ADP2147ACBZ-110-R7 Analog Devices Inc, ADP2147ACBZ-110-R7 Datasheet - Page 13

• Manufacturer Part Number: ADP2147ACBZ-110-R7
• Description: IC REG BUCK 800MA 3MHZ 6WLSCP
• Manufacturer: Analog Devices Inc
• Series: -r
• Type: Step-Down (Buck), PWM - Current Moder

Specifications of ADP2147ACBZ-110-R7

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 1.275V, 0.981V
• Current - Output: 800mA
• Frequency - Switching: 3MHz
• Voltage - Input: 2.3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-UFBGA, WLCSP
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: ADP2147ACBZ-110-R7TR

Vendor
Murata
Coilcraft®
Toko
TDK
Taiyo Yuden
APPLICATIONS INFORMATION
EXTERNAL COMPONENT SELECTION
Trade-offs between performance parameters such as efficiency
and transient response can be made by varying the choice of
external components in the applications circuit, as shown in
Figure 1.
Inductor
The high switching frequency of the ADP2147 allows for the
selection of small chip inductors. For best performance, use
inductor values between 0.7 μH and 3 μH. Recommended
inductors are shown in Table 6.
The peak-to-peak inductor current ripple is calculated using
the following equation:
where:
f
L is the inductor value.
The minimum dc current rating of the inductor must be greater
than the inductor peak current. The inductor peak current is
calculated using the following equation:
Inductor conduction losses are caused by the flow of current
through the inductor, which has an associated internal DCR.
Larger sized inductors have smaller DCR, which may decrease
inductor conduction losses. Inductor core losses are related to
the magnetic permeability of the core material. Because the
ADP2147 is a high switching frequency dc-to-dc regulator,
shielded ferrite core material is recommended for its low core
losses and low electromagnetic interference (EMI). Table 6
shows the suggested inductors that can be used for different
output current requirements; several inductors are also listed to
minimize PCB space for small current applications.
Table 6. Suggested 1.0 μH Inductors
Output Capacitor
Increasing the value of the output capacitor reduces the output
voltage ripple and improves load transient response. When
choosing the capacitor value, it is also important to account for
the loss of capacitance due to dc output voltage bias.
SW
is the switching frequency.
I
I
RIPPLE
PEAK
=
=
I
Model
LQM2MPN1R0NG0B
LQM18PN1R0
EPL2014-102ML
0603LS-102
MDT2520-CN
GLFR1608T1R0M-LR
CBMF1608T1R0M
LOAD
V
OUT
V
(
MAX
IN
×
(
×
V
)
f
IN
+
SW
I
−
RIPPLE
×
V
2
L
OUT
)
Dimensions
(mm)
2.0 × 2.0 × 1.4
1.8 × 1.27 × 1.1
2.0 × 1.6 × 0.9
1.6 × 0.8 × 0.33
2.5 × 2.0 × 1.2
1.6 × 0.8 × 0.8
1.6 × 0.8 × 0.8
I
(mA)
1400
700
900
400
1800
360
290
SAT
DCR
(mΩ)
85
52
59
81
100
80
90
Rev. 0 | Page 13 of 16
Ceramic capacitors are manufactured with a variety of dielectrics,
each with different behavior over temperature and applied voltage.
Capacitors must have a dielectric adequate to ensure the
minimum capacitance over the necessary temperature range
and dc bias conditions. X5R or X7R dielectrics with a voltage
rating of 6.3 V or 10 V are recommended for best performance.
Y5V and Z5U dielectrics are not recommended for use with any
dc-to-dc regulator because of their poor temperature and dc bias
characteristics.
The worst-case capacitance, accounting for capacitor variation
over temperature, component tolerance, and voltage, is
calculated using the following equation:
where:
C
TEMPCO is the worst-case capacitor temperature coefficient.
TOL is the worst-case component tolerance.
In this example, the worst-case temperature coefficient (TEMPCO)
over −40°C to +85°C is assumed to be 15% for an X5R dielectric.
The tolerance of the capacitor (TOL) is assumed to be 10%, and
C
Substituting these values in the equation yields
To guarantee the performance of the ADP2147, it is imperative
that the effects of dc bias, temperature, and tolerances on the
behavior of the capacitors be evaluated for each application.
The peak-to-peak output voltage ripple for the selected output
capacitor and inductor values is calculated using the following
equation:
EFF
OUT
is the effective capacitance at the operating voltage.
C
C
V
is 4.0466 μF at 1.8 V, as shown in Figure 34.
EFF
EFF
RIPPLE
6
5
4
3
2
1
0
0
= C
= 4.0466 μF × (1 − 0.15) × (1 − 0.1) = 3.0956 μF
=
OUT
Figure 34. Typical Capacitor Performance
(
2
× (1 − TEMPCO) × (1 − TOL)
1
π
×
f
SW
DC BIAS VOLTAGE (V)
2
)
V
×
IN
2
×
L
3
×
C
OUT
4
=
8
×
f
I
SW
5
RIPPLE
ADP2147
×
C
OUT
6