74HC7540N,112

Overview

The NXP 74HC7540N,112 is an octal Schmitt trigger buffer and line driver featuring inverting outputs with three-state capability. It utilizes high-speed Si-gate CMOS technology and maintains pin compatibility with Low-power Schottky TTL (LSTTL). The device operates within a supply voltage range of 2.0 V to 6.0 V for the HC variant and includes two active LOW output enable inputs (OE1, OE2) to control the high-impedance OFF-state. It is housed in a DIP20 plastic dual in-line package (SOT146-1) and supports ambient temperatures from -40 °C to +125 °C.

Feature Summary

• Provides eight inverting buffer/line drivers with Schmitt-trigger action on data inputs to transform slowly changing signals into jitter-free outputs.
• Features three-state outputs controlled by separate OE1 and OE2 inputs, allowing high-impedance OFF-states when enabled HIGH.
• Includes robust ESD protection exceeding 2000 V per Human Body Model and 200 V per Machine Model standards.

Applications

• High-speed signal buffering and line driving applications requiring noise immunity.
• Digital systems needing isolated bus lines via three-state output control.
• Interfaces between logic families requiring LSTTL pin compatibility.

Procurement Notes

Verify the specific ordering suffix '112' against current NXP documentation to confirm packaging details, as datasheets may list standard suffixes like 'N' for DIP packages. Ensure the required temperature range (-40 °C to +125 °C) matches the application environment. Confirm that the DIP20 package form factor aligns with PCB layout constraints before finalizing procurement orders.

Selection Notes

Select this component when eight independent inverting buffers with hysteresis are required. The Schmitt trigger inputs are essential for noisy environments or slow-rise/fall-time signals. Choose the HC version for wider supply voltage flexibility (2.0–6.0 V) compared to HCT. Verify that the DIP20 package fits the assembly process and that the power dissipation limits accommodate the thermal design.

Part Context

This part belongs to the 74HC7540/74HCT7540 family of octal buffers. It is functionally identical to the 74HC540 but distinguishes itself by incorporating Schmitt trigger hysteresis on all data inputs. This addition enhances noise rejection capabilities while maintaining the same pinout and three-state functionality as the standard non-hysteretic variants.

Replacement Considerations

The 74HC540 serves as a direct functional substitute if Schmitt trigger inputs are not required. Other 74HC-series octal buffers with three-state outputs may be compatible if pinouts match. Verify that any replacement meets the same electrical specifications and package dimensions.