User guide

20 DS583F2
CS42516
4. APPLICATIONS
4.1 Overview
The CS42516 is a highly integrated mixed-signal 24-bit audio codec comprised of 2 analog-to-digital con-
verters (ADC), implemented using multi-bit delta-sigma techniques, 6 digital-to-analog converters (DAC)
and a 192 kHz digital audio S/PDIF receiver. Other functions integrated within the codec include indepen-
dent digital volume controls for each DAC, digital de-emphasis filters for DAC and S/PDIF, digital gain con-
trol for ADC channels, ADC high-pass filters, an on-chip voltage reference, and an 8:2 mux for S/PDIF
sources. All serial data is transmitted through two configurable serial audio interfaces with standard serial
interface support as well as enhanced one-line modes of operation, allowing up to 6 channels of serial audio
data on one data line. All functions are configured through a serial control port operable in SPI mode or in
I²C mode. 5 show the recommended connections for the CS42516.
The CS42516 operates in one of three oversampling modes based on the input sample rate. Mode selection
is determined by the FM bits in register “Functional Mode (address 03h)” on page 47. Single-Speed Mode
(SSM) supports input sample rates up to 50 kHz and uses a 128x oversampling ratio. Double-Speed Mode
(DSM) supports input sample rates up to 100 kHz and uses an oversampling ratio of 64x. Quad-Speed
Mode (QSM) supports input sample rates up to 192 kHz and uses an oversampling ratio of 32x.
Using the receiver clock recovery PLL, a low-jitter clock is recovered from the incoming S/PDIF data stream.
The recovered clock or an externally supplied clock attached to the OMCK pin can be used as the System
Clock.
4.2 Analog Inputs
4.2.1 Line-Level Inputs
AINR+, AINR-, AINL+, and AINL- are the line-level differential analog inputs. The analog signal must be
externally biased to VQ, approximately 2.7 V, before being applied to these inputs. The level of the signal
can be adjusted for the left and right ADC independently through the ADC Left and Right Channel Gain
Control Registers on page 61. The ADC output data is in two’s complement binary format. For inputs
above positive full scale or below negative full scale, the ADC will output 7FFFFFH or 800000H, respec-
tively and cause the ADC Overflow bit in the register “Interrupt Status (address 20h) (Read Only)” on
page 63 to be set to a ‘1’. The RXP/GPO pins may also be configured to indicate an overflow condition
has occurred in the ADC. See “RXP/General-Purpose Pin Control (addresses 29h to 2Fh)” on page 69
for proper configuration. Figure 6 shows the full-scale analog input levels. See “ADC Input Filter” on
page 73 for a recommended input buffer.
AIN+
AIN-
Full-Scale Input Level= (AIN+) - (AIN-)= 5.6 Vpp
4.1 V
2.7 V
1.3 V
4.1 V
2.7 V
1.3 V
Figure 6. Full-Scale Analog Input