ADP5043ACPZ-1-R7 datasheet(22/30 Pages) AD

22 / 30 page

ADP5043

Data Sheet

Rev. C | Page 22 of 30

The peak-to-peak output voltage ripple for the selected output

capacitor and inductor values is calculated using the following

equation:



1/ 8

RIPPLE

COUT

OUT

ESR







where:

VRIPPLE

is allowable peak-to-peak output voltage ripple in volts.

IRIPPLE

is the inductor ripple current in Amperes.

ESRCOUT

is the equivalent series resistance of the output

capacitor in Ω.

fSW

is the converter switching frequency in Hertz.

The effective capacitance needed for stability, which includes

temperature and dc bias effects, is a minimum of 7 μF and a

maximum of 40 μF.

Table 12. Suggested 10 μF Capacitors

Vendor

Type

Model

Case

Size

Voltage

Rating (V)

Murata

X5R

GRM188R60J106

0603

6.3

Taiyo Yuden

X5R

JMK107BJ475

0603

6.3

TDK

X5R

C1608JB0J106K

0603

6.3

Panasonic

X5R

ECJ1VB0J106M

0603

6.3

The buck regulator requires 10 μF output capacitors to guaran-

tee stability and response to rapid load variations and to transition

in and out the PWM/PSM modes. In certain applications, where

the buck regulator powers a processor, the operating state is

known because it is controlled by software. In this condition,

the processor can drive the MODE pin according to the operating

state; consequently, it is possible to reduce the output capacitor

from 10 μF to 4.7 μF because the regulator does not expect a

large load variation when working in PSM mode (see Figure 50).

VIN1

VIN2

VOUT1

VOUT2

nRSTO

PGND

1µH

4.7µF

1µF

100kΩ

4.7µF

1µF

AVIN

RFILT

30Ω

MICRO PMU

ADP5043

PROCESSOR

VCORE

VDDIO

RESET

GPIO1

MODE

WDIx

GPIO2

ENx

GPIO[x:y]

VIN

2.3V TO 5.5V

Figure 50. Processor System Power Management with PSM/PWM Control

Input Capacitor

Higher value input capacitors help to reduce the input voltage

ripple and improve transient response. Maximum input

capacitor current is calculated using the following equation:

OUT

MAX

LOAD

CIN

)

(

)

(





To minimize supply noise, place the input capacitor as close

to the VIN pin of the buck as possible. As with the output

capacitor, a low ESR input capacitor is recommended.

The effective capacitance needed for stability, which includes

temperature and dc bias effects, is a minimum of 3 μF and a

maximum of 10 μF. Suggested capacitors are shown in Table 13.

Table 13. Suggested 4.7 μF Capacitors

Vendor

Type

Model

Case

Size

Voltage

Rating

(V)

Murata

X5R

GRM188R60J475ME19D

0603

6.3

Taiyo Yuden

X5R

JMK107BJ475

0603

6.3

Panasonic

X5R

ECJ-0EB0J475M

0402

6.3

LDO CAPACITOR SELECTION

Output Capacitor

The ADP5043 LDO is designed for operation with small, space-

saving ceramic capacitors but functions with most commonly

used capacitors as long as care is taken with the

ESR value. The ESR of the output capacitor affects stability of

the LDO control loop. A minimum of 0.70 μF capacitance

with an ESR of 1 Ω or less is recommended to ensure stability

of the LDO. Transient response to changes in load current is

also affected by output capacitance. Using a larger value of

output capacitance improves the transient response of the

LDO to large changes in load current.

Input Bypass Capacitor

Connecting a 1 μF capacitor from VIN2 to GND reduces

the circuit sensitivity to printed circuit board (PCB) layout,

especially when long input traces or high source impedance

is encountered. If greater than 1 μF of output capacitance is

required, increase the input capacitor to match it.

Table 14. Suggested 1.0 μF Capacitors

Vendor

Type

Model

Case

Size

Voltage

Rating

(V)

Murata

X5R

GRM155R61A105ME15

0402

10.0

TDK

X5R

C1005JB0J105KT

0402

6.3

Panasonic

X5R

ECJ0EB0J105K

0402

6.3

Taiyo Yuden

X5R

LMK105BJ105MV-F

0402

10.0

ADP5043ACPZ-1-R7 数据表(PDF) 22 Page - Analog Devices

ADP5043ACPZ-1-R7 数据表(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

数据表下载

链接网址

ADP5043ACPZ-1-R7 数据表(PDF) 22 Page - Analog Devices

ADP5043ACPZ-1-R7 数据表(HTML) 22 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

数据表 下载

链接网址

数据表下载