R5975D datasheet(41/47 Pages) STMICROELECTRONICS

Part #	R5975D

Description	Up to 3 A step-down switching regulator for aerospace applications

PDF	47 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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41 / 47 page

DocID026878 Rev 1

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R5975D

Application information

Figure 27 shows the type III compensation network stabilizing the system with ceramic

capacitors at the output (the optimum components value depends on the application). This

configuration introduces two zeros and a low frequency pole in the designed bandwidth and

so guarantees a proper phase margin.

Figure 27. MLCC compensation network circuit

8.11

External soft-start network

At startup, the device can quickly increase the current up to the current limit in order to

charge the output capacitor. If soft ramp-up of the output voltage is required, an external

soft-start network can be implemented, as shown in Figure 28. The capacitor C is charged

up to an external reference through R and the BJT clamps the COMP pin.

This clamps the duty cycle, limiting the slew rate of the output voltage.

Figure 28. Soft-start network example

R5975D Datasheet(PDF) 41 Page - STMicroelectronics