onsemi NP1500SBT3G

Overview

NP1500SBT3G from onsemi is a bidirectional thyristor surge protector (TSPD) designed for overvoltage clamping in telecom line interfaces. It features 140 V peak off-state voltage (V_DRM), 180 V breakover voltage (V_BO), 4.0 V on-state voltage at 1 A, 150 mA holding current, and supports GR-1089-CORE and IEC 61000-4-5 surge immunity up to 75 A(pk) on 10×360 µs waveform - deployed in central office and customer premises equipment protection circuits.

For engineers reviewing the NP1500SBT3G datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional crowbar action, SMB package compatibility, 150 mA holding current threshold, 90 °C/W junction-to-ambient thermal resistance, and compliance with ITU-T K.20/K.21 surge standards for telecom infrastructure.

Technical Context

The NP1500SBT3G operates as a voltage-triggered bidirectional thyristor that latches into low-impedance conduction upon exceeding V_BO = 180 V in either polarity, sustaining conduction until current falls below I_H = 150 mA. Its 4.0 V on-state voltage limits power dissipation during surge events while maintaining robust clamping stability across −40°C to +150°C operating range.

It delivers non-repetitive surge current ratings of 75 A(pk) on 10×360 µs waveform and 50 A(pk) on 10×560 µs waveform per GR-1089-CORE, with dv/dt immunity ≥5 kV/s and di/dt capability up to 500 A/s - enabling reliable protection against lightning-induced transients and AC power cross-talk in analog telephony and xDSL line cards.

Key Specifications

Pinout & Package

NP1500SBT3G uses the SMB (DO-214AA, Case 403C) surface-mount package with two terminals: MT1 and MT2. This symmetrical bidirectional configuration eliminates polarity dependency and supports direct placement across differential telecom lines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NP1500SAT3G, NP1500SBT3G trades peak single-pulse capacity for superior endurance under standardized 10×360 µs telecom surges; versus SLVU2.8-4, it provides true crowbar action with self-sustaining conduction - critical for protecting analog line interfaces from sustained overvoltages.

Availability

NP1500SBT3G is available at Aetrix Electronics and suitable for central office line cards, xDSL customer premises equipment, and VoIP interface protection requiring stable component supply, RoHS-compliant packaging, and repeatable GR-1089-CORE compliance.

Supply support for NP1500SBT3G 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 management, analog, sensor, and logic solutions for automotive, industrial, and communications markets.

The NP Series TSPDs were developed specifically for telecom infrastructure protection, delivering bidirectional, latching surge suppression in compact SMB packages to replace discrete SCR+diode combinations in central office, access network, and CPE equipment.

FAQ

What is the function of NP1500SBT3G in a telecom line interface?

NP1500SBT3G functions as a bidirectional thyristor surge protector that triggers into low-impedance conduction when line voltage exceeds 180 V in either polarity, diverting surge current away from sensitive analog components. Its 150 mA holding current ensures sustained clamping until the transient decays, and its 4.0 V on-state voltage limits power dissipation during conduction. NP1500SBT3G is commonly used across tip/ring pairs in DSLAMs and VoIP gateways.

Does NP1500SBT3G require a gate trigger signal to operate?

No, NP1500SBT3G is a gateless, voltage-triggered thyristor device. It relies solely on the applied voltage across MT1 and MT2 exceeding its breakover voltage (V_BO = 180 V) to initiate conduction - no external control signal or biasing is needed. This simplifies circuit design and improves reliability in telecom surge protection applications where NP1500SBT3G serves as a passive crowbar element.

What surge standards does NP1500SBT3G meet?

NP1500SBT3G meets GR-1089-CORE (75 A pk, 10×360 µs), IEC 61000-4-5 (10×700 µs, 75 A pk), ITU-T K.20/K.21 (75 A pk, 10×700 µs), and TIA-968-A (90 A pk, 10×160 µs). Its bidirectional architecture and specified surge ratings make NP1500SBT3G suitable for certified telecom equipment requiring compliance with multiple international immunity standards.

Can NP1500SBT3G be used in DC power line protection?

NP1500SBT3G is not recommended for standalone DC power rail protection because its 140 V V_DRM and 180 V V_BO exceed typical DC bus voltages, and its 150 mA holding current may prevent natural turn-off if load current remains above threshold. It is engineered for AC-coupled telecom line protection where current naturally crosses zero. For DC systems, NP1500SBT3G must be paired with series impedance or current-limiting circuitry to ensure reliable reset.

What is the thermal resistance of NP1500SBT3G and how does it affect layout?

NP1500SBT3G has a junction-to-ambient thermal resistance (R_θJA) of 90 °C/W on a standard FR4 PCB (3″×4.5″, 2 oz copper). This means each watt of surge power dissipated results in a 90°C temperature rise at the die. To maintain reliability under repeated surges, designers must provide adequate copper pour around the SMB pads and avoid routing heat-sensitive components nearby. NP1500SBT3G's thermal profile directly impacts its surge repetition rate capability in real-world deployments.