3-Wire Electret Microphone Pre-Amplifier
OPA1692 Pre-Amp: Low-noise, 3-wire electret mic pre-amp. Optimized for high-fidelity wireless audio & battery efficiency.
This 3-wire microphone pre-amplifier is designed using the low-power, low-noise, and low-distortion OPA1692 audio operational amplifier, making it ideal for high-performance electret microphone applications. The circuit is optimized for electret microphones that use a 3-wire interface, providing excellent audio quality while maintaining minimal power consumption.
The primary application of this pre-amplifier is in wireless microphone systems, where high audio fidelity and long battery life are essential. A typical wireless microphone consists of an electret microphone element, an analog pre-amplifier stage, and a transmission circuit that may use either analog or digital communication methods.
Since wireless microphones are usually battery-powered, power efficiency is a critical design requirement. The OPA1692-based pre-amplifier delivers clean signal amplification with very low noise and distortion while consuming minimal power, helping to extend battery life without compromising audio performance. This makes it well suited for portable audio equipment, wireless microphones, voice communication devices, and other battery-operated audio applications.
Credits: Schematic from Texas Instruments Applications, user must refer the data sheet of OPA1692 Op-Amp for details information,
Features
- Power Supply +/-5V DC
- Current Consumption less than 1.5mA (Without LED)
- Maximum Sound Level Pressure SPL 120dB
- On Board Power LED
- Bandwidth 20Hz to 20Khz
- Gain 11.79 V/V or 21.43 dB
- PCB Dimensions: 25.88 x 13.34 mm
Connections
- CN1: Pin 1 = +5V DC, Pin 2 = GND, Pin 3 = -5V
- CN2: Pin 1 = Audio Output, Pin 2 = GND
- D1: Power LED
- MIC: Pin 1 = +5V, Pin Signal, Pin 3 = GND
Schematic
Parts List
| NO. | QNTY. | REF. | DESC. | MANUFACTURER | SUPPLIER | SUPPLIER PART NO |
|---|---|---|---|---|---|---|
| 1 | 1 | CN1 | 3 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5316-ND |
| 2 | 1 | CN2 | 2 PIN MALE HEADER PITCH 2.54MM | WURTH | DIGIKEY | 732-5315-ND |
| 3 | 2 | C1,C3 | 22uF/16V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 4 | 4 | C2,C4,C5,C9 | 100nF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 5 | 1 | C6 | 100PF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 6 | 1 | C7 | 1uF/25V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 7 | 1 | C8 | 6.8nF/50V CERAMIC SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 8 | 1 | D1 | LED RED SMD SIZE 0805 | OSRAM | DIGIKEY | 475-1278-1-ND |
| 9 | 1 | MK1 | 3 PIN MICROPHONE | PRIMO COMPANY | DIGIKEY | 5956-EM273-ND |
| 10 | 1 | R1 | 2.2K 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 11 | 2 | R2,R8 | 100E 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 12 | 1 | R3 | 5.9K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 13 | 2 | R4,R6 | 100K 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 14 | 1 | R5 | 0E 5% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 15 | 1 | R7 | 1.1K 1% SMD SIZE 0805 | YAGEO/MURATA | DIGIKEY | |
| 16 | 1 | U1 | OPA1692 VSOP8 | TI | DIGIKEY | 296-49844-1-ND |
Connections
Gerber View
Photos
