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Home » Switchmode Transformers » EFD Core Style

EFD Power Switchmode Transformers

Precision Inc has developed switchmode transformers utilizing industry standard configurations, such as materials and footprints.  These "standard" switchmode transformers are designed around a sizing factor number.  To determine which core style will work in your application we offer a Product Family Calculator to assist in the selection. 

If you prefer the EFD style core, the sizing factor Calculator is located below.

Features:
  • Low Profile
  • Low Leakage inductance designs
  • IEC-spacing compatible
  • Through hole and surface mount available

 
Mechanical Characteristics

 

EFD Mechnical Drawing
 * For standard product: Please select the quantity for each item you wish to order or receive a quote and click the 'Add To Quote' button below.

* For custom product: Please click 'Custom' button below. You will be directed to a page where you can add custom product information and attach prints.
 
Model
Length (A)
Width (B)
Height (C)
Pin Spacing (F)
Pin Row (G)
No. of Pins-
Sizing Factor
330Khz

Sizing Factor
800Khz

EFD15
Through Hole 
15.4 mm
(.606 in)
16.7 mm
(.657 in)
8 mm
(.315 in)
3.75 mm
(.148 in)
13.75 mm
(.541 in)
8
up to 45
up to 61
EFDSM10
Surface Mount 
11.7 mm
(.461 in)
19.7 mm
(.776 in)
5.7 mm
(.224 in)
3 mm
(.118 in)
13.8 mm
(.543 in)
8
up to 17
up to 22
EFDSM12
Surface Mount 
13.7 mm
(.539 in)
21.2 mm
(.835 in)
6.5 mm
(.256 in)
3 mm
(.118 in)
15.3 mm
(.602 in)
8
up to 35
up to 49
EFDSM15
Surface Mount 
15.4 mm
(.606 in)
23.7 mm
(.933 in)
7.8 mm
(.307 in)
3.75 mm
(.148 in)
17.8 mm
(.701 in)
8
up to 45
up to 61
EFD30
Through Hole 
32.8 mm
(1.201 in)
34.1 mm
(1.343 in)
12.5 mm
(.492 in)
5 mm
(.197 in)
27.5 mm
(1.083 in)
12
up to 280
up to 380
EFD20
Through Hole 
21.7 mm
(.854 in)
21.6 mm
(.85 in)
10 mm
(.394 in)
5 mm
(.197 in)
17.5 mm
(.689 in)
10
up to 78
up to 100
EFD25
Through Hole 
27.7 mm
(1.091 in)
29.1 mm
(1.146 in)
12.5 mm
(.492 in)
5 mm
(.197 in)
22.5 mm
(.886 in)
10
up to 210
up to 280
EFDSM20
Surface Mount 
21.7 mm
(.854 in)
28.7 mm
(1.13 in)
9.8 mm
(.386 in)
3.75 mm
(.148 in)
22.8 mm
(.898 in)
10
up to 78
up to 100
Displaying 1 to 8 (of 8 products) Result Pages:  1 
Custom
Sizing Factor Calculator

 

EFD Sizing Factor

Once the core has been selected please contact our design engineers to assist with the transformer design and manufacturability issues such as; turns ratio, dielectric, wire breakout, pin termination, IEC margins, Rohs, REACH and other construction related requirements.

Sizing factor notes that apply to the chart above:

  1. Sizing constraints: Temperature rise is 40°C, the ambient temperature is 50°C and it does not include IEC Spacing.
  2. Increasing the operational frequency will reduce the sizing factor number and transformer size.
  3. Increasing the temperature rise allowed in the part will reduce sizing factor number and transformer size.
  4. Adding IEC dielectric requirements will increase the sizing factor number and transformer size.