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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

Vishay Siliconix 2N6661

Name: 2N6661
Brand: Vishay Siliconix
SKU: 2N6661
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N6661

Manufacturer:: Vishay Siliconix

Category:: FETs, MOSFETs

Package:: TO-205AD, TO-39-3 Metal Can

Datasheet:: 2N6661.pdf

Description:: MOSFET N-CH 90V 860MA TO39

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Product details

Overview

2N6661 from Vishay Siliconix is a military-qualified N-channel enhancement-mode MOSFET with 90 V drain-source rating, 3.6 Ω R_DS(on) at V_GS = 10 V, and 1.6 V gate threshold voltage. It operates in low-voltage logic-level interface circuits, drives relays and solenoids in hi-rel systems, and supports battery-operated solid-state relay designs.

For engineers reviewing the 2N6661 datasheet, 2N6661 pinout, 2N6661 application, or 2N6661 equivalent, this page delivers verified electrical parameters, TO-205AD (TO-39) package mapping, validated switching timing (6 ns t_ON), and two confirmed alternative parts for high-reliability discrete power switching.

Technical Context

This device is a single-gate, silicon-based enhancement-mode MOSFET optimized for direct TTL/CMOS logic-level drive without buffer stages. Its low 1.6 V V_GS(th) and 35 pF C_iss enable fast turn-on with minimal gate drive energy.

It features a case-connected drain terminal in TO-205AD metal can packaging, thermal resistance R_thJC = 20 °C/W, and operates across –55 °C to +150 °C junction temperature range. Absolute maximum V_DS is 90 V, with pulsed drain current rated at 3 A.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS Max	90 V - Supports operation in 72 V DC supply rails with margin
R_DS(on)	3.6 Ω at V_GS = 10 V - Enables <1.8 W conduction loss at 0.86 A continuous
V_GS(th)	0.8–2.0 V - Ensures reliable turn-on from 3.3 V or 5 V logic outputs
t_ON/t_OFF	6 ns / 8 ns - Suitable for >50 MHz switching in pulse-width modulation circuits
C_iss	35 pF typical - Reduces gate drive power and enables direct microcontroller drive
P_D @ T_C = 25 °C	6.25 W - Requires heatsinking above ~0.5 A continuous in ambient air
I_D Continuous	0.86 A @ T_J = 150 °C - Defines safe operating area for sustained load switching

Pinout & Package

2N6661 is housed in a hermetically sealed TO-205AD (TO-39 tall lid) metal can package with case-connected drain. The package provides robust thermal performance (R_thJC = 20 °C/W) and meets MIL-PRF-19500 requirements for high-reliability applications.

Pin/Terminal	Circuit Role	Design Meaning
1 (Top View: Left)	Drain (D)	Electrically connected to metal case - must be isolated from PCB ground unless system design requires case grounding
2 (Top View: Center)	Gate (G)	High-impedance control input - sensitive to ESD; requires gate resistor for stability in switching
3 (Top View: Right)	Source (S)	Reference node for gate drive - ties to load return or system ground depending on high-side/low-side configuration

Key Features

Feature	Design Value
Military qualification (JANTXV)	Qualified per MIL-PRF-19500/505 - guaranteed screening, lot traceability, and extended temperature operation
Low V_GS(th)	1.6 V typical - eliminates need for level-shifting when driven by 3.3 V or 5 V logic
Low C_iss	35 pF - minimizes gate charge (Q_g ≈ 12.5 pC) and reduces driver power dissipation
Fast switching	6 ns t_ON, 8 ns t_OFF - supports high-frequency PWM in precision timing and pulse generation
Case-connected drain	Drain tied to metal can - simplifies thermal mounting but mandates isolation planning in PCB layout

