AKD4628 Datasheet, PDF (6/39 Pages) Asahi Kasei Microsystems – Evaluation board Rev.B for AK4628

ASAHI KASEI
[AKD4628]
n Analog output circuit
3.0Vpp
AK4628
ROUT1 28
LOUT1 27 ^{Same circuit}
22u
10k
NJM4580
+
-
4.7k
220
330p
ROUT2 26 ^{Same circuit}
4.7k
LOUT2 25 ^{Same circuit}
ROUT3 24 ^{Same circuit}
LOUT3 23 ^{Same circuit}
ROUT4 22 ^{Same circuit}
LOUT4 21 ^{Same circuit}
1st order LPF on this board
6.0Vpp
Signal
1) Frequency response of HPF
The HPF is implemented on board to cancel the DC offset of analog output of AK4628.
Frequency response of 1st-order HPF
| Amplitude |² = 1/{1+(fc/f)²}; fc=1/2πRC=0.7Hz@R=10k,C=22u
fin
20Hz
Frequency Response -0.006dB
2) Gain, S/N and frequency response of op-amp circuit
1st-order filter with non-inverting amp is implemented on board to double the analog output level and attenuate out-of-band
noise.
a) Gain
The gain is
1+4.7k/4.7k = +6.02dB.
Therefore the output level of this board is
0.51dBV(=3.0Vpp) + 6.02dB
= 6.53dBV = 6.00Vpp = 2.12Vrms.
<KM069700>
-6-
2002/9