DM74AS651NT

Overview

The DM74AS651NT is an octal bus transceiver and register manufactured by onsemi, housed in a 24-lead Plastic Dual-In-Line Package (PDIP). It operates within a supply voltage range of 4.5V to 5.5V and supports an operating temperature range of 0°C to +70°C. The device features edge-triggered D-type flip-flops with a maximum clock frequency of 90 MHz. Propagation delays are specified at 28.5 ns for LOW-to-HIGH transitions and 29 ns for HIGH-to-LOW transitions from the clock to the output. Output drive capabilities include a low-level current of 48 mA and a high-level current of -15 mA.

Feature Summary

• Incorporates an octal transceiver and an octal D-type register configured for data transmission between buses or internal registers.
• Features totem-pole 3-STATE outputs designed to drive highly-capacitive or relatively low-impedance loads directly without interface components.
• Includes select controls with a make-before-break configuration to eliminate glitches during transitions between stored and real-time data.

Applications

• Implementing buffer registers
• I/O ports
• Bidirectional bus drivers
• Working registers

Procurement Notes

Verify the package type matches the N24C designation for the 24-lead PDIP variant. Confirm that the application environment remains within the 0°C to +70°C operating temperature range. Ensure power supply voltages do not exceed the 5.5V maximum limit. Check for specific ordering suffixes if tape and reel packaging is required instead of standard tube packaging.

Selection Notes

Select this component when an octal bidirectional bus interface with storage capability is required. The AS logic family provides higher speed performance compared to standard TTL variants. Verify that the 3-STATE output characteristics align with the system's bus loading requirements. Consider the industrial-grade temperature specifications if broader environmental ranges are needed.

Part Context

This device belongs to the Fairchild Semiconductor DM74AS series, which utilizes an advanced oxide-isolated, ion-implanted Schottky TTL process. The DM74AS651 is functionally similar to the DM74AS652 but differs in specific control pin configurations for data direction. Both devices share identical switching specifications and package options.

Replacement Considerations

DM74AS652NT