CRD-42L51 Cirrus Logic Inc, CRD-42L51 Datasheet - Page 6

• Manufacturer Part Number: CRD-42L51
• Description: Audio Modules & Development Tools Ref Bd Low-volt Stereo CODEC
• Manufacturer: Cirrus Logic Inc

Specifications of CRD-42L51

• Product: Audio Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6
3.8
3.9
3.10
3.11
Switch & Pushbutton
The POWER switch engages the AAA battery when switched to the ON position. Power is applied to the
board and the microcontroller initializes. The SELECT pushbutton switches allow the user to navigate back
and forth between the FUNCTION options. When both SELECT buttons are pushed simultaneously, the
state of the function that receives focus (indicated by a blinking LED) is toggled. The ADJUST buttons allow
the user to apply gain, attenuation and move the threshold levels of the ALC and Limiter (the level of each
is shown in the Level Meter LED’s). When both ADJUST buttons are pushed simultaneously, the state of
the CS42L51’s internal beep generator is toggled.
LEDs
The FUNCTION LEDs provide a visual indication of which functions are presently ON (constant illumination)
or OFF (no illumination) and which has received focus (periodic illumination). The Level Meter LEDs provide
a visual indication of the Line, MIC, S/PDIF, Bass and Treble volume levels as well as the Limiter and ALC
threshold levels (see
Level Meter LEDs are illuminated for a brief moment, reflecting the volume/threshold level, and flash when
the adjustment reaches the default level.
Error Indicators
Low Battery: When the battery voltage level in the AAA battery drops below approximately 0.96 V, this LED
will illuminate. Operation will continue until the level drops to approximately 0.70 V; but after a power cycle,
the DC-DC converter will only start up when the level is at least 1.1 V.
Receiver Error: If the S/PDIF function is enabled and the CS8416 loses its PLL lock (triggered by unpluggin
the cable from the optical connector, OPT1, or turning off the S/PDIF audio source), this LED will illuminate.
If the Line or MIC function is presently enabled, the CRD will automatically switch from the CS8416’s master
clock to the on-board oscillator and configure the CS42L51 accordingly for uninterrupted operation of the
Line or MIC input.
Layout
The CS42L51 requires only a minimal set of components to achieve specified performance results. Its inte-
grated ground-centered amplifier eliminates the need for bulky DC-blocking capacitors and only requires
two tiny ceramic capacitors for the charge pump. Additional components include load-stabilization circuitry
and power supply decoupling. See the CS42L51 data sheet for further details.
Figure 1 on page 8
ure 7 on page 14
page 16
out. The decoupling capacitors are located as close to the CS42L51 as possible. Extensive use of ground
plane fill in the reference design yields large reductions in radiated noise.
and
Figure 10 on page 17
show the component placement.
provides an overview of the connections to the CS42L51.
Section 2
for LED luminosity decode). When the selected function receives focus, the
show the inner layers, and
Figure 8 on page 15
Figure 11 on page 18
shows the top layout;
Figure 6 on page 13
shows the bottom lay-
CRD42L51
Figure 9 on
DS679RD1
and
Fig-