Wolfson 公司的WM8737L是低功耗立體聲模數轉換器,特別設計用于手提設備應用如密你盤和存儲器音/視頻記錄儀. WM8737L的SNR為97dB,THD為-84dB,具有可編程的麥克風前置放大器和自動音量控制,模擬電壓1.8V-3.6V,數字I/O電壓1.8V-3.6V,數字內核電壓1.42V-3.6V,主要用在存儲器音/視頻記錄儀,Minidisc記錄儀和手提數字音樂系統.本文介紹了WM8737L主要特性,方框圖以及麥克風輸入電路圖,WM8737L評估板電路圖,材料清單和元件布局圖.
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應用:
Memory Audio/Voice Recorders
Minidisc Recorders
Portable Digital Music Systems
圖1.WM8737L方框圖
圖2.WM8737L麥克風輸入電路圖
WM8737L評估板
The WM8737L is a low power ADC with 3 analogue stereo inputs pairs with the additional capability of d.c. input measurement.
This evaluation platform and documentation should be used in conjunction with the latest version of the WM8737L datasheet. The datasheet gives device functionality information as well as timing and data format requirements.
This evaluation platform has been designed to allow the user ease of use and give optimum performance in device measurement.
圖3.WM8737L評估板電路圖
圖4.WM8737L評估板模擬輸入電路圖
WM8737L評估板材料清單(BOM):
圖5.WM8737L評估板元件布局圖(頂層)
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