The Intersil HD-15531 is a high performance CMOS device intended to service the requirements of MIL-STD-1553 and similar Manchester II encoded, time division multiplexed serial data protocols. This LSI chip is divided into two sections, an Encoder and a Decoder. These sections operate independently of each other, except for the master reset and word length functions. This circuit provides many of the requirements of MIL-STD-1553. The Encoder produces the sync pulse and the parity bit as well as the encoding of the data bits. The Decoder recognizes the sync pulse and identifies it as well as decoding the data bits and checking parity.

The HD-15531 also surpasses the requirements of MILSTD- 1553 by allowing the word length to be programmable (from 2 to 28 data bits). A frame consists of three bits for sync followed by the data word (2 to 28 data bits) followed by one bit of parity, thus, the frame length will vary from 6 to 32 bit periods. This chip also allows selection of either even or odd parity for the Encoder and Decoder separately.

This integrated circuit is fully guaranteed to support the 1MHz data rate of MIL-STD-1553 over both temperature and voltage. For high speed applications the 15531B will support a 2.5 Megabit/sec data rate.

The HD-15531 can also be used in many party line digital data communications applications, such as a local area network or an environmental control system driven from a single twisted pair of fiber optic cable throughout a building.

• Support of MIL-STD-1553
• Data Rate (15531B) 2.5 Megabit/Sec
• Data Rate (15531) 1.25 Megabit/Sec
• Variable Frame Length to 32 Bits
• Sync Identification and Lock-In
• Separate Manchester II Encode, Decode
• Low Operating Power 50mW at 5V