Rainbow Electronics MAX98089 - Manual (Page 125)

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MAX98089
Low-Power, Stereo Audio Codec
with FlexSound Technology
Table 40. Unused Pins
Charge-Pump Flying Capacitor
The value of the flying capacitor (connected between
C1N and C1P) affects the output resistance of the charge
pump. A value that is too small degrades the device’s
ability to provide sufficient current drive, which leads to a
loss of output voltage. Increasing the value of the flying
capacitor reduces the charge-pump output resistance to
an extent. Above 1FF, the on-resistance of the internal
switches and the ESR of external charge- pump capaci-
tors dominate.
Charge-Pump Holding Capacitors
The holding capacitors (bypassing HPVSS to HPGND
and HPVDD to HPGND) value and ESR directly affect the
ripple at HPVSS and HPVDD. Increasing the capacitor’s
value reduces output ripple. Likewise, decreasing the
ESR reduces both ripple and output resistance. Lower
capacitance values can be used in systems with low
maximum output power levels. See the Output Power
vs. Load Resistance graph in the Typical Operating
Characteristics section for more information
Unused Pins
Table 40 shows how to connect the IC’s pins when circuit
blocks are unused.
NAME CONNECTION NAME CONNECTION
SPKRP Unconnected INB1 Unconnected
SPKRVDD Always connect INA2/MICEXTN Unconnected
SPKLVDD Always connect LRCLKS2 Unconnected
SPKLP Unconnected MCLK Always connect
RECN/RXINN Unconnected SDINS2 AGND
HPVDD Unconnected IRQ Unconnected
C1P Unconnected MIC1P/DIGMICDATA Unconnected
HPGND AGND INA1/MICEXTP Unconnected
SPKRN Unconnected DGND Always connect
SPKRGND Always connect BCLKS2 Unconnected
SPKLGND Always connect SDA Always connect
SPKLN Unconnected SCL Always connect
RECP/RXINP Unconnected REG Always connect
C1N Unconnected REF Always connect
HPL Unconnected MIC1N/DIGMICCLK Unconnected
HPVSS Unconnected MIC2P Unconnected
SDINS1 AGND SDOUTS2 Unconnected
LRCLKS1 Unconnected DVDDS2 DVDD
HPSNS AGND DVDD Always connect
INB2 Unconnected AVDD Always connect
HPR Unconnected PVDD Always connect
DVDDS1 DVDD AGND Always connect
SDOUTS1 Unconnected MICBIAS Unconnected
BCLKS1 Unconnected MIC2N Unconnected
JACKSNS Unconnected