ST1S31D-R datasheet(13/35 Pages) STMICROELECTRONICS

部件名	ST1S31D-R

功能描述	3 A DC step-down switching regulator

PDF	35 Pages

Scroll/Zoom	100%

制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

标志

13 / 35 page

DocID022998 Rev 4

13/35

ST1S31

Functional description

The embedded compensation network is RC = 80 k, CC = 55 pF while CP and CO can be

considered as negligible. The error amplifier output resistance is 96 M



so the relevant

singularities are:

Equation 13

So closing the loop, the loop gain GLOOP(s) is:

Equation 14

Example 1:

VIN = 5 V, VOUT = 1.2 V, Iomax = 3 A, L = 1.0 H, Cout = 47 µF (MLCC), R1 = 10 k,

R2 = 20 k

(see Section 5.2 and Section 5.3 for inductor and output capacitor selection

guidelines).

The module and phase bode plot are reported in Figure 7 and Figure 8.

The bandwidth is 117 kHz and the phase margin is 63 degrees.

Figure 7. Module bode plot

36 2 kHz



fP LF

30 Hz

GLOOP s



GCO s

 G

DIV s

 G

EA s





ST1S31D-R 数据表(PDF) 13 Page - STMicroelectronics