Cirrus Logic CDB5378 - Manual (Page 20)

CDB5378
20 DS639DB4
The CS3301A/02A amplifier outputs require a differential anti-alias RC filter, which is created by connect-
ing external 680
Ω
series resistors with 20 nF of high-linearity differential capacitance (2x 10 nF C0G) be-
tween each half of the rough and fine signals.
2.2.3 Delta-Sigma Modulator
The CS5373A
∆Σ modulator performs the A/D function for the differential analog signal from the
CS3301A/02A amplifier. The digital output from the modulator is an oversampled
∆Σ bit stream.
2.2.3.1 Rough-Fine Inputs - INR, INF
The modulator analog inputs are separated into rough and fine signals, each of which has a differential
anti-alias RC filter to limit the input signal bandwidth.
Figure 2. Quad Group Routing of RC Filter Components
INR+
INF+
INF-
INR-
INR+
INF+
INF-
INR-
Analog Signals Description
INR, INF Modulator analog rough / fine inputs
VREF Voltage reference analog inputs
Digital Signals
Description
MDATA Modulator delta-sigma data output
MFLAG Modulator over-range flag output
MCLK Clock input
MSYNC Synchronization input