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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi PN3644_D27Z

Name: PN3644_D27Z
Brand: onsemi
SKU: PN3644_D27Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PN3644_D27Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: PN3644_D27Z.pdf

Description:: TRANS PNP 45V 0.8A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PN3644_D27Z from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor (BJT) designed for amplification and switching applications up to 500 mA collector current. It features V_CEO = 45 V, h_FE = 40–300 (at I_C = 0.1–300 mA), V_CE(sat) = 0.25–0.4 V, and TO-92 package with emitter-first tape-and-reel orientation (EOL code D27Z). It is commonly used in low-voltage DC-DC converter bias circuits and discrete logic-level switching.

For engineers reviewing the PN3644_D27Z datasheet, pinout, applications, or equivalent options, key selection criteria include verified PNP polarity, TO-92 mechanical compatibility, guaranteed h_FE minimum at I_C = 150 mA, V_CE(sat) under specified drive conditions, and thermal resistance R_θJA = 200 °C/W for board-level thermal design.

Technical Context

The PN3644_D27Z implements a silicon planar PNP BJT structure fabricated on Fairchild's Process 63, optimized for stable DC current gain and low saturation voltage across industrial temperature range (−55°C to +150°C). Its breakdown ratings (V_CEO, V_CBO, V_EBO) are symmetric at 45 V / 45 V / 5.0 V, supporting balanced rail operation in complementary designs.

Switching performance is characterized with t_on = 40 ns, t_off = 100 ns, and t_s = 70 ns under pulsed 300 mA load, confirming suitability for medium-speed digital switching and analog amplifier stages where f_T is not critical but gain-bandwidth stability matters.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before avalanche; defines upper rail limit in switch or amplifier stage.
I_C (max)	800 mA - Absolute continuous collector current rating; usable up to 500 mA per functional description.
h_FE	40–300 - DC current gain range across 0.1–300 mA I_C; enables predictable base drive sizing in linear and saturated operation.
V_CE(sat)	0.25–0.4 V - Confirmed saturation voltage at I_C/I_B = 50 mA/2.5 mA and 150 mA/15 mA; determines conduction loss in switching mode.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in free-air; sets worst-case temperature rise for PCB layout without heatsink.
f_T	Not specified - Small-signal current gain h_fe = 2.0 at 100 MHz implies limited RF use; intended for audio/DC/low-MHz applications only.
P_D	625 mW - Total power dissipation at 25°C ambient; derates 5.0 mW/°C above 25°C for thermal management planning.

Pinout & Package

PN3644_D27Z is housed in a standard TO-92 plastic package with straight leads and no lead clip. The EOL code D27Z denotes Style "E" tape-and-reel packaging, where the first wire off the die is the emitter, adhesive tape is on the top side, and the flat side of the transistor faces downward during mounting.

Pin/Terminal	Circuit Role	Design Meaning
Lead 1 (Emitter)	Emitter terminal	Reference node for PNP current flow; connected to most positive rail in common-base or common-collector configurations.
Lead 2 (Base)	Control terminal	Current-controlled input; requires negative bias relative to emitter to forward-bias base-emitter junction.
Lead 3 (Collector)	Output terminal	Current sink node; carries full load current when saturated; tied to lower-potential rail in typical switching layouts.

Key Features

Feature	Design Value
Process 63 fabrication	Ensures consistent h_FE distribution and low leakage (I_CES ≤ 35 nA at 25°C) across production lots.
TO-92 mechanical standardization	Enables drop-in replacement in legacy through-hole designs using JEDEC TO-92 footprint and hole spacing.
V_CE(sat) validated at high I_C	0.4 V at I_C = 150 mA / I_B = 15 mA confirms robust saturation margin for reliable switching at 150 mA loads.
Extended temperature range	Operable from −55°C to +150°C junction temperature supports automotive under-hood and industrial control environments.

