WM8978 Wolfson Microelectronics Ltd., WM8978 Datasheet - Page 12
Manufacturer Part Number
The WM8978 is a low power, high quality stereo codec designed for portable applications such as Digital still camera or Digital Camcorde
Wolfson Microelectronics Ltd.
Table 1 Power Consumption
Sleep (VREF maintained, no clocks)
Stereo Record (8kHz, PLL enabled)
Stereo 16Ω HP Playback (44.1kHz, PLL enabled, quiescent)
Stereo 16Ω HP Playback (44.1kHz, PLL enabled, white noise)
Stereo 16Ω HP Playback (44.1kHz, PLL enabled, sine wave)
1. DBVDD Current will increase with greater loading on digital I/O pins.
2. 5 Band EQ is enabled.
3. AVDD standby current will fall to nearer 15mA when thermal shutdown sensor is disabled.
Typical current consumption for various scenarios is shown below.
ESTIMATING SUPPLY CURRENT
When either the DAC or ADC is enabled approximately 7mA will be drawn from DCVDD when
DCVDD=1.8V and fs=48kHz. When the PLL is enabled approximately 1.5mA additional current will
be drawn from DCVDD.
As a general rule, digital supply currents will scale in proportion to sample rates. Supply current for
analogue and digital blocks will also be lower at lower supply voltages.
Power consumed by the output drivers will depend greatly on the signal characteristics. A quiet
signal, or a signal with long periods of silence will consume less power than a signal which is
Estimated supply current for the analogue blocks is shown in Table 2. Note that power dissipated in
the load is not shown.
PTD Rev 2.6 November 2005
Preliminary Technical Data