GENERAL DESCRIPTION

The AK7742 is a highly integrated audio digital processor, including two stereo 24bit DAC’s and one stereo ADC with input selector. The stereo DAC and ADC feature high performance, archiving 106dB and 96dB dynamic range respectively, 8kHz to 96kHz sampling rate are supported. The audio DSP has 1536step/fs parallel processing power, and 74k-bit delay memory allows surround processing, acoustic effect and parametric equalizers. Asthe AK7742 is a RAM based DSP, it is programmable for user requirements. The AK7742 is available in a space saving small 48pin LQFP package.

FEATURES

■ DSP:

- Word length: 24bit (Data RAM 24bit floating point)

- Instruction cycle: 13.6 ns (1536step/fs fs=48kHz; 9216step/fs fs=8kHz)

- Multiplier 20 x 16 → 36bit (double precision available)

- Divider 20 / 20 →20bit

- ALU: 40bit arithmetic operation (overflow margin 4bit) 24bit floating point arithmetic and

logic operation

- Program RAM: 1536 x 36bit

- Coefficient RAM: 1536 x 16bit

- Data RAM: 1536 x 24-bit (24bit floating point)

- Delay RAM: 74kbit (3072 x 24bit)

- Sampling frequency: 8kHz ~96kHz

- Master / Slave operation

- Serial signal input port (4ch) MSB justified 24bit / LSB justified 24 / 20 / 16bit and I2S

- Serial signal output port (6ch) MSB justified 24bit / LSB justified 24 / 16bit and I2S

■ ADC: 2ch (stereo)

- 24bit 64 x Over-sampling delta sigma (fs=8kHz~48kHz)

- DR, S/N: 96dB (fs=48kHz, fully differential input)

- S/(N+D): 84dB (fs=48kHz)

- Differential, Single-end Inputs

- Digital HPF (fc=1Hz)

- 3:1 Analog input selector

- Digital Volume (24dB~-103dB, 0.5dB Step, Mute)

■ DAC: 4ch (two stereo pairs)

- 24bit 128 x Over-sampling advanced multi-bit (fs=8kHz~96kHz)

- DR, S/N: 106dB

- S/(N+D): 92dB

- Differential output

- Digital Volume (24dB~-103dB, 0.5dB Step, Mute)

■ DSP Through Mode

■ I2C BUS interface for micro-controller

■ Power supply: +3.3V ±0.3V, internal regulator for 1.8V

■ Operating temperature range: -20°C~70°C

■ Package: 48pin LQFP (0.5mm pitch)