ADP2386-EVALZ Analog Devices, ADP2386-EVALZ Datasheet - Page 16

• 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

ADP2386
For a duty cycle that is larger than 50%, the minimum inductor
value is determined using the following equation:
The peak inductor current is calculated by
The saturation current of the inductor must be larger than the peak
inductor current. For ferrite core inductors with a quick saturation
characteristic, the saturation current rating of the inductor must
be higher than the current-limit threshold of the switch. This
prevents the inductor from reaching saturation.
The rms current of the inductor is calculated as follows:
Shielded ferrite core materials are recommended for low core
loss and low EMI. Table 7 lists some recommended inductors.
OUTPUT CAPACITOR SELECTION
The output capacitor selection affects the output ripple voltage
load step transient and the loop stability of the regulator.
For example, during a load step transient where the load is
suddenly increased, the output capacitor supplies the load until
the control loop can ramp up the inductor current. The delay
caused by the control loop causes output undershoot. The
output capacitance that is required to satisfy the voltage droop
requirement can be calculated using the following equation:
Table 7. Recommended Inductors
Vendor
Toko
Vishay
Wurth Elektronik
L (Minimum) =
I
I
C
PEAK
RMS
OUT_UV
=
= I
OUT
=
I
OUT
2
+
×
2
I ∆
(
+
V
2
K
L
IN
V
∆
UV
12
OUT
I
−
L
2
×
V
2
×
OUT
×
∆
I
Part No.
FDVE0630-R47M
FDVE0630-R75M
FDVE0630-1R0M
FDVE1040-1R5M
FDVE1040-2R2M
FDVE1040-3R3M
FDVE1040-4R7M
IHLP3232DZ-R47M-11
IHLP3232DZ-R68M-11
IHLP3232DZ-1R0M-11
IHLP4040DZ-1R5M-01
IHLP4040DZ-2R2M-01
IHLP4040DZ-3R3M-01
IHLP4040DZ-4R7M-01
744 325 120
744 325 180
744 325 240
744 325 330
744 325 420
1 (
f
STEP
SW
)
−
×
D
2
∆
)
×
V
OUT
L
_
UV
Rev. A | Page 16 of 24
where:
K
ΔI
ΔV
Another example occurs when a load is suddenly removed from
the output, and the energy stored in the inductor rushes into
the output capacitor, causing the output to overshoot.
The output capacitance that is required to meet the overshoot
requirement can be calculated using the following equation:
where:
ΔV
K
The output ripple is determined by the ESR and the value of the
capacitance. Use the following equations to select a capacitor
that can meet the output ripple requirements:
where:
ΔI
ΔV
R
in ohms (Ω).
Select the largest output capacitance given by C
and C
performance.
Value (µH)
0.47
0.75
1.0
1.5
2.2
3.3
4.7
0.47
0.68
1.0
1.5
2.2
3.3
4.7
1.2
1.8
2.4
3.3
4.2
ESR
UV
OV
STEP
L
OUT_UV
OUT_OV
OUT_RIPPLE
is the inductor current ripple.
is a factor, with a typical setting of K
is a factor, with a typical setting of K
is the equivalent series resistance of the output capacitor
C
C
R
OUT_RIPPLE
is the load step.
OUT_OV
OUT_RIPPLE
ESR
=
is the allowable undershoot on the output voltage.
is the allowable overshoot on the output voltage.
∆
is the allowable output ripple voltage.
=
V
OUT
to meet both load transient and output ripple
=
(
V
∆
OUT
8
I
_
L
RIPPLE
×
I
15.6
10.9
9.5
13.7
11.4
9.8
8.2
14
14.5
12
27.5
25.6
18.6
17
25
18
17
15
14
SAT
K
+
f
OV
SW
(A)
∆
V
×
×
OUT
∆
∆
∆
I
V
I
L
STEP
_
OUT
OV
_
)
2
RIPPLE
14.1
10.7
9.5
14.6
11.6
25
12
11
2
I
9.0
8.0
22.2
18.2
15
12
10
9.5
20
16
14
RMS
×
−
L
V
(A)
OUT
UV
OV
= 2.
= 2.
2
Data Sheet
OUT_UV
DCR (mΩ)
3.7
6.2
8.5
4.6
6.8
10.1
13.8
2.38
3.22
4.63
5.8
9
14.4
16.5
1.8
3.5
4.75
5.9
7.1
, C
OUT_OV
,