Texas Instruments SN75477PG4

Overview

SN75477PG4 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 - ideal for solenoid, relay, and hammer-driver control in industrial automation systems.

For engineers reviewing the SN75477PG4 datasheet, SN75477PG4 pinout, SN75477PG4 application, or SN75477PG4 equivalent, key selection criteria include its dual-NAND logic function, 70 V output clamp capability, pnp-input architecture reducing input current, 350 ns max propagation delay, and PDIP-8 package with copper-lead frame for thermal reliability.

Technical Context

The SN75477PG4 implements two independent NAND-gated high-voltage drivers with pnp transistor inputs that limit input current to –220 µA (S input) and –110 µA (A input) at 0.8 V, enabling direct interfacing with TTL or MOS logic without external pull-ups. Each output integrates a built-in 70–100 V clamp diode rated for 300 mA transient suppression.

It operates from a single 4.5–5.5 V supply, delivers low-level output voltage of 0.6 V at 300 mA load, and withstands 55 V latch-up immunity after conducting rated current - confirming robustness in inductive load switching applications such as print head actuation and valve control.

Key Specifications

Pinout & Package

SN75477PG4 is housed in an 8-pin plastic DIP (PDIP) package with copper-lead frame for enhanced thermal performance and reliability. Pin numbering follows standard DIP top-view orientation with Pin 1 in upper-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN75477D and ULN2003A, the SN75477PG4 uniquely combines dual-NAND logic, 1000 mW PDIP thermal capability, and guaranteed 55 V latch-up immunity - making it the only option supporting high-reliability hammer-driver applications without supplemental protection circuitry.

Availability

SN75477PG4 is available at Aetrix Electronics and suitable for industrial automation, legacy equipment repair, and electromechanical test fixture design requiring stable component supply and long-lifecycle support.

Supply support for SN75477PG4 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 with broad industrial and automotive qualification.

The SN75477PG4 belongs to TI's legacy peripheral driver family, engineered specifically for robust 5 V logic-to-high-voltage load interfacing in electromechanical systems where reliability under inductive stress is critical.

FAQ

What logic function does the SN75477PG4 implement?

The SN75477PG4 implements two independent 2-input NAND gates, each driving an open-collector high-voltage output. Its truth table shows Y = NOT(A AND S): output goes low only when both A and S inputs are high. This enables active-low enable control of external loads like relays or solenoids, and the SN75477PG4 maintains this behavior across its full operating temperature range of 0°C to 70°C.

Can the SN75477PG4 drive a 24 V relay directly?

Yes, the SN75477PG4 can drive a typical 24 V DC relay coil directly: its outputs support up to 100 V breakdown and 300 mA continuous current, well above the 20–80 mA typical coil requirement. The SN75477PG4's integrated 70 V clamp diodes suppress inductive kickback, eliminating the need for external flyback diodes - simplifying design and improving reliability in relay interface circuits.

What is the maximum allowable supply voltage for the SN75477PG4?

The absolute maximum supply voltage (VCC) for the SN75477PG4 is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. Operating outside this range risks exceeding input voltage limits (VI ≤ 5.5 V), degrading propagation delay consistency, or triggering undefined logic states. The SN75477PG4 is optimized for stable 5 V system rails and must not be used with unregulated or boosted supplies beyond 5.5 V.

Does the SN75477PG4 require external pull-up resistors on its outputs?

Yes, the SN75477PG4 outputs are open-collector and require external pull-up resistors to define the high-state voltage level. Typical values range from 1 kΩ to 10 kΩ, depending on load capacitance and required rise time. The pull-up may connect to VCC (5 V) or a higher rail (e.g., 24 V) since the SN75477PG4 output clamp diodes protect against overvoltage - a key feature distinguishing it from standard logic buffers.

How does the SN75477PG4 handle inductive load transients?

The SN75477PG4 handles inductive transients via integrated output clamp diodes rated for 300 mA and 70 V reverse breakdown, plus guaranteed no-latch-up operation at 55 V after conducting rated current. When a relay or solenoid is switched off, energy dissipates through these internal diodes into the VCC rail or external snubber, preventing voltage spikes from damaging the SN75477PG4 or upstream logic - a core design advantage over discrete transistor solutions.