标签：模拟电子技术基础,模拟电子电路,http://www.5idzw.com
Reference Design for a Class-D,http://www.5idzw.com
Important Design Features
，Reference Design for a Class-D
Reference Design for a Class-D, 2.1 Channel, Audio Amplifier for an MP3 Player Docking Station
Abstract: This reference design demonstrates the use of the Class D audio amplifier in a stereo audio, docking station application. The MAX9736 2.1 demo box is a complete powered speaker dock that uses two MAX9736 ICs to drive a 3-channel speaker system consisting of two 2in satellite speakers and one 5in subwoofer. The reference design is intended to be used with a portable audio player as its main music source. The overall solution size is very compact and features active equalization, power-supply monitoring, and dynamic equalization for the subwoofer.
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- Compact all-in-one design
- Operates from a single 12V to 20V DC power supply
- High SPL output from a small box
- High-efficiency Class-D design
- Active EQ, including dynamic bass equalization
- Excellent sound quality from cost-effective drivers
Bill of Materials
| Designator | Qty | Description |
| C1 | 1 | 470µF ±20% 25V aluminum electrolytic capacitor Panasonic® EEU-FM1E471 |
| C2, C12, C310 | 3 | 0.1µF ±10% 50V X7R ceramic capacitor (0603) Murata® GRM188R71H104K TDK C1608X7R1H104K |
| C321 | 1 | 1µF (0603) |
| C16 | 1 | 10µF (1206) |
| C106, C109–111, C114, C206, C209–211, C214 | 10 | NS (0603) |
| C3–5 | 3 | 0.1µF ±10% 16V X7R ceramic capacitor (0603) Murata GRM188R71C104K TDK C1608X7R1C104K |
| C13 | 1 | 0.1µF (0603) |
| C316–317 | 2 | 0.1µF (0805) |
| C303 | 1 | 0.33µF (0603) |
| C302 | 1 | 0.47µF (0603) |
| C305, C307 | 2 | 100nF (0603) |
| C103–104, C203–204, C301 | 5 | 100pF (0603) |
| C121, C220–221, C120, C314–315 | 6 | 100pF (0603) |
| C117–119, C217–219 | 6 | 10nF (0603) |
| C107, C207 | 2 | 150pF (0603) |
| C306, C308 | 2 | 15nF (0603) |
| C6–10, C15, C313, C318–320 | 10 | 1µF ±10% 16V X7R ceramic capacitor (0603) Murata GRM188R71C105K TDK C1608X7R1C105K |
| C312, C14, C311 | 3 | 1µF (0603) |
| C216, C116 | 2 | 1µF (0805) |
| C100–101, C200–201 | 4 | 2.2µF (0805) |
| C304 | 1 | 2.2µF (0805) |
| C102, C108, C112, C115, C202, C215, C300 | 7 | 33pF (0603) |
| C208, C212 | 2 | 33pF (0603) |
| C322 | 1 | 33pF (0603) |
| C113, C213 | 2 | 4.7nF (0603) |
| C105, C205 | 2 | 68nF (0603) |
| C11, C309 | 2 | 220µF ±20% 35V aluminum electrolytic capacitor (10mm x 12.5mm) Panasonic EEUFM1V221 |
| J30 | 1 | 4-pin header HIROSE DF3A-4P |
| U7 | 1 | Opto-FET (DIP6-SMT) Fairchild™ H11F1SM |
| L100–101, L200–201, L300–301 | 6 | Ferrite bead (1206) |
| FB1 | 1 | Ferrite bead (1206) |
| J3 | 1 | 6-pin header |
| J10, J20 | 2 | 2-pin header HIROSE DF3A-2P |
| J2 | 1 | RCA® dual jack PCB mount |
| D1 | 1 | LED red (0603) |
| D5 | 1 | LED blue (0603) |
| Q2 | 1 | Transistor NPN (SOT23) Fairchild MMBT3904 |
| X1–2 | 2 | Connector, screw mount |
| R7 | 1 | Potentiometer 100K SMT |
| R303 | 1 | Potentiometer 20K SMT |
| J1 | 1 | Power jack, right angle Switchcraft® 722RA |
| R1 | 1 | 10kΩ ±5% resistor (0805) |
| R110, R210 | 2 | NS resistor (0603) |
| R111, R211 | 2 | 10.5kΩ ±5% resistor (0603) |
| R100, R200 | 2 | 100Ω ±5% resistor (0603) |
| R10 | 1 | 100kΩ ±1% resistor (0603) |
| R106, R108, R206, R208 | 4 | 10kΩ ±5% resistor (0603) |
| R300–301 | 2 | 10kΩ ±5% resistor (0603) |
| R2–3 | 2 | 10kΩ ±1% resistor (0603) |
| R113, R213 | 2 | 11kΩ ±5% resistor (0603) |
| R309, R311–312, R314 | 4 | 11kΩ ±5% resistor (0603) |
| R306 | 1 | 12kΩ ±5% resistor (0603) |
| R114, R214 | 2 | 137kΩ ±5% resistor (0603) |
| R305 | 1 | 14.7kΩ ±5% resistor (0603) |
| R112, R212 | 2 | 150Ω ±5% resistor (0603) |
| R317 | 1 | 1kΩ ±5% resistor (0603) |
| R107, R109, R207, R209 | 4 | 1MΩ ±5% resistor (0603) |
| R8–9, R315–316 | 4 | 2.2kΩ ±5% resistor (0603) |
| R101–102, R201–202 | 4 | 20kΩ ±5% resistor (0603) |
| R5 | 1 | 220Ω ±5% resistor (0603) |
| R310, R313 | 2 | 24.3kΩ ±5% resistor (0603) |
| R302 | 1 | 2kΩ ±5% resistor (0603) |
| R308 | 1 | 3.24kΩ ±5% resistor (0603) |
| R307 | 1 | 3.3kΩ ±5% resistor (0603) |
| R115, R215 | 2 | 30.1kΩ ±5% resistor (0603) |
| R4 | 1 | 4.22kΩ ±1% resistor (0603) |
| R103–104, R203–204 | 4 | 40kΩ ±5% resistor (0603) |
| R304 | 1 | 7.15kΩ ±5% resistor (0603) |
| R105, R205 | 2 | 0Ω resistor (0603) |
| D6 | 1 | Diode, dual, common-cathode (SOT-23-3) Fairchild MMBD4148CC |
| D2–3 | 2 | Zener diode 4.3V, 20mA (SOT-23) Central CMPZ5229B |
| SPK1, SPK2 | 2 | 2in full-range loudspeaker Tymphany® 830970 |
| SPK3 | 1 | 5.25in subwoofer loudspeaker Tymphany 830945 |
| U1 | 1 | Maxim® MAX9736BETJ+ (7mm x 7mm, 32-pin TQFN) |
| U2 | 1 | Maxim MAX9736AETJ+ (7mm x 7mm, 32-pin TQFN) |
| U3–5 | 3 | Maxim MAX4234 (TSSOP-14) |
| U6 | 1 | Maxim MAX809_EUR-T (SOT-23) |