Analog MEMS Microphone Breakout - SPH8878LR5H-1 Hookup Guide
El Duderino, 
jenfoxbot 
Hardware Overview
The SparkFun Analog MEMS Microphone Breakout uses the SPH8878LR5H-1 microphone and amplifies the signal with an OPA344 OpAmp. Let's take a closer look at the SPH8878LR5H-1 and the other hardware on the board.
SPH8878LR5H-1 Microphone
The SPH8878LR5H-1 microphone from Knowles Electronics is a bottom port analog microphone that supports both single-ended and differential modes.
We opted for a single-ended output design on this breakout so it can act as a drop-in replacement for users with previous versions of the SparkFun MEMS microphone breakouts. The Left Out- pin is connected to a test point so savvy users who wish to use this microphone in differential mode can tap into that signal with some careful soldering.
The table below outlines some relevant specifications of the SPH8878LR5H-1. For a complete technical overview of the microphone, refer to the datasheet.
| Parameter | Min | Typ | Max | Units | Notes |
|---|---|---|---|---|---|
| Sensitivity | -45 | -44 | -43 | dBV/Pa | 94 dB SPL @ 1kHz, Single-Ended Mode |
| Signal-to-Noise Ratio ("SNR") | - | 66 | - | dBV/Pa | 94 dB SPL @ 1kHz, A-weighted Single-Ended Mode |
| Frequency Range | 7 | - | 36 | Hz(min)/kHz(max) | |
| Acoustic Overload Point | - | 134 | - | dB SPL |
The microphone receives audio input from the bottom of the board. The board breaks out the power pins (VCC and Ground) and the audio output (AUD) from the microphone:
- AUD - Audio signal output.
- VCC - Voltage input (2.3V to 3.6V). Supply current of about 265µA.
- GND - Ground.
OpAmp
The SparkFun breakout board includes an OPA344 operational amplifier with a gain of *64 and a frequency response range of 7.2Hz-19.7KHz. The amplifier's AUD output floats at one-half VCC when the mic detects no sound. When held at arms length and talked into, the amplifier will produce a peak-to-peak output of just about 200 mV.
Board Dimensions
The board measures 0.50"x 0.40" (12.70mm x 10.16mm).
