Databus interface designed for space use

Citation

(2000), "Databus interface designed for space use", Aircraft Engineering and Aerospace Technology, Vol. 72 No. 6. https://doi.org/10.1108/aeat.2000.12772fad.001

Databus interface designed for space use

Databus interface designed for space use

Keywords: DDC, Data bus, Satellites

It is reported that DDC's BU-61582 radiation hardened version of its ACE MIL-STD-1553 data bus terminal is intended for use on launch vehicles, satellites, space stations, the space shuttle and other extraterrestrial vehicles (Plate 1). Implemented in Honeywell's 0.8 micron RICMOS (Radiation-Insensitive CMOS) process, it claims to retain all of the flexibility of the ACE family, including the ability to be configured as a bus controller (BC), remote terminal (RT) or monitor terminal (MT).

Whilst the MIL-STD-1553 serial data bus was primarily developed for military avionic use, it is now said to be widely used in space applications, such as commercial satellites. However, the additional requirements of radiation hardness and high reliability mean that special attention has to be paid to the process technology of the product.

The BU-61582 is available with or without DDC's bipolar transceivers in voltage options of +5V/–15V o-12V. Transceiverless options may be used with an external- electrical or fibre-optic transceiver. DDC also offers the BU-65691 BC/RT.MT chip, which may be used with external transceivers and RAM.

Plate 1 DDC's BU-61582 radiation hardened version of its ACE MIL-STD-1553 data bus terminal

In DDC's opinion, the BU-61582 brings the full range of features of the ACE (Advanced Communications Engine) technology to customers requiring radiation tolerance and higher reliability characteristics necessary for space applications. It uses DDC's proprietary JRAD protocol chip and a 32k x 8 RAM.

Units with the transceivers can reportedly withstand a total gamma ray dose of 70 Krads and provide gamma ray dose rate characteristics of 2.0 x 107 rads (Si)/sec with no upset. A gamma dose rate as high as 1.0 x 10¹⁰ is said to be tolerated with 25s recovery.

Neutron fluence tolerance is stated as 2 x 10¹³ neutrons/cm². Because the digital components are RICMOS and the transceivers are bipolar, the BU-61582 hybrid is thought to be inherently immune to radiation-induced latch-up.

Transceiverless versions of the BU-61582 are said to exhibit higher radiation tolerance, with total gamma dose capability of 1.0 Mrad, gamma dose rate survivability of 1.0 x 10¹² rads (Si)/sec and neutron fluence tolerance of up to 10¹⁴ neutrons/cm².

The 32k x 8 RICMOS RAM is utilized in a shared RAM microprocessor interface, as if it were configured as 16k x 16. Package choices are 70-pin DIP or 70-pin flat pack for the BU-61582 or 196-pin ceramic quad flat pack for the BU-65621.

Customers can specify the reliability screening level they require, from Class R (formerly Class S, "full" space-level). This includes element evaluation, X-ray inspection, non-destructive 100 per cent wire bond pull test, 320 hours burn-in, SEM micrographs, and particle-impact noise detection (PIND) testing. Customized screening levels are also possible and particular getters, which attract and hold foreign bodies inside the hybrid case, may be included.

Details available from Data Device Corporation (DDC). Tel:+44 (0) 1635 811140; Fax: +44 (0)1635 32264.