ZXLD1601 datasheet(9/12 Pages) DIODES

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Capacitor selection

A ceramic capacitor grounded close to the GND pin of

the package is recommended at the output of the

device. Surface mount types offer the best

performance due to their lower inductance. A

minimum value of 0.22

µF is advised, although higher

values will lower switching frequency and improve

efficiency especially at lower load currents. A higher

value will also minimize ripple when using the device

to provide an adjustable dc output current.

A good quality, low ESR capacitor should also be used

for input decoupling, as the ESR of this capacitor is

effectively in series with the source impedance and

lowers overall efficiency. This capacitor has to supply

the relatively high peak current to the coil and smooth

the current ripple on the input supply. A minimum

value of 4.7

µF is acceptable if the input source is close

to the device, but higher values will improve

performance at lower input voltages, when the source

impedance is high. The input capacitor should be

mounted as close as possible to the IC

Inductor selection

The choice of inductor will depend on available board

space as well as required performance. Small value

inductors have the advantage of smaller physical size

and may offer lower series resistance and higher

saturation current compared to larger values. A

disadvantage of lower inductor values is that they

result in higher frequency switching, which in turn

causes reduced efficiency due to switch losses. Higher

inductor values can provide better performance at

lower supply voltages. However, if the inductance is

too high, the output power will be limited by the

internal oscillator, which will prevent the coil current

from reaching its peak value. This condition will arise

whenever the ramp time (ILX(peak) x L/VIN) exceeds the

nominal 5

µs maximum ‘on’ time limit for the LX output.

Part No.

( H)

DCR

( )

ISAT

(A)

Manufacturer

CMD4D11-100MC

0.457

0.5

Sumida

www.sumida.com

DO1608-103

0.16

1.1

Coilcraft

www.coilcraft.com

LQH31CN100

1.3

0.23

Murata

www.murata.com

LB2012Y100MR

0.5

0.1

Taiyo Yuden

www.t-yuden.com

For maximum stability over temperature, capacitors

with X7R dielectric are recommended, as these have a

much smaller temperature coefficient than other types.

A table of recommended manufacturers is provided

below:

Manufacturer

Website

Murata

www.murata.com

Taiyo Yuden

www.t-yuden.com

Kemet

www.kement.com

AVX

www.avxcorp.com

Recommended inductor values for the ZXLD1601 are

in the range 6.8

µHto22µH. The inductor should be

mounted as close to the device as possible with low

resistance connections to the LX and VIN pins.

Suitable coils for use with the ZXLD1601 are shown in

the table below:

ZXLD1601

SEMICO NDUC TORS

ISSUE 3 - AUGUST 2004

ZXLD1601 Fiches technique(PDF) 9 Page - Diodes Incorporated

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