[AK4201]
OPERATION OVERVIEW
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Charge Pump Circuit
The charge pump operates by the output of a regulator which uses PVDD voltage. The negative power supply (PVEE) for
headphone amplifiers is generated from internal charge pump circuit. The external capacitors are showed in
Low ESR (Equivalent Series Resistance) capacitors with 1uF to 2.2uF (+/-35% or less difference including temperature
drift and a deviation over samples) are recommended for C1 and C2. The minimum value of capacitors should be more
than 0.65uF if temperature drifts and a deviation over samples are big.
Headphone-amp negative voltage
PVEE pin
C1: 1uF
CN pin
Charge Pump Circuit
C2: 1uF
CP pin
VSS1
Figure 3. Charge Pump Circuit External Capacitor
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Headphone-Amp (LOUT/ROUT pins)
Power supply voltage for headphone amplifiers is supplied by a regulator for positive power and a charge-pump for
negative power. The headphone amplifier output is single-ended and centered on VSS1(0V). Therefore, a capacitor for
AC-coupling can be removed. The minimum load resistance is 16Ω. The output impedance is 20Ω (typ) when
powered-down.
MS1077-E-01
-9-
2011/02
AKM [ ASAHI KASEI MICROSYSTEMS ]
