LT8316 SENSE Pin RC

Hi,

Thanks for contacting Analog Devices!

Please find my response below:

Flyback (primary-side regulation):

• The SENSE pin samples the reflected secondary voltage during a short flyback window.
• High-frequency ringing and leakage spikes are common.
• A small RC filter helps reject switching spikes without affecting regulation, because sampling happens at a specific time.
• The control scheme is tolerant of a small delay.

Buck (continuous conduction, direct sensing):

• The SENSE pin sees a continuous DC + ripple representation of VOUT.
• The internal control loop expects fast, undelayed feedback.
• Adding RC:
  • Adds phase delay in the feedback path
  • Can slow load transient response
  • Can cause DC regulation error if R is too large (due to SENSE input bias current)
  • May reduce phase margin and cause instability in some conditions

This is why datasheet buck examples connect SENSE directly (or with only minimal series resistance for protection).

Regards,

Harshal

Hi,

Thanks for contacting Analog Devices!

Please find my response below:

Flyback (primary-side regulation):

• The SENSE pin samples the reflected secondary voltage during a short flyback window.
• High-frequency ringing and leakage spikes are common.
• A small RC filter helps reject switching spikes without affecting regulation, because sampling happens at a specific time.
• The control scheme is tolerant of a small delay.

Buck (continuous conduction, direct sensing):

• The SENSE pin sees a continuous DC + ripple representation of VOUT.
• The internal control loop expects fast, undelayed feedback.
• Adding RC:
  • Adds phase delay in the feedback path
  • Can slow load transient response
  • Can cause DC regulation error if R is too large (due to SENSE input bias current)
  • May reduce phase margin and cause instability in some conditions

This is why datasheet buck examples connect SENSE directly (or with only minimal series resistance for protection).

Regards,

Harshal