VEB HFO B 461 G
B 416 G is a Hall sensor IC that was manufactured by VEB Halbleiterwerk Frankfurt (Oder). B 461 G and B 462 G were specified in East German standard TGL 38658. Following German reunification it appears to have remained in production under new ownership.
Usage in keyboards
Two companies are confirmed to have used B 461 G in keyboards. A Hall version of Sasse Series 25 is highly likely, but the choice of Hall IC is not confirmed. It is possible that they sourced this chip from an alternative supplier.
TGL 38855 specifies B 461 G as the Hall IC for RFT TSH 19 F keyboard switches. TSH (“Tastenschalter mit Hallelement”: keyboard switch with Hall element) was RFT’s Hall keyboard switch series. RFT TSH 19 F appears to have superseded TSH 19, which used a larger MH1SS1 Hall sensor from Czechoslovak manufacturer TESLA, itself appearing to be a copy of the Hall sensor used in Micro Switch SW Series.
B 416 G is or was also used in RAFI RS 76 C switches:
The above example—received as a sample from RAFI in 2016—uses a B 461 G chip made in May 1991. This is indicated by the code “B5” at the lower right, per the Kodiertes Herstellungsdatum auf elektronischen Bauelementen aus DDR-Produktion (manufacturing date codes for East German electronic components).
Although this was a DDR chip, by 1991, VEB HFO had become Halbleiterwerk GmbH, as seen on the box label at eBay auction Lot of 5 pieces B461 = SAS261S4 HALL IC SWITCH static 4-SIP NEW *. RAFI did not comment on the age of the sample switches, and whether the switches are the same age as the chips, or if the chips are old stock.
B 461 G is a small four-terminal Hall sensor. It is marked simply “B 61”, with the “4” and “G” omitted, supposedly due to the small component size (even though the full model name would have fitted).
The four terminals are:
- Masse (ground/GND)
- Ausgang (output) or offener Kollektorausgang (open collector output)
- Freigabeeingang (enable input)
- Betriebsspannung (operating voltage, VCC)
Unlike some other four-terminal Hall sensors (such as those of Micro Switch and Panasonic), B 461 G only provides a single non-redundant output. Instead, the fourth terminal is used to activate the sensor.