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Home > Products > Discrete Semiconductor Products > Transistors > JFETs

onsemi 2N5639

Name: 2N5639
Brand: onsemi
SKU: 2N5639
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N5639

Manufacturer:: onsemi

Category:: JFETs

Package:: TO-226-3, TO-92-3 Long Body

Datasheet:: 2N5639.pdf

Description:: JFET N-CH 35V TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N5639 from Fairchild Semiconductor is an N-channel junction field-effect transistor (JFET) designed for low-level analog switching, sample-and-hold circuits, and chopper-stabilized amplifiers. It features V_BRGSS = –30 V, I_DSS = 25 mA, r_DS(on) = 60 Ω, C_iss = 10 pF, and operates across –55°C to +150°C.

For engineers reviewing the 2N5639 datasheet, pinout, applications, or equivalent options, key selection considerations include gate-source breakdown voltage, zero-gate drain current tolerance, on-resistance stability at low V_GS, thermal resistance (R_θJA = 357°C/W), and TO-92 mechanical compatibility in precision analog signal paths.

Technical Context

The 2N5639 is a depletion-mode N-channel JFET with symmetrical source/drain terminals and a reverse-biased gate controlling channel conduction. Its low input capacitance (C_iss = 10 pF, C_rss = 4.0 pF) and fast switching (t_d(on) = 6.0 ns, t_f = 20 ns) support high-fidelity analog sampling up to ~10 MHz.

It operates with V_GS ranging from –30 V to 0 V, exhibits minimal gate leakage (I_GSS = –1.0 nA at –15 V), and maintains stable I_DSS across temperature due to its process 51 fabrication-optimized for low-noise, low-distortion analog control functions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_BRGSS	–30 V: Maximum reverse gate-source voltage before breakdown; defines safe gate bias range in high-impedance control circuits.
I_DSS	25 mA: Zero-gate drain saturation current; sets maximum analog signal swing capability in linear operation.
r_DS(on)	60 Ω: Drain-source on-resistance at V_GS = 0 V and I_D = 1.0 mA; determines insertion loss and distortion in switch-mode applications.
C_iss	10 pF: Input capacitance at V_GS = 12 V; limits bandwidth and charge injection in sample-and-hold timing accuracy.
T_J Range	–55°C to +150°C: Operating junction temperature range; enables use in industrial and automotive under-hood environments.
P_D	350 mW at 25°C: Total power dissipation; requires derating above ambient (2.8 mW/°C) for sustained analog biasing.

Pinout & Package

2N5639 is housed in a standard TO-92 plastic package with 3 leads: Lead 1 = Drain, Lead 2 = Source, Lead 3 = Gate. The package measures 4.58 mm × 3.60 mm × 14.47 mm and is compatible with through-hole wave soldering and manual prototyping.

Pin/Terminal	Circuit Role	Design Meaning
1 (Drain)	Current output terminal	Connected to load or signal path; carries full I_DSS current in on-state with minimal voltage drop (r_DS(on) = 60 Ω).
2 (Source)	Current return/reference node	Serves as common reference for gate bias; symmetrical with drain for bidirectional analog signal routing.
3 (Gate)	Control electrode	Reverse-biased PN junction; accepts DC bias from –30 V to 0 V to modulate channel conductivity without gate current draw.

Key Features

Feature	Design Value
Low gate leakage	I_GSS = –1.0 nA at –15 V ensures minimal bias error and long time-constant hold in precision sample-and-hold stages.
Fast switching	t_d(on)/t_f = 6.0/20 ns enables sub-100 ns total transition for high-speed multiplexing and chopper clocking.
Stable I_DSS	25 mA nominal with tight process control (Process 51) reduces unit-to-unit gain variation in matched amplifier pairs.
High V_BRGSS	–30 V rating supports robust gate protection against ESD and transient overvoltage in unbuffered front-end designs.

