Texas Instruments SN75477DE4

Overview

SN75477DE4 from Texas Instruments is a dual NAND peripheral driver IC designed for high-voltage, high-current switching in electromechanical interface circuits. It delivers 300 mA continuous output current per channel, supports 100 V typical output breakdown voltage, features diode-clamped TTL/MOS-compatible inputs, and operates across 0°C to 70°C - commonly used in relay drivers, solenoid controls, and printer hammer-driver systems.

For engineers reviewing the SN75477DE4 datasheet, SN75477DE4 pinout, SN75477DE4 application, or SN75477DE4 equivalent, key selection criteria include output clamp diode capability (70 V, 300 mA), propagation delay (200–350 ns), low-level input current (–160 µA on S-input), and SOIC-8 package compatibility with industrial temperature range requirements.

Technical Context

The SN75477DE4 implements two independent NAND logic gates with open-collector, high-voltage NPN output stages. Each channel integrates internal clamp diodes rated for 300 mA transient suppression at up to 70 V reverse voltage, enabling direct drive of inductive loads without external flyback components.

Input structure uses PNP transistor-based diode clamping to limit input current and ensure TTL- or MOS-level compatibility. The device is characterized for operation at VCC = 4.5 V to 5.5 V, with guaranteed latch-up immunity at 55 V after conducting 300 mA - critical for robustness in noisy industrial environments.

Key Specifications

Pinout & Package

SN75477DE4 is housed in an 8-pin SOIC (D) package with 1.27 mm lead pitch and 1.75 mm max height, optimized for surface-mount assembly and thermal performance in compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual high-voltage NAND driver applications.

Compared with SN75477DE4, SN75477P offers identical functionality in through-hole form but sacrifices thermal efficiency and board space savings, while ULN2003A trades NAND logic and enable control for greater channel count and higher current - making each suitable for distinct system architecture choices.

Availability

SN75477DE4 is available at Aetrix Electronics and suitable for relay driver interfaces, printer hammer control, solenoid actuator modules, and industrial annunciator panels requiring stable component supply across extended production lifecycles.

Supply support for SN75477DE4 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 SN75477DE4 belongs to TI's legacy peripheral driver family, engineered specifically for robust electromechanical interfacing in 5 V logic systems - emphasizing latch-up immunity, integrated transient protection, and direct inductive load compatibility.

FAQ

What logic function does the SN75477DE4 implement?

The SN75477DE4 implements two independent NAND logic gates with open-collector outputs. Its truth table shows that output Y goes LOW only when both inputs A and S are HIGH; otherwise, the output remains HIGH (open-circuit) when pulled up externally. This behavior is confirmed in the official SLRS025A datasheet's function tables and logic diagrams, and applies directly to the SN75477DE4 variant in SOIC-8 packaging.

Does the SN75477DE4 require external clamp diodes for inductive loads?

No, the SN75477DE4 does not require external clamp diodes. It integrates internal output clamp diodes rated for 300 mA and 70 V reverse voltage, as verified in the "Output Clamp Diodes for Transient Suppression" feature and electrical characteristics table of the SLRS025A datasheet. These diodes connect to the dedicated CLAMP pin (Pin 4), allowing centralized connection to the inductive supply rail - a core design advantage of the SN75477DE4.

What is the maximum continuous output current per channel of the SN75477DE4?

The SN75477DE4 is characterized for 300 mA continuous output current per channel, as stated in the "Characterized for Use to 300 mA" headline feature and confirmed in the Absolute Maximum Ratings table (continuous output current = 400 mA, with recommended operating limit at 300 mA). This rating holds across the full 0°C to 70°C operating range and is validated with the SOIC-8 package's thermal dissipation profile.

Is the SN75477DE4 pin-compatible with other members of the SN75476–SN75478 family?

Yes, the SN75477DE4 shares identical pinout and package (SOIC-8) with SN75476DE4 and SN75478DE4, as confirmed by the shared "D OR P PACKAGE (TOP VIEW)" diagram in the SLRS025A datasheet. However, logic function differs: SN75476 is AND, SN75477 is NAND, and SN75478 is OR - so while mechanical and electrical interface is identical, functional replacement requires verification of logic intent in the target circuit.

What is the operating supply voltage range for the SN75477DE4?

The SN75477DE4 operates over a supply voltage range of 4.5 V to 5.5 V, as specified in the Recommended Operating Conditions table of the SLRS025A datasheet. This 5 V ±10% range ensures compatibility with standard TTL and CMOS logic systems, and all electrical characteristics - including VOL, VOH, and propagation delay - are guaranteed within this window for the SN75477DE4 in its SOIC-8 configuration.