Vishay Siliconix 3N163-2

Overview

3N163 from Siliconix is a hermetically sealed, lateral P-channel enhancement-mode MOSFET designed for ultra-low-leakage analog switching and high-impedance preamplifier circuits. It features –40 V drain-source breakdown voltage, –2 to –5 V gate threshold, 250 Ω maximum on-resistance at –20 V V_GS, –5 mA minimum on-state drain current, and 0.7 pF reverse transfer capacitance - enabling precision smoke detector front-ends and electrometer input stages.

For engineers reviewing the 3N163 datasheet, 3N163 pinout, 3N163 application, or 3N163 equivalent, key selection criteria include ultra-low gate leakage (<0.02 pA typ.), high gate-body breakdown (125 V), normally-off operation, TO-206AF (TO-72) metal-can package compatibility with military processing, and verified performance at 125 °C junction temperature.

Technical Context

This device operates as a normally-off, voltage-controlled switch with lateral channel geometry optimized for minimal Crss and high input impedance. Its gate-threshold range (–2 to –5 V) ensures reliable turn-on under low-power biasing, while the 0.7 pF Crss supports fast analog switching with minimal feedthrough.

The TO-206AF package provides hermetic sealing and thermal stability up to 150 °C junction temperature. Absolute maximum ratings include –50 mA continuous drain current, 375 mW power dissipation at 25 °C (derated 3 mW/°C above), and –65 to +200 °C storage range - meeting MIL-STD processing requirements.

Key Specifications

Pinout & Package

Package: TO-206AF (TO-72), hermetically sealed metal can with glass-sealed leads, compliant with military processing standards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar P-channel MOSFET switching applications.

Compared with 3N164 and 2N7000, the 3N163 delivers superior voltage rating and lower on-resistance for ultra-low-leakage P-channel switching - making it irreplaceable in smoke detector and electrometer designs requiring guaranteed <0.02 pA gate leakage and –40 V blocking.

Availability

3N163 is available at Aetrix Electronics and suitable for smoke detector manufacturing, electrometer instrumentation, and analog multiplexer design requiring stable component supply across extended product lifecycles.

Supply support for 3N163 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

Siliconix, acquired by Vishay in 1998, specialized in high-reliability discrete semiconductors with emphasis on low-leakage, high-voltage, and hermetic packaging technologies.

The 3N163 belongs to Siliconix's legacy lateral MOSFET product line, engineered specifically for ultra-high-input-impedance analog signal conditioning in safety-critical and metrology-grade applications.

FAQ

What is the maximum operating junction temperature for the 3N163?

The 3N163 has a specified operating junction temperature range of –55 °C to +150 °C. This wide range supports deployment in sealed, high-temperature environments such as enclosed fire alarm housings or industrial sensor enclosures. The 3N163 maintains its ultra-low gate leakage and stable r_DS(on) within this envelope, as confirmed by characterization data up to 125 °C in the official datasheet.

Is the 3N163 pin-compatible with the 3N164?

Yes, the 3N163 and 3N164 share identical TO-206AF (TO-72) pinout and mechanical footprint - pins 1 (Drain), 2 (Gate), 3 (Source), and 4 (Case/Source) are functionally and physically aligned. However, they differ electrically: the 3N163 offers –40 V V(BR)DSS and 250 Ω r_DS(on), while the 3N164 is rated for –30 V and 300 Ω. The 3N163 is not a drop-in replacement unless the design requires the higher voltage rating.

Does the 3N163 require external gate protection against ESD?

Although the 3N163 features high gate-body breakdown (125 V), its ultra-low gate leakage makes it susceptible to ESD damage during handling. The datasheet explicitly states "Minimize Handling ESD Problems" as a key benefit of its high input impedance isolation. Therefore, standard ESD precautions - including grounded workstations, conductive foam storage, and ionized air - are mandatory when assembling or testing the 3N163.

Can the 3N163 be used in linear amplification mode?

The 3N163 is characterized for analog switching and preamplifier applications, with published g_fs (2–4 mS) and output conductance (150–250 µS) confirming usable small-signal gain. However, it lacks guaranteed linearity specs (THD, distortion vs. frequency) and is not optimized for Class-A biasing. While functional in low-frequency, high-Z gain stages (e.g., electrometer front-ends), the 3N163 should not replace purpose-built JFETs or op-amps in precision linear amplifiers.

What is the meaning of "normally off" for the 3N163?

"Normally off" means the 3N163 conducts no significant drain current (I_DSS ≤ –8 nA) when V_GS = 0 V - ensuring intrinsic safety in fault conditions. This behavior is inherent to its enhancement-mode P-channel structure: conduction only occurs when a sufficiently negative V_GS (≤ –2 V) is applied. In smoke detectors, this guarantees open-circuit default state, preventing false alarms due to gate floating or power loss.