UJA1078_2 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.
Product data sheet Rev. 02 — 27 May 2010 6 of 53
NXP Semiconductors
UJA1078
High-speed CAN/dual LIN core system basis chip
The exposed die pad at the bottom of the package allows for better heat dissipation from
the SBC via the printed circuit board. The exposed die pad is not connected to any active
part of the IC and can be left floating, or can be connected to GND.
6. Functional description
The UJA1078 combines the functionality of a high-speed CAN transceiver, two LIN
transceivers, two voltage regulators and a watchdog (UJA1078/xx/WD versions) in a
single, dedicated chip. It handles the power-up and power-down functionality of the ECU
and ensures advanced system reliability. The SBC offers wake-up by bus activity, by
cyclic wake-up and by the activation of external switches. Additionally, it provides a
periodic control signal for pulsed testing of wake-up switches, allowing low-current
operation even when the wake-up switches are closed in Standby mode.
All transceivers are optimized to be highly flexible with regard to bus topologies. In
particular, the high-speed CAN transceiver is optimized to reduce ringing (bus reflections).
V1, the main voltage regulator, is designed to power the ECU's microcontroller, its
peripherals and additional external transceivers. An external PNP transistor can be added
to improve heat distribution. V2 supplies the integrated high-speed CAN transceiver. The
watchdog is clocked directly by the on-chip oscillator and can be operated in Window,
Timeout and Off modes.
WAKE1 18 local wake-up input 1
WAKE2 19 local wake-up input 2
V2 20 5 V voltage regulator output for CAN
CANH 21 CANH bus line
CANL 22 CANL bus line
GND 23 ground
SPLIT 24 CAN bus common mode stabilization output
LIN1 25 LIN1 bus line
DLIN 26 LIN termination resistor connection
LIN2 27 LIN2 bus line
WBIAS 28 control pin for external wake biasing transistor
VEXCC 29 current measurement for external PNP transistor; this pin is connected to
the collector of the external PNP transistor
TEST2 30 test pin; pin should be connected to ground
VEXCTRL 31 control pin of the external PNP transistor; this pin is connected to the base
of the external PNP transistor
BAT 32 battery supply for the SBC
Table 2. Pin description
…continued
Symbol Pin Description
