LTC3225 Datasheet, PDF (10/12 Pages) Linear Technology – 150mA Supercapacitor Charger

LTC3225
APPLICATIONS INFORMATION
Table 1 contains a list of ceramic capacitor manufacturers
and how to contact them.
Table 1. Capacitor Manufacturers
AVX
www.avxcorp.com
Kemet
www.kemet.com
Murata
www.murata.com
Taiyo Yuden
www.t-yuden.com
Vishay
www.vishay.com
TDK
www.component.tdk.com
Layout Considerations
Due to the high switching frequency and high transient
currents produced by the LTC3225, careful board layout is
necessary for optimum performance. An unbroken ground
plane and short connections to all the external capacitors
improves performance and ensures proper regulation
under all conditions.
The voltages on the flying capacitor pins C⁺ and C^– have
very fast rise and fall times. The high dv/dt values on
these pins can cause energy to capacitively couple to
adjacent printed circuit board traces. Magnetic fields can
also be generated if the flying capacitors are far from the
part (i.e. the loop area is large). To prevent capacitive
energy transfer, a Faraday shield may be used. This is a
grounded PC trace between the sensitive node and the
LTC3225 pins. For a high quality AC ground it should be
returned to a solid ground plane that extends all the way
to the LTC3225.
Table 2. Supercapacitor Manufacturers
CAP-XX
www.cap-xx.com
NESS CAP
www.nesscap.com
Maxwell
www.maxwell.com
Bussmann
www.cooperbussmann.com
AVX
www.avx.com
TYPICAL APPLICATION
5V Supercapacitor Backup Supply
V_IN
5V
C2
2.2μF
10V
PGOOD
C1
1μF
V_O ^10V
R3
100k
5%
D2
9
V_IN
10
C_OUT
8
GND
3
CX
1
LTC3225
C⁺
2 _C–
4 _SHDN
7
PROG
5
6
PGOOD V_SEL
GND
11
C_OUT
0.80F
5.5V
HS208F
R1
23.7k
1%
D3 ⁺
C5
0.22μF
6.3V
C3
150μF
10V
C4
47μF
10V
R1
15k
1%
7
V_IN
8
V_IN
10
ENA
1
V_O
2
V_O
3
SEN
4
TYCO V_O
AUSTIN
SUPERLYNX
9
5
TRIM GND
6
GND
V_O
1.8V
C7
C8
1μF
1μF
10V
10V
3225 TA02
3225f
10