTPUT VOLTAGE (VOUT)

The VOUT pin is the drain of the internal Power MOSFET

and supplies a current-limited voltage to the load. The load

connects between the VOUT and VPWR pins.

POSITIVE SUPPLY VOLTAGE INPUT (VPWR)

The VPWR pin is the most-positive power supply input.

The load connects between the VPWR and VOUT pins.

DISABLE INPUT CONTROL (DISABLE)

The DISABLE pin is used to easily disconnect or connect

the load from the main power line by disabling or enabling the

34653. It can also be used to reset the fault conditions that

cause a “Power No Good” signal.

If left open or connected to VPWR, the DISABLE pin is

inactive and the device is enabled. If a positive voltage

(above VPWR) or a negative voltage (below VPWR) is applied

to DISABLE, it is active and the device is disabled. The

disable function has a 1.0 ms filter timer.

This pin is referenced to VPWR.

CURRENT LIMIT CONTROL (ILIM)

The ILIM pin is used to set the overcurrent limit during

normal operation. This pin can be left unconnected for a

default overcurrent limit value of 1.0 A or the user can

connect an external resistor between the ILIM and VIN pins

to set the overcurrent limit value. This value can vary

between 0.15 A and 1.25 A. The overcurrent detection circuit

has a 100

µs filter timer.

CHARGING CURRENT LIMIT CONTROL (ICHG)

The ICHG pin is used to set the current limit that is used to

charge the load’s input capacitor, hence limiting the inrush

current to a known constant value. This pin can be left

unconnected for a default charging current limit value of 0.1 A

and a default ICHG rise time of 1.0 ms. Or the user can

connect an external resistor between the ICHG and VIN pins

to set the current limit value between 0.05 A and 0.5 A and an

external capacitor to increase the ICHG rise time. The

recommended maximum rise time is 10 ms.

MC34653EF/R2 Datasheet(PDF) 9 Page - Freescale Semiconductor, Inc

MC34653EF/R2 Datasheet(HTML) 9 Page - Freescale Semiconductor, Inc

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