onsemi 2SA1478E

Overview

2SA1478E from SANYO Semiconductor is a PNP epitaxial planar silicon transistor designed for high-voltage video output stages in CRT displays, featuring VCEO ≥ −200 V, hFE = 100–200 (Rank E), fT = 150 MHz, Cre = 1.7 pF, and VCE(sat) = −0.6 V at IC = −20 mA/IB = −2 mA.

For engineers reviewing the 2SA1478E datasheet, pinout, applications, or equivalent options, this device is selected for high-definition CRT deflection and video driver circuits requiring stable high-voltage switching, low reverse transfer capacitance, and precise DC gain control in analog display systems.

Technical Context

The 2SA1478E employs SANYO's FBET (Flat Base Epitaxial Transistor) process to achieve tight hFE binning (Rank E: 100–200), low Cre (1.7 pF), and high fT (150 MHz) under −30 V VCE bias - enabling clean high-frequency video signal amplification with minimal phase distortion.

Its −200 V VCBO and VCEO ratings support operation in CRT anode drive and horizontal deflection flyback circuits, while its TO-126ML package provides thermal dissipation up to 5 W at Tc = 25°C and junction temperature tolerance to 150°C.

Key Specifications

Pinout & Package

SANYO TO-126ML package: 3-pin vertical through-hole, molded plastic case with metal tab (collector-connected), dimensions 15.5 mm × 11.0 mm × 3.3 mm, lead pitch 2.54 mm, tab thermally and electrically tied to collector.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage transistor applications.

Compared with 2SA1478E, 2SA1943 offers superior power handling but requires board redesign, while MJD2955G lacks both voltage headroom and bandwidth for CRT video roles - making 2SA1478E uniquely balanced for high-definition analog display output stages where compact size, −200 V rating, and 150 MHz fT converge.

Availability

2SA1478E is available at Aetrix Electronics and suitable for high-definition CRT horizontal deflection, analog video output driver stages, and legacy display power switching requiring stable component supply and long-term obsolescence mitigation.

Supply support for 2SA1478E 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

SANYO Semiconductor was a Japanese semiconductor manufacturer specializing in analog, power, and display interface ICs and discrete devices before its acquisition by ON Semiconductor in 2013; known for high-reliability video and power transistors.

The 2SA1478E belongs to SANYO's high-voltage PNP/NPN transistor family engineered specifically for CRT-based display systems - emphasizing high breakdown voltage, low capacitance, and gain consistency in analog video signal paths.

FAQ

What is the exact pin configuration of the 2SA1478E in TO-126ML package?

The 2SA1478E uses a standardized TO-126ML pinout: Pin 1 is Emitter, Pin 2 is Collector (internally connected to the metal tab), and Pin 3 is Base. This configuration is confirmed in SANYO's No.2253-2/5 datasheet diagram and matches JEDEC TO-126 mechanical specifications. The 2SA1478E must be mounted with electrical isolation between tab and heatsink unless the heatsink is intentionally tied to collector potential.

Does the 2SA1478E have a specified gain-bandwidth product (fT), and under what conditions is it measured?

Yes, the 2SA1478E has a guaranteed fT of 150 MHz, measured at VCE = −30 V, IC = −10 mA, and f = 1 MHz per SANYO's No.2253-2/5 datasheet. This value reflects small-signal AC performance relevant to video amplifier stability and edge response in CRT horizontal deflection circuits - not large-signal switching speed.

How does the hFE ranking system apply to the 2SA1478E, and what does Rank E signify?

The 2SA1478E is binned into Rank E per SANYO's classification table: hFE = 100–200 at VCE = −10 V and IC = −10 mA. This tight gain range ensures predictable biasing in production CRT video output stages, reducing calibration effort. The 2SA1478E's Rank E designation is laser-marked on the package and verified during final test.

Can the 2SA1478E replace the 2SA1051 in existing CRT designs?

The 2SA1478E can serve as a functional upgrade to the 2SA1051 in many CRT applications due to identical TO-126ML packaging, same E-C-B pinout, and improved specs: −200 V VCEO (vs. −150 V), 150 MHz fT (vs. ~100 MHz), and lower VCE(sat) (−0.6 V vs. −1.0 V). However, layout validation is recommended due to differences in Cre and thermal impedance.

What is the maximum allowable collector dissipation for the 2SA1478E at ambient temperature?

The 2SA1478E specifies PC = 1.3 W at Ta = 25°C (free-air) and PC = 5 W at Tc = 25°C (case temperature), per Absolute Maximum Ratings table in No.2253-1/5. For sustained operation, derating curves show linear reduction above 25°C ambient - e.g., ~0.8 W at Ta = 75°C with no heatsink. The 2SA1478E's thermal resistance RθJA is approximately 100°C/W in standard PCB mounting.