MAX9791AEVKIT+

19-4315; Rev 0; 10/08 MAX9791A Evaluation Kit The MAX9791A evaluation kit (EV kit) demonstrates the MAX9791A IC, which combines a stereo Class D power amplifier, a DirectDrive® stereo headphone amplifier, and a 120mA, 4.75V low-dropout regulator (LDO) for notebook, tablet PC, and portable media player applications. Maxim’s DirectDrive technology eliminates the need for bulky DC-blocking capacitors at the output of the headphone amplifier. The EV kit is configured for a 12dB speaker amplifier gain and a 0dB headphone amplifier gain. It is designed to operate from a 4.5V to 5.5V speaker supply and an optional separate 2.7V to 5.5V headphone supply. The EV kit is capable of delivering up to 2W into a pair of 4Ω speakers and 180mW into a 32Ω headphone load. Features ♦ No DC-Blocking Output Capacitors Required at Headphone Output ♦ Speaker and Headphone Operation Speaker: 2W Stereo Output Headphone: 180mW DirectDrive Stereo Output ♦ Wake-on-Beep Function ♦ 120mA, 4.75V LDO ♦ Lead-Free and RoHS Compliant ♦ Fully Assembled and Tested Ordering Information PART TYPE MAX9791AEVKIT+ EV Kit +Denotes lead-free and RoHS compliant. Component List DESIGNATION QTY DESCRIPTION REQUIRED COMPONENTS 8 1μF ±10%, 10V X7R ceramic capacitors (0603) Murata GRM188R71A105K C3, C4, C29 3 1μF ±10%, 50V X7R ceramic capacitors (0805) Murata GRM21BR71H105K C7, C8, C9 3 0.1μF ±10%, 16V X7R ceramic capacitors (0603) Murata GRM188R71C104K 3 10μF ±10%, 10V X7R ceramic capacitors (0805) Murata GRM21BR71A106K C1, C2, C5, C6, C25–C28 C10, C30, C31 DESIGNATION QTY DESCRIPTION OPTIONAL COMPONENTS AVDD, HPVDD, PGND, SPOUTL+, SPOUTL-, SPOUTR+, SPOUTR- 7 Binding posts C11–C24, C32, C33 0 Not installed, ceramic capacitors (0603) HPL, HPR, PGND, SENSE, SPOL+, SPOL-, SPOR+, SPOR- 0 Not installed, small PCB test points R1, R2 2 20k
±1% resistors (0603) R3, R4, R13 3 40.2k
±1% resistors (0603) U1 1 Speaker and headphone amplifier with LDO (28 TQFN-EP*) Maxim MAX9791AETI+ HPOUT 1 3.5mm stereo headphone jack JU1, JU2, JU3 3 3-pin headers — 1 PCB: MAX9791A Evaluation Kit+ JU4, JU6 2 2-pin headers JU5 0 Not installed, 2-pin header L1–L4 0 Not installed, inductors (6.4mm x 6mm x 1.5mm) R5–R8 4 0
±5% resistors (0805) R9–R12, R14, R15 0 Not installed, resistors (0603) DirectDrive is a registered trademark of Maxim Integrated Products, Inc. HPINL, SPINL 2 White side-entry phono jacks HPINR, SPINR 2 Red side-entry phono jacks R16 0 Not installed, resistor (0805) — 5 Shunts (JU1–JU5) *EP = Exposed pad. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 Evaluates: MAX9791A General Description Evaluates: MAX9791A MAX9791A Evaluation Kit Component Suppliers SUPPLIER PHONE Murata Electronics North America, Inc. WEBSITE 770-436-1300 www.murata-northamerica.com Note: Indicate that you are using the MAX9791A when contacting this component supplier. Quick Start Detailed Description of Hardware Recommended Equipment The MAX9791A evaluation kit (EV kit) demonstrates the MAX9791A IC in a 28-pin TQFN package. The IC combines a stereo Class D amplifier, a stereo DirectDrive headphone amplifier, and a 120mA, 4.75V low-dropout regulator (LDO) for notebook, tablet PC, and portable media player applications. Maxim’s DirectDrive technology eliminates the need for bulky DC-blocking capacitors at the headphone amplifier output. The IC features adjustable gain. Before beginning, the following equipment is needed: • One 5V, 3A DC supply • Two 4Ω speakers • One stereo headphone • Two audio signal sources Procedure The MAX9791A EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. 1) Verify that shunts are installed as follows: JU1: Pins 2-3 (speaker amplifier enabled) JU2: Pins 1-2 (headphone amplifier enabled) JU3: Pins 1-2 (LDO enabled) JU4: Installed (HPVDD connected to AVDD) JU6: Installed (wake-on-beep function disabled) 2) Set the power-supply output to 5V. 3) Disable the power-supply output. 4) Connect the power-supply ground to the PGND PCB pad and the power-supply positive output to the AVDD PCB pad. 5) Verify that the audio source output is disabled. 6) Connect the audio sources’ right channels to the SPINR and HPINR phono jacks and the left channels to the SPINL and HPINL phono jacks. 7) Plug the headphone into the HPOUT headphone jack. 8) Connect one speaker across the SPOUTL+ and SPOUTL- PCB pads and the other speaker across the SPOUTR+ and SPOUTR- PCB pads. 9) Enable the power-supply output. 10) Enable the audio source. 