3/5/2001

3

215 Topaz Street, Milpitas, California 95035



Tel: (408) 263-3214

Fax: (408) 263-7846

www.calmicro.com

CMPWR130

CALIFORNIA MICRO DEVICES

© 2001 California Micro Devices Corp. All rights reserved. SmartOR™ is a trademark of California Micro Devices Corp

Interface Signals

V

monitored continuously by an internal controller circuit.

Whenever V

regulator (300mA MAX) will be enabled and deliver a

fixed 3.3V at V

TYP) the regulator will be disabled.

Internal loading on this pin is typically 0.6mA when the

regulator is enabled, which reduces to 0.2mA whenever

the regulator is disabled. If V

the V

few microamperes.

During a V

effective step increase in V

regulator is enabled. The amplitude of this step increase

will depend on the DC load current and any necessary

current required for charging/discharging the load

capacitance. This line current transient will cause a

voltage disturbance at the V

disturbance will be directly proportional to the effective

power supply source impedance being delivered to the

V

To prevent chatter during Select and Deselect transi-

tions, a built-in hysteresis voltage of 200mV has been

incorporated. It is recommended that the power supply

connected to the V

tance of less than 0.25

Ω to minimize the event of chatter

during the enabling/disabling of the regulator.

An input filter capacitor in close proximity to the V

will reduce the effective source impedance and help

minimize any disturbances. If the V

inches of the main input filter, a capacitor may not be

necessary. Otherwise an input filter capacitor in the

range of 1µF to 10µF will ensure adequate filtering.

GND is the negative reference for all voltages. This

current that flows in the ground connection is very low

(TYP 550µA) and has minimal variation over all load

conditions.

V

power the load. An output capacitor of 4.7µF 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 V

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 PFET

whenever the regulator is disabled. This will allow the

voltage at V

voltage (3.3V).

The Drive pin is pulled HIGH to V

regulator is enabled, this ensures the auxiliary remains

isolated during normal regulator operation.

The output current sinking ability of this logic signal is

equivalent to a 100W resistor. The current sourcing

ability is equivalent to a 4k

Ω resistor.

NC pins are electrically isolated from the internal

circuitry. These pins can be connected to any external

voltage level without impacting the device functionality.

PIN FUNCTIONS

Pin

Symbol

Description

1

6, 7

Continuous output voltage (3.3V) is derived from either the internal regulator or low impedance

switch connected to the auxiliary supply input.

8

DRIVE

Output drive signal to control external MOSFET switch

4

GND

Negative reference for all voltages

2, 3, 5

NC

Unconnected pin which is electrically isolated from internal circuitry.

3.3V

300mA

3.3V

+

–

+

–

4.1V

GND

DRIVE

ENABLE

Simplified Electrical Schematic