Datasheet

(2) Load capacitance: C

= C

)

Figure 6a shows the change of oscil-

lation voltage when load capacitance

is varied. C

is an important para-

meter that affects the stability and fre-

quency of oscillation. Load capaci-

tance must be carefully selected to

match the IC as, when C

gets too

small, the wave form becomes dis-

torted (Figure 6b) and oscillation

becomes unstable. When C

gets too

large, the oscillation voltage decreas-

es (Figure 6c) and the oscillation may

well stop altogether.

(3) Damping resistance: Rd

Figure 7 (a) shows the change of the

oscillation voltage when damping

resistance Rd is varied. There are

many cases where an overshoot or

undershoot of oscillation voltage is

generated when the Rd is zero

(Figure 7 b). This can be avoided by

adding Rd (Figure 7 c). Also, Rd

forms a low pass filter with load

capacitance C

, and mak es the

loop gain smaller at higher fre-

quency and suppresses unwanted

oscillation in the high frequency

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Figure 5 - Oscillation characteristics when feedback resistance R

is changed

Figure 6 - Oscillation characteristics when load capacitance C

= C

) is changed