[AK4646]
<Caution for using Piezo Speaker>
When a piezo speaker is used, resistances more than 10Ω should be inserted between SPP/SPN pins and speaker in series,
respectively, as shown in Figure 34. Zener diodes should be inserted between speaker and GND as shown in Figure 34, in
order to protect SPK-Amp of AK4646 from the power that the piezo speaker outputs when the speaker is pressured. Zener
diodes of the following zener voltage should be used.
0.92 x SVDD ≤ Zener voltage of zener diodo (ZD in Figure 34) ≤ SVDD+0.3V
Ex) In case of SVDD = 3.8V: 3.5V ≤ ZD ≤ 4.1V
For example, zener diode which zener voltage is 3.9V (Min: 3.7V, Max: 4.1V) can be used.
ZD
SPK-Amp
≥10Ω
SPP
SPN
≥10Ω
ZD
Figure 34. Speaker Output Circuit (In case of using piezo spearker)
MS0557-E-05
2011/01
- 50 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
