Renesas 74LS156P-E

Overview

74LS156P-E from Renesas Electronics is a dual 2-line-to-4-line decoder/demultiplexer with open-collector outputs, designed for address decoding and data routing in TTL-based digital systems. It features independent strobes (1G, 2G), shared binary address inputs (A, B), and inverted data path (1C) enabling 3-to-8-line decoding without external gates. Typical use includes memory address selection in industrial control logic operating at 5 V.

For engineers reviewing the 74LS156P-E datasheet, 74LS156P-E pinout, 74LS156P-E application, or 74LS156P-E equivalent, key selection criteria include open-collector output drive capability (IOL = 8 mA), propagation delay (tPHL ≤ 51 ns), operating temperature range (–20 to +75 °C), and DIP-16 package compatibility with legacy board layouts.

Technical Context

The 74LS156P-E integrates two independent 1-to-4 demultiplexers sharing address lines A and B, each controlled by dedicated strobe inputs (1G, 2G). Each section routes its data input (1C or 2C) to one of four open-collector outputs (1Y0–1Y3 or 2Y0–2Y3) based on the binary state of A and B.

Its internal inverter on the 1C path allows cascading with the second section to implement a 3-to-8-line decoder: connecting 1C and 2C together as input C, and tying 1G and 2G together as G, yields full 8-output decoding per the function table. All outputs are open-collector, requiring external pull-ups for wired-AND or bus interface applications.

Key Specifications

Pinout & Package

74LS156P-E uses a 16-pin plastic dual in-line package (DIP-16), designated PRDP0016AE-B (JEITA code DP-16FV), with 2.54 mm pitch and 19.2 mm × 6.3 mm body dimensions.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar decoder/demultiplexer applications.

Compared with SN74LS139N and MC74LS155, the 74LS156P-E uniquely supports 3-to-8-line decoding via internal 1C inversion and retains through-hole DIP-16 compatibility-critical for repair, legacy system upgrades, and prototyping where mechanical fit and wiring simplicity are prioritized.

Availability

74LS156P-E is available at Aetrix Electronics and suitable for industrial control systems, test instrumentation, and legacy computer refurbishment requiring stable component supply and long-term obsolescence management.

Supply support for 74LS156P-E 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

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and timing solutions for industrial, automotive, and infrastructure markets.

The 74LS156P-E belongs to Renesas' legacy TTL logic product line, engineered for backward compatibility, reliability in harsh environments, and seamless integration into established 5 V digital systems.

FAQ

What is the maximum sink current per output of the 74LS156P-E?

The 74LS156P-E guarantees a minimum output sink current (IOL) of 8 mA per open-collector output at VOL ≤ 0.5 V, enabling direct drive of standard TTL loads or indicator LEDs with appropriate series resistance. This rating holds across the full operating temperature range (–20 to +75 °C) and supply voltage (4.75–5.25 V), making the 74LS156P-E suitable for robust industrial interface applications without additional buffering.

Can the 74LS156P-E be used as a 3-to-8-line decoder, and how is it configured?

Yes, the 74LS156P-E supports 3-to-8-line decoding by connecting 1C and 2C together as the third address input (C), tying 1G and 2G together as the master strobe (G), and applying A and B as the lower two address bits. The internal inverter on 1C ensures complementary activation of the two 4-output sections, producing eight distinct active-low outputs (2Y0–2Y3 and 1Y0–1Y3) as documented in the function table. This configuration requires no external logic and is fully supported in the 74LS156P-E datasheet.

What is the propagation delay specification for the 74LS156P-E, and under what conditions is it measured?

The 74LS156P-E has a maximum propagation delay (tPHL) of 51 ns and (tPLH) of 40 ns, measured at VCC = 5 V, TA = 25 °C, with CL = 15 pF and RL = 2 kΩ. These values apply to transitions at address inputs (A, B), strobes (1G, 2G), or data inputs (1C, 2C) driving any Y output. The 74LS156P-E maintains consistent timing performance across its rated industrial temperature range, supporting reliable operation in real-time control circuits.

Is the 74LS156P-E RoHS compliant, and what is its lead finish?

Yes, the 74LS156P-E features Ni/Pd/Au plating on its leads, meeting RoHS Directive 2011/65/EU requirements for restricted substances. This finish ensures solderability and corrosion resistance while complying with environmental regulations for commercial and industrial electronics. Renesas confirms RoHS compliance for this part in its official documentation, and Aetrix Electronics supplies only RoHS-compliant units of the 74LS156P-E.

Does the 74LS156P-E require external pull-up resistors on its outputs, and why?

Yes, the 74LS156P-E requires external pull-up resistors on all open-collector outputs (1Y0–1Y3, 2Y0–2Y3) to establish defined high-level logic states. Because the outputs can only sink current (not source), pull-ups are necessary to achieve VOH ≥ 2.4 V under load. Typical values range from 1.8 kΩ to 10 kΩ depending on bus capacitance and speed requirements. This design feature enables wired-AND logic and voltage-level translation-core capabilities of the 74LS156P-E in system integration.