New multi-level storage technology delivers uncompressed analogue storage on-chip

2005-03-01

Available from DT Electronics, the OKI ML2500 uses a new multi-level storage technology that enables on-chip storage of uncompressed analogue audio. By charging flash cells to levels equivalent to the analogue signal amplitude using 256 discrete levels, an 8-fold increase in storage compared to digital sampling is achieved. The technique also eliminates the noise and distortion introduced by encoding and decoding in systems that use intermediate digital processing, while still retaining record and playback times of up to 256 seconds using 1 MB of on-chip flash memory.

Designed for use in portable terminals, the ML2500 is a 3V chip that needs no back-up. It retains data for at least 10 years and is capable of 10,000 program/erase cycles. It operates from an internal oscillator at 8.192 MHz or can use an external reference between 4MHz and 8.192 MHz. An integral SPI interface provides connectivity to an external microcontroller.

Sampling frequencies are selectable at 4 kHz, 5.3 kHz, 6.3 kHz or 8 kHz and up to 320 phrases can be recorded. Phrase control features user-definable start/stop addresses and a low pass filter provides -40dB per octave attenuation to minimize noise.

Typical operating temperature range is -10 to +70°C and the ML2500 comes in a 32-pin TSOP package.