Texas Instruments SN74LS109ADRE4

Overview

SN74LS109ADRE4 from Texas Instruments is a dual positive-edge-triggered J-K flip-flop with individual Set and Reset inputs, fabricated in LS-TTL logic technology, operating from 4.75 V to 5.25 V supply, with propagation delay of 20 ns (max) at V_CC = 5 V, and rated for 0°C to 70°C industrial temperature range. It serves as a synchronous storage element in digital control logic, state machines, and clock-domain synchronization circuits.

For engineers reviewing the SN74LS109ADRE4 datasheet, SN74LS109ADRE4 pinout, SN74LS109ADRE4 application, or SN74LS109ADRE4 equivalent, key selection considerations include its dual independent J-K functionality, edge-triggered operation, asynchronous active-low Set/Reset, SOIC-16 RoHS-compliant packaging, and compatibility with legacy 74LS logic families in industrial timing and sequencing designs.

Technical Context

The SN74LS109ADRE4 implements two identical, electrically isolated J-K flip-flops in a single SOIC-16 package, each with separate J, K, Clock, Set, and Reset terminals. Its positive-edge-triggered clock input ensures state updates only on rising transitions, while asynchronous Set and Reset override clock action when asserted low.

Designed for TTL-compatible interfacing, it features standard LS-TTL input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), output drive capability of –0.4 mA (high) / 8 mA (low), and guaranteed fan-out of 20 LS-TTL loads. No internal pull-ups or level-shifting circuitry is present - all inputs require defined logic states.

Key Specifications

Pinout & Package

SN74LS109ADRE4 is housed in a 16-pin Small Outline Integrated Circuit (SOIC) package with 1.27 mm pitch, 10.3 mm body width, and 6.5 mm body length. Pin 1 is located at the top-left corner with quadrant Q1 orientation in tape-and-reel delivery.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS109ADR and SN74LS109ANSR, the SN74LS109ADRE4 offers identical logic behavior and timing but distinguishes itself via E4-specific marking and SOIC-16 tape-and-reel configuration - making it optimal for programs requiring consistent lot traceability and standard SOIC placement tooling.

Availability

SN74LS109ADRE4 is available at Aetrix Electronics and suitable for industrial control sequencing, digital test equipment state logic, and legacy system logic upgrades requiring stable component supply, long-term obsolescence mitigation, and RoHS-compliant manufacturing support.

Supply support for SN74LS109ADRE4 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 global semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and consumer applications.

The SN74LS109ADRE4 belongs to TI's legacy 74LS logic family, designed specifically to provide robust, low-power TTL-compatible sequential logic for industrial control, instrumentation, and educational platforms requiring proven reliability and long-lifecycle support.

FAQ

What is the primary logic function of the SN74LS109ADRE4?

The SN74LS109ADRE4 is a dual positive-edge-triggered J-K flip-flop with independent Set and Reset inputs. Each section implements standard J-K behavior: when J=K=1, it toggles on each clock edge; when J=1/K=0, it sets Q=1; when J=0/K=1, it resets Q=0. The SN74LS109ADRE4 does not include master-slave architecture - it is a true edge-triggered device with asynchronous controls.

Does the SN74LS109ADRE4 support 3.3 V operation?

No, the SN74LS109ADRE4 is strictly a 5 V TTL device with specified operation only from 4.75 V to 5.25 V. Its input thresholds, output drive strength, and internal biasing are optimized for 5 V rails. Applying 3.3 V to V_CC will result in undefined logic states, excessive current draw, or permanent damage. For 3.3 V systems, consider LVCMOS or LVT logic alternatives - not the SN74LS109ADRE4.

Is the SN74LS109ADRE4 pin-compatible with SN74LS109AN?

Yes, the SN74LS109ADRE4 and SN74LS109AN share identical pin functions and numbering in their respective SOIC-16 and PDIP-16 packages. Signal assignments (J, K, CLK, Set, Reset, Q, Q̅, GND, V_CC) match exactly. However, physical replacement requires PCB footprint adaptation - the SN74LS109ADRE4 cannot be soldered into a PDIP socket without an adapter.

What is the meaning of the "E4" suffix in SN74LS109ADRE4?

The "E4" suffix in SN74LS109ADRE4 is a Texas Instruments internal packaging designation indicating a specific tape-and-reel configuration and marking variant. It denotes NIPDAU lead finish, SOIC-16 package, RoHS compliance, and part marking "LS109A". The E4 suffix does not reflect a functional or parametric revision - the SN74LS109ADRE4 performs identically to SN74LS109ADR under identical operating conditions.

Can the SN74LS109ADRE4 be used in place of SN74LS76A?

No, the SN74LS109ADRE4 is not a direct substitute for SN74LS76A. While both are dual J-K flip-flops, the SN74LS76A uses negative-edge triggering and has complementary outputs routed differently (Q and Q̅ on adjacent pins). The SN74LS109ADRE4 uses positive-edge triggering and places Q/Q̅ on opposite sides of the package. Interchanging them without circuit modification will cause incorrect state transitions or timing failures.