AR1688 is a programmable chip, used for low cost IP phones, it replaces the famous open source PA1688. The architecture is the same, with 8-bit controller for VoIP protocol and 24-bit DSP for voice compression algorithm.
If you compare both chips, the AR1688 has more CPU processing speed and higher and better integration. The IP phone based on AR1688 has improved performance, better voice quality, more features at lower cost.
AR1688 specifications and cross reference with the PA1688:
- CPU clock speed: 48Mhz, the PA1688 ticks at 22Mhz
- DSP runs 60MIPS, the PA1688 runs 33MIPS
- Integrated high-quality audio codec, the PA1688 need external codec
- Integrated SRAM, no external SDRAM needed, the PA1688 needs 1×16 external SDRAM
- RoHS ready
- ICMP response time for 1472 bytes: 10ms, the PA1688 response 21ms)
- TFTP server data put through: 140kbytes/s
- MD5 48 bytes encryption calculation: 4.8ms, the PA1688 needs 9.9ms)
- Software API use open source SDCC compiler, the PA1688 uses commercial Keil C51
Bottom line, the AR1688 is faster, better and cheaper to integrate.