Wolfson 公司的WM8737L是低功耗立体声模数转换器,特别设计用于手提设备应用如密你盘和存储器音/视频记录仪. WM8737L的SNR为97dB,THD为-84dB,具有可编程的麦克风前置放大器和自动音量控制,模拟电压1.8V-3.6V,数字I/O电压1.8V-3.6V,数字内核电压1.42V-3.6V,主要用在存储器音/视频记录仪,Minidisc记录仪和手提数字音乐系统.本文介绍了WM8737L主要特性,方框图以及麦克风输入电路图,WM8737L评估板电路图,材料清单和元件布局图.
The WM8737L is a low power stereo audio ADC designed specifically for portable applications such as minidisc and memory audio / voice recorders.
The device offers three sets of stereo inputs, which can be configured for line-level signals, for internal or table-top microphones, or for DC measurement (battery monitor). A programmable gain amplifier can be used for automatic level control (ALC) with user programmable hold, attack and decay times. The device also has a selectable high pass filter to remove residual DC offsets.
If the signal source is mono, the WM8737L can run in mono mode, saving power. It can also mix two channels to mono, either in the analogue or the digital domain.
Master or slave mode clocking schemes are offered. Stereo 24-bit multi-bit sigma-delta ADCs are used with digital audio output word lengths from 16-32 bits, and sampling rates from 8kHz to 96kHz supported.
The device is controlled via a 2 or 3 wire serial interface. The interface provides access to all features including gain controls, analogue or digital mono mixing, and power management facilities. The device is supplied in a leadless 5x5mm QFN package.

WM8737L主要特性:
SNR 97dB (‘A’weighted @ 3.3V, 48kHz, normal power mode)
THD –84dB (at –1dB, 3.3V, normal power mode)
Complete Stereo / Mono Microphone Interface
- Programmable microphone preamp
- Automatic Level Control
- Low-noise microphone bias voltage
Configurable Power / Performance
Low Power Mode
- 8.5mW at AVDD = 1.8V (stereo, mic preamps off)
- 20mW at AVDD = 3.3V (stereo, mic preamps off)
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, 12, 16, 22.05, 24,32, 44.1,48,88.2,96kHz generated internally from master clock
32-pin QFN package, 5 x 5 x 0.9mm

WM8737L应用:
Memory Audio/Voice Recorders
Minidisc Recorders
Portable Digital Music Systems