Dual 105mW Headphone Amplifier with Digital Volume Control and Shutdown Mode

  • Rajkumar Sharma
  • 29 Views
  • moderate
  • Tested
  • SKU: EL125275
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This is a low noise Headphone Amplifier capable of delivering 105mW per channel of continuous average power into a 16Ω load with 0.1% (THD+N) from a 5V power supply. The project is based on the LM4811 chip from the boomer series. The board provides high-quality output power with a minimal number of external components. It features a digital volume control that sets the amplifier’s gain from +12dB to −33dB in 16 discrete steps using a two−wire interface or onboard 3 tactile switches. On-board jumper implements the shutdown feature. The chip also has an internal thermal shutdown protection mechanism.

Connector CN1 Audio Input

  • Pin 1 Audio Signal Input 1
  • Pin 2 GND
  • Pin 3 GND
  • Pin 4 Audio Signal Input 2

Connector CN3 Power Supply

  • Pin 1 +5V DC Input
  • Pin 2 GND

Others

  • Connector LS1 and LS2: Optional Speaker or Headphone Connection
  • Connector CN4: 3.5MM Stereo EP Female socket for Headphone
  • Connector CN2: External/Optional 2 Wire Gain Control
  • Jumper J1: Closes = Enable, J1 Open Shutdown
  • LED D1: Power LED
  • Switch 1: Clock Input, Increment Steps
  • Switch 2: Volume Down Operation
  • Switch 3: Volume Up Operation

Features

  • Operating Power Supply 5V DC
  • Output 105mW Stereo
  • On-Board Power LED
  • Digital Volume Control Range from +12dB to −33dB
  • “Click and Pop” Suppression Circuitry
  • THD+N at 1kHz, 105mW Continuous Average Output Power into 16Ω 0.1 % (typ)
  • THD+N at 1kHz, 70mW Continuous Average Power into 32Ω 0.1 % (typ)
  • Low Shutdown Current
  • 3 Tactile Switches to set the Gain
  • Optional 3 Pin Header Connector for 2 Wire Interface for Micro-Controller for Gain
  • On-Board Stereo EP Socket for Easy Headphone Interface
  • Optional 2 x Header Connector for Headphone/Speaker Connections
  • Header Connector for Power Supply
  • Jumper for Shutdown
  • PCB Dimensions 39.21 x 37.47 mm
  • 4 x 2.5MM Mounting Holes

Schematic

Parts List

NOQNTY.REFDESCMANUFACTURERSUPPLIERPART NO
11CN14 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5317-ND
21CN23 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5316-ND
31CN32 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
41CN43.5MM STEREO EP SOCKETCUI AUDIODIGIKEYCP1-3525N-ND
52C1,C2100uF/25VUNITED CHECMDIGIKEY565-EMHL250ARA101MF80GCT-ND
63C3,C4,C61uF/16V SMD SIZE 1206YAGEO/MURATADIGIKEY
72C5,C70.1uF/25V SMD SIZE 0805YAGEO/MURATADIGIKEY
81C8220uF/15V SMD SIZE 0805WURTHDIGIKEY732-8524-2-ND
91D1LED RED SMD SIZE 0805LITE ON INCDIGIKEY160-1427-1-ND
101J1JUMPERWURTHDIGIKEY732-5315-ND
112LS1,LS22 PIN MALE HEADER PITCH 2.54MMWURTHDIGIKEY732-5315-ND
121R1100K 5% SMD SIZE 0805YAGEO/MURATADIGIKEY
132R2,R3100E 5% SMD SIZE 0805YAGEO/MURATADIGIKEY
141R4330E 5% SMD SIZE 0805YAGEO/MURATADIGIKEY
151SW14 PIN TACTILE SWITCHNKK SWITCHDIGIKEYHP0215AFKP2-ND
161SW24 PIN TACTILE SWITCHNKK SWITCHDIGIKEYHP0215AFKP2-ND
171SW34 PIN TACTILE SWITCHNKK SWITCHDIGIKEYHP0215AFKP2-ND
181U1LM4811 10VSSOPTIDIGIKEYLM4811MM/NOPBTR-ND
191J1SHUNT FOR JUMPER SULLINS CONECTDIGIKEYS9001-ND

Connections



Gerber View

Photos

Video

LM4811 Datasheet

lm4811

PCB

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