General Description

The AK7712A is a DSP(Digital Signal Processor) with built-in high performance 20bit 2ch ADC and 4ch DAC, on purposeto control the sound field. It is possible to calculate 383 steps on 44.1kHz and 48kHz sampling respectively. In case of 32kHz sampling, it can caluculate up to 511 steps. With a combination of this LSI and external memory for delay data,it can berealized easily to control the sound field such as Echo, Surround Presence Controller, and Key-control which are needed forsomething like Karaoke. Parametric Equalizing can be done without external memory.

特性 Features

[ DSP unit ]

?Word length: 24-bit (data RAM)

?Instruction cycle time: 54ns(maximum speed)

?Multiplier: 24 ×16 →40-bit

?Divider: 16 ÷16 →16-bit

?Program RAM: 384 ×32 bit

?External memory: DRAM,Pseudo-SRAM and SRAM can be connected (only use for delay data).

?Sampling frequency: 32kHz～48kHz

?Automatic clear function of external RAM:

47msec after bringing RST high at fs=48kHz (include internal data RAM)

?Microcomputer interface:

synchronized signal type 8-bit serial input 1 channel,

synchronized signal type 24-bit serial output 1 channel

?Master clock: 512(511)/384(383)/256(255)fs

The value inside ( ) is maximum calculation steps.

512fs mode is available when 32kHz sampling is chosen.

?Conversion of master/slave mode for LRCK and BCLK:

When master mode is selected, the outputs of LRCK and BCLK depend on the set-up for input format.

?Serial input ports(2~4ch), and output ports(2~6ch) : 16/20/24 bit words

[ ADC unit ]

?20-bit 64 ×Oversampling ?ΣADC: 2ch

?S/(N+D): 92dB

?DR, S/N: 98dB

[ DAC unit ]

?20-bit 128 ×Oversampling ?ΣDAC: 4ch

?S/(N+D): 86dB

?DR, S/N: 97dB

?Digital HPF (fc=1Hz)

[ Total ]

?Power supply: +5V

?Package: 100pin LQFP(0.5mm pitch)