Document 328-1

Planar Magnetics

For National Semiconductor
LM5041 ICThis planar transformer and inductor pair were designed
specifically for National Semiconductor’s LM5041 IC.
The A9786-A transformer is engineered for use in highcurrent telecom power supply applications that require highefficiency in a low-profile package.The auxiliary winding
can be used to control input current to PWMs. It offers
very high current handling capability and extremely low
DC resistance in a low profile package.
Coilcraft’s A9787-A inductor is designed as the output
choke for the LM5041.
Planar magnetics offer high power densities along withgreat reliability and repeatability. Windings are etched
into a printed circuit board, ensuring high efficiency andconsistency.
Request free evaluation samples by contacting Coilcraftor visiting www.coilcraft.com.

Transformer			Input		OutputPrimary
Leakage		Pri/sec
DCR maxPart
Outputvoltage
Outputcurrent	 inductance1 inductance2
isolation(mOhms)number1 power (W) range (V) voltage (V)(A rms)min (mH)max (µH)(Vdc)
A9786-AL_150
36 – 75
2.560.0
1.250.90
Primary: 62.5 (1 – 3)
1100								Secondary: 0.91 (5,6 – 9,10)									 200 (4 – 11)
1. When ordering, please specify packaging code:
Packaging:

A9786-ALD
D = 13″ machine-ready reel. EIA-481 embossed plastictape (125 parts per full reel). Quantities less than full
reel available: in tape (not machine ready) or withleader and trailer ($25 charge).
B = Less than full reel. In an effort to simplify our partnumbering system, Coilcraft is eliminating the needfor multiple packaging codes. When ordering, simply
change the last letter of your part number from B to D.

2. Inductance measured on an Agilent/HP 4284 between pins 1 and 3 at
250 kHz, 0.1 Vrms, 0 Adc.
3. Leakage inductance measured between pins 1 and 3 at 100 kHz, 0.1 Vrms,0 Adc with all secondary pins shorted.
4. Operating temperature range: –40°C to +85°C.
5. Electrical specifications at 25°C.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.

5,6

0.45
max
11,43
0.004 /0,10

5
4

1.23
max 2
31,24
1

10.285
7,24Pri

0.075

1,91

7,8

2

9,10

3
10

11

5Recommended
Land Pattern4Aux

4T
110.31
7,87

2

Sec

1T8T

3

11108T

1.32
33,53
1.21
30,73
1.15
29,21

1.48
max
37,59

31T

1

4

0.12
3,05

0.175
4,45

US +1-847-639-6400 sales@coilcraft.com
UK +44-1236-730595 sales@coilcraft-europe.com
Taiwan +886-2-2264 3646 sales@coilcraft.com.tw
China +86-21-6218 8074 sales@coilcraft.com.cn
Singapore + 65-6484 8412 sales@coilcraft.com.sg

Weight: 33.4 g
Terminations: Matte tin over nickel over brass
Tape and reel: 125/13″ reel 56 mm tape

Document 328-1

Revised 06/09/08© Coilcraft Inc. 2020
This product may not be used in medical or highrisk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check web site for latest information.

Document 328-2

Planar Magnetics for National Semiconductor LM5041
Output Inductor		 Inductance2
Part@ 0 Adc
number1(µH)
A9787-AL_
57 ±7%

Inductance2@ 7.5 Adc
min (µH)
47.0

DCR max(mOhms)
17.0

1. When ordering, please specify packaging code:
Packaging:

A9787-ALD
D = 13″ machine-ready reel. EIA-481 embossed plastic
tape (125 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.

Typical L vs Frequency

Irms5(A)
12.0

Typical L vs Current
1000

Inductance (µH)

Inductance (µH)

Isat4(A)
8.1

2. Inductance measured on an Agilent/HP 4284 at 250 kHz, 0.1 Vrms.
3. Isolation measured from pins 1,2 to the core.
4. DC current at which inductance drops 10% (typ) from its value withoutcurrent.
5. Current that causes a 40°C rise from 25°C ambient.
6. Operating temperature range: –40°C to +85°C.
7. Electrical specifications at 25°C.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.

1000

100

101

Isolation3(Vdc)
1100

10.1

10100

Frequency (MHz)

1000

100

101

10000

0.1

110100Document 328-2

Revised 06/09/08

Current (A)

1,2

0.45
max
11,43
0.004 /0,10

3,4

For mounting
stability only
1.30
max
37,59

1.145
29,08

0.12
3,05
14

1.23
max
31,24
1For mounting
stability only

0.34
8,64

0.30
7,62

40.075

1,91

Recommended
Land PatternWeight: 31.0 g
Terminations: Matte tin over nickel over brass
Tape and reel: 125/13″ reel 56 mm tape

US +1-847-639-6400 sales@coilcraft.com
UK +44-1236-730595 sales@coilcraft-europe.com
Taiwan +886-2-2264 3646 sales@coilcraft.com.tw
China +86-21-6218 8074 sales@coilcraft.com.cn
Singapore + 65-6484 8412 sales@coilcraft.com.sg© Coilcraft Inc. 2020
This product may not be used in medical or highrisk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check web site for latest information.