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Home > Products > Discrete Semiconductor Products > Transistors > JFETs

onsemi J105_D27Z

Name: J105_D27Z
Brand: onsemi
SKU: J105_D27Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: J105_D27Z

Manufacturer:: onsemi

Category:: JFETs

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: J105_D27Z.pdf

Description:: JFET N-CH 25V TO92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

J105_D27Z from ON Semiconductor (formerly Fairchild) is an N-channel junction field-effect transistor (JFET) switch optimized for low-on-resistance analog and digital switching in signal routing, voltage-controlled resistors, and constant-current source applications. It features V_GS(off) = −4.5 V (max), R_DS(on) = 3.0 Ω, I_DSS = 500 mA, and TO-92 package with 3-pin straight-lead configuration.

For engineers reviewing the J105_D27Z datasheet, pinout, applications, or equivalent options, key selection criteria include gate threshold voltage tolerance, drain-source on-resistance at zero gate bias, thermal derating above 25°C, and compatibility with low-voltage control logic in precision analog front-ends.

Technical Context

The J105_D27Z operates as a depletion-mode N-channel JFET, requiring no gate drive current and enabling true voltage-controlled resistance behavior. Its gate-source cutoff voltage range (−4.5 V to −10.0 V) and low R_DS(on) support stable operation in linear and saturated regions across −55°C to +150°C ambient.

It exhibits predictable transconductance (g_m) and output conductance (g_ds) characteristics per Figure 8 and Figure 7 of the datasheet, with capacitance values C_dg(on) = 160 pF and C_sg(on) = 35 pF enabling reliable high-frequency switching up to several MHz in buffered configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_GS(off)	−4.5 V (max); defines maximum gate-source voltage needed to pinch off channel - critical for turn-off margin in analog switches
R_DS(on)	3.0 Ω; on-resistance at V_GS = 0 V and V_DS ≤ 0.1 V - enables low insertion loss in signal path applications
I_DSS	500 mA; zero-gate-voltage drain current - sets upper bound for constant-current sink capability
P_D	625 mW at T_A = 25°C; power dissipation limit - requires 5.0 mW/°C derating above ambient for thermal safety
V_(BR)GSS	−25 V; gate-source breakdown voltage - determines maximum allowable reverse gate bias during transient events
R_θJA	357 °C/W; junction-to-ambient thermal resistance on standard FR-4 PCB - informs heatsinking requirements for continuous DC operation

Pinout & Package

Package: TO-92, 3-lead molded plastic case with standard straight leads (no EOL code). Dimensions per Fairchild drawing ZA03D.

Pin/Terminal	Circuit Role	Design Meaning
Drain (D)	Main current-carrying terminal (N-channel)	Connected to load or signal path; handles full I_DSS current and must be routed with adequate copper area for thermal management
Gate (G)	Control electrode (reverse-biased PN junction)	Accepts DC or AC control voltage; zero gate current simplifies bias network design and eliminates loading on driver stage
Source (S)	Reference terminal for gate voltage and current return	Typically tied to ground or common reference; establishes V_GS potential and defines current direction in circuit topology

Key Features

Feature	Design Value
Depletion-mode operation	Conducts at V_GS = 0 V - eliminates need for active gate bias circuitry in always-on or normally-closed switch designs
Low gate leakage (I_GSS)	≤ −3.0 nA at V_GS = −15 V - preserves high-impedance control node integrity in precision sensor interfaces
Wide temperature range	−55°C to +150°C operating junction - supports deployment in automotive under-hood and industrial motor-control environments
Stable R_DS(on) vs. ID	Minimal variation below 200 mA per Figure 6 - ensures consistent signal attenuation in audio and instrumentation amplifiers

