APA0715 Просмотр технического описания (PDF) - Anpec Electronics

Номер в каталоге

Компоненты Описание

производитель

APA0715

3W Mono Fully Differential Audio Power Amplifier

Anpec Electronics 

APA0715

Function Description

Fully Differential Amplifier

The power amplifiers are fully differential amplifiers with

differential inputs and outputs. The fully differential ampli-

fier has some advantages versus traditional amplifiers.

First, don’t need the input coupling capacitors because

the common-mode feedback compensates the input bias.

The inputs can be biased from 0.5V to VDD-0.5V, and the

outputs are still biased at mid-supply of the power

amplifier. If the inputs are biased out of the input range,

the coupling capacitors are required. Second, the fully

differential amplifier has outstanding immunity against

supply voltage ripple (217Hz) cuased by the GSM RF trans-

mitters’ signal which is better than the typical audio

amplifier.

Thermal Protection

The over-temperature circuit limits the junction tempera-

ture of the APA0715. When the junction temperature ex-

ceeds TJ = +150oC, a thermal sensor turns off the

amplifiers, allowing the device to cool. The thermal sen-

sor allows the amplifiers to start-up after the junction tem-

perature cools down to about 125 oC. The thermal protec-

tion is designed with a 25 oC hysteresis to lower the aver-

age TJ during continuous thermal overload conditions,

increasing lifetime of the IC.

Over-Current Protection

The APA0715 monitors the output buffers’current. When

the over-current occurs, the output buffers’current will be

reduced and limited to a fold-back current level.

The power amplifier will go back to normal operation until

the over-current situation has been removed. In addition,

if the over-current period is long enough and the IC’s

junction temperature reaches the thermal protection

threshold, the IC enters thermal protection mode.

vide maximum device performance. By switching the SD

pin to a low level, the amplifier enters a low-consump-

tion-current state, IDD for APA0715 is in shutdown mode.

Under normal operating, APA0715’s SD pin should pull

to a high level to keep the IC out of the shutdown mode.

The SD pin should be tied to a definite voltage to avoid

unwanted state changing.

Shutdown Function

In order to reduce power consumption while not in use,

the APA0715 contains a shutdown function to externally

turn off the amplifier bias circuitry. This shutdown feature

turns the amplifier off when logic low is placed on the SD

pin for APA0715. The trigger point between a logic high

and logic low level is typically 1.8V. It is best to switch

between the ground and the supply voltage VDD to pro-

Copyright © ANPEC Electronics Corp.

15

Rev. A.1 - Dec., 2008

www.anpec.com.tw

Share Link: