OTTAWA Nortel Networks Inc.'s microelectronics group is making its first big merchant semiconductor thrust since the Bay Networks merger, debuting a 28-channel T1 framer with an integrated M13 multiplexer the company calls the Lunar chip. Lunar is intended to address the channelized T3 market by carrying up to 672 DS-0 (64-kbit) or 28 DS-1 (1.5-Mbit) channels, a density several times that of traditional quad or octal framers on the market.
Meanwhile, Cirrus Logic Inc. (Fremont, Calif.) is concentrating on improved density for mixed-signal T1 line interface units (LIUs). The CS61584A device, a 68-mm LIU from Cirrus' Crystal Semiconductor subsidiary, reduces space by as much as 45 percent over traditional single-channel or quad analog interfaces for T1.
In Nortel's new framer, the T1/DS-1 interface of the Lunar chip can be configured in an octet bus-interface mode with robbed-bit signaling, or in a traditional four-pin-per-DS1 configuration. The 8-bit bus interface can be selected for synchronous or asynchronous operation. For special-purpose networks, the chip also supports DS-2 framing and M12 multiplexing. Superframe, extended superframe and transparent framing modes are also supported.
A remote test unit on the 204-pin Lunar chip generates and detects pseudo-random bit patterns at DS-0, DS-1 and DS-3 levels. Loop timing and reference timing at 1.544 MHz or 8 kHz are provided, as are all diagnostic and loopback M23 functions. The current BGA package is the limiting factor for the number of channels, and Nortel plans to examine other surface-mount packages to carry framing densities beyond 28 channels. The chip is available now at a price of $300 each in quantities of 10,000. Nortel also offers an evaluation board for $2,995.
The Cirrus/Crystal LIU device supports 3.3-V and 5-V operation, and is the only 3.3-V LIU to meet European CTR-12 and ETSI 300 011 jitter specs. The chip features a JTAG boundary-scan test port to verify chip-to-chip interconnects and path integrity. The LIU supports both predefined T1 and E1 pulse shapes, as well as user-programmable custom transmit pulse shapes. Cirrus uses a special patented technique for impedance matching, to eliminate the need for external load-matching resistors.
The CS61584A is offered in 64-pin thin quad flat pack and 68-pin plastic leadless chip carrier, in 3.3-V and 5-V versions for both packages. Pricing starts at $19.00 each in quantities of 1,000.