Datasheet
LTC1871-1
18
18711fb
APPLICATIONS INFORMATION
Table 1. Recommended Component Manufacturers
VENDOR COMPONENTS TELEPHONE WEB ADDRESS
AVX Capacitors (207) 282-5111 avxcorp.com
BH Electronics Inductors, Transformers (952) 894-9590 bhelectronics.com
Coilcraft Inductors (847) 639-6400 coilcraft.com
Coiltronics Inductors (407) 241-7876 coiltronics.com
Diodes, Inc Diodes (805) 446-4800 diodes.com
Fairchild MOSFETs (408) 822-2126 fairchildsemi.com
General Semiconductor Diodes (516) 847-3000 generalsemiconductor.com
International Rectifi er MOSFETs, Diodes (310) 322-3331 irf.com
IRC Sense Resistors (361) 992-7900 irctt.com
Kemet Tantalum Capacitors (408) 986-0424 kemet.com
Magnetics Inc Toroid Cores (800) 245-3984 mag-inc.com
Microsemi Diodes (617) 926-0404 microsemi.com
Murata-Erie Inductors, Capacitors (770) 436-1300 murata.co.jp
Nichicon Capacitors (847) 843-7500 nichicon.com
On Semiconductor Diodes (602) 244-6600 onsemi.com
Panasonic Capacitors (714) 373-7334 panasonic.com
Sanyo Capacitors (619) 661-6835 sanyo.co.jp
Sumida Inductors (847) 956-0667 sumida.com
Taiyo Yuden Capacitors (408) 573-4150 t-yuden.com
TDK Capacitors, Inductors (562) 596-1212 component.tdk.com
Thermalloy Heat Sinks (972) 243-4321 aavidthermalloy.com
Tokin Capacitors (408) 432-8020 nec-tokinamerica.com
Toko Inductors (847) 699-3430 tokoam.com
United Chemicon Capacitors (847) 696-2000 chemi-com.com
Vishay/Dale Resistors (605) 665-9301 vishay.com
Vishay/Siliconix MOSFETs (800) 554-5565 vishay.com
Vishay/Sprague Capacitors (207) 324-4140 vishay.com
Zetex Small-Signal Discretes (631) 543-7100 zetex.com
which is typically in the range of 10µF to 100µF. A low ESR
capacitor is recommended, although it is not as critical as
for the output capacitor.
The RMS input capacitor ripple current for a boost con-
verter is:
I
RMS(CIN)
= 0.3 •
V
IN(MIN)
L•f
•D
MAX
Please note that the input capacitor can see a very high
surge current when a battery is suddenly connected to
the input of the converter and solid tantalum capacitors
can fail catastrophically under these conditions. Be sure
to specify surge-tested capacitors!
Burst Mode Operation and Considerations
The choice of MOSFET R
DS(ON)
and inductor value also
determines the load current at which the LTC1871-1 en-
ters Burst Mode operation. When bursting, the controller
clamps the peak inductor current to approximately:
I
BURST(PEAK)
=
30mV
R
DS(ON)
which represents about 20% of the maximum 150mV
SENSE pin voltage. The corresponding average current
depends upon the amount of ripple current. Lower inductor
values (higher ΔI
L
) will reduce the load current at which