Product Brief AS3510

Rev. 1v2, June 2004

CONFIDENTIAL

Page 7 of 19

Power Amplifier

Block Description

The Power Amplifier Block converts the differential output

signals from the AudioDAC into single ended signals with

the drive capability for impedances

≥4 ohms.

With the conversion from differential to single ended, the

transformation of DC level from AGND (=AVDD/2) to BGND

(=BVDD/2) is done. The gain of this driver stage can be set

by 4 digital input signals in the range from –39dB to +3dB in

steps of 3dB. With the maximum gain of +3dB, full scale

gives 4.95Vpp at the single ended output.

With I2S data giving full-scale swing, clipping will occur with

the max. gain-step. With min. BVDD of 3.0V the same is

true for the two highest gain-steps.

When the control signals Gain(3:0) are all set to “L”, the

block is set to power-down.

There is a BGND generation, which needs an external

capacitor of 100nF for blocking of low frequency

components at BVDD. With this external capacitor, a so

called “Klickless On” is performed so that at power-up, the

output terminals have a smooth startup to avoid any

transient noise in the headphone.

Gain

(3:0)

Gain

dif

se

FS Swing

Gain

(3:0)

Gain

dif

se

FS

Swing

H

H

H

H

+3dB

4.95Vpp

L

H

H

H

-21dB

309mVpp

H

H

H

L

0dB

3.50Vpp

L

H

H

L

-24dB

219mVpp

H

H

L

H

-3dB

2.47Vpp

L

H

L

H

-27dB

155mVpp

H

H

L

L

-6dB

1.75Vpp

L

H

L

L

-30dB

109mVpp

H

L

H

H

-9dB

1.24Vpp

L

L

H

H

-33dB

77mVpp

H

L

H

L

-12dB

0.87Vpp

L

L

H

L

-36dB

55mVpp

H

L

L

H

-15dB

0.62Vpp

L

L

L

H

-39dB

39mVpp

H

L

LL

-18dB

0.44Vpp

L

LLL

OFF

-

Table 9

Table of Gain Steps