ADP2302-EVALZ Analog Devices Inc, ADP2302-EVALZ Datasheet - Page 19

• Manufacturer Part Number: ADP2302-EVALZ
• Description: Nonsynchronous Step-Down Regulator Eval. Board
• Manufacturer: Analog Devices Inc

Specifications of ADP2302-EVALZ

• Silicon Manufacturer: Analog Devices
• Application Sub Type: Step Down DC/DC Converter
• Kit Application Type: Power Management - Voltage Regulator
• Silicon Core Number: ADP2302
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

INPUT CAPACITOR
The input capacitor must be able to support the maximum input
operating voltage and the maximum RMS input current. The
rms ripple current flowing through the input capacitor is, at
maximum, I
withstanding the rms ripple current for an application’s maxi-
mum load current using the following equation:
where D is the duty cycle and is equal to
The recommended input capacitance is ceramic with X5R or X7R
dielectrics due to its low ESR and small temperature coefficients.
A capacitance of 10 μF should be adequate for most applications.
To minimize supply noise, place the input capacitor as close as
possible to the VIN pin of the ADP2302/ADP2303.
OUTPUT CAPACITOR
The output capacitor selection affects both the output voltage ripple
and the loop dynamics of the regulator. The ADP2302/ADP2303
are designed to operate with small ceramic capacitors that have
low ESR and equivalent series inductance (ESL) and are, therefore,
easily able to meet stringent output voltage ripple specifications.
When the regulator operates in continuous conduction mode,
the overall output voltage ripple is the sum of the voltage spike
caused by the output capacitor equivalent series resistance
(ESR) plus the voltage ripple caused by the charging and
discharging of the output capacitor
Capacitors with lower ESR are preferable to guarantee low
output voltage ripple, as shown in the following equation:
Ceramic capacitors are manufactured with a variety of dielec-
trics, each with different behavior over temperature and applied
voltage. X5R or X7R dielectrics are recommended for best
performance, due to their low ESR and small temperature
Table 9. Recommended Capacitors for V
Vendor
Murata
TDK
I
D
Δ
ESR
IN
V
=
(
RIPPLE
RMS
Cout
V
V
OUT
)
IN
LOAD(max)
=
≤
=
+
I
+
Δ
Δ
V
Δ
LOAD
V
V
I
I
D
RIPPLE
D
RIPPLE
RIPPLE
/2. Select an input capacitor capable of
(max)
Value
22 μF, 6.3 V, X5R
47 μF, 6.3 V, X5R
22 μF, 6.3 V, X5R
33 μF, 6.3 V, X5R
47 μF, 6.3 V, X5R
×
×
⎛
⎜
⎜
⎝
8
D
×
×
f
sw
(
1
1
×
−
C
D
OUT
)
+
OUT
ESR
≤ 5.0 V
C
OUT
⎞
⎟
⎟
⎠
GRM31CR60J226KE19
C3216X5R0J226MB
C3216X5R0J336MB
Part No.
GRM32ER60J476ME20
C3225X5R0J476MB
Rev. 0 | Page 19 of 28
coefficients. Y5V and Z5U dielectrics are not recommended
because of their poor temperature and dc bias characteristics.
In general, most applications require a minimum output
capacitor value of 2 × 22 μF.
Some recommended output capacitors for V
provided in Table 9.
THERMAL CONSIDERATION
ADP2302/ADP2303 have an internal high-side MOSFET and
its drive circuit. Only a small amount of power dissipates inside
the ADP2302/ADP2303 package under typical load conditions,
which reduces thermal constraints.
However, in applications with maximum loads at high ambient
temperature and high duty cycle, the heat dissipated in the
package may cause the junction temperature of the die to
exceed the maximum junction temperature of 125°C. If the
junction temperature exceeds 150°C, the regulator goes into
thermal shutdown and recovers when the junction temperature
drops below 135°C.
The junction temperature of the die is the sum of the ambient
temperature and the temperature rise of the package due to
power dissipation, as indicated in the following equation:
where:
T
T
T
dissipation.
The rising temperature of the package is directly proportional
to the power dissipation in the package. The proportionality
constant for this relationship is the thermal resistance from the
junction of the die to the ambient temperature, as shown in the
following equation:
where:
T
θ
ambient temperature of the package.
P
JA
D
J
A
R
R
is the junction temperature.
is the rising temperature of the package due to power
is the rising temperature of the package.
is the ambient temperature.
is the power dissipation in the package.
is the thermal resistance from the junction of the die to the
T
T
J
R
= T
= θ
A
JA
+ T
× P
R
D
Dimensions L × W × H (mm)
3.2 × 2.5 × 2.0
3.2 × 2.5 × 2.0
3.2 × 1.6 × 0.85
3.2 × 1.6 × 1.3
3.2 × 2.5 × 2.5
ADP2302/ADP2303
OUT
≤ 5.0 V are