Applications

Instrumentation Amplifier Front-End	Chopper-Stabilized Op-Amp Core
Use Scenario: Low-drift DC measurement in portable multimeters and sensor interfaces requiring <1 µV offset drift. IC Role / Device Role / Timing Role: JFET used as ultra-low-input-bias-current switch in auto-zeroing feedback path. Use Value: I_GSS = –1.0 nA minimizes input current error; r_DS(on) = 60 Ω ensures <0.1% gain error in 10 kΩ feedback networks.	Use Scenario: Precision nulling in medical-grade EEG amplifiers where offset must remain stable over temperature and time. IC Role / Device Role / Timing Role: N-channel JFET acts as synchronous chopper gate driven by 100 kHz square wave. Use Value: C_iss = 10 pF and t_f = 20 ns limit charge injection to <5 fC, preserving sub-µV baseline stability.
Sample-and-Hold Circuit	Analog Multiplexer Channel
Use Scenario: High-resolution data acquisition in industrial PLC analog input modules sampling at 100 kSPS. IC Role / Device Role / Timing Role: 2N5639 serves as hold capacitor switch with controlled on-resistance and low feedthrough. Use Value: r_DS(on) = 60 Ω and C_rss = 4.0 pF reduce aperture uncertainty and settling time to <100 ns.	Use Scenario: 8-channel analog signal routing in test equipment requiring low crosstalk and consistent ON impedance. IC Role / Device Role / Timing Role: Discrete JFET configured as bidirectional analog switch per channel. Use Value: Symmetrical source/drain and V_BRGSS = –30 V allow ±10 V signal handling with <0.01% THD at 1 kHz.

Instrumentation Amplifier Front-End

Chopper-Stabilized Op-Amp Core

Use Scenario: Low-drift DC measurement in portable multimeters and sensor interfaces requiring <1 µV offset drift.

IC Role / Device Role / Timing Role: JFET used as ultra-low-input-bias-current switch in auto-zeroing feedback path.

Use Value: I_GSS = –1.0 nA minimizes input current error; r_DS(on) = 60 Ω ensures <0.1% gain error in 10 kΩ feedback networks.

Use Scenario: Precision nulling in medical-grade EEG amplifiers where offset must remain stable over temperature and time.

IC Role / Device Role / Timing Role: N-channel JFET acts as synchronous chopper gate driven by 100 kHz square wave.

Use Value: C_iss = 10 pF and t_f = 20 ns limit charge injection to <5 fC, preserving sub-µV baseline stability.

Sample-and-Hold Circuit

Analog Multiplexer Channel

Use Scenario: High-resolution data acquisition in industrial PLC analog input modules sampling at 100 kSPS.

IC Role / Device Role / Timing Role: 2N5639 serves as hold capacitor switch with controlled on-resistance and low feedthrough.

Use Value: r_DS(on) = 60 Ω and C_rss = 4.0 pF reduce aperture uncertainty and settling time to <100 ns.

Use Scenario: 8-channel analog signal routing in test equipment requiring low crosstalk and consistent ON impedance.

IC Role / Device Role / Timing Role: Discrete JFET configured as bidirectional analog switch per channel.

Use Value: Symmetrical source/drain and V_BRGSS = –30 V allow ±10 V signal handling with <0.01% THD at 1 kHz.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel JFET switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
J310	I_DSS = 24–60 mA (wider spread); C_iss = 12 pF; V_BRGSS = –25 V	Higher gain variability affects matched-pair performance in chopper cores	Preferred when higher I_DSS margin is needed but gate voltage headroom is limited to –25 V
2N4416A	I_DSS = 5–15 mA (lower); r_DS(on) = 100 Ω; T_J max = +125°C	Reduced drive capability and narrower temp range limit use in high-temp industrial hold circuits	Selected where lower leakage (<0.5 nA) is prioritized over on-resistance and temperature range

Compared with J310 and 2N4416A, the 2N5639 offers tighter I_DSS distribution, superior thermal rating (+150°C), and optimized C_iss/C_rss ratio-making it preferred for precision sample-and-hold and chopper amplifier designs demanding stability across extended temperature and time.

