onsemi NP0720SCT3G

Overview

NP0720SCT3G from onsemi is a bidirectional thyristor surge protector (TSPD) designed for overvoltage protection in telecom line interfaces. It features 65 V peak off-state voltage (V_DRM), 88 V breakover voltage (V_BO), 4.0 V on-state voltage (V_T), 150 mA holding current (I_H), and supports 2.2 A on-state current (I_T). It is used in central office and customer premises equipment to meet GR-1089-CORE and IEC 61000-4-5 surge immunity requirements.

For engineers reviewing the NP0720SCT3G datasheet, pinout, applications, or equivalent options, key selection factors include bidirectional crowbar action, SMB package compatibility, 10×160 µs surge rating up to 90 A(pk), thermal resistance of 90 °C/W, and RoHS-compliant lead-free construction.

Technical Context

The NP0720SCT3G operates as a voltage-triggered bidirectional crowbar device: it remains high-impedance below V_DRM (65 V), triggers into low-impedance conduction at V_BO (88 V), and latches until current falls below I_H (150 mA). Its dv/dt rating is 5.0 kV/s, ensuring robust immunity against fast transients without false triggering.

It is rated for operation from −40 °C to +150 °C, with thermal resistance J-A of 90 °C/W on standard FR4 PCB layout (3″×4.5″, 2 oz copper). Capacitance is 79 pF at 1 MHz/2 Vdc bias - optimized for minimal signal distortion in voice-grade and broadband telecom lines.

Key Specifications

Pinout & Package

SMB (DO-214AA) package per JEDEC case 403C, with cathode/anode terminals identified by marking orientation and physical pin assignment.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thyristor surge protector applications.

Compared with NP0720SAT3G, NP0720SCT3G offers identical protection performance and SMB footprint but with C-suffix marking for distinct supply chain tracking; compared with SM712.TCT, NP0720SCT3G delivers higher voltage handling, lower capacitance, and telecom-specific surge certification - making it the only validated choice for central office and DSLAM applications.

Availability

NP0720SCT3G is available at Aetrix Electronics and suitable for central office line cards, DSLAM protection modules, and VoIP gateway interfaces requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for NP0720SCT3G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and communications markets.

The NP Series TSPDs were developed specifically for telecom infrastructure protection - delivering bidirectional crowbar performance, industry-standard surge ratings, and SMB packaging optimized for high-density line card layouts.

FAQ

What is the primary function of the NP0720SCT3G in a telecom circuit?

The NP0720SCT3G functions as a bidirectional thyristor surge protector (TSPD) that acts as a crowbar device: it remains non-conductive below 65 V (V_DRM), triggers at 88 V (V_BO) during overvoltage events, and diverts surge current away from sensitive downstream components such as SLICs and codecs. Its role in the NP0720SCT3G is to provide fail-safe, low-residual-voltage clamping for AC-coupled telephone line interfaces.

Does the NP0720SCT3G require a gate trigger signal to operate?

No, the NP0720SCT3G is a gateless, voltage-triggered device - it requires no external control signal. Conduction initiates automatically when applied voltage exceeds its symmetrical breakover voltage (V_BO = 88 V) in either polarity. Once triggered, it latches on until current drops below its holding current (I_H = 150 mA), making the NP0720SCT3G ideal for passive, maintenance-free surge protection.

What is the significance of the "C" suffix in NP0720SCT3G?

Per onsemi's ordering documentation, the "C" suffix in NP0720SCT3G denotes a specific tape-and-reel packaging variant with marking "072C", distinguishing it from "A" and "B" variants (e.g., NP0720SAT3G). All three share identical electrical characteristics, SMB package, and RoHS compliance - the "C" identifies a discrete logistics configuration for traceability and inventory control, not a functional revision of the NP0720SCT3G itself.

Can the NP0720SCT3G be used in DC-powered circuits?

Yes, the NP0720SCT3G is inherently bidirectional and functions identically on DC circuits - it will trigger if DC voltage exceeds ±88 V and remain latched until current falls below ±150 mA. However, its primary validation and application focus is AC-coupled telecom lines (e.g., POTS, xDSL); for pure DC bus protection, ensure the protected load can tolerate the 4.0 V on-state voltage and verify thermal dissipation under sustained fault conditions for the NP0720SCT3G.

How does the NP0720SCT3G compare to TVS diodes for telecom surge protection?

Unlike unidirectional or bidirectional TVS diodes, the NP0720SCT3G uses thyristor-based crowbar action - resulting in lower clamping voltage (4.0 V vs. typical 15–30 V for TVS), higher surge current capacity (90 A vs. ~50 A for comparably sized TVS), and inherent latching behavior. This makes the NP0720SCT3G more effective for high-energy telecom surges where low residual voltage and robust energy diversion are critical, as confirmed in GR-1089-CORE testing.