Texas Instruments SN74276N

Overview

SN74276N from Texas Instruments is a dual 4-bit binary counter with asynchronous reset, implemented as a TTL-compatible bipolar logic IC in a 20-pin PDIP package, operating over 0°C to 70°C, and featuring ripple-carry output for cascading, direct clock enable control, and complementary Q/Q̅ outputs per stage.

For engineers reviewing the SN74276N datasheet, SN74276N pinout, SN74276N application, or SN74276N equivalent, key selection considerations include its asynchronous clear functionality, TTL-level input thresholds, 20-pin DIP footprint compatibility with legacy board layouts, and suitability for discrete timing, frequency division, and state sequencing in industrial control panels and test equipment.

Technical Context

The SN74276N integrates two independent 4-bit binary counters sharing common clock and reset lines, each implementing synchronous counting with asynchronous reset. Its internal architecture uses standard TTL NAND/NOR gate-based flip-flops without internal prescaling or latch-enable logic.

It requires a single +5 V supply, draws typical ICC of 54 mA at 5 MHz, and provides fan-out of 10 LS-TTL loads. Output propagation delay is 30 ns (max) from clock to Q, and setup time for clock enable is 20 ns relative to clock edge.

Key Specifications

Pinout & Package

SN74276N is housed in a 20-pin plastic dual in-line package (PDIP) with 0.3-inch body width, 2.54 mm pin pitch, and standard DIP pin numbering (pin 1 marked by notch or dot). Pin 10 is GND; pin 20 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar binary counter applications.

Compared with SN74LS276N and CD4022BE, the SN74276N offers higher drive strength and faster propagation but consumes more power and lacks CMOS supply flexibility-making it best suited for legacy TTL systems where robust fan-out and known timing margins are prioritized.

Availability

SN74276N is available at Aetrix Electronics and suitable for industrial timer control, test equipment counting, frequency division, and legacy system state sequencing requiring stable component supply and long-term obsolescence mitigation support.

Supply support for SN74276N 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 solutions for industrial, automotive, and communications markets.

The SN74276N belongs to TI's legacy 74xx TTL logic family, designed specifically for discrete digital timing, counting, and sequencing in non-microcontroller-based systems where deterministic hardware behavior and interoperability with vintage logic families were essential.

FAQ

What is the operating voltage range for the SN74276N?

The SN74276N operates exclusively at +5 V ±5%, with no tolerance for 3.3 V or other supply voltages. Its TTL input thresholds and output drive characteristics are specified only at this nominal rail. Using SN74276N outside this range risks incorrect logic states, excessive current draw, or permanent damage. Always verify VCC stability within ±0.25 V during operation.

Does the SN74276N support synchronous reset?

No, the SN74276N implements only asynchronous active-low reset (CLR₁ and CLR₂). Reset occurs immediately upon assertion, independent of clock edges. There is no provision for synchronous reset or clock-enabled reset functionality. For synchronous behavior, external gating of the clock or use of alternative parts like SN74LS163 would be required.

Can the SN74276N be used in place of the SN74LS276N?

Yes, the SN74276N is functionally and pin-compatible with the SN74LS276N, though it draws higher supply current and has slightly different AC timing. The SN74276N may be substituted in existing LS276 designs if power dissipation and noise margin are acceptable, but SN74LS276N is preferred for new builds due to its lower ICC and improved noise immunity.

What is the maximum clock frequency supported by the SN74276N?

The SN74276N supports a maximum clock frequency of 32 MHz under typical conditions (VCC = 5 V, TA = 25°C), with guaranteed minimum operation up to 25 MHz across the full 0°C to 70°C range. Performance degrades above 25 MHz at temperature extremes, and propagation delay increases to 30 ns (max) at worst-case conditions.

Is the SN74276N RoHS-compliant?

No official RoHS compliance documentation exists for the SN74276N. Per TI's packaging addendum, its eco plan is listed as "TBD", indicating no Pb-Free or Green conversion was completed prior to obsolescence. Legacy SN74276N devices contain leaded solder and are not compliant with current RoHS directives unless explicitly reprocessed or certified by a third-party recycler.