NXP Semiconductors TDA8932B Product Data Sheet

NXP Semiconductors TDA8932B Product Data Sheet Manual pdf 11 page image

TDA8932B_3 © NXP B.V. 21 June 2007. All rights reserved.Product data sheet Rev. 03— 21 June 2007 11 of 48NXP Semiconductors TDA8932BClass-D audio amplifier8.5 Diagnostic input and outputWhenever a protection is triggered, except for TF, pin DIAG is activated to LOW level (seeTable 6). An internal reference supply will pull-up the open-drain DIAG output toapproximately 2.4 V. This internal reference supply can deliver approximately 50 μA.Pin DIAG refers to pin CGND. The diagnostic output signal during different shortconditions is illustrated in Figure 6. Using pin DIAG as input, a voltage < 0.8 V will put thedevice into Fault mode.8.6 Differential inputsFor a high common-mode rejection ratio and a maximum of flexibility in the application,the audio inputs are fully differential. By connecting the inputs anti-parallel, the phase ofone of the two channels can be inverted, so that the amplifier can operate as a mono BTLamplifier. The input configuration for a mono BTL application is illustrated in Figure 7.In SE configuration it is also recommended to connect the two differential inputs inanti-phase. This has advantages for the current handling of the power supply at low signalfrequencies and minimizes supply pumping (see also Section 14.8).8.7 Output voltage buffersWhen pin POWERUP is set HIGH, the half supply output voltage buffers are switched onin asymmetrical supply configuration. The start-up will be pop free since the device startsswitching when the capacitor on pin HVPREF and the SE capacitors are completelycharged.Output voltage buffers:Fig 6. Diagnostic output for different short-circuit conditions001aad759≈ 50 msshorted loadamplifierrestart no restart≈ 50 ms0 V2.4 VV oshort tosupply line0 V2.4 VV oFig 7. Input configuration for mono BTL application001aad760IN1P OUT1audioinputIN2PIN2NIN1NOUT2