Texas Instruments SN65240PG4

Overview

SN65240PG4 from Texas Instruments is a quadruple unidirectional transient voltage suppressor (TVS) IC designed for ESD protection of USB full-speed and low-speed data lines (D+, D−). It features 6.5-V minimum breakdown voltage, 35-pF typical input capacitance, ≤1-µA leakage at 6 V, −40°C to 85°C operating range, and PDIP-8 package. It protects USB transceivers in host, hub, and peripheral ports against 15-kV HBM ESD events.

For engineers reviewing the SN65240PG4 datasheet, SN65240PG4 pinout, SN65240PG4 application, or SN65240PG4 equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed USB port protection use cases, and real-world layout-aware design guidance - all specific to the SN65240PG4 PDIP-8 variant.

Technical Context

The SN65240PG4 integrates four independent unidirectional TVS diodes in a single PDIP-8 package, each with Zener-triggered transistor-assisted clamping for precise 6.5–8-V breakdown and fast response to ESD transients. Its structure combines Zener diode D1 and NPN transistor Q1 for positive-voltage clamping and discrete diode D2 for negative-voltage conduction.

It operates passively without external power, relying solely on transient overvoltage to trigger conduction. The device enters low-impedance mode only when input voltage exceeds its 6.5-V breakdown threshold, shunting surge current directly to local GND pins - all four ground terminals must be connected to maintain effective 15-kV HBM protection and minimize inductive impedance in the return path.

Key Specifications

Pinout & Package

SN65240PG4 uses an 8-pin plastic dual in-line package (PDIP), 9.09 mm × 6.35 mm body size, with 0.300″ lead spacing. All ground pins must be soldered to a solid ground plane to ensure low-inductance surge-current return paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient suppression applications.

Compared with SN65240PWR and TPD2E001DRSR, the SN65240PG4 uniquely balances quadruple-channel integration, 15-kV HBM robustness, and through-hole manufacturability - making it the only option supporting legacy USB full-speed systems requiring field-serviceable, thermally stable, and layout-tolerant ESD protection.

Availability

SN65240PG4 is available at Aetrix Electronics and suitable for USB host interfaces, industrial USB hubs, medical peripheral devices, and legacy test equipment requiring stable component supply and long-term obsolescence management.

Supply support for SN65240PG4 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets since 1930.

The SN65240PG4 belongs to TI's USB port protection product line, engineered specifically to extend system-level ESD immunity beyond internal transceiver limits while preserving signal fidelity in sub-480-Mbps USB implementations.

FAQ

What is the primary function of the SN65240PG4 in a USB interface?

The SN65240PG4 serves as a quadruple unidirectional transient voltage suppressor that protects USB D+, D−, and auxiliary signal lines from electrostatic discharge (ESD) and electrical noise transients. It clamps voltages above 6.5 V to safeguard 3-V or 5-V USB transceivers, and its 35-pF capacitance ensures compatibility with full-speed (12 Mbps) and low-speed USB 1.1 operation - but not USB 2.0 high-speed. The SN65240PG4 operates passively without external power.

Does the SN65240PG4 support USB 2.0 high-speed (480 Mbps) applications?

No, the SN65240PG4 does not support USB 2.0 high-speed applications. Its 35-pF typical input capacitance introduces excessive signal distortion and timing skew at 480 Mbps, as explicitly stated in the datasheet: "The input capacitance of 35 pF makes it unsuitable for high-speed USB 2.0 applications." For high-speed USB, designers must select lower-capacitance alternatives such as the TPD2E001 series (1.5 pF), though those offer fewer channels and lower ESD ratings than the SN65240PG4.

How many ground connections does the SN65240PG4 require, and why?

The SN65240PG4 requires connection of all four ground pins (Pins 1, 3, 5, and 7) to the PCB ground plane. This is mandatory to minimize inductive impedance in the surge-current return path during ESD events. Layout guidelines specify that a single trace is inadequate due to parasitic inductance (~20 nH/cm), which degrades clamping speed and protection effectiveness. Solid ground-plane connection via multiple vias ensures low-L return paths essential for achieving the rated 15-kV HBM performance.

What is the maximum operating temperature range for the SN65240PG4?

The SN65240PG4 is rated for operation from −40°C to +85°C ambient temperature. This range is specified in the "Recommended Operating Conditions" table and applies to both the SN65240 and SN65220 variants. The SN75240 variant has a narrower 0°C to +70°C range, but the SN65240PG4 maintains full functionality across the extended industrial temperature span - critical for deployment in embedded controllers, factory automation, and outdoor USB peripherals.

Can the SN65240PG4 replace discrete TVS diodes in an existing USB design?

Yes, the SN65240PG4 can replace up to four discrete unidirectional TVS diodes in a USB design, provided the layout accommodates its PDIP-8 footprint and all four ground pins are properly tied to the ground plane. Its integrated quadruple structure reduces component count, improves channel-to-channel matching, and simplifies layout versus discrete solutions. However, because it uses Zener-transistor hybrid clamping (not pure diodes), designers should verify that the 6.5–8-V breakdown range aligns with their transceiver's absolute maximum ratings - especially for 3.3-V systems where margin above V_CC is critical.