3180

393

Audio ICs

BA3528AFP / BA3529AFP

FAttached components

(1)

Preamplifier

is below 30dB for a frequency of f = 1kHz, oscillation may

occur.

(2)

Playback equalizer terminal (NAB)

The playback equalizer characteristics are determined

by the RC circuit connected between the output and NF

pins.

For the circuit in Fig. 9, with a closed-loop voltage gain

of GVC at an input frequency of 1 kHz, the relationships

between the values of the RC circuit components are as

follows:

The equalizer can be switched on and off using the mute

amplifier. If equalization for metal tape is added, deter-

(3)

Pre-mute switching noise

If you use the mute amplifier for pre-muting,

the voltage difference between the pre-output and pin 22

will generate switching noise (a “pop” sound) when the

mute is switched on and off. To reduce the DC gain and

reduce this switching noise, we recommend that you

connect a resistor (R = 51 k

Ω) as shown in Fig. 10. This

resistor reduces the gain of the circuit in the bass region

of the playback equalizer as shown in the graph in Fig.

11. By using different combinations of component values

in the low-frequency region as shown in the graph in Fig.

12.