Availability

2N5639 is available at Aetrix Electronics and suitable for instrumentation front-ends, chopper-stabilized amplifiers, and sample-and-hold circuits requiring stable component supply, long-lifecycle availability, and traceable sourcing.

Supply support for 2N5639 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

Fairchild Semiconductor was a U.S.-based semiconductor manufacturer specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The 2N5639 belongs to Fairchild's legacy analog switching JFET product line, engineered specifically for low-noise, low-leakage signal routing in precision measurement and stabilization circuits.

FAQ

What is the maximum gate-source voltage rating for the 2N5639?

The 2N5639 has a maximum gate-source voltage rating (V_BRGSS) of –30 V, measured at I_G = –10 µA. This specifies the reverse breakdown limit of the gate-channel PN junction. Exceeding this voltage risks permanent gate damage. The 2N5639 must be biased within –30 V ≤ V_GS ≤ 0 V during normal operation to ensure reliable function and longevity.

Does the 2N5639 support bidirectional analog signal switching?

Yes, the 2N5639 supports bidirectional analog signal switching because its source and drain terminals are physically symmetrical and electrically interchangeable in depletion-mode operation. This symmetry allows the 2N5639 to pass AC signals equally in both directions when used with appropriate gate biasing-making it suitable for analog multiplexer and chopper applications where polarity independence is required.

What is the typical drain-source on-resistance of the 2N5639 and under what conditions is it specified?

The 2N5639 has a typical drain-source on-resistance (r_DS(on)) of 60 Ω, specified at V_GS = 0 V and I_D = 1.0 mA. This value reflects the channel resistance when the device is fully enhanced (zero gate bias), and it directly impacts insertion loss and linearity in analog switch applications. The 2N5639 maintains this resistance with low temperature coefficient across its operating range.

Can the 2N5639 be used in high-temperature industrial environments?

Yes, the 2N5639 is rated for operation from –55°C to +150°C junction temperature, making it suitable for high-temperature industrial environments such as motor control feedback paths or under-hood automotive sensors. Its R_θJA of 357°C/W and PD = 350 mW at 25°C require appropriate PCB copper area and airflow-but the 2N5639 itself remains functional and stable up to its maximum T_J.

How does the 2N5639 compare to MOSFETs for low-level analog switching?

The 2N5639 offers significantly lower gate leakage (–1.0 nA vs. typical MOSFET gate leakage >100 pA) and no threshold voltage shift with temperature-critical for precision sample-and-hold and chopper circuits. Unlike enhancement-mode MOSFETs, the 2N5639 is depletion-mode and requires no positive gate drive, simplifying bias design. Its 60 Ω r_DS(on) and 10 pF C_iss provide better linearity than most small-signal MOSFETs in sub-10 V analog paths.

2N5639 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body

Packaging:: Bulk

Product Status:: Obsolete

FET Type:: N-Channel

Voltage - Breakdown (V(BR)GSS):: 35 V

Drain to Source Voltage (Vdss):: 30 V

Current - Drain (Idss) @ Vds (Vgs=0):: 25 mA @ 20 V

Current Drain (Id) - Max:: -

Voltage - Cutoff (VGS off) @ Id:: -

Input Capacitance (Ciss) (Max) @ Vds:: 10pF @ 12V (VGS)

Resistance - RDS(On):: 60 Ohms

Power - Max:: 310 mW

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

2N5639 FAQ

1.How can I place an order for 2N5639 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N5639 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 2N5639 reliable?

The price and inventory of 2N5639 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N5639 is usually 5 days.

3.What payment methods are accepted for 2N5639?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N5639 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N5639?

2N5639 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N5639 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 2N5639?

For technical support, including 2N5639 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N5639 requirements.

6.How does Aetrix verify that 2N5639 is sourced from the original manufacturer or authorized distributors?

All 2N5639 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 2N5639 meets industry standards.

7.What is the process for return or replacement of 2N5639?

All 2N5639 units undergo pre-shipment inspection (PSI). If there is an issue with 2N5639, 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 2N5639 part is unused and in its original packaging.

Return procedure for 2N5639:

1.Submit a request within 90 days.

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

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