Nexperia USA Inc. 74HC7540DB,118

Overview

74HC7540DB,118 from Nexperia is an 8-bit inverting Schmitt-trigger buffer/line driver with 3-state outputs, dual active-low output enables (OE1, OE2), and CMOS-level inputs. It operates from 2.0 V to 6.0 V, delivers 7.8 mA sink/source drive at 4.5 V, and features 3.5 pF input capacitance and 24 ns typical propagation delay (VCC = 4.5 V, CL = 50 pF). It is used in industrial bus interface conditioning where noise immunity and slow-edge signal cleanup are required.

For engineers reviewing the 74HC7540DB,118 datasheet, 74HC7540DB,118 pinout, 74HC7540DB,118 application, or 74HC7540DB,118 equivalent, key selection criteria include Schmitt-trigger hysteresis (0.5 V typ. at VCC = 6.0 V), dual enable control for flexible bus arbitration, -40 °C to +125 °C operation, and SO20 (SOT163-1) package compatibility with legacy 74-series layouts.

Technical Context

This device implements eight independent inverting buffer channels, each with Schmitt-trigger input thresholds (VT+ = 4.2 V, VT− = 1.8 V at VCC = 6.0 V) and high-impedance 3-state outputs controlled by two separate enable inputs. The dual OE architecture allows partial bus isolation without full device disable.

Input clamp diodes permit safe interfacing to voltages exceeding VCC when current-limiting resistors are used. Static current consumption is ≤160 μA over temperature (VCC = 6.0 V), and dynamic power is determined by CPD = 29 pF, enabling accurate switching-power estimation in high-frequency digital systems.

Key Specifications

Pinout & Package

74HC7540DB,118 is supplied in a plastic small outline package (SO20, SOT163-1) with 20 leads and 7.5 mm body width. Pin 1 is index-marked; pins are numbered counterclockwise from the index corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting Schmitt buffer applications.

Compared with 74HC7540DB,118, the 74HCT7540DB,118 offers guaranteed TTL input compatibility at 5 V but sacrifices 2.0 V minimum supply capability; the SN74LVTH16244DGGR provides double channel count and higher drive but lacks Schmitt inputs and requires 3.3 V-only operation.

Availability

74HC7540DB,118 is available at Aetrix Electronics and suitable for industrial bus interface, switch debounce, legacy logic translation, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for 74HC7540DB,118 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a global semiconductor expert delivering high-performance, reliable logic, discrete, and MOSFET solutions optimized for efficiency and miniaturization in industrial, automotive, and consumer applications.

The 74HC7540 belongs to Nexperia's HC logic family, designed for low-power, wide-supply-voltage digital interfacing with robust noise immunity and legacy pin compatibility.

FAQ

What is the maximum clock frequency supported by the 74HC7540DB,118?

The 74HC7540DB,118 is not a clocked device-it has no internal clock or synchronous operation. Its usable signal frequency depends on propagation delay (24 ns typ. at 4.5 V) and load capacitance. For clean 50% duty-cycle square waves, maximum reliable toggle rate is ~20 MHz with 50 pF load; higher frequencies require derating for rise/fall time and skew.

Can OE1 and OE2 be tied together for single-enable operation?

Yes-OE1 and OE2 may be paralleled and driven by a common control signal. This configuration behaves identically to a single-enable 8-bit buffer. No additional components are needed, and the combined enable threshold remains compatible with standard CMOS logic levels across the full 2.0–6.0 V supply range.

Does the 74HC7540DB,118 support hot-swap or live-insertion?

No-74HC7540DB,118 is not hot-swap rated. Its inputs lack powered-off protection, and applying signals while VCC is absent risks forward-biasing internal clamp diodes, potentially causing latch-up or excessive current draw. Power sequencing must ensure VCC is stable before input signals are applied.

How does the Schmitt trigger improve performance versus a standard buffer?

The Schmitt trigger provides hysteresis (0.5 V typ. at 6 V), meaning the input threshold rises to VT+ on positive transitions and falls to VT− on negative transitions. This prevents multiple output toggles when input signals cross the threshold slowly or with noise-critical for mechanical switches, long traces, or unshielded sensors where edge jitter would otherwise cause false triggering.