LT1054

SWITCHEDCAPACITOR VOLTAGE CONVERTERS

WITH REGULATORS

SLVS033F − FEBRUARY 1990 − REVISED NOVEMBER 2004

9

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

current. An input supply bypass capacitor supplies part of the peak input current drawn by the LT1054 and averages

the current drawn from the supply. A minimum input-supply bypass capacitor of 2

µF, preferably tantalum or some

other low equivalent-series-resistance (ESR) type, is recommended. A larger capacitor is desirable in some cases.

An example of this would be when the actual input supply is connected to the LT1054 through long leads or when

the pulse currents drawn by the LT1054 might affect other circuits through supply coupling.

general-purpose transistor such as a 2N2222 or a 2N2219 device can be used. Resistor R1 should be chosen to

provide enough base drive to the external transistor so that it is saturated under nominal output voltage and maximum

output current conditions.

R1

v

V

I

OUT

R1

CIN

Load

VOUT

VREF

OSC

VCC

CAP−

GND

CAP+

FB/SD

VIN

VOUT

COUT

Pin numbers shown are for the P package.

+

+

1

2

3

4

LT1054

8

7

6

5

(4)