Physical Layer - CAN System Engineering - page 96

Table 2.3 Coupling circuitry-compliant IC measurement methods
Coupling circuitry

Purpose Implementation

HF1 Symmetric DPI coupling into

CAN

Parallel circuit of two times
R = 120 Ω + C = 4,7 nF

HF2 DPI coupling into VBAT C = 4,7 nF

HF3 DPI coupling into wake C = 4,7 nF

IMP1 Symmetric transients coupling

into CAN

Parallel circuit of two times
C = 1 nF

IMP2 Transients coupling into VBAT D (standard diode)

IMP3 Transients coupling into wake C = 1 nF

EMI1 Symmetric 150 Ω voltage mea-

surement CAN

Parallel circuit of two times
R = 120 Ω + C = 4,7 nF with matching
resistor of R = 51 Ω

Table 2.4 Transceiver operational modes, pins for noise injection and evaluation
Operational
mode

Noise injection pins Evaluation pins Purpose

Normal CAN, VBAT, Wake RxD Evaluation: Communication

ERR Evaluation: Error

INH Evaluation: Inhibit output

Standby CAN, VBAT, Wake RxD Unintentional-wake-up observation

INH Evaluation: Inhibit output

Sleep CAN, VBAT, Wake RxD, INH,

respectively

Unintentional-wake-up observation

Communication Specifications

Corresponding to the individual test parts, communication will be performed by
various sequences of signals which are transmitted by node 1. The transmitted in-
formation will be received by all other nodes and monitored through their RxD
outputs:

• Test signal 1: Symmetric square wave with a 50 % duty cycle (CAN signal with
continuous 0-1 data swing) and a frequency of 250 kHz or a bit rate of 500
kbit/s, respectively.
• Test signal 2: Non-symmetrical square wave with 90 % duty cycle and a fre-
quency of 50 kHz.

For noise immunity tests with communication, only test signal 1 must be applied.
Noise emission measurements are to be performed using test signals 1 and 2.

Definitions for Test Modes and Error Criteria for Tests on Malfunction.

Table 2.4 shows the relation between operational modes of the transceivers, pins for
noise injection and evaluation as well as the intended test purpose for measurements
to be executed for noise immunity checking a resulting malfunction.