onsemi NP1800SAT3G

Overview

NP1800SAT3G from onsemi is a bidirectional thyristor surge protector (TSPD) designed for overvoltage protection in telecom line interfaces. It features 170 V peak off-state voltage (V_DRM), 220 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 compliance in central office and customer premises equipment.

For engineers reviewing the NP1800SAT3G datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional crowbar action, SMB package compatibility, 10×1000 µs surge rating up to 50 A(pk), thermal resistance of 90 °C/W, and RoHS-compliant lead-free construction.

Technical Context

The NP1800SAT3G operates as a voltage-triggered bilateral crowbar device: it remains high-impedance below V_DRM (170 V), switches to low-impedance conduction above V_BO (220 V), and latches until current falls below I_H (150 mA). Its dv/dt immunity exceeds 5 kV/s, preventing false triggering under fast transients.

Designed for telecom primary protection, it handles repetitive 2×10 µs and 10×160 µs surges per TIA-968-A and GR-1089-CORE, with peak pulse current ratings of 150 A (A-level), 90 A (B-level), and 50 A (C-level) depending on waveform and test configuration.

Key Specifications

Pinout & Package

SMB package (JEDEC DO-214AA, Case 403C), surface-mount, bidirectional two-terminal device with MT1 and MT2 terminals. No gate control; symmetrical operation across both polarities.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NP1800SBT3G and NP1800SCT3G, the NP1800SAT3G provides the highest validated surge current capability (150 A(pk) at 2×10 µs) and broadest regulatory coverage, making it the default choice for central office and carrier-grade infrastructure requiring A-level robustness.

Availability

NP1800SAT3G is available at Aetrix Electronics and suitable for central office line cards, DSLAM protection modules, and customer premises equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant surge protection.

Supply support for NP1800SAT3G 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 thyristor surge protectors were developed specifically for telecom infrastructure protection, delivering high-voltage bidirectional crowbar performance in compact SMB packages compliant with GR-1089-CORE and IEC 61000-4-5 standards.

FAQ

What is the maximum surge current rating for NP1800SAT3G under GR-1089-CORE 2×10 µs waveform?

The NP1800SAT3G is rated for 150 A(pk) under the GR-1089-CORE 2×10 µs double-exponential surge waveform. This A-level rating reflects its highest validated non-repetitive short-circuit current capability and is specified in the official onsemi datasheet (NP0640S/D, Rev. 5). The NP1800SAT3G maintains stable triggering and recovery at this level without parametric shift or degradation when operated within its thermal limits.

Does NP1800SAT3G require a gate drive signal to operate?

No, the NP1800SAT3G is a gateless, voltage-triggered thyristor surge protector. It operates solely based on applied voltage across MT1 and MT2: it blocks up to 170 V (V_DRM) and triggers into low-impedance conduction only when voltage exceeds 220 V (V_BO). There is no gate terminal or control signal-its behavior is fully autonomous and bidirectional, making it ideal for passive line protection without supporting circuitry.

What is the junction-to-ambient thermal resistance (R_θJA) of NP1800SAT3G in standard PCB layout?

The NP1800SAT3G has a specified R_θJA of 90 °C/W when mounted on an FR4 PCB measuring 3″ × 4.5″ × 0.06″ with 2 oz copper, using a 3×3 inch fan-out pattern per EIA/JESD51-3. This value defines the steady-state temperature rise above ambient per watt of power dissipated during crowbar conduction, and is critical for calculating safe surge repetition rates and thermal derating in high-density telecom line cards.

How does the 39 pF capacitance of NP1800SAT3G affect high-frequency signal integrity?

The NP1800SAT3G's typical junction capacitance of 39 pF at 1 MHz/2 Vdc introduces minimal loading on telecom lines: insertion loss remains below 0.5 dB up to 10 MHz, preserving voice-band fidelity and DSL upstream/downstream signal integrity. This low capacitance enables direct placement at line connectors without requiring compensation networks-unlike higher-capacitance MOVs or multilayer varistors that degrade high-speed data transmission.

Is NP1800SAT3G compatible with lead-free reflow soldering processes?

Yes, the NP1800SAT3G is explicitly marked "G" for lead-free and RoHS-compliant construction, and its SMB package is qualified for standard Pb-free reflow profiles (J-STD-020). The device withstands peak temperatures up to 260 °C for 10 seconds, matching IPC/JEDEC specifications. Thermal resistance and surge performance remain unchanged post-reflow, and no special pre-conditioning or moisture sensitivity handling is required beyond standard MSL-1 guidelines.