1 analog input configurations, Cs53l30 – Cirrus Logic CS53L30 User Manual

Page 21

DS992F1

CS53L30

4.4 Capture-Path Inputs

Fig. 4-4

shows details of the various analog input gain settings, including control register fields.

Figure 4-4. Input Gain Paths

4.4.1

Analog Input Configurations

The CS53L30 implements fully differential analog input stages, as shown in

Fig. 4-5

. In addition to accepting fully

differential input signals, the inputs can be used in a pseudodifferential configuration to improve common mode noise
rejection with single-ended signals. In this configuration, a low-level reference signal is sensed at the ground point of the
internal mic or external mic jack and used as a pseudodifferential reference for the internal input amplifiers. Sitting between
the preamp and the PGA is an internal antialias filter with a first-order pole at 95 kHz and a first-order pole at 285 kHz.

Figure 4-5. Op-Amp Level Schematic—Analog Inputs

Fig. 4-6

shows the INx interface and the related connections recommended for a fully differential internal mic. These

connections are truncated in

Fig. 4-6

–6 to +12 dB

with 0.5-dB

steps

Bypass, +10,

or +20 dB

0 or +20 dB

and/or