BD9C301FJ-LB Datasheet, PDF (14/22 Pages) Rohm – 4.5V to 18V Input, 3.0A Integrated MOSFET Single Synchronous Buck DC/DC Converter

BD9C301FJ-LB
(3) Loop Stability
To ensure the stability of the DC/DC converter, make sure that a sufficient phase margin is provided. A phase margin
of at least 45º in the worst conditions is recommended.
V_OUT
R_UP
FB
COMP
R_DW
0.8V
【dB】
R_CMP
C_CMP
Phase
【°】
Figure 26. Phase Compensation Circuit
A
Gain [dB]
0
Phase[deg] 0
－90
－180
(a)
GBW(b)
f
FCRS
－90°
PHASE MARGIN
－180°
f
Figure 27. Bode Plot
I/O Equivalent Circuit Diagram
4.FB
VIN
5.COMP
VREG
VIN
FB
20kΩ
10kΩ
AGND
10kΩ
6.EN
VIN
2kΩ
0.5kΩ
COMP
2kΩ
0.5kΩ
7,8.SW
ＶＩＮ
AGND
EN
250kΩ
ＳＷ
725kΩ
AGND
Figure 28.
ＰＧＮＤ
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TSZ22111・15・001
14/19
TSZ02201-0J3J0AJ00540-1-2
21.Feb.2014 Rev.002