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■ OPERATIONAL EXPLANATION (Continued)

< Output Voltage Setting>

Output voltage can be set by adding external split resistors. Output voltage is determined by the following equation, based

30kHz. Adjustments are required depending on the application, value of inductance (L), and value of load capacity (CL).

fzfb = 30kHz (L=10μH)

[ Example of Equation ]

fzfb = 20kHz (L=22μH)

fzfb = 10kHz (L=47μH)

: 47pF

(fzfb = 30kHz, L = 10μH)

68pF

(fzfb = 20kHz, L = 22μH)

130pF (fzfb = 10kHz, L = 47μH)

< The use of ceramic capacitor CL >

The circuit of the XC9103/04/05 series is organized by a specialized circuit, which reenacts negative feedback of both

voltage and current. Also by insertion of approximately 100mΩ of a low and inexpensive sense resistor as current sense,

a high degree of stability is possible even using a ceramic capacitor, a condition which used to be difficult to achieve.

Compared to a tantalum condenser, because the series can be operated in a very small capacity, it is suited to use of the

ceramic capacitor, which is cheap and small.

< External Components >

Tr

:*When a MOSFET is used:

XP161A1355PR (N-ch Power MOSFET, TOREX)

Note*: As the breakdown voltage of XP161A1355 is 8V, take care

with the power supply voltage.

With output voltages over 6V, use the XP161A1265 with a

breakdown voltage of 12V.

VST1: XP161A1355PR =1.2V (MAX.)

XP161A1265PR = 1.5V (MAX.)

SD

:MA2Q737 (Schottky type, MATSUSHITA)

:When Using Ceramic Type

L

:22μH (CDRH5D28, SUMIDA, FOSC = 100, 180kHz)

10μH (CDRH5D18, SUMIDA, FOSC = 300, 500kHz)

:10V 10μF (Ceramic Type, LMK325BJ106ML, TAIYO YUDEN)

Use the formula below when step-up ratio and output current is

large.

:100mΩ (FOSC = 180, 300, 500kHz)

50mΩ (FOSC = 100kHz)

:Tantalum Type

L

:22μH (CDRH5D28, SUMIDA, FOSC = 300kHz)

47μH (CDRH5D28, SUMIDA, FOSC = 100, 180kHz)

10μH (CDRH5D18, SUMIDA, FOSC = 500kHz)

:16V, 47μF (Tantalum Type 16MCE476MD2, NICHICHEMI)

Use the formula below when step-up ratio and output current is

large.

:Not required, but short out the wire.

:AL Electrolytic Type

L

:22μH (CDRH5D28 SUMIDA, FOSC = 300kHz)

47μH (CDRH5D28 SUMIDA, FOSC = 100, 180kHz)

:16V, 100μF (AL Electrolytic Type) + 10V, 2.2μF (Ceramic Type)

Strengthen appropriately when step-up ratio and output current is

large.

:Not required, but short out the wire.

CFB

:Set up so that fzfb = 100kHz.

*When a NPN Tr. Is used:

2SD1628 (SANYO)

pole is less than 70% of FOSC)