Cirrus Logic CRD35L01 User Manual
Shutdown
Control (J2)
Speaker
Outpu t ( J 3)
Optional
Gain
Adjustment
Analog
Inpu t ( J 1 )
CS35L01
(SD Mode)
Optional
Output
Filter
VBATT
Power (J4 )
Shutdown
Control (J2)
Speaker
Outpu t ( J 3)
Optional
Gain
Adjustment
Analog
Inpu t ( J 1 )
CS35L01
(FSD Mode)
Optional
Output
Filter
VBATT
Power (J4)
Shutdown
Control (J2)
Speaker
Outpu t ( J 3)
Optional
Gain
Adjustment
Analog
Inpu t ( J 1 )
CS35L01
(HD M ode)
Optional
Output
Filter
VBATT
Power (J4)
Shutdown
Control (J2)
Speaker
Outpu t ( J 3)
Optional
Gain
Adjustment
Analog
Inpu t ( J 1 )
CS35L01
(FHD Mod e)
Optional
Output
Filter
VBATT
Power (J4)
CRD35L01
1 x 1.7 W CS35L01 Amplifier Reference Design Kit
Features
Four boards provided in the CS35L01 Amplifier
Reference Design Kit
Separate boards for each mode configuration
– SD, FSD, HD, and FHD
CS35L01 produces a default +6-dB Gain
Delivers 1.4 W/Ch into 8 at 1% THD+N
Delivers 1.7 W/Ch into 8 at 10% THD+N
Differential mono analog inputs
Demonstrates recommended 4-layer layout
and grounding arrangements
– Optional output filter connections
– Optional gain adjustment resistors
Powered by a single 2.5- to 5.5-V power supply
Device shutdown control
Description
The CRD35L01 demonstrates the CS35L01 high-efficiency Hybrid Class-D audio amplifier. This reference
design implements a single-channel amplifier that delivers 1.7 W per full-bridge channel into 8- loads using a
single +5-V supply.
Differential audio inputs can easily be connected
through the J1 header. If desired, the gain can be adjusted through the optional input resistors.
The -SD, -FSD, -HD, or -FHD suffix designates the
CS35L01’s operational mode. Each of the four boards
is configured to operate in each of the four corresponding modes of the CS35L01 device.
Device shutdown control is available through the J2
header.
ORDERING INFORMATION
CRD35L01 CS35L01 Reference Design
http://www.cirrus.com
Copyright Cirrus Logic, Inc. 2010
(All Rights Reserved)
APR '10
DS914RD2
TABLE OF CONTENTS
1. SYSTEM OVERVIEW ............................................................................................................................. 4
1.1 CS35L01 Hybrid Class-D Amplifier .................................................................................................. 4
1.2 Power Supply ................................................................................................................................... 4
1.3 Operational Modes ........................................................................................................................... 4
1.4 Shutdown Control ............................................................................................................................ 4
1.5 Amplifier Gain .................................................................................................................................. 4
1.5.1 Optional Input Gain Adjustment Resistors ...................................................... ... ... .... ... ... ........ 4
1.6 Differential Analog Inputs ................................................................................................................. 5
1.7 Speaker Outputs .............................................................................................................................. 5
1.7.1 Optional Speaker Output EMI Filter Components ........... ........................................................ 5
2. GROUNDING AND POWER SUPPLY DECOUPLING .......................................................................... 6
2.1 Power Supply Decoupling ................................................................................................................ 6
2.2 Electromagnetic Interference (EMI) ................................................................................................. 6
2.2.1 Suppression of EMI at the Source ......................... ... .... ... ... ... ... ....................................... ... ..... 6
3. SYSTEM CONNECTORS AND JUMPERS ....... ... ... ... .... ...................................... .... ... ... ... ... .... ... ... ... .... . 7
4. CRD SCHEMATIC .................................................................................................................................. 8
4.1 Bill of Materials ................................................................................................................................. 9
5. CRD LAYOUT ....................................................................................................................................... 10
6. REVISION HISTORY ............................................................................................................................ 14
CRD35L01
LIST OF FIGURES
Figure 1.Optional Bypass Trace Cut Locations ........................................................................................... 5
Figure 2.CRD35L01-SD Schematic ................... .... ... ... ... .... ... ... ... .... ... ... ... ... .... ... ... ..................................... 8
Figure 3.CRD35L01-FSD Schematic .................................................. .......................................... ... ........... 8
Figure 4.CRD35L01-HD Schematic .................................................... ... ... ... .... ... ... ... .... ... ... ........................ 8
Figure 5.CRD35L01-FHD Schematic .................................. ... ... ... .... ... ... ... ... .... ........................................... 8
Figure 6.CRD35L01-SD Top Side Component Placement . ... ... ... .... ... ... ... ... .... ... ... ... .... ... ... ... ... .... ... ... ... ... 10
Figure 7.CRD35L01-SD Bottom Side Component Placement .................. ............................................. ... 10
Figure 8.CRD35L01-SD Layer 1 Copper ........................ .... ... ... ... .... ... ... .......................................... ... ...... 10
Figure 9.CRD35L01-SD Layer 2 Copper ........................ .... ... ... ... .... ... ... .......................................... ... ...... 10
Figure 10.CRD35L01-SD Layer 3 Copper ................................................................................................ 10
Figure 11.CRD35L01-SD Layer 4 Copper ................................................................................................ 10
