AS3435 datasheet(86/102 Pages) AMSCO

86 / 102 page

AS3415/AS3435 – 86

ams Datasheet, Confidential: 2014-Jun-13 [v1-30]

P C B La y o ut Re comme nda t ion

Charge Pump

The Printed Circuit Board (PCB) layout of the charge pump is

essential for good audio performance. The layout

recommendation shown in Figure 107 shows the most

important components of the charge pump. These are CVBAT,

CFLY, CVNEG and the battery terminal. To guarantee lowest

output noise all three capacitors must be placed as close as

possible to the related pin on the AS3435/15 as shown in

Figure 1 & Figure 107. Additionally, it is recommended that the

ground pins on CVNEG, CVBAT and the AS3435/15 charge pump

pin (GND) have a short connection to each other. This will avoid

distribution of high frequency switching currents over the PCB.

All the ground pins should be connected with a single ground

plane or at least a strong connection directly to the battery

terminal. The layout example shown in Figure 107 makes use of

a ground plane on the top layer that is directly connected to

the negative battery terminal to feature a star shaped ground

concept.

Figure 107:

Charge Pump Layout Recommendation

AS3435 Charge Pump Layout Recommendation: This diagram shows the layout recommendation of the

AS3435 charge pump.

Charge Pump Ground Layout:

It is important to minimize the ground loops between all charge pump components and AGND pin.

A dedicated ground plane with a connection back to the negative battery terminal should be used.

PCB Layout Recommendation

GND

BAT

VNEG

FLY

AS3435

TOP LAYER

SILK SCREEN TOP LAYER

BOARD OUTLINE

VBAT

AS3435 데이터시트(PDF) 86 Page - ams AG