CALIFORNIA MICRO DEVICES

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

3/6/2001

3

215 Topaz Street, Milpitas, California 95035



Tel: (408) 263-3214

Fax: (408) 263-7846

www.calmicro.com

CMPWR101

Interface Signals

V

monitored continuously by an internal controller circuit.

Whenever V

internal regulator will be enabled and deliver a fixed

3.3V at V

cally), the regulator will be disabled.

Internal loading on this pin is typically 0.6mA when the

regulator is enabled, which reduces to 0.1mA whenever

the regulator is disabled. If V

the V

few microamperes.

During a V

will be an effective step increase in V

when the regulator is enabled/disabled. This line current

transient will cause a voltage disturbance at the V

The magnitude of the disturbance will be directly

proportional to the effective power supply source

impedance being delivered to the V

A built-in hysteresis voltage of 150mV has been

incorporated to minimize any chatter during supply

changeover. It is recommended that the power supply

connected to the V

resistance of less than 0.25

Ω to minimize the event of

chatter during the enabling/disabling of the regulator.

If the V

filter, a capacitor may not be necessary. Otherwise an

input filter capacitor in the range of 1µF to 10µF will help

to lower the effective source impedance.

V

(V

to V

integrated switch.

The internal loading on this pin is typically less than

10µA and will increase to 100µA if V

voltage on V

When V

prevents the regulator from being disabled.

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.

DRIVE is a CMOS output logic signal (Active Low)

referenced to the V

whenever the internal regulator is not enabled. This

output is intended only as a control signal for external

circuitry.

GND is the negative reference for all voltages. The

current that flows in the ground connection is very low

(typically 0.6mA) and has minimal variation over all load

conditions.

NC is an unconnected pin which is electrically isolated

from the internal circuitry.

PIN FUNCTIONS

Pin

Symbol

Description

1

2, 3

Auxiliary supply input is connected directly to the output via a low impedance

when the regulator is disabled.

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

4

GND

Negative reference for all voltages

5

NC

Unconnected pin which is electrically isolated from internal circuitry.

Simplified Electrical Schematic

3.3V

250mA

+

–

+

–

4.1V

3.3V

GND

0.2

Ω

DRIVE

ENABLE

3.3V