SP6138_06 Datasheet, PDF (6/9 Pages) Sipex Corporation – Evaluation Board Manual

The simple guidelines for positioning the poles and zeros and for calculating the
component values for a Type III compensation scheme are as follows:
Where ZSF=(f compensation double zero)/(f circuit double pole)
Here ZSF is set at 1.2.
As a particular example, consider for the following SP6138EB, 3AMAX with a type III
Voltage Loop Compensation component selections:
Vin_max = 15V
Vout = 3.30V @ 0 to 3A load
Select L = 2.2 uH => 15% current ripple.
Select Cout = 22uF Ceramic capacitors (Resr ≈ 5mΩ)
fs = 2500KHz SP6138ER1 internal Oscillator Frequency
Vramp_pp = 1.0V SP6138ER1 internal Ramp Peak-to-Peak Amplitude
Aug 24-06
SP6138 Evaluation Manual
Page 6 of 9
©2006 Sipex Corporation