Texas Instruments SN74ALS29827DWR

Overview

SN74ALS29827DWR from Texas Instruments is a 10-bit non-inverting buffer/bus driver with dual 3-state enable (OE1/OE2), designed for high-performance bus interfacing in wide data paths and memory address register buffering. It operates at 4.75–5.25 V, delivers ±48 mA output drive, features pnp input structure to reduce DC loading, and maintains high-impedance state at power-up. Used in industrial control backplanes and legacy TTL-compatible memory subsystems.

For engineers reviewing the SN74ALS29827DWR datasheet, SN74ALS29827DWR pinout, SN74ALS29827DWR application, or SN74ALS29827DWR equivalent, key selection criteria include its true-output logic, dual-enable 3-state architecture, SOIC-24 package compatibility, ALS family propagation delay (7–15 ns), and operation over 0°C to 70°C.

Technical Context

The SN74ALS29827DWR implements a 2-input NOR gate for 3-state control: either OE1 or OE2 high forces all ten Y outputs into high-impedance. Its pnp-based input stage minimizes input current draw, reducing loading on upstream TTL or ALS sources. The device uses bipolar ALS (Advanced Low-Power Schottky) technology, ensuring compatibility with standard TTL logic levels while improving speed-power trade-offs.

It features data-flow-through pinout-inputs A1–A10 on one side, outputs Y1–Y10 on the opposite-with dedicated ground (Pin 12) and VCC (Pin 13) centrally located. Absolute maximum ratings include 7 V supply voltage and –1.2 V input clamp voltage, supporting robust operation in noisy industrial environments.

Key Specifications

Pinout & Package

SN74ALS29827DWR is housed in a 24-pin SOIC (DW) package with 300-mil body width, gull-wing leads, and RoHS-compliant NiPdAu finish. Pin 1 is marked by a beveled corner or notch; pin numbering follows standard counter-clockwise convention from top view.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit non-inverting bus driver applications.

Compared with SN74ALS244N, SN74ALS29827DWR provides two additional data channels and finer-grained bus control via dual OE; compared with AM29827, it offers identical performance with TI's extended lifecycle support and modern packaging compliance.

Availability

SN74ALS29827DWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy memory subsystems, and programmable logic controller (PLC) I/O interfaces requiring stable component supply and long-term obsolescence management.

Supply support for SN74ALS29827DWR 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 leader founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74ALS29827DWR belongs to TI's legacy ALS logic family, engineered for high-speed, low-power TTL-compatible interfacing in mission-critical industrial and computing systems where reliability and long-term availability are essential.

FAQ

What logic family does the SN74ALS29827DWR belong to, and how does it differ from standard TTL?

The SN74ALS29827DWR belongs to the Advanced Low-Power Schottky (ALS) logic family. Unlike standard TTL, ALS uses Schottky diodes to prevent transistor saturation, reducing propagation delay to 7 ns while lowering power consumption. It maintains full TTL voltage-level compatibility (VIH = 2 V, VIL = 0.8 V) but draws less input current due to its pnp input structure - a key advantage in high-fan-out bus designs where the SN74ALS29827DWR is commonly deployed.

Does the SN74ALS29827DWR support hot-swap or live insertion?

The SN74ALS29827DWR is not explicitly rated for hot-swap operation. While its absolute maximum input voltage is 5.5 V and it features –1.2 V input clamp (VIK), the datasheet does not specify bus-hold, power-up sequencing immunity, or I²C-style slew-rate control. For live-insertion applications, external protection circuitry and controlled enable sequencing are recommended. The SN74ALS29827DWR should be powered and stabilized before applying input signals to avoid undefined states.

What is the purpose of the dual output-enable inputs (OE1 and OE2) on the SN74ALS29827DWR?

The dual output-enable inputs (OE1 and OE2) implement a 2-input NOR gate controlling all ten outputs. If either OE1 or OE2 is high, all Y1–Y10 outputs enter high-impedance mode. This architecture allows flexible bus arbitration - for example, OE1 can be tied to a master CPU's bus grant signal while OE2 responds to a DMA controller, enabling seamless handoff without external logic. This feature is integral to the SN74ALS29827DWR's role in multi-master backplane systems.

Can the SN74ALS29827DWR drive a 300-pF load, and what is the resulting propagation delay?

Yes, the SN74ALS29827DWR is fully characterized driving a 300-pF load: tPLH and tPHL are 15 ns max (at VCC = 4.75–5.25 V, TA = 25°C). This specification confirms its suitability for driving heavily loaded buses, such as those found in legacy VME or Multibus systems. The SN74ALS29827DWR maintains consistent timing across its full operating temperature range (0°C to 70°C), making it reliable in thermally variable industrial enclosures.

Is the SN74ALS29827DWR pin-compatible with the SN74ALS29828?

No, the SN74ALS29827DWR is not pin-compatible with the SN74ALS29828. Although both share identical pinouts and package footprints, they differ functionally: SN74ALS29827DWR provides true (non-inverting) outputs, while SN74ALS29828 provides inverted outputs. Swapping them without logic redesign will invert all ten data bits. The SN74ALS29827DWR must be used where signal polarity preservation is required - for example, in address buffering where inversion would cause memory mapping errors.