Silicon Epitaxial Small Signal Transistor
Manufacturer: TOSHIBA
Application: Low noise audio ampifier
Package: TO-98
Discontinued: 1976
【Photo placeholder: 2SA493-2SC1000 (TO-98)】
| 2SA493 | 2SC1000 | |
|---|---|---|
| Vcbo (V) | -50 | 50 |
| Vceo (V) | -50 | 50 |
| Vebo (V) | -5 | 5 |
| Ic (A) | -0.05 | 0.1 |
| Pc (W) (Ta=25℃/77°F) | 0.2 | 0.2 |
| HFE (Vce=6V,Ic=2mA) | O:70-140 (1973-1974) Y:120-240 GR:200-400 | GR:200-400 BL:350-700 |
| fT (MHz) (Vce=6V,Ic=1mA) | – | typ.80 |
| Cob (PF) (Vcb=6V) | – | typ.6 max.10 |
Source: TOSHIBA Semiconductor Databook 1973/1975
Overview
The 2SA493-2SC1000 is a complementary low-noise transistor pair from TOSHIBA. This pair represents one of Japan’s earliest PNP low-noise transistors and became a staple product of the 1970s.
A sister model, 2SA494 with lower breakdown voltage, also existed but was discontinued 1974.
Key Features
High Breakdown Voltage
With Vceo of 50V, these transistors had high breakdown voltage for silicon small-signal transistors of that era, leading to rapid adoption in audio amplifier applications.
Memorable Part Number
The 2SC1000, in particular, with its round-number designation, was easy to remember and became very popular. Beyond audio applications, it frequently appeared in radio construction magazines and amateur radio project articles.
TO-98 Package Characteristics
Distinctive Shape
While conforming to TO-92 standards, the package has a distinctive shape resembling a silk hat. This became a major characteristic of TOSHIBA’s small-signal transistors.
Manufacturing Process (Speculation)
The manufacturing process likely involved:
- Preparing an inverted epoxy resin silk-hat shaped case
- Inserting round pin leads with mounted semiconductor chip
- Pouring liquid epoxy resin
- Curing to completion
TO-98 History
This manufacturing method was first applied to the following products, initially listed in the 1966 databook:
- 2SC36X series
- 2SC37X series (later became the ultimate standard in electronics hobbyist circles)
Subsequently, it was applied to various TOSHIBA small-signal transistors, continuing until the 2SA842-2SC1682, which debuted in 1975.
Transition to TO-92
New products released from 1977 onward (2SA817-2SC1627, 2SC1815, etc.) adopted transfer molding process, resulting in the TO-92 shape commonly seen today.
Products that debuted in TO-98 shape continued to be manufactured in that form after 1977, but all were discontinued in 1980. Thereafter, some high-demand products were converted to transfer molding and TO-92 packaging.
The 2SA493-2SC1000 was a standard transistor produced over a long period, spanning both the TO-98 and TO-92 eras.
Green Series (G-Type)
Part Number: 2SA493G-2SC1000G
Application: Low noise audio amplifier (Industrial Application)
Package: TO-98
Discontinued: 1980
High-reliability products for communication industrial use. “G” represents TOSHIBA’s Green Series for communication industrial applications.
| 2SA493G | 2SC1000G | |
|---|---|---|
| Vcbo (V) | -50 | 55(1973-1974) 50(1975-1980) |
| Vceo (V) | -50 | 50 |
| Vebo (V) | -5 | 5 |
| Ic (A) | -0.05 | 0.1 |
| Pc (W) (Ta=25℃/77°F) | 0.2 | 0.2 |
| HFE (Vce=6V,Ic=2mA) | Y:120-240 (1973-1980) GR:200-400 (1973-1980) BL:350-700 (1977-1980) | GR:200-400 BL:350-700 |
| fT (MHz) (Vce=6V,Ic=1mA) | – | typ.80 |
| Cob (PF) (Vcb=6V) | – | typ.6 max.10 |
Source: TOSHIBA Semiconductor Databook 1973/1975/1977
Features:
- Designed for applications requiring strict quality, such as industrial equipment and broadcasting facilities
- Stringent quality control and characteristic variation management
- More comprehensive characteristic data in datasheets compared to non-G types
- Higher cost
Variations by Era
2SA493-2SC1000 (TO-98, 1973-1976)
Debut: 1973
Discontinued: 1976
HFE Rank Mystery: Unlisted BL Rank Products in Catalog
TOSHIBA’s official datasheets list only the following HFE ranks:
2SA493 (PNP):
- Y rank (HFE 120-240)
- GR rank (HFE 200-400)
2SC1000 (NPN):
- GR rank (HFE 200-400)
- BL rank (HFE 350-700)
According to these listings, only GR rank pairs can be matched as complementary pairs. There is no NPN rank corresponding to Y rank, nor a PNP rank corresponding to BL rank in the catalog.
However, 2SA493 BL rank products actually exist.
In my collection, I have confirmed the existence of BL rank products (likely HFE 350-700) that are not listed in TOSHIBA’s official datasheets.
Characteristics of TOSHIBA PNP Products
This imbalance is a phenomenon often observed in TOSHIBA’s complementary pairs, not limited to 2SA493-2SC1000.
