onsemi NP3500SAT3G

Overview

NP3500SAT3G from onsemi is a bidirectional thyristor surge protector device (TSPD) designed for overvoltage protection in telecom line interfaces. It features 320 V peak off-state voltage (V_DRM), 400 V breakover voltage (V_BO), 4 V on-state voltage (V_T), 150 mA holding current (I_H), and supports 500 A_(pk) 10×1000 µs surge current per GR-1089-CORE. It is used in central office and customer premises equipment to meet IEC 61000-4-5 and ITU-T K.20/21 compliance.

For engineers reviewing the NP3500SAT3G datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, SMB package dimensions, surge waveform ratings, thermal resistance (90 °C/W), and direct alternatives for telecom-grade transient protection design.

Technical Context

The NP3500SAT3G operates as a voltage-triggered crowbar device: it remains high-impedance until V_BO (400 V) is exceeded in either polarity, then latches into low-impedance conduction with V_T ≤ 4.0 V at 1.0 A_(pk). Its bidirectional symmetry enables single-device replacement of back-to-back diac-based protectors.

It sustains repetitive surges per TIA-968-A (10×160 µs, 90 A_(pk)) and GR-1089-CORE (10×1000 µs, 50 A_(pk)), with dv/dt rating of 5.0 kV/s and di/dt capability of 500 A/s - critical for fast-rising lightning-induced transients in xDSL and POTS lines.

Key Specifications

Pinout & Package

SMB package (JEDEC DO-214AA, Case 403C), surface-mount, bidirectional two-terminal device with no internal polarity distinction. MT1 and MT2 terminals are electrically symmetric.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NP3500SBT3G and SLVU2.8-4, the NP3500SAT3G uniquely delivers bidirectional 320 V standoff with certified 10×1000 µs surge handling - a combination essential for GR-1089-CORE-compliant central office equipment where long-tail energy absorption and polarity-agnostic operation are non-negotiable.

Availability

NP3500SAT3G is available at Aetrix Electronics and suitable for central office DSLAMs, customer premises xDSL modems, and analog telephone equipment requiring stable component supply with full GR-1089-CORE and IEC 61000-4-5 certification traceability.

Supply support for NP3500SAT3G 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 logic solutions for automotive, industrial, cloud, and communications markets.

The NP Series TSPDs were developed specifically for telecom infrastructure protection, targeting GR-1089-CORE and ITU-T K.20/21 compliance in space-constrained, high-reliability line interface designs.

FAQ

What is the maximum continuous operating voltage for NP3500SAT3G?

The NP3500SAT3G has a peak off-state voltage (V_DRM) of 320 V, meaning it can safely block up to 320 V in either polarity under steady-state conditions. This rating applies across its full operating temperature range of −40 °C to +150 °C and is validated per JEDEC test methods. The NP3500SAT3G must not be subjected to sustained voltages exceeding this value to avoid unintended conduction.

Does NP3500SAT3G require a gate trigger signal to operate?

No, the NP3500SAT3G is a gateless, voltage-triggered thyristor device. It operates autonomously based solely on applied voltage across MT1 and MT2 terminals. When either polarity exceeds the 400 V breakover voltage (V_BO), the device self-triggers into low-impedance conduction without external control. The NP3500SAT3G contains no gate terminal or control circuitry.

Can NP3500SAT3G be used in DC circuits?

Yes, the NP3500SAT3G functions identically in DC applications as in AC - its bidirectional structure allows it to protect positive- or negative-going transients on a single DC rail. However, the 150 mA holding current (I_H) must be maintained until the surge decays; in low-current DC systems, ensure downstream current paths exceed I_H during clamping to sustain conduction and prevent premature dropout.

What is the thermal resistance of NP3500SAT3G and how does it affect layout?

The NP3500SAT3G has a junction-to-ambient thermal resistance (R_θJA) of 90 °C/W on a standard FR4 PCB (3″×4.5″, 2 oz copper, 3×3 inch fan-out). This means each watt of surge power dissipated raises the junction temperature by 90 °C. To avoid exceeding the 150 °C max operating temperature, limit average power and use adequate copper area - the NP3500SAT3G's SMB footprint supports thermal relief via solder mask defined pads and thermal vias.

How does NP3500SAT3G differ from MOV-based protectors in telecom applications?

Unlike metal-oxide varistors (MOVs), the NP3500SAT3G offers precise, repeatable 400 V breakover voltage with negligible leakage (<5 µA), no degradation after repeated surges, and 28 pF capacitance that avoids signal distortion. MOVs exhibit voltage drift, higher capacitance (>100 pF), and wear-out mechanisms. For GR-1089-CORE-certified telecom gear where reliability and signal fidelity are critical, the NP3500SAT3G provides superior long-term stability compared to MOV alternatives.