28R1128-200 Laird Technologies, 28R1128-200 Datasheet - Page 4

• Manufacturer Part Number: 28R1128-200
• Description: EMI/RFI Suppressors & Ferrites Flat Ferrite Filter
• Manufacturer: Laird Technologies
• Series: 28Rr

Specifications of 28R1128-200

• Product Category: EMI/RFI Suppressors & Ferrites
• Rohs: yes
• Product: Data Line EMI/RFI Filters
• Impedance: 145 Ohms
• Operating Temperature Range: - 40 C to + 125 C
• Termination Style: SMD/SMT
• Case Height: 5.38 mm
• Case Length: 28.58 mm
• Case Width: 14 mm
• Dimensions: 14 mm W x 28.58 mm L x 5.38 mm H
• Shielding: Unshielded
• Test Frequency: 100 MHz

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FERRITE MATERIAL
LF, 28 & HF MATERIAL IMPEDANCE VS FREQUENCY (300 KHz - 2 GHz)
Impedance Materials for Cable & Wiring Harness Cores
DESIGN & SELECTION
SELECT THE APPROPRIATE FERRITE MATERIAL
For the EMI frequency range to be attenuated, refer to cable core material impedance vs.frequency chart above.
FERRITE MATERIAL COMPOSITION AFFECTS CORE PERFORMANCE MOST
High-performance material is best. Cheap, low-performance materials require the use of larger, heavier cores.
SHAPE (DESIGN) AND MASS OF THE FERRITE CORE SIGNIFICANTLY AFFECT IMPEDANCE
DON’T OVER SIZE
Use high-performance ferrite material and select the smallest core that will do the job. High-performance material
allows the use of smaller, lighter and lower cost cores.
SELECT A FERRITE CORE THAT FITS OVER THE CABLE’S OUTSIDE DIMENSIONS
Core should slide easily over the cable during installation.
WHEN POSSIBLE, INSTALL A CABLE CORE OVER WIRES IN A COMMON MODE CONFIGURATION
(Out and back lines inside the same ferrite cable core). A differential cable pair inside the same core will make the ferrite core a
common mode choke that is not susceptible to saturation from very high currents.
INSTALL THE FERRITE CORE NEAR THE NOISE SOURCE
ADDITIONAL TURNS THROUGH A CORE WILL PROVIDE MULTIPLE AMOUNTS OF PEAK IMPEDANCE
Example: Two wire turns provide four times the impedance of one turn (pass through) the ferrite core. Also, with each added turn,
the peak impedance shifts to a slightly lower frequency.
TWO-PIECE SPLIT CORES ARE AVAILABLE
One-piece cylindrical or flat ribbon ferrite core shapes are usually preferable, but split cores can be used in applications where
cores cannot slide over cable ends and connectors. Some split cores are available with snap-on plastic cases or metal clips.
SIDE-BY-SIDE IMPEDANCE TESTING OF FERRITE CORES IS THE BEST WAY TO COMPARE
PERFORMANCE OF DIFFERENT CORES
Ferrite core impedance measurement equipment and test methods are not standardized in the industry.
Every ferrite company has their own test methods. Catalog (web site) impedance data cannot be accurately compared.
Optimized, high-performance, low-cost custom part designs are available.
FERRITE EMI CABLE CORES
0.3
0.5
LF Low Frequency
28 Broadband High Performance
HF High Frequency
500
1
LF
5
10
Frequency (MHz)
50
100
“RULES OF THUMB”
COMPARISON
28
HF
1000
2000