Cirrus Logic CRD35L01 - Manual (Page 4)

4 DS914RD2
CRD35L01
1. SYSTEM OVERVIEW
The CRD35L01 reference design is a practical means for evaluating the CS35L01 high-efficiency Class-D audio am-
plifier with idle current consumption. A differential mono analog input signal interface is provided. Optional input gain
and output filtering component placeholders are provided for easy modification to custom tune the CS35L01 for the
user’s specific system requirements.
1.1 CS35L01 Hybrid Class-D Amplifier
The CS35L01 Hybrid Class-D amplifier is a mono, full-bridge, closed-loop, +6-dB gain, audio amplifier avail-
able in a 9-ball, WLCSP package. A complete description of the CS35L01 device is included in the CS35L01
product data sheet.
1.2 Power Supply
A single +2.5 to +5.5 VDC power supply is required to power the CRD35L01. The supply must be capable
of delivering sufficient current for the intended power output. The supply provides power to the CS35L01.
The power supply connection to the board is provided by the header J4. The positive terminal is labeled
VBATT. The ground terminal is labeled GND.
1.3 Operational Modes
The CS35L01 device has four operational modes, each of which require slightly different hardware connec-
tions. Four boards are available to illustrate the hardware design differences between each of the four
modes. More information on the specifics of each operational mode can be found in the CS35L01/03 prod-
uct datasheet. The CRD names listed below are populated with a CS35L01 device.
• CRD35L01-SD: Standard Class-D Mode
• CRD35L01-FSD: Reduced-Frequency Standard Class-D Mode
• CRD35L01-HD: Hybrid Class-D Mode
• CRD35L01-FHD: Reduced-Frequency Hybrid Class-D Mode
The CRD35L01-SD schematic is shown in Figure 2 on page 8 . The CRD35L01-FSD schematic is shown in
Figure 3 on page 8 . The CRD35L01-HD schematic is shown in Figure 5 on page 8 . The CRD35L01-FHD
schematic is shown in Figure 5 on page 8 .
1.4 Shutdown Control
The J2 header contains shutdown control for the CS35L01 device. Placing a jumper across the J2 header
pulls the SD line LOW and shuts down the amplifier. When no jumper is present, the SD line is pulled HIGH
by the R3 resistor, enabling normal operation.
1.5 Amplifier Gain
The amplifier gain of the CS35L01 device is +6 dB by default. The amplifier gain can be reduced through
the use of the optional input gain adjustment resistors on the CRD35L01.
1.5.1 Optional Input Gain Adjustment Resistors
The CRD35L01 contains optional gain adjustment resistor placeholders (R1 and R2). By default, these
placeholders are not populated and are bypassed with a signal trace configuring the CS35L01 to operate
at its default gain. The gain adjustment resistors are necessary only when a gain of +6 dB is not desired.