AK4201 Datasheet, PDF (9/13 Pages) Asahi Kasei Microsystems – Stereo Cap-less HP-Amp

CONFIDENTIAL
[AK4201]
OPERATION OVERVIEW
■ 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 Figure 3.
Low ESR (Equivalent Series Resistance) capacitors (more than –35% difference including temperature characteristics
and piece to piece variations) are recommended for C1 and C2.
Headphone-amp negative voltage
Charge Pump Circuit
PVEE pin
CN pin
C1: 1uF
VSS1
CP pin
C2: 1uF
Figure 3. Charge Pump Circuit External Capacitor
■ 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 positive power supply for Charge pump is generated from the output of a regulator which is driven
by PVDD. 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.
Rev 0.2
2008/07
-9-