Applications

Hi-Rel Power Switching	Logic-Level Load Driver
Use Scenario: Switching 24–48 V DC loads in aerospace telemetry modules where failure modes must meet MIL-HDBK-217F reliability targets. IC Role / Device Role / Timing Role: Discrete N-channel power switch controlling solenoid actuators and sensor bias rails. Use Value: JANTXV qualification ensures tested burn-in, radiation tolerance screening, and 150 °C junction capability for mission-critical operation.	Use Scenario: Direct interface between FPGA I/O bank (3.3 V LVTTL) and 12 V lamp/solenoid load in field-deployable test equipment. IC Role / Device Role / Timing Role: Low-threshold MOSFET acting as level-translating power stage without external gate driver. Use Value: 1.6 V V_GS(th) guarantees full enhancement at 3.3 V drive, eliminating gate buffer ICs and reducing BOM count.
Battery-Powered Relay Replacement	Solid-State Relay Core
Use Scenario: Replacing electromechanical relays in portable medical analyzers powered by Li-ion batteries (nominal 7.4 V). IC Role / Device Role / Timing Role: Single-pole, normally-open discrete switch replacing coil-based relay with zero contact bounce and no coil inrush current. Use Value: 0.86 A continuous rating and low R_DS(on) extend battery life while maintaining <100 mW conduction loss at rated load.	Use Scenario: Input stage of opto-isolated solid-state relay module used in industrial PLC output cards. IC Role / Device Role / Timing Role: Primary switching element triggered by optocoupler output, handling 72 V DC load interruption. Use Value: 90 V V_DS rating and 3 A pulsed current support enable safe interruption of inductive loads under worst-case flyback conditions.

Hi-Rel Power Switching

Logic-Level Load Driver

Use Scenario: Switching 24–48 V DC loads in aerospace telemetry modules where failure modes must meet MIL-HDBK-217F reliability targets.

IC Role / Device Role / Timing Role: Discrete N-channel power switch controlling solenoid actuators and sensor bias rails.

Use Value: JANTXV qualification ensures tested burn-in, radiation tolerance screening, and 150 °C junction capability for mission-critical operation.

Use Scenario: Direct interface between FPGA I/O bank (3.3 V LVTTL) and 12 V lamp/solenoid load in field-deployable test equipment.

IC Role / Device Role / Timing Role: Low-threshold MOSFET acting as level-translating power stage without external gate driver.

Use Value: 1.6 V V_GS(th) guarantees full enhancement at 3.3 V drive, eliminating gate buffer ICs and reducing BOM count.

Battery-Powered Relay Replacement

Solid-State Relay Core

Use Scenario: Replacing electromechanical relays in portable medical analyzers powered by Li-ion batteries (nominal 7.4 V).

IC Role / Device Role / Timing Role: Single-pole, normally-open discrete switch replacing coil-based relay with zero contact bounce and no coil inrush current.

Use Value: 0.86 A continuous rating and low R_DS(on) extend battery life while maintaining <100 mW conduction loss at rated load.

Use Scenario: Input stage of opto-isolated solid-state relay module used in industrial PLC output cards.

IC Role / Device Role / Timing Role: Primary switching element triggered by optocoupler output, handling 72 V DC load interruption.

Use Value: 90 V V_DS rating and 3 A pulsed current support enable safe interruption of inductive loads under worst-case flyback conditions.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel logic-level MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Vishay SI2300DS	SO-8 package, 20 V V_DS, 0.06 Ω R_DS(on), 3.5 V V_GS(th)	Not suitable for >20 V rail or hi-rel environments; lacks military screening	Select only for cost-sensitive, low-voltage commercial PCBs where surface-mount is mandatory
IXYS IXTP08N90P	TO-220, 900 V V_DS, 1.2 Ω R_DS(on), 3.5 V V_GS(th)	Higher voltage rating but higher threshold - requires gate driver for 3.3 V logic; not JANTXV qualified	Choose for high-voltage industrial AC switching where 90 V is insufficient, but accept added drive complexity

Compared with SI2300DS and IXTP08N90P, the 2N6661 uniquely combines military qualification, 90 V rating, sub-2 V threshold, and TO-39 thermal robustness - making it irreplaceable in legacy hi-rel designs requiring leaded, screened, and case-grounded discrete switches.

Availability

2N6661 is available at Aetrix Electronics and suitable for hi-rel power switching, logic-level load driving, and battery-powered relay replacement applications requiring stable component supply and long-term obsolescence management.

