EVALPM6680 STMicroelectronics, EVALPM6680 Datasheet - Page 39
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EVALPM6680
Manufacturer Part Number
EVALPM6680
Description
BOARD EVALUATION FOR PM6680
Manufacturer
STMicroelectronics
Datasheet
1.PM6680TR.pdf
(49 pages)
Specifications of EVALPM6680
Mfg Application Notes
PM6680 Eval Kit, AN2566 App Note
Main Purpose
DC/DC, Step Down with LDO
Outputs And Type
3, Non-Isolated
Power - Output
13.25W
Voltage - Output
1.05V, 1.5V, 5V
Current - Output
5A, 5A, 100mA
Voltage - Input
6 ~ 28V
Regulator Topology
Buck
Frequency - Switching
200kHz, 300kHz
Board Type
Fully Populated
Utilized Ic / Part
PM6680
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
497-6241
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
PM6680
The T node voltage is the sum of the output voltage and the triangular waveform generated
by the virtual ESR network. In fact the virtual ESR network behaves like a further equivalent
ESR R
A good trade-off is to design the network in order to achieve an R
Equation 28
where ∆I
voltage. It should be chosen higher than approximately 30 mV.
The new closed loop gain depends on C
that:
Equation 29
Where:
Equation 30
where R
given by the virtual ESR network R
Moreover C
Equation 31
Where k is a free design parameter greater than 3 and determines the minimum integrator
capacitor value C
Equation 32
C must be selected as shown:
Equation 33
ESR
TOT
L
is the inductor current ripple and V
.
INT
is the sum of the ESR of the output capacitor Rout and the equivalent ESR
must meet the following condition:
INT
:
f
C
sw
INT
>
C
ESR
R
f
Z
k
INT
>
ESR
×
=
2
.
f
π
C
>
2
Z
INT
=
π
×
2
=
>
V
×
⎛
⎜ ⎜
⎝
. In order to ensure stability it must be verified
π
g
g
RIPPLE
5
2
f
C
sw
∆
RIPPLE
k
×
m
m
π
×
I
out
L
f
×
Z
C
1
−
C
INT
×
×
f
Z
−
out
R
V
⎞
⎟ ⎟
⎠
k
is the overall ripple of the T node
R
Vr
TOT
OUT
×
×
out
V
R
Vr
OUT
TOT
ESR
given by:
Device description
39/49