Texas Instruments SN75477P

Overview

SN75477P 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 - enabling robust hammer-driver and relay-control applications.

For engineers reviewing the SN75477P datasheet, SN75477P pinout, SN75477P application, or SN75477P equivalent, key selection criteria include its dual-NAND logic function, 5 V nominal supply operation, output clamp diodes rated for 300 mA/70 V transients, and plastic DIP-8 package with copper-lead frame for thermal reliability.

Technical Context

The SN75477P implements two independent NAND-gated high-voltage drivers, each with pnp transistor input stages that reduce input current and enable direct TTL/MOS interfacing without external level-shifting. Its output stage integrates built-in clamp diodes rated for 300 mA transient suppression at up to 70 V reverse voltage.

Each channel operates with propagation delays under 350 ns (tPLH/tPHL) and transition times under 125 ns (tTLH/tTHL) into 100 Ω/15 pF loads, while maintaining latch-up immunity at 55 V after conducting full-rated 300 mA output current.

Key Specifications

Pinout & Package

SN75477P is housed in an 8-pin plastic dual in-line package (PDIP) with copper-lead frame for enhanced thermal performance and reliability. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN75477P, SN75477DR offers superior manufacturability and thermal performance in modern layouts, while ULN2003A trades logic integration for raw current capacity and channel count - making SN75477P optimal for compact, logic-aware electromechanical interfaces requiring precise dual-NAND control.

Availability

SN75477P is available at Aetrix Electronics and suitable for printer hammer control, industrial relay driving, and legacy peripheral interface applications requiring stable component supply, long-term obsolescence management, and through-hole assembly support.

Supply support for SN75477P 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 SN75477P belongs to TI's legacy peripheral driver family, engineered specifically for robust electromechanical interface applications where high-voltage tolerance, latch-up immunity, and integrated transient protection are critical design requirements.

FAQ

What logic function does the SN75477P implement?

The SN75477P implements two independent NAND gate drivers. Each channel has two inputs - A (data) and S (enable) - and one open-collector output Y. The output goes low only when both A and S are high; otherwise, it remains high-impedance. This function is explicitly defined in the datasheet's function tables and logic diagrams for SN75477P, distinguishing it from the AND-type SN75476P and OR-type SN75478P in the same family.

Can SN75477P drive inductive loads without external diodes?

Yes, SN75477P can drive inductive loads such as relays and solenoids without external flyback diodes. Its integrated output clamp diodes are rated for 300 mA continuous and 70 V reverse voltage, providing built-in transient suppression. This capability is confirmed in the "Output Clamp Diodes for Transient Suppression" feature bullet and electrical characteristics table (VR(K) = 70–100 V) of the SN75477P datasheet.

What is the maximum continuous output current per channel for SN75477P?

The SN75477P is characterized for 300 mA continuous output current per channel under recommended operating conditions. Absolute maximum ratings specify 400 mA continuous, but the device is tested and guaranteed at 300 mA - a value consistently cited in the "Characterized for Use to 300 mA" headline, function tables, and electrical characteristics (VOL measured at IOL = 300 mA).

Is SN75477P compatible with 3.3 V logic inputs?

No, SN75477P is not reliably compatible with 3.3 V logic inputs. Its input thresholds require VIH ≥ 2.0 V and VIL ≤ 0.8 V under 4.5–5.5 V supply, but the datasheet specifies TTL- and MOS-compatible *diode-clamped* inputs optimized for 5 V systems. While 3.3 V may exceed VIL, it falls below the guaranteed VIH margin and risks marginal noise immunity - confirmed by absence of 3.3 V operating condition testing in the recommended conditions table.

What package type and lead finish does SN75477P use?

SN75477P uses an 8-pin plastic dual in-line package (PDIP) with copper-lead frame and NIPDAU (nickel-palladium-gold) lead finish. This is documented in TI's official Package Option Addendum, where SN75477P is listed as "PDIP (P) | 8" with "NIPDAU" under Lead finish/Ball material and "N/A for Pkg Type" for MSL rating - consistent with through-hole packages not requiring moisture sensitivity handling.