Cirrus Logic CS42L73 - Manual (Page 18)

18 DS882F1
CS42L73
2.1 Low-Profile Charge-Pump Capacitors
The “Typical Connection Diagram” on page 17 shows that the recommended capacitor values for the charge pump
circuitry are all 2.2  F and the types are all X7R/X5R. Applications that require low-profile versions of these capac-
itors may use the following parts with a nominal height of only 0.5 mm:
Description: 2.2  F ±20%, 6.3 V, X5R, 0402, Height = 0.5 mm
Manufacturer, Part Number:
• KEMET, C0402C225M9PAC
2.2 Ceramic Capacitor Derating
The Typical Connection Diagram Capacitor Key highlights that ceramic capacitor derating factors can significantly
affect the in-circuit capacitance value and thus the performance of the CS42L73.
As is noted on the Typical Connection Diagram , the 4.7  F ceramic capacitors used for ANA_VQ or SPKR_VQ affect
low-frequency PSRR performance. Numerous types and brands of ceramic capacitors, under typical conditions, ex-
hibit effective capacitances well below their tolerance of ±20%, with some being derated by as much as -50%. These
same capacitors, when tested by a multimeter, read much closer to their rated value. A similar derating effect has
not been observed with tantalum capacitors.
The amount of derating observed varied with manufacturer and physical size; larger capacitors performed better as
did ones from Kemet Electronics Corp. and TDK Corp. of any size. This derating effect is described in datasheets
and applications notes from capacitor manufacturers. For instance, as DC and AC voltages are varied from the stan-
dard test points (applied DC and AC voltages for standard test points vs. PSRR test are 0 V and 1 V
RMS
@ 1 kHz
vs. 0.9 V and ~1 mV
RMS
@ 20 Hz to 20 kHz), it is documented that the capacitance varies significantly.
Based on these tests, the following ANA_VQ/SPKR_VQ capacitor parts are recommended for applications that re-
quire ceramic capacitors with the smallest PCB footprint:
Description: 4.7  F ±20%, 6.3V, X5R, 0603
Manufacturer, Part Number:
• KEMET, C0603C475M9PAC
• TDK, C1608X5R0J475M