Texas Instruments SN74AS824ANT

Overview

SN74AS824ANT from Texas Instruments is a 9-bit inverting bus-interface D-type flip-flop with 3-state outputs, designed for high-drive bidirectional bus interfacing in TTL-compatible systems. It operates from 4.5 V to 5.5 V, supports 0°C to 70°C ambient, delivers ±48 mA output drive, and features independent asynchronous clear (CLR), clock enable (CLKEN), and output enable (OE) controls - used in parity bus expansion and wide I/O port buffering.

For engineers reviewing the SN74AS824ANT datasheet, SN74AS824ANT pinout, SN74AS824ANT application, or SN74AS824ANT equivalent, key selection criteria include its inverting data path, 3-state output timing (tPZH = 1 ns min), undershoot-protection circuitry, and NT-package compatibility with legacy 300-mil DIP footprints.

Technical Context

This device implements nine edge-triggered D-type flip-flops with non-overlapping control logic: CLKEN gates the clock buffer, CLR asynchronously forces all Q outputs low, and OE independently places outputs in high-impedance without affecting internal state retention. The inverting D-input architecture distinguishes SN74AS824A from SN74AS823A.

It uses advanced Schottky-clamped bipolar (AS) technology to achieve propagation delays as low as 3.5 ns (tPLH/tPHL), 1 ns minimum enable/disable times (tPHZ/tPLZ), and robust drive capability into 50-pF loads at 5 V - enabling reliable operation in high-speed bus-hold and address/data widening applications.

Key Specifications

Pinout & Package

SN74AS824ANT is supplied in a 24-pin plastic dual-in-line package (NT), 300-mil width, with through-hole mounting and standard DIP footprint compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 9-bit bus-interface flip-flop applications.

Compared with SN74AS823ANT and AM29824PC, SN74AS824ANT uniquely provides inverting D-input behavior within the same 24-pin NT package - making it the only option when system-level signal polarity requires inversion at the latch stage rather than external logic.

Availability

SN74AS824ANT is available at Aetrix Electronics and suitable for industrial control panels, legacy system upgrades, and embedded bus expansion requiring stable component supply across extended production lifecycles.

Supply support for SN74AS824ANT 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 with broad industrial and automotive reach.

The SN74AS824A belongs to TI's legacy Advanced Schottky TTL logic family, engineered for high-speed, high-drive bus interfacing in systems where compatibility with 5 V TTL infrastructure is mandatory.

FAQ

What is the logic polarity of the data inputs on SN74AS824ANT?

The SN74AS824ANT features inverting data inputs: each D input (pins 1–9) is inverted internally before being latched on the rising edge of CLK. This means the Q outputs reflect the logical complement of the D inputs sampled at clock transition. This behavior is explicitly defined in the SN74AS824A function table and differentiates it from the noninverting SN74AS823ANT. The SN74AS824ANT datasheet confirms this inversion applies uniformly across all nine channels.

Does SN74AS824ANT support hot insertion or live bus swapping?

SN74AS824ANT does not include explicit hot-swap protection circuitry, but its power-up high-impedance state and undershoot-protection diodes provide partial robustness during live insertion. When VCC is applied, all outputs default to high-impedance (Z-state) until OE is actively driven low - preventing bus contention. However, the device lacks bus-hold or Ioff partial-power-down features, so full hot-swap compliance requires external current-limiting and sequencing controls. Always verify timing margins under dynamic supply ramp conditions per SN74AS824ANT recommended operating conditions.

Can SN74AS824ANT be used with 3.3 V logic systems?

SN74AS824ANT is not 3.3 V compatible: it requires a minimum VCC of 4.5 V and has TTL input thresholds (VIH = 2.0 V, VIL = 0.8 V) that do not guarantee reliable recognition of 3.3 V logic levels. Driving its inputs directly from 3.3 V CMOS may result in marginal or failed high-level detection, especially over temperature. To interface with 3.3 V systems, level-shifting buffers such as SN74LVC245A or discrete resistor-divider networks meeting VIH/VIL margins must be used. The SN74AS824ANT datasheet specifies operation strictly within 4.5–5.5 V.

What is the maximum clock frequency supported by SN74AS824ANT?

SN74AS824ANT does not specify a maximum clock frequency in its datasheet, but timing parameters support reliable operation up to approximately 100 MHz. Based on tPLH/tPHL ≤ 7.5 ns (min) and tw(CLK high/low) ≥ 8 ns, the minimum clock period is ~16 ns, implying a theoretical upper limit near 62.5 MHz for guaranteed timing closure. With margin, practical use in 50 MHz synchronous bus systems is well established. The SN74AS824ANT switching characteristics table confirms stable performance under CL = 50 pF load conditions typical of board-level routing.

Is SN74AS824ANT RoHS compliant?

SN74AS824ANT is not RoHS compliant: it is a legacy plastic DIP (NT) package device manufactured with leaded solder and tin-lead finish, as confirmed by TI's packaging addendum. The part marking and material type indicate SNPB (tin-lead) lead finish with no RoHS exemption code. For RoHS-compliant alternatives, consider surface-mount equivalents like SN74AS824ADW (SOIC-24), though functional equivalence must be verified per application requirements. TI's official status listing shows SN74AS824ANT as "No" under RoHS column.