ADP2386-EVALZ Analog Devices, ADP2386-EVALZ Datasheet - Page 19

• Manufacturer Part Number: ADP2386-EVALZ
• Description: Power Management IC Development Tools 20V 6A Evaluation Board
• Manufacturer: Analog Devices
• Type: DC/DC Converters, Regulators & Controllersr
• Series: ADP2386r

Specifications of ADP2386-EVALZ

• Rohs: yes
• Tool Is For Evaluation Of: ADP2386
• Input Voltage: 4.5 V to 20 V
• Factory Pack Quantity: 1

Data Sheet
OUTPUT CAPACITOR SELECTION
The output capacitor is required to meet both the output voltage
ripple and load transient response requirements.
To meet the output voltage ripple requirement, use the following
equation to calculate the ESR and capacitance value of the output
capacitor:
This calculation results in C
To meet the ±5% overshoot and undershoot transient
requirements, use the following equations to calculate the
capacitance:
where:
K
∆I
∆V
∆V
This calculation results in C
According to the calculation, the output capacitance must be
greater than 63 μF, and the ESR of the output capacitor must be
smaller than 18 mΩ. It is recommended that one 100 μF/X5R/
6.3 V ceramic capacitor and one 47 μF/X5R/6.3 V ceramic
capacitor be used, such as the GRM32ER60J107ME20 and
GRM32ER60J476ME20 from Murata, with an ESR of 2 mΩ.
COMPENSATION COMPONENTS
For better load transient and stability performance, set the cross
frequency, f
therefore, the f
OV
STEP
OUT_OV
OUT_UV
= K
C
R
C
C
ESR
= 4 A is the load transient step.
OUT_RIPPLE
OUT_OV
OUT_UV
UV
=
= 5% V
= 5% V
= 2 are the coefficients for estimation purposes.
C
∆
=
=
, to f
V
OUT
C
=
(
2
∆
V
is set to 60 kHz.
OUT
OUT
×
SW
I
OUT
8
_
L
RIPPLE
(
/10. In this case, f
×
V
is the overshoot voltage.
is the undershoot voltage.
K
K
IN
+
f
UV
OV
SW
∆
−
V
×
×
V
×
OUT_RIPPLE
OUT_OV
OUT
OUT
∆
∆
∆
∆
I
I
I
V
_
STEP
L
STEP
)
OV
OUT
= 63.1 μF, and C
×
)
2
2
= 11.4 μF, and R
∆
_
2
×
RIPPLE
×
V
SW
−
L
OUT
L
V
is running at 600 kHz;
OUT
_
UV
2
OUT_UV
ESR
= 18 mΩ.
= 24.5 μF.
Rev. A | Page 19 of 24
The 100 µF and 47 µF ceramic output capacitors have a derated
value of 62 µF and 32 µF.
Choose standard components, as follows: R
C
Figure 34 shows the bode plot at 6 A. The cross frequency is
58 kHz, and the phase margin is 61°.
SOFT START TIME PROGRAM
The soft start feature allows the output voltage to ramp up in a
controlled manner, eliminating output voltage overshoot during
soft start and limiting the inrush current. Set the soft start time
to 4 ms.
Choose a standard component value, as follows: C
INPUT CAPACITOR SELECTION
Place a minimum 10 μF ceramic capacitor near the PVIN pin.
In this application, it is recommended that one 10 μF, X5R, 25 V
ceramic capacitor be used.
C
= 1200 pF, and C
–12
–24
–36
–48
–60
R
C
C
C
60
48
36
24
12
C
0
C
CP
SS
1k
= 2
= (0.55
=
= 0.002
t
SS
× ×
0.6 V 480 μs 8.7 A/ V
π
_
EXT
46.7 kΩ
Ω +
0
3.3V 94 μF 60 kHz
Ω ×
×
×
6 .
46.7 kΩ
CP
0.002
I
Figure 34. Bode Plot at 6 A
94 μF
SS
10k
= 4.7 pF.
×
_
UP
FREQUENCY (Hz)
×
Ω ×
=
) 94 μF
= 4.0 pF
4
×
ms
0
×
6 .
3
100k
V
2 .
= 1111 pF
= 46.7 kΩ
μA
C
= 44.2 kΩ,
= 21.3 nF
ADP2386
SS
= 22 nF.
1M
180
144
108
72
36
0
–36
–72
–108
–144
–180