Speculated Reasons:
- PNP products are generally more difficult to manufacture with high HFE
- NPN side can mass-produce up to high HFE rank (BL)
- PNP side has difficulty in mass-producing high HFE rank (BL)
- Catalogs list only ranks that can be reliably supplied
- High HFE rank products supplied as custom orders for large-volume customers
Comparison with Other Manufacturers:
Compared to other manufacturers like NEC, TOSHIBA’s complementary pairs show a tendency to not offer high HFE rank products for PNP variants. This may reflect characteristics of TOSHIBA’s PNP manufacturing process.
2SA493GTM-2SC1000GTM (TO-92, 1980-1988)
【Photo placeholder: 2SA493GTM-2SC1000GTM】
Application: Low noise audio amplifier (Industrial Application)
Package: TO-92
Handover: Designated by TOSHIBA itself as replacement after TO-98 discontinuation
Discontinued: 1988
| 2SA493GTM | 2SC1000GTM | |
|---|---|---|
| Vcbo (V) | -50 | 60 |
| Vceo (V) | -50 | 50 |
| Vebo (V) | -5 | 5 |
| Ic (A) | -0.15 | 0.15 |
| Pc (W) (Ta=25℃/77°F) | 0.4 | 0.4 |
| HFE (Vce=6V,Ic=2mA) | Y:120-240 GR:200-400 | GR:200-400 BL:350-700 |
| fT (MHz) (Vce=6V,Ic=1mA) | typ.80 | typ.80 |
| Cob (PF) (Vcb=6V) | typ.6 | typ.6 max.10 |
Source: TOSHIBA Semiconductor Databook 1980
Meaning of TM
The “TM” suffix indicates that ratings were changed due to package modification.
Continuation of G Series
Continued as Green Series, specialized for industrial equipment use. However, being an extremely famous product, it was widely available in electronics parts districts like Akihabara and Nihonbashi, making it easily accessible to amateur electronics hobbyists.
Data Availability
Data is published in TOSHIBA semiconductor handbooks from 1980 and 1984. However, it is not uploaded to online sites like AllDatasheet and may be unfamiliar to overseas audiences.
Lot Number Mystery
Based on lot number markings, products manufactured from 1977-1979 have been confirmed to exist. This suggests that GTM was already being manufactured during the TO-98 to TO-92 transition period.
Existence of BL Rank Products (TO-92 Era)
2SA493GTM manufactured from 1977 onward includes BL rank products (likely HFE 350-700) not listed in TOSHIBA’s official datasheets. This situation is similar to the TO-98 era.
Rating Improvements
With the TO-92 conversion, leads were changed from iron round pins to copper flat leads, improving heat dissipation and significantly increasing Pc.
2SA493TM-2SC1000TM (TO-92, circa 1977-1983)
【Photo placeholder: 2SA493TM-2SC1000TM】
Maximum Obscurity Level
This is a TO-92 version for general consumer use, not G Series. It is not listed in official datasheets and its existence is confirmed only in TOSHIBA’s maintenance/discontinued product list, making it extremely obscure.
Speculated Ratings
Based on lot number markings and the font/shape of body printing, maximum ratings and basic characteristics are speculated to be identical to 2SA493GTM-2SC1000GTM.
Production Period
Believed to have been manufactured for a very short period, circa 1977-1983.
Speculated Manufacturing Background
Because the original TO-98 2SA493-2SC1000 was a standard product, demand remained high even after maintenance discontinuation announcement, leading to continued supply as maintenance products in response to large-volume customer demands.
Distribution Status
It was occasionally distributed and sold at general electronics parts stores, indicating the popularity of 2SA493-2SC1000.
HFE Rank List
【Table placeholder: Catalog-listed ranks vs. confirmed existing ranks】
Complementary pair matching possibilities:
- According to catalog: GR rank pairs only
- In reality: GR rank pairs, BL rank pairs (BL possibly custom orders)
Maximum Ratings & Representative Characteristics
【Table placeholder: Comparison of TO-98 version and TO-92 version (GTM)】
Main changes:
- Improved Pc (collector loss) due to improved heat dissipation from TO-92 conversion
- Other electrical characteristics remain largely identical
Successors & Alternatives
【Table placeholder: TOSHIBA official recommended alternatives and compatible products from other manufacturers】
Summary
The 2SA493-2SC1000 is an important product in the history of Japanese low-noise transistors.
Historical Value:
- Pioneer of Japanese PNP low-noise transistors
- Standard product representing the 1970s electronics hobbyist world
- Symbolic product of the TO-98 to TO-92 transition
Technical Value:
- High breakdown voltage (Vceo 50V)
- Low-noise characteristics
- High amplification
Collector Value:
- Distinctive TO-98 package appearance
- Multiple variations (G, GTM, TM)
- Rare products not listed in catalogs, such as BL rank
- Mystery of HFE rank imbalance
Research Value:
- Suggests characteristics of TOSHIBA’s PNP manufacturing process
- Discrepancy between catalog and actual products
- Existence of custom products for large-volume customers
Update History:
- 2025/10/07: First edition published