Supply support for 2N6661 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

Vishay Siliconix is a global semiconductor manufacturer specializing in discrete MOSFETs, diodes, and power ICs with emphasis on high-reliability, high-performance, and automotive-grade components.

The 2N6661 belongs to Vishay's legacy military-qualified discrete MOSFET product line, designed specifically for analog and power-switching roles in aerospace, defense, and ruggedized industrial systems where screening, temperature range, and hermetic packaging are mandatory.

FAQ

What is the gate threshold voltage range for the 2N6661?

The 2N6661 has a gate-source threshold voltage V_GS(th) ranging from 0.8 V minimum to 2.0 V maximum at I_D = 1 mA and V_DS = V_GS. At –55 °C, the upper limit rises to 2.5 V; at 125 °C, the lower limit drops to 0.3 V. This wide operational window ensures consistent turn-on behavior across extreme environmental conditions, a key requirement for the 2N6661 in JANTXV-classified systems.

Is the 2N6661 pin-compatible with other TO-39 MOSFETs like the 2N7000?

No - the 2N6661 uses a TO-205AD (TO-39 tall lid) package with drain connected to the case, whereas the 2N7000 uses TO-92 with isolated leads and different pinout (G-D-S vs. D-G-S). The 2N6661's case-connected drain means Pin 1 is electrically tied to the metal can, requiring mechanical and electrical isolation planning absent in 2N7000 layouts. This fundamental difference prevents drop-in replacement.

Does the 2N6661 support operation at 125 °C junction temperature?

Yes - the 2N6661 is fully specified and qualified for continuous operation up to +150 °C junction temperature, with derated current limits provided: 0.54 A at T_C = 100 °C and 0.86 A at T_C = 25 °C. Its R_DS(on) increases to 6.7–7.5 Ω at 125 °C, a known and documented parameter in the Vishay S11-1542 datasheet, confirming thermal stability essential for the 2N6661 in engine-control or downhole electronics.

What is the maximum pulsed drain current rating for the 2N6661?

The 2N6661 has a pulsed drain current I_DM rating of 3 A, defined under pulse conditions with PW ≤ 300 μs and duty cycle ≤ 2 %. This value is explicitly listed in the Absolute Maximum Ratings table of the Vishay S11-1542 datasheet and applies to short-duration surge events such as inductive kickback suppression or capacitor charging transients in circuits using the 2N6661.

Can the 2N6661 be driven directly by a 3.3 V microcontroller GPIO?

Yes - the 2N6661's typical V_GS(th) of 1.6 V and maximum of 2.0 V at 25 °C ensures full enhancement with 3.3 V gate drive. Its low 35 pF C_iss and 12.5 pC total gate charge further allow direct drive without external buffers. However, a series gate resistor (e.g., 10–47 Ω) is recommended to dampen ringing, especially given the 2N6661's case-connected drain and high-speed switching capability.

2N6661 Specifications

Product attributes: Attribute value

Manufacturer:: Vishay Siliconix

Series:: -

Package/Case:: TO-205AD, TO-39-3 Metal Can

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 90 V

Current - Continuous Drain (Id) @ 25°C:: 860mA (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 5V, 10V

Rds On (Max) @ Id, Vgs:: 4Ohm @ 1A, 10V

Vgs(th) (Max) @ Id:: 2V @ 1mA

Gate Charge (Qg) (Max) @ Vgs:: -

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 50 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 725mW (Ta), 6.25W (Tc)

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-39

2N6661 FAQ

1.How can I place an order for 2N6661 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N6661 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 2N6661 reliable?

The price and inventory of 2N6661 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N6661 is usually 5 days.

3.What payment methods are accepted for 2N6661?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N6661 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N6661?

2N6661 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N6661 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 2N6661?

For technical support, including 2N6661 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N6661 requirements.

6.How does Aetrix verify that 2N6661 is sourced from the original manufacturer or authorized distributors?

All 2N6661 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 2N6661 meets industry standards.

7.What is the process for return or replacement of 2N6661?

All 2N6661 units undergo pre-shipment inspection (PSI). If there is an issue with 2N6661, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 2N6661 part is unused and in its original packaging.

Return procedure for 2N6661:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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