Applications

DC-DC Converter Bias Circuit	Discrete Logic-Level Switch
Use Scenario: Providing base drive to main power PNP pass transistor in linear-regulated DC-DC buck stage. IC Role / Device Role / Timing Role: PNP current amplifier enabling low-loss, thermally stable bias delivery to high-current output stage. Use Value: V_CE(sat) ≤ 0.4 V minimizes quiescent power loss; h_FE ≥ 100 at I_C = 10 mA ensures sufficient gain for clean turn-on without excessive base current draw.	Use Scenario: Replacing logic-level MOSFETs in cost-sensitive 5 V/12 V microcontroller-peripheral interface boards. IC Role / Device Role / Timing Role: Discrete PNP switch controlling LED banks, relays, or small solenoids via GPIO-driven base. Use Value: Verified t_on/t_off < 100 ns supports 5–10 MHz toggle rates; TO-92 footprint allows direct retrofit into existing through-hole layouts.
Audio Preamp Stage	Industrial Sensor Signal Conditioning
Use Scenario: Low-noise, single-ended audio preamplifier stage for electret microphone bias and signal amplification. IC Role / Device Role / Timing Role: Linear-mode PNP amplifier operating in common-emitter configuration with emitter degeneration. Use Value: h_FE ≥ 80 at I_C = 1 mA ensures stable gain; Cob = 8.0 pF limits high-frequency roll-off in 20 kHz bandwidth designs.	Use Scenario: Amplifying millivolt-level outputs from RTDs or strain gauges in programmable logic controller (PLC) analog input modules. IC Role / Device Role / Timing Role: Discrete PNP configured as emitter follower for impedance buffering and level shifting. Use Value: V_EBO = 5.0 V permits safe operation with ±5 V sensor excitation rails; TJ range −55°C to +150°C matches industrial ambient requirements.

DC-DC Converter Bias Circuit

Discrete Logic-Level Switch

Use Scenario: Providing base drive to main power PNP pass transistor in linear-regulated DC-DC buck stage.

IC Role / Device Role / Timing Role: PNP current amplifier enabling low-loss, thermally stable bias delivery to high-current output stage.

Use Value: V_CE(sat) ≤ 0.4 V minimizes quiescent power loss; h_FE ≥ 100 at I_C = 10 mA ensures sufficient gain for clean turn-on without excessive base current draw.

Use Scenario: Replacing logic-level MOSFETs in cost-sensitive 5 V/12 V microcontroller-peripheral interface boards.

IC Role / Device Role / Timing Role: Discrete PNP switch controlling LED banks, relays, or small solenoids via GPIO-driven base.

Use Value: Verified t_on/t_off < 100 ns supports 5–10 MHz toggle rates; TO-92 footprint allows direct retrofit into existing through-hole layouts.

Audio Preamp Stage

Industrial Sensor Signal Conditioning

Use Scenario: Low-noise, single-ended audio preamplifier stage for electret microphone bias and signal amplification.

IC Role / Device Role / Timing Role: Linear-mode PNP amplifier operating in common-emitter configuration with emitter degeneration.

Use Value: h_FE ≥ 80 at I_C = 1 mA ensures stable gain; Cob = 8.0 pF limits high-frequency roll-off in 20 kHz bandwidth designs.

Use Scenario: Amplifying millivolt-level outputs from RTDs or strain gauges in programmable logic controller (PLC) analog input modules.

IC Role / Device Role / Timing Role: Discrete PNP configured as emitter follower for impedance buffering and level shifting.

Use Value: V_EBO = 5.0 V permits safe operation with ±5 V sensor excitation rails; TJ range −55°C to +150°C matches industrial ambient requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSA92	V_CEO = 300 V, h_FE min = 25 at I_C = 10 mA; higher breakdown but lower gain consistency at low I_C.	Suitable for high-voltage switching (e.g., flyback snubbers); less optimal for precision low-I_C amplification.	Select MPSA92 only when >100 V V_CEO is required; PN3644_D27Z preferred for gain-critical 45 V systems.
BC557	V_CEO = 45 V, h_FE = 110–800; tighter h_FE spread but rated for only 100 mA I_C continuous.	Better for low-power signal amplification; insufficient for 500 mA switching loads.	Choose BC557 for low-noise audio or sensor interfaces below 100 mA; retain PN3644_D27Z for higher-current switching roles.

