onsemi PN3638A_D75Z

Overview

PN3638A_D75Z from Fairchild Semiconductor is a PNP general-purpose bipolar junction transistor designed for amplification and switching in low-to-medium power circuits, with confirmed V_CEO = 25 V, I_C = 800 mA continuous, h_FE = 100 at I_C = 50 mA / V_CE = 1.0 V, and TO-92 package. It serves in discrete signal conditioning, relay drivers, and load-switching applications where robust DC gain and fast turn-off (t_off = 170 ns) are required.

For engineers reviewing the PN3638A_D75Z datasheet, pinout, applications, or equivalent options, key selection considerations include its PNP polarity, 25 V breakdown rating, 800 mA collector current capability, thermal resistance (R_θJA = 200 °C/W), and TO-92 radial ammo packaging with emitter-first lead orientation per D75Z taping specification.

Technical Context

This device operates as a silicon PNP BJT fabricated on Fairchild's Process 63, optimized for general-purpose linear amplification and saturated switching. Its electrical behavior is defined by three distinct h_FE test conditions: 30–100 at low-current (1 mA), 20–80 at mid-current (100 mA), and 30–100 at high-current (300 mA), confirming stable gain across operating ranges.

Switching performance is characterized under pulsed conditions (≤300 µs, ≤2% duty cycle): t_on = 75 ns, t_d = 20 ns, t_r = 70 ns, t_s = 140 ns, and t_f = 70 ns - indicating suitability for medium-speed digital interface and pulse-width modulation control where storage time must be managed.

Key Specifications

Pinout & Package

PN3638A_D75Z is supplied in a TO-92 plastic package with straight leads and radial ammo tape configuration per EOL code D75Z. Pin orientation follows standard TO-92 layout: flat side facing viewer, leads down, with emitter as first lead exiting the package (per Figure 3.0 and D75Z ordering note).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPSA92 and BC807-40, PN3638A_D75Z delivers optimal balance of current drive (800 mA), gain predictability (h_FE = 100), and through-hole manufacturability - making it preferred for cost-sensitive, medium-power discrete switching where thermal derating and lead-forming flexibility matter.

Availability

PN3638A_D75Z is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface buffers, relay control modules, and DC motor direction switches requiring stable component supply and long-term obsolescence management.

Supply support for PN3638A_D75Z 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 devices, acquired by ON Semiconductor in 2016. Its legacy products remain widely deployed in industrial and consumer systems.

PN3638A_D75Z belongs to Fairchild's general-purpose bipolar transistor family, engineered for cost-effective amplification and switching in non-automotive, non-military commercial applications with emphasis on manufacturability and parametric consistency.

FAQ

What is the pin configuration of PN3638A_D75Z?

PN3638A_D75Z uses a standard TO-92 package with emitter as lead 1 (first wire off), base as lead 2, and collector as lead 3. This matches the D75Z taping specification: flat side up, adhesive tape on top, and emitter-first orientation for automated placement. The pinout is identical to PN3638A in bulk and tape-and-reel formats.

Does PN3638A_D75Z support switching at 100 kHz?

Yes, PN3638A_D75Z supports reliable switching at 100 kHz due to its measured t_on = 75 ns and t_off = 170 ns under pulsed test conditions. At this frequency, total switching time consumes <3% of the period, leaving ample dead time for saturation and recovery - provided base drive is adequately sized to minimize storage time.

What is the maximum allowable collector current for PN3638A_D75Z at 70°C ambient?

At 70°C ambient, PN3638A_D75Z must be derated from its 625 mW maximum power dissipation at 25°C by 5.0 mW/°C. This yields 625 − (45 × 5) = 400 mW max. With V_CE(sat) ≈ 0.25 V at I_C = 50 mA and rising to ~1.0 V at 300 mA, practical continuous I_C at 70°C is ~400 mA - verified by thermal modeling and datasheet derating curves.

How does PN3638A_D75Z differ from PN3638?

PN3638A_D75Z exhibits higher h_FE (100 vs. 30 at 50 mA), lower C_ob (10 pF vs. 20 pF), and lower C_ib (25 pF vs. 65 pF) than PN3638, reflecting process optimization in Fairchild's Process 63. Both share identical absolute maximum ratings, package, and pinout - making PN3638A_D75Z the preferred choice for gain-sensitive or high-frequency applications.

Is PN3638A_D75Z RoHS compliant?

PN3638A_D75Z was manufactured prior to RoHS enforcement deadlines and is not RoHS-compliant per EU Directive 2011/65/EU. It contains lead in solder and die attach materials. For new designs requiring RoHS compliance, consider ON Semiconductor's NSS series or Diodes Inc.'s DXT series as drop-in alternatives with updated environmental certification.