10/16

●Application Information (Continued)

8. Care must be taken when laying out the PC Board, in order to prevent misoperation of the current limit mode.

Depending on the state of the PC Board, latch time may become longer and latch operation may not work.

In order to

avoid the effect of noise, the board should be laid out so that capacitors are placed as close to the chip as possible.

9. Use of the IC at voltages below the recommended voltage range may lead to instability.

10. This IC should be used within the stated absolute maximum ratings in order to prevent damage to the device.

11. Depending on the input-output voltage differential, or load current, some pulses may be skipped, and the ripple voltage

may increase. When the series' duty cycle is digitally signalized, the linear duty cycle and the digitally signalized duty

cycle cannot carry out completely the same change, which means that the duty cycle does not change linearly.

The

output is stabilized by applying the phase compensation and adjusting the duty cycle, even when the duty cycle loses the

linear change in the whole circuit.

When the state where the output was stabilized is continued by applying phase

compensation to duty cycle which lost linearity, ripple voltage does not increase more than it. The ripple voltage may

increase to about several 10mV according to operating conditions.

It is possible, by increasing the capacitance values,

to reduce the ripple voltage.

The operating conditions are greatly influenced by the dropout voltage, the load current, the

delay-time, or the external components, such as the coil inductance, and the capacitance values.

Verification with actual

parts should be done.

●The Increase of Ripple Voltage (1.2MHz)

CH1: Lx

AC-COUPLED

CH1: Lx

AC-COUPLED

CH1: Lx

AC-COUPLED

■ NOTES ON USE (Continued)

L

: 4.7

μH

(CDRH3D16,

SUMIDA)

SD

: CRS02

(TOSHIBA)

: 4.7

μF

(Ceramic)

: 10

μF

(Ceramic)