Texas Instruments SN74AS823ANT

Overview

SN74AS823ANT from Texas Instruments is a 9-bit bus-interface D-type flip-flop with noninverting inputs and 3-state outputs, designed for high-capacitance bus driving in industrial control and memory interface applications. It operates at 4.5–5.5 V, delivers ±24 mA output drive, supports 0°C to 70°C ambient, and features independent asynchronous clear (CLR), clock enable (CLKEN), and output enable (OE) controls.

For engineers reviewing the SN74AS823ANT datasheet, SN74AS823ANT pinout, SN74AS823ANT application, or SN74AS823ANT equivalent, this device is selected for wide-data-path buffering where high-speed edge-triggered latching, bus contention avoidance via 3-state control, and undershoot-protected outputs are required in legacy TTL-compatible systems.

Technical Context

The SN74AS823ANT implements nine independent D-type edge-triggered flip-flops synchronized to the rising edge of CLK when CLKEN is low; CLKEN high disables clock propagation, holding Q outputs static. CLR asynchronously forces all Q outputs low regardless of clock state, while OE independently places all outputs in high-impedance without affecting internal latch states.

Each output includes undershoot-protection circuitry and buffered control inputs (OE, CLKEN, CLR) to minimize DC loading on upstream drivers. The device uses bipolar AS (Advanced Schottky) technology, delivering tPLH/tPHL ≤ 7.5 ns (VCC = 4.5–5.5 V, CL = 50 pF) and IOL up to 48 mA for robust low-impedance bus termination.

Key Specifications

Pinout & Package

SN74AS823ANT is supplied in a 24-pin plastic dual-in-line package (NT), 300-mil width, through-hole mountable with 0.100" lead pitch. Pin 1 is index-marked; pins 13 and 14 are GND and VCC respectively.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AS824ANT and AM29823PC, the SN74AS823ANT provides noninverting data path transparency and TI's commercial temperature qualification, making it optimal for new industrial designs requiring long-term supply continuity and documented application support.

Availability

SN74AS823ANT is available at Aetrix Electronics and suitable for industrial control systems, legacy test equipment upgrades, and memory subsystem design requiring stable component supply and long-lifecycle support.

Supply support for SN74AS823ANT 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 SN74AS823ANT belongs to TI's legacy Advanced Schottky (AS) logic family, engineered for high-speed, low-noise bus interfacing in systems demanding TTL compatibility, robust drive strength, and deterministic timing behavior.

FAQ

What is the maximum clock frequency supported by the SN74AS823ANT?

The SN74AS823ANT does not specify a maximum clock frequency in its datasheet; instead, it guarantees timing margins via minimum pulse widths and setup/hold times. With t_w(CLK) ≥ 8 ns (high/low), t_su ≥ 6 ns, and t_PLH/t_PHL ≤ 7.5 ns, the device reliably operates at effective clock rates up to ~60 MHz in well-terminated 50-pF bus environments. For SN74AS823ANT, always verify timing closure using worst-case propagation and skew values from the SDAS231A datasheet.

Does the SN74AS823ANT support hot insertion or live bus swapping?

The SN74AS823ANT supports controlled bus arbitration via its 3-state outputs but is not rated for hot insertion. Its absolute maximum rating for voltage on disabled outputs is 5.5 V, and it lacks built-in current-limiting or fault protection. While OE can isolate outputs before system reconfiguration, safe hot-swap operation requires external current-limiting resistors and sequencing control - SN74AS823ANT itself does not provide hot-plug safety features.

How does the undershoot-protection circuitry in the SN74AS823ANT function?

The undershoot-protection circuitry in the SN74AS823ANT limits negative voltage excursions at output pins to –1.2 V (VIK) under transient conditions, achieved via integrated clamping diodes to GND. This protects connected receivers from damage during fast edge transitions on heavily loaded buses. For SN74AS823ANT, this feature eliminates need for external Schottky clamps in most industrial bus designs.

Can the SN74AS823ANT operate with a 3.3 V supply?

No, the SN74AS823ANT is not rated for 3.3 V operation. Its recommended VCC range is strictly 4.5 V to 5.5 V, and absolute maximum supply voltage is 7 V. At 3.3 V, internal bipolar transistors fail to saturate properly, resulting in degraded noise margins, increased propagation delay (>20 ns), and potential metastability. Use SN74AS823ANT only with regulated +5 V supplies.

Is the SN74AS823ANT pin-compatible with the SN74AS823ADW?

Yes, the SN74AS823ANT and SN74AS823ADW share identical pin functions and electrical specifications, differing only in package type: NT is a plastic DIP (through-hole), while DW is a SOIC-24 (surface-mount). Both use the same 24-pin layout with matching pin 1 indexing, CLK/CLR/OE/CLKEN placement, and 1D–9D / 1Q–9Q assignments. Mechanical mounting differs, but PCB layout adaptation is limited to footprint change - no signal routing modification is needed for SN74AS823ANT replacement with SN74AS823ADW.