11) Verify that the headphones and speakers are playing the audio source signal. The EV kit is configured for a 12dB speaker amplifier gain and 0dB headphone amplifier gain. The gains can be adjusted by modifying the corresponding gain-setting resistors R1–R4. R1 and R2 set the speaker amplifier gain while R3 and R4 set the headphone amplifier gain. The EV kit is designed to operate from a 4.5V to 5.5V speaker supply and an optional separate 2.7V to 5.5V headphone supply. The EV kit is capable of delivering up to 2W into a pair of 4Ω speakers, 180mW into a 32Ω headphone load, and 120mA from the LDO output. In applications where speaker leads exceed 225mm, replace resistors R5–R8 with a surface-mount 0805 ferrite bead and install surface-mount 0603 capacitors for C11–C14. The speaker outputs do not require an output filter as the MAX9791A relies on the inherent inductance of the speaker coil and the natural filtering of an attached speaker. For optimum results, use a speaker with a series inductance > 10µH. The EV kit layout shows an optional speaker output filter for evaluation purposes. Shutdown Jumpers JU1, JU2, and JU3 enable or disable the speaker amplifier (SPKR_EN), the headphone amplifier (HP_EN), and the LDO (LDO_EN), respectively. See Tables 1, 2, and 3 for jumper JU1, JU2, and JU3 configuration. Table 1. Speaker Amplifier (Jumper JU1) SHUNT POSITION SPKR_EN PIN MAX9791A SPEAKER AMPLIFIER 1-2 Connected to AVDD Disabled 2-3* Connected to PGND Enabled *Default position. 2 _______________________________________________________________________________________ MAX9791A Evaluation Kit SHUNT POSITION HP_EN PIN MAX9791A HEADPHONE AMPLIFIER 1-2* Connected to AVDD Enabled 2-3 Connected to PGND Disabled Speaker and Headphone Gain Setting The default gain-setting resistors (R1 and R2) configure the speaker amplifier gain to 12dB. While the default gain-setting resistors (R3 and R4) configure the headphone amplifier gain to 0dB. The gain can be changed by replacing these resistors with other surface-mount 0603 resistors. Resistors with a tolerance of 1% are recommended for optimum performance. Use Table 5 and the following equations to select new gain-setting resistors for the corresponding channel: *Default position. Table 5. Component Function Table 3. LDO (Jumper JU3) CHANNEL RIN MAX9791A LDO Speaker right R1 Speaker left R2 Connected to AVDD Enabled Headphone right R3 Headphone left R4 Connected to PGND Disabled SHUNT POSITION LDO_EN PIN 1-2* 2-3 *Default position. Wake-on-Beep ⎛ 20kΩ ⎞ RIN = - 4 ⎜ ⎟kΩ ⎝ A VSPKR ⎠ Jumper JU6 controls the MAX9791A EV kit’s wake-onbeep feature. See Table 4 for jumper JU6 configuration. Refer to the Wake-on-Beep section of the MAX9791/ MAX9792 IC data sheet for more information. where AVSPKR is the desired speaker voltage gain. Table 4. Wake-on-Beep (Jumper JU6) where AVHP is the desired headphone voltage gain. SHUNT POSITION BEEP PIN* Installed** Connected to GND Wake-on-beep feature is disabled Connected to a user-supplied BEEP output A qualified BEEP signal† overrides HP_EN and SPKR_EN enabling the speaker and headphone amplifiers. The LDO must be enabled (see Table 3). Not installed RIN = − ⎛ 40.2kΩ ⎞ ⎜ ⎟ kΩ ⎝ A VHP ⎠ EV KIT FUNCTION *Do not leave the BEEP pin unconnected. **Default position. †Refer to MAX9791/MAX9792 IC data sheet. _______________________________________________________________________________________ 3 Evaluates: MAX9791A Table 2. Headphone Amplifier (Jumper JU2) Evaluates: MAX9791A MAX9791A Evaluation Kit Figure 1. MAX9791A EV Kit Schematic 4 _______________________________________________________________________________________ MAX9791A Evaluation Kit Evaluates: MAX9791A Figure 2. MAX9791A EV Kit Component Placement Guide—Component Side _______________________________________________________________________________________ 5 Evaluates: MAX9791A MAX9791A Evaluation Kit Figure 3. MAX9791A EV Kit PCB Layout—Component Side 6 _______________________________________________________________________________________ MAX9791A Evaluation Kit Evaluates: MAX9791A Figure 4. MAX9791A EV Kit PCB Layout—Layer 2 _______________________________________________________________________________________ 7 Evaluates: MAX9791A MAX9791A Evaluation Kit Figure 5. MAX9791A EV Kit PCB Layout—Layer 3 8 _______________________________________________________________________________________ MAX9791A Evaluation Kit Evaluates: MAX9791A Figure 6. MAX9791A EV Kit PCB Layout—Solder Side _______________________________________________________________________________________ 9 Evaluates: MAX9791A MAX9791A Evaluation Kit Figure 7. MAX9791A EV Kit Component Placement Guide—Solder Side Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 10 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.