CDB-43L21 Cirrus Logic Inc, CDB-43L21 Datasheet - Page 28

• Manufacturer Part Number: CDB-43L21
• Description: EVAL BOARD FOR CS43L21
• Manufacturer: Cirrus Logic Inc

Specifications of CDB-43L21

• Number Of Dac's: 2
• Number Of Bits: 24
• Outputs And Type: 2, Single Ended
• Sampling Rate (per Second): 96k
• Data Interface: I²C, SPI™
• Dac Type: Voltage
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -10°C ~ 70°C
• Utilized Ic / Part: CS43L21
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 598-1282; CDB-43L21

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4.3.8
4.4
Serial Port Clocking
The D/A serial audio interface port operates either as a slave or master. It accepts externally generated
clocks in slave mode and will generate synchronous clocks derived from an input master clock (MCLK) in
master mode.
The frequency of the MCLK must be an integer multiple of, and synchronous with, the system sample rate,
Fs. The LRCK frequency is equal to Fs, the frequency at which audio samples for each channel are clocked
into or out of the device.
The SPEED and MCLKDIV2 software control bits or the M/S and MCLKDIV2 stand-alone control pins, con-
figure the device to generate the proper clocks in Master Mode and receive the proper clocks in Slave Mode.
The value on the M/S pin is latched immediately after powering up in Hardware Mode.
On-Chip Charge Pump
An on-chip charge pump derives a negative supply voltage from the VA_HP supply. This provides dual
rail supplies allowing a full-scale output swing centered around ground and eliminates the need for large,
DC-blocking capacitors. Added benefits include greater pop suppression and improved low frequency
(bass) response. Note: Series resistance in the path of the power supplies must be avoided. Any voltage
drop on the VA_HP supply will directly impact the derived negative voltage on the charge pump supply,
VSS_HP, and may result in clipping.
The FLYN and FLYP pins connect to internal switches that charges and discharges the external capacitor
attached, at a default switching frequency. This frequency may be adjusted in the control port registers.
Increasing the charge-pumping capacitor will slightly decease the pumping frequency. The capacitor con-
nected to VSS_HP acts as a charge reservoir for the negative supply as well as a filter for the ripple in-
duced by the charge pump. Increasing this capacitor will decrease the ripple on VSS_HP. Refer to the
typical connection diagrams in
values for the charge pump circuitry.
Software
Controls:
Hardware
Software
Control:
Control:
,
“DAC Control (Address 09h)” on page
“Charge Pump Frequency (Address 21h)” on page
“MCLKDIV2” pin 2
Figure 1 on page 9
“M/S” pin 29
Pin
or
Figure 2 on page 10
47 kΩ Pull-down
47 kΩ Pull-up
Setting
42.
LO
HI
53.
for the recommended capacitor
Slave
Master
No Divide
MCLK is divided by 2 prior
to all internal circuitry.
Selection
CS43L21
DS723A1