General description

The TJA1085G is a FlexRay active star coupler that can connect up to 4 branches of a

FlexRay network. The TJA1085G is compliant with the FlexRay electrical physical layer

specification V3.0.1/ISO17458-4 (see Ref. 1 and Ref. 2).

Several TJA1085G devices can be connected via their TRXD0/1 interfaces to increase

the number of branches in the network. A dedicated Communication Controller (CC)

interface allows for integration into an ECU. The TJA1085G supports low-power

management by offering bus wake-up capability along with battery supply and voltage

regulator control. The TJA1085G meets industry standards for EMC/ESD performance

and provides enhanced bus error detection, low current consumption and unmatched

asymmetric delay performance.

Features and benefits

General

 Compliant with FlexRay Electrical Physical Layer specification V3.0.1/ISO17458-4

 Automotive product qualification in accordance with AEC-Q100

 Data transfer rates from 2.5 Mbit/s to 10 Mbit/s

 Supports 60 ns minimum bit time at 400 mV differential voltage

 Low-power management for battery-supplied ECUs

 Very low current consumption in AS_Sleep mode

 Leadless HVQFN44 package with improved Automated Optical Inspection (AOI)

capability

Functional

 Supports autonomous active star operation independent of the host ensuring the

TJA1085G remains active even if the host fails or is switched off

 Branches can be independently configured

 Branch extension via TRXD0/1 inner star interface

 16-bit bidirectional SPI interface up to 2 Mbit/s for host communication

 Full host control over branch status

 Enhanced wake-up capability:

 Remote wake-up via wake-up pattern and dedicated FlexRay data frames

 Local wake-up via pin LWU

 Wake-up source recognition

 configurable per branch

 Enhanced supply voltage monitoring on VIO, VCC, VBUF and VBAT

 Auto I/O level adaptation to host controller supply voltage VIO

 Can be used in 14 V, 24 V and 48 V powered systems

 Enhanced bus error detection - detects short-circuit conditions on the bus

 Instant transmitter shut-down interface (BGE pin)

 Selective branch shut-down (partial networking)

Robustness

 Bus pins protected against 8 kV ESD pulses according to HBM and 6 kV ESD

pulses according to IEC61000-4-2

 All pins protected against 1000 V ESD according to CDM

 All pins protected against 200 V ESD according to MM

 No reverse currents from the digital input pins to VIO or VCC when the TJA1085G is not powered up

 Bus pins short-circuit proof to battery voltage (14 V, 24 V or 48 V) and ground

 Overtemperature detection and protection

 Bus pins protected against transients in automotive environment (according to ISO

7637 class C)

Active star functional classes

 Active star - communication controller interface

 Active star - bus guardian interface

 Active star - voltage regulator control

 Active star - logic level adaptation

 Active star - host interface

 Active star - increased voltage amplitude transmitter