APA2011 datasheet(16/27 Pages) ANPEC

16 / 27 page

Rev. A.4 - Aug., 2013

www.anpec.com.tw

APA2011/2011A

Function Description

Fully Differential Amplifier

The APA2011/2011A is a fully differential amplifier with

differential inputs and outputs. The fully differential has

some advantages versus traditional amplifier. First, don’t

need the input coupling capacitors because the com-

mon-mode feedback will compensate the input bias. The

inputs can biased from 0.5V to V

DD-0.5V, and the outputs

still be biased at mid-supply of APA2011/2011A. If the in-

puts are biased out of the input range, the coupling ca-

pacitors are required. Second, don’t need the mid-sup-

ply capacitor (C

B) because any shift of the mid-supply of

APA2011/2011A will have the same affect for both positive

& negative channel, and will cancel at the differential

outputs. Third, the fully differential amplifier will cancel

the GSM RF transmitter’s signal (217Hz).

Class D Operation

OUTP

OUT

OUTP-VOUTN)

OUT

Output = 0V

Output > 0V

OUT

Output < 0V

OUTN

OUTP

OUTN

OUTP

OUT

OUTP-VOUTN)

OUT

OUTP-VOUTN)

Figure 1. APA2011/2011 Output Waveform (Voltage &

Current)

The APA2011/2011A modulation scheme is shown in fig-

ure 1. The outputs V

OUTP and VOUTN are in phase with each

other when no input signals. When output > 0V, the duty

cycle of V

OUTP is greater than 50% and VOUTN is less than

50%; when output <0V, the duty cycle of V

OUTP is less than

50% and V

OUTN is greater than 50%. This method reduces

the switching current across the load and reduces the I2R

losses in the load that improves the amplifier’s efficiency.

This modulation scheme has very short pulses across

the load, this making the small ripple current and very

little loss on the load, and the LC filter can be eliminated

in most applications. Added the LC filter can increase the

efficiency by filter the ripple current.

Non-Clipping Function (APA2011A)

Figure 2. APA2011A Non-Clipping Control Function

V=15dB

Maximum Output Power

V=0dB

The APA2011A provides the 15 steps Non-Clipping

Control, and the range is from 15dB to 0dB, 1dB/step.

When the output reaches the maximum power setting

value, the internal Programmable Gain Amplifier (PGA)

will decrease the gain for prevent the output waveform

clipping. This feature prevents speaker damage from

occurring clipping.

Using the DR pin to set the non-clipping function and

limit the output power. Disable the AGC, when V

DR<0.2VDD,

and if the 0.2V

DD<VDR<0.55VDD, the VDR is set to 0.55VDD by

internal, this is maximum power limit (Minimum the out-

put power).

(1)

Ω

SPK

)

(

−

SPK: Speaker Resistor (2)

APA2011 Datasheet(PDF) 16 Page - Anpec Electronics Coropration

APA2011 Datasheet(HTML) 16 Page - Anpec Electronics Coropration

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

Datasheet Descarga

Enlace URL