Compared with MPSA92 and BC557, PN3644_D27Z uniquely balances 45 V breakdown, 500 mA capability, and verified h_FE ≥ 100 at mid-range currents-making it optimal for industrial DC-DC bias and medium-power discrete switching where both voltage margin and current drive matter.

Availability

PN3644_D27Z is available at Aetrix Electronics and suitable for industrial control systems, legacy equipment repair, and discrete power management circuits requiring stable component supply and long-term obsolescence support.

Supply support for PN3644_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

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

The PN3644_D27Z belongs to Fairchild's general-purpose PNP BJT family, engineered for reliability in cost-sensitive linear amplification and switching applications across consumer, industrial, and computing markets.

FAQ

What is the pin configuration of PN3644_D27Z in TO-92 package?

The PN3644_D27Z uses standard TO-92 pinout: Lead 1 = Emitter, Lead 2 = Base, Lead 3 = Collector, with flat side facing down and emitter lead first in D27Z tape orientation. This matches JEDEC TO-92 mechanical specification and is confirmed in Fairchild's PN3644 datasheet Figure 1.0 and Tape & Reel Data Rev. B1.

Does PN3644_D27Z support operation at elevated temperatures?

Yes, PN3644_D27Z is rated for junction temperature from −55°C to +150°C and storage temperature over the same range. Its R_θJA = 200 °C/W and derating factor of 5.0 mW/°C above 25°C allow thermal design up to 125°C ambient with appropriate PCB copper area, as validated in Fairchild's Thermal Characteristics table.

Is PN3644_D27Z a direct replacement for PN2907A?

No-while the PN3644_D27Z datasheet references PN2907A for characteristics, it is a distinct device with different process (Process 63 vs. older process), higher I_C rating (800 mA vs. 600 mA), and tighter V_CE(sat) spec (0.25 V min). Cross-substitution requires validation of h_FE and switching timing in the target circuit.

What does the EOL code D27Z indicate for PN3644_D27Z?

D27Z identifies Style "E" tape-and-reel packaging per Fairchild's TO-92 Tape and Reel Data: emitter-first orientation, adhesive tape on top side, flat side down, 2,000 units per reel. This ensures correct automated placement direction and distinguishes it from D26Z (Style "A") or D74Z (collector-first ammo pack).

Can PN3644_D27Z be used in switching power supplies?

Yes-PN3644_D27Z is qualified for switching use with t_on = 40 ns, t_off = 100 ns, and t_s = 70 ns at 300 mA. Its V_CEO = 45 V and I_C = 800 mA support auxiliary bias windings and low-power gate drivers in offline SMPS, provided layout minimizes parasitic inductance and thermal rise stays within R_θJA limits.

PN3644_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

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 800 mA

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 15mA, 150mA

Current - Collector Cutoff (Max):: 35nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 150mA, 10V

Power - Max:: 625 mW

Frequency - Transition:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

PN3644_D27Z FAQ

1.How can I place an order for PN3644_D27Z through Aetrix?

Please submit a Request for Quotation (RFQ) for PN3644_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 PN3644_D27Z reliable?

The price and inventory of PN3644_D27Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PN3644_D27Z is usually 5 days.

3.What payment methods are accepted for PN3644_D27Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PN3644_D27Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PN3644_D27Z?

PN3644_D27Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PN3644_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 PN3644_D27Z?

For technical support, including PN3644_D27Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PN3644_D27Z requirements.

6.How does Aetrix verify that PN3644_D27Z is sourced from the original manufacturer or authorized distributors?

All PN3644_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 PN3644_D27Z meets industry standards.

7.What is the process for return or replacement of PN3644_D27Z?

All PN3644_D27Z units undergo pre-shipment inspection (PSI). If there is an issue with PN3644_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 PN3644_D27Z part is unused and in its original packaging.

Return procedure for PN3644_D27Z:

1.Submit a request within 90 days.

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

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