LA5683T

No.8214-10/12

CT1 and CT2

The waveform of CT1 is 180 degrees out of phase with that of CT2. Their frequency cannot be set independently.

The capacitance of the capacitors to be connected to pins CT1 and CT2 must be the same.

• Setting the oscillation frequency

(1) The oscillation frequency of the oscillator can be set by selecting the capacitance of the capacitors connected to

pins CT1 and CT2 (see Figure 1).

(2) The oscillation frequency can also be determined by the resistance of the resistor connected to the RT pin

(see Figure 2).

Sample Circuits

Sample Circuit That Makes Use of VBIAS (1)

This IC can be used to implement the circuit that is shown below since the power to the channels 3 and 4 output stages

is supplied via VBIAS.

Apply VO1 that is dropped to 3.3V in channel 1 to VBIAS. A voltage of approx. VBIAS3-1 volt develops at VOUT3,

so that the IC can drive MOS transistors in a low-voltage environment like this sample circuit.

to IN3−

VO3=3.3V

to OUT1

VCC

VBIAS Circuit Example 1

VBIAS

OUT3

SW

VO1=3.3V

to IN1−

VOUT3

MCH3409

L

MCH3309

VCC

Schottky barrier diode

L

Schottky barrier diode

100

1k

23

5

7

23

5

7

7

10k

0

600

800

200

400

2000

1800

1400

1600

1200

1000

ILA07008

Ta=25°C

VCC=3.0V

RT=5.6kΩ

10

23

5

7

23

1.0

5

0

600

800

200

400

1400

1200

1000

ILA07009

Ta=25°C

VCC=3.0V

CT1/CT2=560pF

Reference data

Reference data

Capacitors CT1 and CT2 Capacitance - pF

CT1 and CT2 have the

same capacitance.

Resistor RT Resistance - kΩ

Figure 1 Oscillation Frequency vs.

Timing Capacitance Characteristics

Figure 2 Oscillation Frequency vs.

Timing Resistance Characteristics