ISD8101 Datasheet, PDF (14/21 Pages) List of Unclassifed Manufacturers – 1.5W Audio Amplifier with Chip Enable

ISD8101
7.2 SINGLE-ENDED ANALOG INPUT
The following application example is for reference. It is only to give a general idea of how to use the
ISD8101. Each end-product design must be optimized in its own system for the best performance in
terms of voice quality, power consumption, functionality, and other issues.
+5Vdc
Vin
Cin
Rg _{INV 5}
INP ₄
VREF
6
Cref
R3
R1
55k
5k
-
R2
5k
55k
+
R4
Device=Power^DD^eIvfo^iCcew_E=ln^Eenf,_taai^bf_sled CE
CE left as no-connon-ceocnntect
7
Bias
Generator
-
+
R5
R6
Vdd
8
0.1µF
1 ^SPN
Cbulk
RL
-
SPP
+
2
GND
ISD8101 ³
Figure 8-1 ISD8101 Application Diagram
DESIGN SUGGESTIONS
1.) Choose the desired Gain or amplification factor: G = R3/(R1+Rg) and then calculate the value for
Rg = R3/G - R1 and use R1=5.5k-ohm and R3=55k-ohm.
2.) Choose the desired high pass frequency: Fc = 1/(6.28*Rin*Cin) and then calculate the value for
Cin = 1/(6.28*Rin*Fc) and use Rin=Rg+R1 and Fc = high-pass frequency in Hz. Cin value is Farads.
It is best to choose Cin as small as possible. This will minimize cost and any pop/click sound.
3.) Choose the value for Cref. Note that Cref does not generate any pop/click timing and that the
main use for Cref is to filter any supply voltage noise. So, if the power supply noise is not a big
concern, then Cref can be small. Typical values for Cref can be between 0.1uF and 10uF, and a
recommended value for general applications is from 1uF to 4.7uF. In general, it is best if Cref is at
least 3x larger in value than Cin. This can help minimize the first-time power-on pop noise. After the
first-time power-on, the Cref value has no effect on pop/click performance.
4.) Choose the value for Cbulk. This value will depend on the both the physical layout (size and
length of PCB traces/wires) and the power supply properties. The suggested value for Cbulk is
100uF and is recommending to put close to the device . If the power supply is far away or weak, then
Cbulk may need to be a larger value. If the power supply is very close and has high current capacity,
then it may be possible to use a smaller value for Cbulk. If Cbulk is too small, the system can be
unstable and may oscillate.
ISD8101 Datasheet Rev. 1.8
- 14 -
Nov, 2012