CMPWR280TB Ver la hoja de datos (PDF) - California Micro Devices Corp

Número de pieza

componentes Descripción

Fabricante

CMPWR280TB

1.5A SmartOR™ Dual Regulator with VAUX Drive

California Micro Devices Corp 

CMPWR280

PACKAGE / PINOUT DIAGRAM

VSBY

VCC

GND

VOUT

DRIVE

Top View

1

2

3

4

5

5-pin TO-263

CMPWR280TO/TN

Note: These drawings are not to scale.

Top View

VSBY

1

VCC

2

GND

3

VOUT

4

DRIVE

5

5-pin Thin TO-263

CMPWR280TA/TB

PIN(S)

1

2

3

4

5

NAME

VSBY.

VCC

GND

VOUT

DRIVE

PIN DESCRIPTIONS

DESCRIPTION

VSBY is the standby 5V supply power source, which is only selected on when VCC < VCCDES. If VSBY is

selected, the regulator can deliver a maximum of 375mA load current. Whenever VSBY exceeds both VCC

and VOUT, it will be used to provide all the internal bias currents and any necessary regulator current.

VCC is the primary 5V power supply for the internal regulator. Whenever VCC exceeds VCCSEL (4.5V), the

internal regulator (up to 1500mA) will be enabled and deliver a fixed 3.3V at VOUT. When VCC falls below

VCCDES (4.1V typically) the regulator will be disabled.

Internal loading on this pin is typically 1.5mA when the regulator is enabled, which reduces to 0.2mA

whenever the regulator is disabled. If VCC falls below either the VSBY or VOUT voltage, the loading on

VCC will reduce to only a few microamperes.

During a VCC power up sequence, there will be an effective step increase in VCC line current when the

regulator is enabled. The amplitude of this step increase will depend on the dc load current and any cur-

rent required for charging/discharging the load capacitance. This line current transient will cause a volt-

age disturbance at the VCC pin proportional to the effective power supply source impedance being

delivered to the VCC input.

To prevent chatter during Select and Deselect transitions, a built-in hysteresis voltage of 400mV has

been incorporated. It is recommended that the power supply connected to the VCC input should have a

source impedance of less than 0.15Ω to minimize the chatter during the enabling/disabling of the regula-

tor.

GND is the negative reference for all voltages. The current that flows in the ground connection is very

low (typically 2.0mA) and has minimal variation over all load conditions.

VOUT is the regulator output voltage connection used to power the load. An output capacitor of ten

microfarads is used to provide the necessary phase compensation, thereby preventing oscillation. The

capacitor also helps to minimize the peak output disturbance during power supply changeover.

When both VCC and VSBY falls below VOUT, then VOUT will be used to provide the necessary quiescent

current for the internal reference circuits. This ensures excellent start-up characteristics for the regulator.

Drive is an active LOW logic output intended to be used as the control signal for driving an external P-

channel MOSFET switch whenever the regulator is disabled. This will allow the voltage at VOUT to be

powered from an auxiliary supply voltage (3.3V).

The Drive pin is pulled HIGH to VCC whenever the regulator is enabled, thus ensuring that the auxiliary

supply remains isolated during normal regulator operation.

© 2004 California Micro Devices Corp. All rights reserved.

2 430 N. McCarthy Blvd., Milpitas, CA 95035-5112 ● Tel: 408.263.3214 ● Fax: 408.263.7846 ● www.calmicro.com 08/16/04

Share Link: