CDB44L11 Cirrus Logic Inc, CDB44L11 Datasheet - Page 5

• Manufacturer Part Number: CDB44L11
• Description: EVALUATION BOARD FOR CS44L11
• Manufacturer: Cirrus Logic Inc
• Series: Popguard®r

Specifications of CDB44L11

• Amplifier Type: Class D
• Output Type: Headphones, 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 23mW x 2 @ 16 Ohm
• Voltage - Supply: 1.8 V ~ 2.4 V
• Operating Temperature: -10°C ~ 70°C
• Board Type: Fully Populated
• Utilized Ic / Part: CS44L11
• Description/function: Audio DSPs
• Operating Supply Voltage: 5 V
• Product: Audio Modules
• For Use With/related Products: CS44L11
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

CDB44L11
switching current. In most designs this may be omitted due to other system components loading
the supply line and dissipating the current. The resistive load is only used to simulate a circuit
load.
In the CS44L11, the output MOSFETs directly switch between ground and VA_HP, therefore the
performance of the audio output from the amplifier is adversely affected any disturbance on the
power rails. To get the best performance power supply characteristics and power supply de-cou-
pling are critical.
Dynamic Range will be affected by switching noise. To reduce switching noise large value power
supply bypass capacitors must be used. This circuit uses a 0.1 µF and 1.0 µF ceramic capacitor
as well as a 100 µF low ESR tantalum capacitor between the VA_HP supply rail and ground. Op-
timally these should be placed as close to the CS44L11 pins 12 and 13 as possible. If a DC-DC
converter is used in the system its switching frequency should be locked to the CS44L11 PWM
switching frequency to reduce switching noise.
Power supply source impedance has a direct affect on the output distortion. A DC-DC converter
is a very low impedance source and will offer the best THD+N performance. Using a linear power
supply offers the next lowest impedance, while running directly from batteries to the VA_HP pins
offers the highest impedance and therefore the highest distortion.
A 47 µH inductor (L1) is used on the digital power supply of the CS44L11 to suppress noise. This
may be omitted if system noise is not an issue in your design.
DS640DB1
5