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AS3421 AS3422

Datasheet - D e t a i l e d D e s c r i p t i o n

9.3.4

Over-Current Protection

The over-current protection has a threshold of 150-200mA and a debouncing time of 8 s. The stage is forced to OFF mode in an over-current

situation. After this, the headphone stage tries to power up again every 8ms as long as the over-current situation still exists or the stage is turned

off manually.

9.3.5

Parameter

9.4 Operational Amplifier

While AS3421 offers only one operational amplifier for feed-forward ANC, AS3422 features an additional operational amplifier stage to support

feed-back ANC or any other additional needed filtering.

Both operational amplifiers stages can be activated and used individually. While OP1 stage is always configured as inverting amplifier, OP2

stage can be also switched to a non-inverting mode with an adjustable gain of 0...+10.5dB.

Figure 21. Operational Amplifiers

Table 6. Headphone Output Parameter

Symbol

Parameter

Condition

Min

Typ

Max

Unit

Load Impedance

Stereo mode

16

Ω

Load Capacitance

Stereo mode

100

pF

Nominal Output Power

RL=64

Ω

12

mW

RL=32

Ω

24

mW

RL=16

Ω

34

mW

Power Supply Rejection Ratio

200Hz-20kHz, 720mVpp, RL=16

90

dB

AGND

IOP1L

OP1

IOP1R

QOP1R

QOP1L

IOP2L

OP2 non-inverting mode

IOP2R

QOP2R

QOP2L

AGND

0..10.5dB

AGND

0..10.5dB

AGND

IOP2L

OP2 inverting mode

IOP2R

QOP2R

QOP2L