Applications

Audio Signal Switching	Constant-Current Source
Use Scenario: Routing line-level analog audio between multiple inputs (e.g., microphone, instrument, aux) in mixer or audio interface without audible distortion or crosstalk. IC Role / Device Role / Timing Role: Voltage-controlled analog switch acting as bidirectional signal path with minimal harmonic generation due to linear R_DS(on) behavior. Use Value: 3.0 Ω R_DS(on) and <160 pF capacitance preserve wide bandwidth and low THD across 20 Hz–20 kHz range.	Use Scenario: Providing stable bias current for LED drivers, op-amp input stages, or sensor excitation circuits where temperature drift must be minimized. IC Role / Device Role / Timing Role: Depletion-mode JFET configured as two-terminal current source with self-regulating behavior via V_GS(off) and I_DSS. Use Value: I_DSS = 500 mA and tight V_GS(off) tolerance enable ±2% current accuracy over −40°C to +85°C without external feedback.
Voltage-Controlled Resistor	Low-Voltage Logic Interface
Use Scenario: Implementing programmable gain stages or variable attenuators in test equipment using analog voltage control instead of digital potentiometers. IC Role / Device Role / Timing Role: Three-terminal JFET operated in ohmic region with V_GS as control input - functions as tunable resistor with sub-ohm resolution. Use Value: Linear R_DS(on) vs. V_GS response (Figure 5) allows precise 0–3 Ω adjustment using 0–4.5 V control range.	Use Scenario: Level-shifting and interfacing 3.3 V or 5 V microcontroller GPIO outputs to higher-voltage analog subsystems while maintaining fast edge rates. IC Role / Device Role / Timing Role: Digital switch controlled by logic-level gate voltage - turns on fully at V_GS = 0 V and turns off completely at V_GS ≤ −4.5 V. Use Value: Gate threshold aligns with standard TTL/CMOS logic levels; <100 ns switching time supports >1 MHz digital control signals.

Audio Signal Switching

Constant-Current Source

Use Scenario: Routing line-level analog audio between multiple inputs (e.g., microphone, instrument, aux) in mixer or audio interface without audible distortion or crosstalk.

IC Role / Device Role / Timing Role: Voltage-controlled analog switch acting as bidirectional signal path with minimal harmonic generation due to linear R_DS(on) behavior.

Use Value: 3.0 Ω R_DS(on) and <160 pF capacitance preserve wide bandwidth and low THD across 20 Hz–20 kHz range.

Use Scenario: Providing stable bias current for LED drivers, op-amp input stages, or sensor excitation circuits where temperature drift must be minimized.

IC Role / Device Role / Timing Role: Depletion-mode JFET configured as two-terminal current source with self-regulating behavior via V_GS(off) and I_DSS.

Use Value: I_DSS = 500 mA and tight V_GS(off) tolerance enable ±2% current accuracy over −40°C to +85°C without external feedback.

Voltage-Controlled Resistor

Low-Voltage Logic Interface

Use Scenario: Implementing programmable gain stages or variable attenuators in test equipment using analog voltage control instead of digital potentiometers.

IC Role / Device Role / Timing Role: Three-terminal JFET operated in ohmic region with V_GS as control input - functions as tunable resistor with sub-ohm resolution.

Use Value: Linear R_DS(on) vs. V_GS response (Figure 5) allows precise 0–3 Ω adjustment using 0–4.5 V control range.

Use Scenario: Level-shifting and interfacing 3.3 V or 5 V microcontroller GPIO outputs to higher-voltage analog subsystems while maintaining fast edge rates.

IC Role / Device Role / Timing Role: Digital switch controlled by logic-level gate voltage - turns on fully at V_GS = 0 V and turns off completely at V_GS ≤ −4.5 V.

Use Value: Gate threshold aligns with standard TTL/CMOS logic levels; <100 ns switching time supports >1 MHz digital control signals.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N5457	V_GS(off) = −0.5 to −6.0 V (wider spread); R_DS(on) ≈ 5.0 Ω; lower I_DSS (1–5 mA)	Less suitable for high-current switching; better for ultra-low-power bias networks	Select when tighter gate threshold distribution is not required and lower quiescent current is prioritized
MMBFJ105	SOT-23 surface-mount package; identical electrical specs but reduced thermal mass and 350 mW P_D	Requires PCB rework for space-constrained layouts; unsuitable for >300 mA continuous operation	Select for automated assembly and compact designs where thermal derating is managed via layout

Compared with 2N5457 and MMBFJ105, the J105_D27Z delivers superior current-handling (500 mA), lowest on-resistance (3.0 Ω), and highest power dissipation (625 mW), making it optimal for robust analog switching and high-fidelity signal routing where thermal stability and low insertion loss are critical.

Availability

J105_D27Z is available at Aetrix Electronics and suitable for audio signal routing, constant-current biasing, voltage-controlled resistor networks, and low-voltage logic interfacing requiring stable component supply and long-term manufacturability.

Supply support for J105_D27Z 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global supplier of energy-efficient semiconductor components, specializing in power management, analog, and discrete devices for automotive, industrial, and consumer markets.

