Features: • Stereo Codec:
• DAC SNR 98dB, THD -84dB ('A' weighted @ 48kHz)
• ADC SNR 90dB, THD -80dB ('A' weighted @ 48kHz)
• On-chip Headphone Driver with 'capless' option- 40mW output power into 16 / 3.3V SPKVDD
• 0.9W output power into 8 BTL speaker / 5V SPKVDD- Capable of driving piezo speakers- Stereo speaker drive configuration
• Mic Preamps:
• Stereo Differential or mono microphone Interfaces- Programmable preamp gain- Psuedo differential inputs with common mode rejection- Programmable ALC / Noise Gate in ADC path
• Low-noise bias supplied for electret microphones
• Other features:
• Enhanced 3-D function for improved stereo separation
• Digital playback limiter
• 5-band Equaliser (record or playback)
• Programmable ADC High Pass Filter (wind noise reduction)
• Programmable ADC Notch Filter
• Aux inputs for stereo analog input signals or 'beep'
• On-chip PLL supporting 12, 13, 19.2MHz and other clocks
• Low power, low voltage- 2.5V to 3.6V (digital core: 1.62V to 3.6V)- power consumption <30mW all-on with 2.5V supplies
• 5x5mm 32-pin QFN packageApplication• Stereo Camcorder or DSCPinout
Specifications
| CONDITION |
MIN |
MAX |
| Digital supply voltage: DVDD |
GND - 0.3V |
GND + 7V |
| Analogue supply voltage: AVDD |
GND - 0.3V |
GND + 7V |
| Digital ground: DGND. Analogue ground: AGND1, AGND2 |
GND - 0.3V |
GND + 0.3V |
| Digital inputs: MCLK, VSMP, CLAMP |
GND - 0.3V |
GND + 0.3V |
| Digital outputs: DOUT |
GND - 0.3V |
DVDD2 + 0.3V |
| Analogue inputs: VINM, VINP, VREFIN |
GND - 0.3V |
AVDD + 0.3V |
| Reference pins: VRT, VRB |
GND - 0.3V |
AVDD + 0.3V |
| Operating temperature range: TA |
0°C |
+70°C |
| Storage temperature prior to soldering |
30°C max / 85% RH max |
| Storage temperature |
-65°C |
+150°C |
DescriptionThe WM8978 is a low power, high quality stereo codecdesigned for portable applications such as Digital still camera orDigital Camcorder.
The device integrates preamps for stereo differential mics, andincludes drivers for speakers, headphone and differential orstereo line output. External component requirements arereduced as no separate microphone or headphone amplifiersare required.
Advanced on-chip digital signal processing of the WM8978 includes a 5-bandequaliser, a mixed signal Automatic Level Control for themicrophone or line input through the ADC as well as a purelydigital limiter function for record or playback. Additional digitalfiltering options are available in the ADC path, to cater forapplication filtering such as 'wind noise reduction'.
The WM8978 CODEC can operate as a master or a slave. Aninternal PLL can generate all required audio clocks for theCodec from common reference clock frequencies, such as12MHz and 13MHz.
The WM8978 operates at analogue supply voltages from 2.5Vto 3.3V, although the digital core can operate at voltages downto 1.62V to save power. The speaker outputs and OUT3/4 lineoutputs can run from a 5V supply if increased output power isrequired. Individual sections of the chip can also be powereddown under software control.
WM8978 Data Sheet
