54ACT11885, 74ACT11885
8-BIT MAGNITUDE COMPARATORS

features

• Latchable P Input ports with Power-Up Clear
• Choice of Logical or Arithmetic (2's Complement) Comparison
• Data and PLE Inputs Utilize P-N-P Input Transistors to Reduce DC Loading Effects
• Approximately 35% Improvement in AC Performance Over Schottky TTL while Performing More Functions
• Cascadable to n-Bits while Maintaining High Performance
• 10% Less Power than STTL for an 8-Bit Comparison
• Inputs are TTL-Voltage Compatible
• New flow-Through Architecture to Optimize PCB Layout
• Center-Pin V_CC and GND Configurations to Minimize High-Speed Switching Noise
• EPIC^TM (Enhanced-Performance Implanted CMOS) 1-m Process

description

These advanced Schottky devices are capable of performing high-speed arithmetic or logic comparisons on two 8-bit binary or two's complement words. Two full decoded decisions about words P and Q are externally available at two outputs. These devices are full expandable to any number of bits without external gates. The P > Q and P < Q outputs of a stage handling less-significant bits may be connected to the P > Q and P < Q inputs of the next stage handling more-significant bits to obtain comparisons of words of longer lengths. The cascading paths are implemented with only a two-gate-level delay to reduce overall comparison times for long words. Two alternative methods of cascading are shown in the typical application data.

The latch is transparent when P Latch Enable (PLE) is high; the P input port is latched when PLE is low. This provides the designer with temporary storage for the P data word. The enable circuitry is implemented with minimal delay times to enhance performance when cascaded for longer words. The PLE and P and Q data inputs utilize p-n-p input transistors to reduce the low-level current input requirements to typically - 0.25 mA, which minimizes dc loading effects.

The 54ACT11885 is characterized for operation over the full military temperature range of -55°C to 125°C. The 74ACT11885 is characterized for operation from - 40°C to 85°C.