XC9104D092ML datasheet(8/23 Pages) TOREX

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XC9103/XC9104/XC9105 Series

■ 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

on the values of RFB1 and RFB2. The sum of RFB1 and RFB2 should normally be 2 MΩor less.

VOUT = 0.9 x (RFB1 + RFB2) / RFB2

The value of CFB1, speed-up capacitor for phase compensation, should result in fzfb = 1/(2π×CFB×RFB1) equal to 5 to

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)

RFB1 : 120kΩ

RFB2 : 45kΩ

fzfb = 10kHz (L=47μH)

CFB

: 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 >

:*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.)

:MA2Q737 (Schottky type, MATSUSHITA)

L, CL

:When Using Ceramic Type

: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.

CL = (CL standard value) x (IOUT(mA) / 300mA x VOUT / VIN)

RSENSE

:100mΩ (FOSC = 180, 300, 500kHz)

50mΩ (FOSC = 100kHz)

:Tantalum Type

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

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

Except when IOUT(mA) / 100mA x VOUT / VIN > 2 → 22μH

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

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

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

large.

CL = (CL standard value) x (IOUT(mA) / 300mA x VOUT / VIN)

RSENSE

:Not required, but short out the wire.

:AL Electrolytic Type

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

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

Except when IOUT(mA) / 100mA x VOUT / VIN > 2 → 22μH

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

Strengthen appropriately when step-up ratio and output current is

large.

RSENSE

:Not required, but short out the wire.

CFB

:Set up so that fzfb = 100kHz.

*When a NPN Tr. Is used:

2SD1628 (SANYO)

RB : 500Ω(Adjust with Tr's HSE or load)

CB : 2200pF (Ceramic type set so that RB and

pole is less than 70% of FOSC)

CB<1 / (2

πx RB x FOSC x 0.7)

XC9104D092ML Datasheet(PDF) 8 Page - Torex Semiconductor

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