Nexperia USA Inc. 74HCT154BQ,115

Overview

74HCT154BQ,115 from Nexperia is a TTL-level-compatible 4-to-16 line decoder/demultiplexer in DHVQFN24 package, operating from 4.5 V to 5.5 V over -40 °C to +125 °C. It decodes four binary address inputs (A0–A3) into sixteen active-LOW outputs (Y0–Y15), with dual active-LOW enable inputs (E0, E1) for cascading or demux mode. Used in memory address decoding and I/O expansion in industrial control logic systems.

For engineers reviewing the 74HCT154BQ,115 datasheet, 74HCT154BQ,115 pinout, 74HCT154BQ,115 application, or 74HCT154BQ,115 equivalent, key selection criteria include TTL input compatibility, 16-output active-LOW decoding behavior, thermal-enhanced QFN packaging, propagation delay ≤53 ns at 4.5 V, and operation across extended automotive-grade temperature range.

Technical Context

The 74HCT154BQ,115 implements a combinational logic decoder with two independent active-LOW enable inputs that force all outputs HIGH when asserted. Its internal architecture maps A0–A3 directly to one-of-sixteen decoded outputs without latching or clocking - output state changes synchronously with input transitions.

Input thresholds are fixed at VIH ≥ 2.0 V and VIL ≤ 0.8 V under 4.5–5.5 V supply, ensuring robust interfacing with legacy TTL families. All outputs drive ±4 mA at VCC = 4.5 V with VOL ≤ 0.25 V and VOH ≥ 3.98 V, supporting direct connection to standard CMOS/TTL loads without level-shifting.

Key Specifications

Pinout & Package

DHVQFN24 package (SOT815-1) with 24 terminals, no leads, exposed thermal pad (non-electrical, optional VCC or floating), body size 3.5 mm × 5.5 mm × 0.85 mm, pitch 0.5 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-to-16 decoder applications.

Compared with 74HC154BQ,115 and SN74LS154DR, the 74HCT154BQ,115 uniquely balances TTL input compatibility, low static current (<160 μA), and QFN thermal performance - making it optimal for new designs requiring robust 5 V interoperability and space-constrained layouts.

Availability

74HCT154BQ,115 is available at Aetrix Electronics and suitable for industrial control logic, automotive subsystem enable, memory address decoding, and I/O port expansion requiring stable component supply across extended temperature ranges.

Supply support for 74HCT154BQ,115 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, analog, and MOSFET solutions for automotive, industrial, and consumer markets.

The 74HCT series targets interoperability between legacy TTL and modern CMOS systems, emphasizing robust input compatibility, low power, and extended temperature operation for mission-critical control functions.

FAQ

What is the function of the two enable inputs (E0 and E1) on the 74HCT154BQ,115?

E0 and E1 are active-LOW enables: both must be LOW for normal decoding operation. If either is HIGH, all sixteen outputs (Y0–Y15) go HIGH regardless of address inputs. This allows cascading multiple 74HCT154s or using one enable as a data input in demultiplexer mode while holding the other LOW.

Can the 74HCT154BQ,115 operate at 3.3 V supply?

No - the 74HCT154BQ,115 is specified only for 4.5 V to 5.5 V operation. At 3.3 V, input thresholds (VIH ≥ 2.0 V) may not be reliably met by standard 3.3 V logic, and output drive capability degrades significantly. Use 74HC154BQ,115 instead for 2.0–6.0 V flexibility including 3.3 V systems.

Is the exposed thermal pad on the DHVQFN24 package electrically connected?

No - the exposed pad (terminal 1 index area) has no electrical function. Per Nexperia's datasheet, it may remain floating or be soldered to VCC, but must never be connected to GND or left unconnected with solder bridging. Thermal performance improves when tied to a VCC plane with adequate copper area.

How does the 74HCT154BQ,115 behave when address inputs are invalid (e.g., floating)?

With floating inputs, outputs become unpredictable due to undefined logic states. The device lacks internal pull-ups/downs; external biasing (e.g., 10 kΩ to VCC/GND) is required on A0–A3 and E0/E1 to ensure deterministic behavior. Unbiased inputs risk increased ICC, noise susceptibility, and potential latch-up in noisy environments.