CAT660

http://onsemi.com

9

Capacitor Suppliers

The following manufacturers supply low−ESR capacitors:

Table 6. CAPACITOR SUPPLIERS

Manufacturer

Capacitor Type

Phone

WEB

Email

Comments

AVX/Kyocera

TPS/TPS3

843−448−9411

www.avxcorp.com

avx@avxcorp.com

Tantalum

Vishay/Sprague

595

402−563−6866

www.vishay.com

−

Aluminum

Sanyo

MV−AX, UGX

619−661−6835

www.sanyo.com

Svcsales@sanyo.com

Aluminum

Nichicon

F55

847−843−7500

www.nichicon−us.com

−

Tantalum

HC/HD

Aluminum

Capacitor manufacturers continually introduce new series and offer different package styles. It is recommended that before

a design is finalized capacitor manufacturers should be surveyed for their latest product offerings.

Controlling Loss in CAT660 Applications

There are three primary sources of voltage loss:

1. Output resistance:

VLOSS

W = ILOAD x ROUT, where ROUT is the

CAT660 output resistance and ILOAD is the load

current.

2. Charge pump (C1) capacitor ESR:

VLOSSC1

≈ 4 x ESRC1 x ILOAD, where

ESRC1 is the ESR of capacitor C1.

3. Output or reservoir (C2) capacitor ESR:

VLOSSC2 = ESRC2 x ILOAD, where ESRC2 is

the ESR of capacitor C2.

Increasing the value of C2 and/or decreasing its ESR will

reduce noise and ripple.

The effective output impedance of a CAT660 circuit is

approximately:

Rcircuit [ Rout 660 ) (4

ESRC1) ) ESRC2