Figure 12.CRD35L01-FSD Top Side Component Placement ................................................................... 11
Figure 13.CRD35L01-FSD Bottom Side Component Placement ........................ ... ... .... ... ... ... ... .... ... ... ... ... 11
Figure 14.CRD35L01-FSD Layer 1 Copper .............................................................................................. 11
Figure 15.CRD35L01-FSD Layer 2 Copper .............................................................................................. 11
Figure 16.CRD35L01-FSD Layer 3 Copper .............................................................................................. 11
Figure 17.CRD35L01-FSD Layer 4 Copper .............................................................................................. 11
Figure 18.CRD35L01-HD Top Side Component Placement ............................ ... ... ... .... ... ... ... ................... 12
Figure 19.CRD35L01-HD Bottom Side Component Placement ............. ................ ................... ................ 12
Figure 20.CRD35L01-HD Layer 1 Copper ................................................................................................ 12
Figure 21.CRD35L01-HD Layer 2 Copper ................................................................................................ 12
Figure 22.CRD35L01-HD Layer 3 Copper ................................................................................................ 12
Figure 23.CRD35L01-HD Layer 4 Copper ................................................................................................ 12
Figure 24.CRD35L01-FHD Top Side Component Placement .......................... ................ ................ ......... 13
Figure 25.CRD35L01-FHD Bottom Side Component Placement ............................................................. 13
Figure 26.CRD35L01-FHD Layer 1 Copper .............................................................................................. 13
Figure 27.CRD35L01-FHD Layer 2 Copper .............................................................................................. 13
Figure 28.CRD35L01-FHD Layer 3 Copper .............................................................................................. 13
Figure 29.CRD35L01-FHD Layer 4 Copper .............................................................................................. 13
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LIST OF TABLES
Table 1. System Input and Output Connections ......................................................................................... 7
Table 2. J2 Shutdown Control Settings ....................................................................................................... 7
Table 3. Bill of Materials Listing .................................................................................................................. 9
CRD35L01
DS914RD2 3
CRD35L01
1. SYSTEM OVERVIEW
The CRD35L01 reference design is a practical means for eva luating the CS35L01 high-efficiency Class-D audio amplifier with idle current consumption. A differential mono analog input signal interface is provided. Option al input gain
and output filtering component placeholders are provided for easy modificatio n to custom tune the CS3 5L01 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 available in a 9-ball, WLCSP package. A complete description of the CS35 L01 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 r equire slightly differ ent hardware connections. 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 pro duct 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
by the R3 resistor, enabling normal operation.
line LOW and shuts down the amplifier. When no jumper is present, the SD line is pulled HIGH
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 CS35 L01 to operate
at its default gain. The gain adjustment resistors are necessary only when a gain of +6 dB is not desired.
4 DS914RD2
By adding series resistance to the input, the signal amplitude to the CS35L01 will be reduced, and will
Figure 1. Optional Bypass Trace Cut Locations
Cut the bypass
traces before inserting the optional
input gain adjustment resistors
Cut the bypass
traces before inserting the optional output filter ferrite
beads
reduce the overall system gain. The typical input impedance values of the CS35L01 can be found in the
device datasheet.
In order to use the optional gain adjustment resistors, the traces between the R1 pads and the traces between the R2 pads must be cut to break the bypass circuit, before populatin g R1 and R2 with the desired
resistance values. The location of these required cuts are sho wn in F i gure 1 . After th e trace be twe en th e
pads has been broken, the gain adjustment resistors can be added to the board.
1.6 Differential Analog Inputs
The differential audio inputs into the CS35L01 are provided by the 3-pin header (J1) through DC blocking
capacitors (C1 and C2). The C1 and C2 capacitors allow for an analog source to connect directly to the
CS35L01 regardless of any DC bias that may be present between the analog audio source’s outputs and
CS35L01 inputs.
1.7 Speaker Outputs
The CS35L01 power outputs are configured for a full-bridge, single audio channel. The outputs are routed
through an optional EMI output filter and then presented at the J3 header (OUT- and OUT+).
1.7.1 Optional Speaker Output EMI Filter Components
CRD35L01
As mentioned above, the CS35L01 contains optional placeholders for a series ferrite bead and shunt capacitor output filter. For most applications with very short speaker leads between the CS35L01 and the
speaker, use of these components will not be necessary. However, if there is a long signal path between
the CS35L01 and the speaker or if the system requires connecting to cables off the PCB, it is suggested
that the ferrite bead and capacitor are populated with the recommended values shown in Figure 3 on
page 9.
In order to use the optional output filter ferrite beads, the traces between the L1 pads and the traces between the L2 pads must be cut to break the bypass circuit, before populating L1 and L2 with the desired
component values. The location of these required cuts are shown in Figure 1.
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