UA7902 Flyback Transformer for Silicon Labs Si88xx 5kV DC-DC Converter | Coilcraft
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Flyback Transformer for Silicon Labs
Si88xx 5kV Isolated DC-DC Converter

  • UA7902 was developed for use with Silicon Labs Si88xx isolated dc-dc-converter reference designs. Learn more about these miniature transformers for digital isolators.
  • 5000 Vrms, one minute isolation (hipot), from primary to secondary
  • Designed to meet reinforced insulation class with 8 mm creepage and clearance.
  • Ultra-miniature flyback tranformer, measures only 10.0 × 17.07 × 5.97 mm
  • AEC-Q200 Grade 1 (−40°C to +125°C)
  • Low leakage inductance, only 971 nH
  • RoHS-compliant. 260°C compatible. RoHS tin-silver-copper (95.5/3.8/0.7) over tin over nickel over phos bronze terminations.


Part number1
Click to get parts
±5% (µH)
Leakage L3
max (µH)
DCR max4
pri : sec
pri  sec 
UA7902-AL_ 7 – 24 25.0 0.971 0.075 0.106 3 : 1 5000 1.3 5 V, 0.4 A
1 When ordering, please specify packaging code: e.g.UA7902-ALD
Packaging: D = 13" reel, machine-ready 
EIA-481 embossed plastic tape (700 parts per full reel).
B = Less than full reel
In tape, but not machine-ready. To have a leader and trailer added ($25 charge), use code letter D instead.
2 Inductance measured at 250 kHz, 0.1 Vrms, 0 Adc
3 Leakage inductance measured between pins 1 and 3 at 250 kHz, 0.1 Vrms, 0 Adc with all secondary pins shorted.
4 DCR for secondary is for the windings connected in parallel, measured at 25°C. For other operating temperatures, use this DCR at Temperature calculator.
5 Isolation (hipot) measured between windings for one minute.
6 DC current that causes an inductance drop of 30% (typ) from its value without current.
7 Ambient temperature range: −40°C to +125°C
8 Storage temperature range: Component: −40°C to +160°C
Tape and reel packaging: −40°C to +80°C
9 Maximum part temperature: +160°C
10 Resistance to soldering heat: Three reflows at >217°C for 90 seconds (+260°C ±5°C for 20 – 40 seconds), allowing parts to cool to room temperature between.
11 Electrical specifications at 25°C.
Refer to Soldering Coilcraft Components before soldering.
PCB washing: Tested to MIL-STD-202 Method 215 plus an additional aqueous wash. More info.

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Updated: April 26, 2018