ADP5304ACPZ-2-R7 datasheet(13/17 Pages) AD

13 / 17 page

Data Sheet

ADP5304

Rev. 0 | Page 13 of 17

APPLICATIONS INFORMATION

This section describes the external components selection for the

ADP5304. The typical application circuit is shown in Figure 26.

2.2µH

PGND

10µF

MLCC

10µF

MLCC

VOUT = 1.8V

PVIN

MODE

VID

VIN =

2.15V TO 6.50V

ADP5304

19.6kΩ

VINOK

EPAD

AGND

1MΩ

Figure 26. Typical Application Circuit

EXTERNAL COMPONENT SELECTION

The ADP5304 is optimized for operation with a 2.2 μH inductor

and 10 μF output capacitors for various output voltages using

the closed-loop compensation and adaptive slope compensation

circuits. The selection of components depends on the efficiency,

the load current transient, and other application requirements.

The trade-offs among performance parameters, such as

efficiency and transient response, are made by varying the

choice of external components.

SELECTING THE INDUCTOR

The high switching frequency of the ADP5304 allows the use of

small surface-mount power inductors. The dc resistance (DCR)

value of the selected inductor affects efficiency. In addition, it is

recommended to select a multilayer inductor rather than a

magnetic iron inductor because the high switching frequency

increases the core temperature rise and enlarges the core loss.

A minimum requirement of the dc current rating of the inductor

is for it to be equal to the maximum load current plus half of the

inductor current ripple (ΔIL), as shown by the following equations:

























OUT

–

IPK = ILOAD (MAX) +











 

where IPK is the peak inductor current.

Use the inductor series from the different vendors shown in Table 6.

OUTPUT CAPACITOR

Output capacitance is required to minimize the voltage overshoot,

the voltage undershoot, and the ripple voltage present on the

output. Capacitors with low equivalent series resistance (ESR)

values produce the lowest output ripple. Furthermore, use

capacitors such as X5R and X7R dielectric capacitors. Do not

use Y5V and Z5U capacitors, because they are unsuitable

choices due to their large capacitance variation over temperature

and their dc bias voltage changes. Because ESR is important,

select the capacitor using the following equation:

RIPPLE

COUT

ESR



where:

ESRCOUT is the ESR of the chosen capacitor.

VRIPPLE is the peak-to-peak output voltage ripple.

Increasing the output capacitor value has no effect on stability

and may reduce output ripple and enhance load transient response.

ADP5304 can charge up the conventional capacitor or super

capacitor. When choosing the output capacitor value, it is

important to account for the loss of capacitance due to output

voltage dc bias.

Use the capacitor series from the different vendors shown in Table 7.

Table 6. Recommended Inductors

Vendor

Model

Inductance (μH)

Dimensions (mm)

DCR (mΩ)

ISAT1 (A)

TDK

MLP2016V2R2MT0S1

2.2

2.0 × 1.6 × 0.85

280

1.0

Wurth

74479889222

2.2

2.5 × 2.0 × 1.2

250

1.7

Coilcraft

LPS3314-222MR

2.2

3.3 × 3.3 × 1.3

100

1.5

1 ISAT is the dc current at which the inductance drops 30% (typical) from its value without current.

Table 7. Input and Output Capacitors

Vendor

Model

Capacitance (μF)

Size

Murata

GRM188D71A106MA73

0603

Murata

GRM21BR71A106KE51

0805

Murata

GRM31CR60J107ME39

100

1206

ADP5304ACPZ-2-R7 Folha de dados(PDF) 13 Page - Analog Devices

ADP5304ACPZ-2-R7 Folha de dados(HTML) 13 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Folha de dados Download

Ligação URL