1. Background
In a circuit, switching transients (to cut off inductive load, relay contact bounce, etc.) usually interferences with other electrical and electronic equipment in the same circuit. The characteristics of this type of interference are high amplitude, short rise-time, high repetition rate and low energy. The narrow pulses appeared in groups can charge the capacitance of the semiconductor device, which may cause circuit or device errors when accumulated to a certain extent. To simulate the effect of such interference on the equipment, EFT (electrical fast transient)/burst testing are conducted to test the stability of the equipment.
2. Overview
1) EFT testing belongs to the EMS field, the effects of external interferences on the equipment.
2) The repetitive fast transient test is a test with bursts consisting of a number of fast transients, coupled into power, control, signal and earth ports of electrical and electronic equipment.
3) Repetition frequency of the of impulses specified by IEC/EN 61000-4-4 is 5 kHz and 100kHz.
When the repetition frequency is 5 kHz, burst duration is 15ms
When the repetition frequency is 100 kHz, burst duration is 0.75ms
5k & 100k repetition waveform, rise time 5ns, pulse width 50ns.
4) Test levels
The preferred test levels for the electrical fast transient test, applicable to power, control, signal and earth ports of the equipment.
3. Typical test setup
Table-top and floor standing equipment test setup for laboratory type tests:
1) Ground reference plane
2) EFT/burst generator
3) CDN (if applicable)
4) Capacitive coupling clamp (if applicable)
5) Insulating support
6) Grounding cable
4. Evaluation of test results
The test results shall be classified in terms of the loss of function or degradation of performance of the EUT.
a) normal performance within limits specified by the manufacturer
b) temporary loss of function or degradation of performance which ceases after the disturbance ceases
c) temporary loss of function or degradation of performance
d) loss of function or degradation of performance which is not recoverable
The classification may be used as a guide for the manufacturer to help them to do product rectification and product improvement.
EMCSOSIN have been committed to the EMC testing field, specializing in providing EMC testing instruments, product rectification and training service. Our self-developed EMC equipment including: ESD simulator, EFT/burst generator, surge generator, voltage dips generator, power frequency magnetic field generator, damped oscillatory wave generator, automotive pulse simulator etc. EMCSOSIN also provide customers with professional EMC system integration solutions. Please do not hesitate to contact us for more details. Thank you!
