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Product(s)

- Obsolete

Product(s)

AN1645 - APPLICATION NOTE

14/22

STSR2PM does not have this function and the two outputs follow the clock input even for very low duty-

cycle values.

9. OUTPUT DRIVERS

The two output drivers have a high current capability, being able to source up to 2A and to sink up to

3.5A peak current. Consequently, the two mosfet are switched very quickly, allowing paralleling of

several mosfets to reduce conduction losses. The high level driving voltage is equal to Vcc voltage;

therefore the device drives properly logic level mosfets.

Figure 18: Rds(on) -sink/source vs Temp

10. TRANSIENT BEHAVIOUR

During very heavy load changes, the duty cycle can vary very fast from a low value to a high value and

vice versa in a few switching periods.

The calculation to turn off OUTGate1 is based on On-time, so if the on time is changing very fast, the

anticipation time cannot be provided. In any case, STSR2P has a safety feature, which turns off

OUTGate1 when the CK input goes low. OUTgate1 will be turned off with a small delay with respect to

the Ck input- 30ns max (Figure 19 b).

If the anticipation time for OUTGate2 is based on the calculation of the switching period (frequency) and

not on duty cycle, even during fast duty cycle changes the anticipation time is provided correctly, always

providing correct driving for the Synchronous Mosfet (Figure 19 c).

0

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-20

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T [°C]

Source

Sink

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T [°C]

Source

Sink