WM8987: CODEC with BTL headset driver


Description

The WM8987L is a low power, high quality stereo CODEC designed for portable digital audio applications. 

The device integrates complete interfaces to stereo or mono microphones and a stereo BTL (differential) or single-ended headset. External component requirements are reduced as no separate microphone or headphone amplifiers are required. Advanced on-chip digital signal processing performs equalisation, 3-D sound enhancement and automatic level control for the microphone or line input. 

The WM8987L can operate as a master or a slave, with various master clock frequencies including 12 or 24MHz for USB devices, or standard 256fs rates like 12.288MHz and 24.576MHz. Different audio sample rates such as 96kHz, 48kHz, 44.1kHz are generated directly from the master clock without the need for an external PLL. 

The WM8987L operates at supply voltages down to 1.8V, although the digital core can operate at voltages down to 1.42V to save power, and the maximum for all supplies is 3.6 Volts. Different sections of the chip can also be powered down under software control. 

The WM8987L is supplied in a very small and thin 4x4mm COL package, ideal for use in ultra-portable and wearable systems.

Features

  • DAC SNR 98dB, ADC 90dB (‘A’ weighted) at 48kHz, 3.3V
  • On-chip Headphone Driver
    - Single-ended or BTL (differential) drive
    - >40mW output power on 16Ω / 3.3V
    - DAC to 32Ω BTL headphone: SNR 86dB, THD -66dB
  • Complete Stereo / Mono Microphone Interface
    - Differential or single-ended mic connection
    - Programmable ALC / Noise Gate
  • Digital Equaliser
  • Low Power
    - Stereo playback 8 mW (1.8V / 1.5V supplies)
    - Record & playback 13 mW (1.8V / 1.5V supplies)
  • Low Supply Voltages
    - Analogue 1.8V to 3.6V
    - Digital core: 1.42V to 3.6V
    - Digital I/O: 1.8V to 3.6V
  • 256fs / 384fs or USB master clock rates: 12MHz, 24MHz
  • Audio sample rates: 8, 11.025, 16, 22.05, 24, 32, 44.1, 48, 88.2, 96kHz generated internally from master clock
  • 4x4mm COL package
  • Register compatible with WM8750L