lt3572 Linear Technology Corporation, lt3572 Datasheet - Page 9

• Manufacturer Part Number: lt3572
• Description: Dual Full-bridge Piezo Driver With 900ma Boost Converter
• Manufacturer: Linear Technology Corporation

Inductor Selection
A 10μH inductor is recommended for most LT3572 ap-
plications. Choose an inductor that will handle at least
1A without saturating, and ensure that the inductor has a
low DCR (copper-wire resistance) to minimize I
losses. Table 1 lists several inductor manufacturers.
Table 1. Inductor Manufacturers
Sumida
TDK
Murata
FDK
Capacitor Selection
The small size of ceramic capacitors makes them ideal
for LT3572 applications. Only X5R or X7R types should
be used because they retain their capacitance over wider
voltage and temperature ranges than other types such as
Y5V or Z5U. A 4.7μF to 15μF output capacitor is suffi cient
for stable transient response, however, more output ca-
pacitance can help limit the voltage droop on V
transients.
Ceramic capacitors also make a good choice for the input
decoupling capacitor, which should be placed as close as
possible to the LT3572. A 1μF to 4.7μF input capacitor
APPLICATIONS INFORMATION
[phone]
[phone]
[phone]
[phone]
C3
L1
D1
R4
www.sumida.com
www.tdk.com
www.murata.com
www.tdk.co.jp
SYNC
GND
SW
V
RT
IN
1
2
3
4
5
OUT
2
C1
R power
PWMB
during
PWMA
OUTA
OUTA
V
GND
OUT
is suffi cient for most applications. Table 2 shows a list
of several ceramic capacitor manufacturers. Consult the
manufacturers for detailed information on their entire
selection of ceramic parts.
Table 2. Ceramic Capacitor Manufacturers
Taiyo Yuden
AVX
Murata
Diode Selection
A Schottky diode is recommended for use with the LT3572.
The Philips PMEG 3005 is a good choice. If the switch
voltage exceeds 30V, a PMEG 4005 (a 40V diode) can be
used. These diodes are rated to handle an average forward
current of 0.5A. For higher effi ciency, use a diode with bet-
ter thermal characteristics such as the On Semiconductor
MBRM140 (a 40V diode).
Layout Hints
As with all switching regulators, careful attention must be
paid to the PCB board layout and component placement.
To maximize effi ciency, switch rise and fall times are made
as short as possible. Note the vias under the Exposed Pad.
These should connect to a local ground plane for better
thermal performance.
OUTB
SHDN
OUTB
15
14
13
12
11
PGOOD
SS
FB
SHDNB
SHDNA
[phone]
[phone]
[phone]
C
C2
R2
R1
FF
3572 BD LAYOUT
www.t-yuden.com
www.avxcorp.com
www.murata.com
LT3572
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3572f