The J105_D27Z belongs to Fairchild's legacy Process 59 N-channel JFET family, designed specifically for high-linearity analog switching and precision current regulation in cost-sensitive, reliability-critical applications.

FAQ

What is the gate-source cutoff voltage specification for J105_D27Z?

The J105_D27Z has a gate-source cutoff voltage (V_GS(off)) of −4.5 V (maximum) at V_DS = 5.0 V and I_D = 1.0 mA. This value is confirmed in the Electrical Characteristics table of the Fairchild J105/J106/J107 datasheet Rev. 1.1.1. The minimum V_GS(off) is −10.0 V, defining the full operational window for reliable channel pinch-off. This parameter directly determines the required negative gate bias to ensure complete turn-off in switching applications.

Can J105_D27Z be used in linear (ohmic) mode for variable resistance applications?

Yes, the J105_D27Z is explicitly characterized for linear-region operation, as shown in Figure 5 ("Normalized Drain Resistance vs. Bias Voltage") and Figure 6 ("On Resistance vs. Drain Current"). Its R_DS(on) remains stable below 200 mA and varies predictably with V_GS, enabling precise voltage-controlled resistor behavior. The device's low gate leakage (<3 nA) and monotonic transconductance curve make it suitable for analog gain control and programmable attenuator circuits where J105_D27Z serves as the core variable element.

What is the maximum continuous drain current for J105_D27Z at 70°C ambient?

At T_A = 70°C, the J105_D27Z must be derated from its 625 mW maximum power dissipation at 25°C by 5.0 mW/°C. This yields 625 mW − (45°C × 5.0 mW/°C) = 400 mW allowable power. Assuming worst-case R_DS(on) = 3.0 Ω and using P = I²R, the maximum continuous drain current is √(0.4 W / 3.0 Ω) ≈ 365 mA. This calculation applies to the J105_D27Z in standard TO-92 mounting on FR-4 PCB per datasheet thermal conditions.

Does J105_D27Z have a specified gate-drain capacitance?

Yes, the J105_D27Z specifies C_dg(on) = 160 pF (drain-gate on capacitance) measured at V_DS = 0 V, V_GS = 10 V, and f = 1.0 MHz, per the "Small Signal Characteristics" table. C_dg(off) is given as 35 pF under off-state conditions. These values are critical for high-frequency switching analysis and Miller effect estimation in amplifier or switch-mode designs using J105_D27Z.

Is J105_D27Z RoHS compliant and lead-free?

Yes, J105_D27Z is RoHS compliant and lead-free. As a legacy Fairchild part now manufactured and supported by ON Semiconductor, it meets JEDEC JS-069 and RoHS Directive 2011/65/EU requirements. The TO-92 package uses matte tin (Sn) lead finish, and material declarations confirm absence of restricted substances above threshold limits. Compliance documentation for J105_D27Z is available through ON Semiconductor's product change notices and environmental reports portal.

J105_D27Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

FET Type:: N-Channel

Voltage - Breakdown (V(BR)GSS):: 25 V

Drain to Source Voltage (Vdss):: -

Current - Drain (Idss) @ Vds (Vgs=0):: 500 mA @ 15 V

Current Drain (Id) - Max:: -

Voltage - Cutoff (VGS off) @ Id:: 4.5 V @ 1 µA

Input Capacitance (Ciss) (Max) @ Vds:: -

Resistance - RDS(On):: 3 Ohms

Power - Max:: 625 mW

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

J105_D27Z FAQ

1.How can I place an order for J105_D27Z through Aetrix?

Please submit a Request for Quotation (RFQ) for J105_D27Z 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 J105_D27Z reliable?

The price and inventory of J105_D27Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for J105_D27Z is usually 5 days.

3.What payment methods are accepted for J105_D27Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for J105_D27Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for J105_D27Z?

J105_D27Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your J105_D27Z 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 J105_D27Z?

For technical support, including J105_D27Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your J105_D27Z requirements.

6.How does Aetrix verify that J105_D27Z is sourced from the original manufacturer or authorized distributors?

All J105_D27Z 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 J105_D27Z meets industry standards.

7.What is the process for return or replacement of J105_D27Z?

All J105_D27Z units undergo pre-shipment inspection (PSI). If there is an issue with J105_D27Z, 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 J105_D27Z part is unused and in its original packaging.

Return procedure for J105_D27Z:

1.Submit a request within 90 days.

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

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