ST1843 - ST1845

Test circuit

Doc ID 019049 Rev 1

13/25

7

Test circuit

Figure 4.

Open loop test circuit

High peak currents associated with capacitive loads necessitate careful grounding

techniques. Timing and bypass capacitors should be connected close to pin 5 in a single

point ground. The transistor and 5 k

Ω potentiometer are used to sample the oscillator

waveform and apply an adjustable ramp to pin 3.

Figure 5.

Timing resistor vs. oscillator

frequency

Figure 6.

Output dead-time vs. oscillator

frequency