Datasheet

12
LTC1174
LTC1174-3.3/LTC1174-5
1174fe
APPLICATIO S I FOR ATIO
WUUU
Solving for L in the above equation and with V
D
= 0.6V,
L = 44.8µH. The next higher standard value of L is 50µH
(example: Coiltronics CTX50-4). The operating frequency,
neglecting voltage across diode V
D
is:
f
V
V
kHz
OUT
IN
≈−
=
2 5 10 1
111
5
.•
With the value of L determined, the requirements for C
IN
and C
OUT
are calculated. For C
IN
, its RMS current rating
should be at least:
I
IVVV
V
A
mA
RMS
OUT OUT IN OUT
IN
RMS
=
()
[]
()
=
12
174
/
For C
OUT
, the RMS current rating should be at least:
I
I
A
mA
RMS
PEAK
RMS
()
=
2
300
Now allow V
IN
to drop to 6V. At this minimum input voltage
the operating frequency will decrease. The new frequency
is 42kHz.
Table 1. Inductor Manufacturers
MANUFACTURER PART NUMBER
Coilcraft DT3316 Series
1102 Silver Lake Road
Cary, IL 60013
(708) 639-2361
Coiltronics Inc. Econo-Pac
6000 Park of Commerce Blvd. Octa-Pac
Boca Raton, FL 33487
(407) 241-7876
Gowanda Electronics Corporation GA10 Series
1 Industrial Place
Gowanda, NY 14070
(716) 532-2234
Sumida Electric Co. Ltd. CD 54 Series
637 E. Golf Road, Suite 209 CD 75 Series
Arlington Heights, IL 60005
(708) 956-0666/7
Table 2. Capacitor Manufacturers
MANUFACTURER PART NUMBER
AVX Corporation TPS Series
P.O. Box 887 TAJ Series
Myrtle Beach, SC 29578
(803) 448-9411
Nichicon America Corporation PL Series
927 East State Parkway
Schaberg, IL 60173
(708) 843-7500
Sanyo Video Components OS-CON Series
2001 Sanyo Avenue
San Diego, CA 92173
(619) 661-6385
Attn: Sales Dept.