مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

AM25S557 and AM25S558 are high-speed combinational 8×8-bit multipliers. Both use a full adder array to form and sum partial products in a single unclocked operation, yielding a 16-bit parallel output product. Mode control inputs XM and YM allow the multiplier to accept either unsigned or two's complement numbers from their respective inputs, providing unsigned or signed outputs. Mode control lines are held low for unsigned input words and high for two's complement inputs. Both devices are easily expandable to longer word lengths; S₁₅ and S̄₁₅ can be used for expansion in either signed or unsigned mode without external inverters. In a 16-bit×16-bit configuration (32-bit output), typical multiply time is 110ns. Both configurations offer three-state output flexibility, with the AM25S557 adding a 16-bit transparent latch between the multiplier array and the three-state output buffers. The rounding configuration for 8-bit truncated output is specially optimized for maximum flexibility.

Features

• Multiplies two 8-bit numbers, producing a 16-bit result
• Combinatorial, no clock required
• Completes full 8×8 multiplication in 45ns typical
• Cascadable to 16×16 within 110ns
• Expandable in multiples of 8 bits
• LSB and MSB outputs provided for easy expansion
• Supports unsigned, two's complement, or mixed operands
• Common rounding algorithms implementable with additional logic
• Three-state outputs
• AM25S557 features 16-bit transparent latch
• Industry-standard pinout

Applications

• High-speed 16×16 two's complement multiplication