Nexperia USA Inc. 74HCT540DB,118

Overview

74HCT540DB,118 from Nexperia is an octal inverting 3-state buffer/line driver with dual active-low output enables (OE1, OE2), TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5 V), ±6 mA output drive capability, and operation over -40 °C to +125 °C. It interfaces microcontroller address/data buses to high-capacitance backplanes in industrial control I/O modules.

For engineers reviewing the 74HCT540DB,118 datasheet, 74HCT540DB,118 pinout, 74HCT540DB,118 application, or 74HCT540DB,118 equivalent, key selection criteria include TTL-level input compatibility, 3-state bus contention control, propagation delay (13–36 ns at VCC = 4.5 V), thermal derating for SSOP20 package, and latch-up immunity exceeding 100 mA per JESD78 Class II Level B.

Technical Context

This device implements eight identical inverting buffer stages, each with independent input-to-output signal path and shared 3-state control via two low-active enable inputs. Its dual OE architecture allows selective activation of subsets of outputs-e.g., OE1 controls Y0–Y3 while OE2 controls Y4–Y7-enabling partial bus gating without external logic.

The SSOP20 package (SOT339-1) features 0.65 mm pitch, 5.3 mm body width, and thermal resistance (Rthj-a) requiring derating above 100 °C at 10.0 mW/K. Input clamp diodes permit safe interfacing to voltages exceeding VCC when used with current-limiting resistors.

Key Specifications

Pinout & Package

SSOP20 plastic shrink small outline package (SOT339-1), 20-pin, 0.65 mm pitch, 5.3 mm body width, exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.

Compared with 74HCT540D,118, the 74HCT540DB,118 reduces board area by 45 % and improves thermal response in airflow-limited enclosures; versus SN74HCT540PWR, it offers 20 % higher creepage distance and simplified rework due to larger SSOP pad geometry.

Availability

74HCT540DB,118 is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, microcontroller bus expansion modules, legacy TTL bus repeaters, and automated test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for 74HCT540DB,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 logic, analog, and MOSFET solutions optimized for efficiency, reliability, and manufacturability in industrial and automotive applications.

The 74HCT540 belongs to Nexperia's high-speed CMOS logic family designed specifically for robust 5 V TTL-compatible interfacing in harsh industrial environments with guaranteed operation from -40 °C to +125 °C.

FAQ

Can 74HCT540DB,118 operate at 3.3 V supply?

No. The 74HCT540DB,118 is specified only for VCC = 4.5 V to 5.5 V per Table 5. At 3.3 V, input thresholds (VIH ≥ 2.0 V) remain valid, but VOH drops below 2.4 V and VOL rises above 0.55 V-violating TTL output swing requirements and risking downstream logic misreads. Use 74LVC540A for 3.3 V operation.

What is the maximum capacitive load this device can drive reliably?

At VCC = 4.5 V and Tamb = 25 °C, the device maintains tpd ≤ 30 ns and tt ≤ 15 ns up to CL = 50 pF (per Table 7). Driving >75 pF causes measurable rise/fall time degradation (>20 ns) and potential timing violations in 20 MHz systems; add series termination or reduce trace length for heavier loads.

How do OE1 and OE2 interact when driven independently?

Both OE1 and OE2 are active-low and OR-connected internally: if either is HIGH, all outputs (Y0–Y7) enter high-impedance state regardless of the other's state. They cannot enable disjoint output subsets-simultaneous LOW on both is required for full 8-bit operation. This differs from devices with AND-gated enables.

Is the SSOP20 package RoHS-compliant and lead-free?

Yes. Per Nexperia's product compliance documentation, 74HCT540DB,118 (SOT339-1) is manufactured in full compliance with RoHS Directive 2011/65/EU and uses lead-free matte tin terminations. The package contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits.