UPD63210GT NEC, UPD63210GT Datasheet - Page 13

• Manufacturer Part Number: UPD63210GT
• Description: 16-BIT D/A CONVERTER WITH BUILT-IN DIGITAL FILTER FOR AUDIO
• Manufacturer: NEC

3.8 Configuration of Analog LPF
configuration of the analog LPF can be simple. Furthermore, by incorporating the output buffer (BUFF) of the
D/A converter and the operational amplifier for LPF configuration, an analog LPF can be configured based on
an extremely small number of external components. LPF’s cutoff frequency can be set with an external constant
in accordance with the sampling frequency.
inserting an RC circuit between the BUFF output and AMP input. This diagram shows an example of configuring
a Butterworth filter whose gain is 0 dB.
electrical specifications (RL of the recommended operation range).
Because the stop band rejection of the built-in 8-times oversampling digital filter is large (90 dB), the
Figure 3-9 shows the configuration of the D/A converter output section. As such, an LPF is configured by
In this case, R1 becomes the load of the BUFF output pin; therefore, ensure that the selection satisfies the
Figure 3-9. Configuration of D/A Converter Output Section (Configuration of Analog LPF)
LPF Configuration Example
Conditions
Cutoff frequency : fc = 30 kHz
Configuration
Gain
IC used
DF
DAC
DAC
Rch
Lch
: Primary Butterworth
: 0 dB
: PD63210
BUFF(R)
BUFF(L)
LO
RO
R1
LPF
LPF
C1
ANIL
APIL
APIR
ANIR
Parts constants
R1 = 7.5 k
C1 = 680 pF
AMP(R)
AMP(L)
-
+
+
-
AOL
AOP
PD63210, 63210L
Lch
analog out
Rch
analog out
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