Texas Instruments SN74LS73ANE4

Overview

SN74LS73ANE4 from Texas Instruments is a dual J-K flip-flop with individual asynchronous clear inputs, implemented in TTL logic, operating over 0°C to 70°C, with typical propagation delay of 15 ns at V_CC = 5 V and I_OL = 8 mA, used for synchronous data storage and clocked state control in digital logic systems.

For engineers reviewing the SN74LS73ANE4 datasheet, SN74LS73ANE4 pinout, SN74LS73ANE4 application, or SN74LS73ANE4 equivalent, this device supports edge-triggered bistable operation with independent J/K inputs per section, TTL-compatible voltage thresholds, and PDIP-14 packaging suitable for prototyping, industrial control sequencers, and legacy system repair.

Technical Context

The SN74LS73ANE4 implements two independent negative-edge-triggered J-K flip-flops, each with active-low asynchronous clear (CLR̅), no clock enable, and direct Q and Q̅ outputs. Its internal structure uses bipolar TTL circuitry with Schottky-clamped transistors to limit saturation and reduce propagation delay.

It operates strictly from a single 5-V supply, requires no external pull-ups or biasing, and interfaces directly with other LS-TTL devices. The device does not support master-slave latching or preset functionality - only clear and clock-synchronized J/K toggling.

Key Specifications

Pinout & Package

SN74LS73ANE4 is housed in a 14-pin plastic dual in-line package (PDIP-N), 0.300-inch wide body, with standard through-hole mounting and RoHS-compliant NiPdAu lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual J-K flip-flop applications.

Compared with SN74LS112N and SN74HC109N, the SN74LS73ANE4 delivers optimized performance for legacy TTL systems requiring strict 5-V operation, guaranteed negative-edge response, and minimal external component count - making it the preferred choice for repair, maintenance, and cost-sensitive commercial logic designs.

Availability

SN74LS73ANE4 is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, educational lab kits, and legacy system refurbishment requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS73ANE4 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

Texas Instruments is a U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and aerospace qualification coverage.

The SN74LS73ANE4 belongs to TI's legacy 74LS logic product line, designed specifically for robust, low-cost, medium-speed digital control in commercial-grade equipment where TTL compatibility and through-hole serviceability are essential.

FAQ

What logic family does SN74LS73ANE4 belong to, and why does that matter for interfacing?

SN74LS73ANE4 belongs to the LS-TTL (Low-Power Schottky Transistor-Transistor Logic) family. This matters because it defines specific voltage thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), output drive capability (8 mA sink), and noise margins that ensure reliable interoperability with other 74LS, 74S, and 74F devices. Using it with non-TTL logic (e.g., CMOS) without level translation may cause incorrect switching or excessive loading.

Does SN74LS73ANE4 support preset functionality, and how is its clear input structured?

No, SN74LS73ANE4 does not support preset (PRE̅). It provides only active-low asynchronous clear inputs - CLR̅A for Flip-Flop A and CLR̅B for Flip-Flop B - each operating independently. These inputs force Q = 0 and Q̅ = 1 immediately upon assertion, overriding clock and J/K states, with no built-in debouncing or synchronization.

What is the maximum recommended clock frequency for reliable operation of SN74LS73ANE4?

The maximum reliable clock frequency for SN74LS73ANE4 is determined by its 15 ns typical propagation delay and setup/hold time requirements. At V_CC = 5 V and C_L = 15 pF, the device supports toggle frequencies up to approximately 30 MHz under ideal conditions. For production designs, derating to ≤20 MHz is recommended to accommodate temperature variation, supply tolerance, and layout-induced skew.

Can SN74LS73ANE4 be used in place of SN74LS73AN, and what is the difference between them?

Yes, SN74LS73ANE4 is a direct replacement for SN74LS73AN. The "E4" suffix indicates TI's green packaging standard (lead-free NiPdAu finish), while SN74LS73AN uses older leaded finish. Both share identical electrical specifications, PDIP-14 package dimensions, pinout, and temperature rating (0°C to +70°C), and are fully interchangeable in existing designs without modification.

Is SN74LS73ANE4 suitable for use in industrial environments with extended temperature ranges?

No, SN74LS73ANE4 is rated only for 0°C to +70°C operation and is designated as a commercial-grade part. It is not qualified for industrial (-40°C to +85°C) or extended temperature applications. For such environments, consider the military-grade SN54LS73AJ (–55°C to +125°C) or modern alternatives like SN74AHC109, but note these require pinout or logic-family adaptation.