ATX/ATX12V Power Supply Design Guide
Version 1.1
Page 31
6. Electromagnetic Compatibility
The following subsections outline sample product regulations requirements for a typical
power supply. Actual requirements will depend on the design, product end use, target
geography, and other variables. Consult your company’s Product Safety and Regulations
department for more details.
6.1. EMI
The power supply shall comply with CISPR 22, Class B, for both conducted and radiated
emissions with a 4 dB margin. Tests shall be conducted using a shielded DC output cable
to a shielded load. The load shall be adjusted as follows for three tests: No load on each
output; 50% load on each output; and 100% load on each output. Tests will be performed
at 100 VAC 50 Hz, 120 VAC 60 Hz, and 220 VAC 50 Hz power.
6.2. Input Line Current Harmonic Content and Line Flicker
Required for Sales in Europe and Japan
For sales in Japan or Europe, the power supply shall meet the requirements of EN 61000-3-
2 Class D, and EN 61000-3-3, and the Guidelines for the Suppression of Harmonics in
Appliances and General Use Equipment Class D for harmonic line current content at full-
rated power.
6.3. Magnetic Leakage Fields
A PFC choke magnetic leakage field should not cause any interference with a high-
resolution computer monitor placed next to or on top of the end-use chassis.
