PCB Assembly Cost Savings – Another Benefit of System-In-Package

 

One of the key benefits delivered by System-In-Package (SiP) technology is the savings realized in the Printed Circuit Board (PCB) Assembly process.  This is a benefit that is commonly overlooked by designers on the front end.  Typically, they only look at the cost of the individual components on the Bill of Material (BOM) and don’t consider the cost of assembly.  With System-In-Package technology, the number of components that need be placed during the assembly process can be significantly reduced.  This reduction decreases the component set up time and actual time spent on the Pick and Place machine. Simultaneously driving down the assembly cost and the total cost of the finished product.

As an example of this, we went to a local PCB assembly house and had them quote the assembly cost of two boards.  One board had only the OSD3358-512M-BAS System-in-Package device on it.  The other board had over 120 components that would be needed to build an equivalent system to the OSD3358.  The parts we used for the discrete design are listed below:

QTYDescriptionManufacturerPart Number
21CAP CER 10UF 10V Y5V 0805MurataGRM21BR71A106KE51L
5CAP CER 1UF 6.3V 10% X5R 0402MurataGRM155R60J105KE19D
3CAP CER 2.2UF 6.3V 10% X5R 0402TDKC1005X5R0J225K050BC
1CAP CER 470PF 50V 10% X7R 0402MurataGRM155R71H471KA01D
69CAP CER 0.1UF 6.3V 10% X5R 0402MurataGRM155R60J104KA01D
2CAP_CER_0.001UF_16V_X7R_0402YageoCC0402KRX7R7BB102
3INDUCTOR 2.2UH 20% 1300MA 1008MurataLQM2HPN2R2MG0L
1RES 4.75K OHM 1/16W 1% 0402 SMDVishayCRCW04024K75FKED
2RES 1.50K OHM 1/16W 1% 0402 SMDYageoRC0402FR-071K5L
4Resistor Zero ohm Jumper 0402VishayCRCW04020000Z0ED
5Resistor 10Kohm 1/16W 5% 0402VishayCRCW040210K0JNED
1Resistor 1Mohm 1/16W 1% 0402VishayCRCW04021M00FKED
1RES 49.9 OHM 1/16W 1% 0402 SMDYageoRC0402FR-0749R9L
1RES TF 1/16W 280K OHM 1% 0402VishayCRCW0402280KFKED
1RES 240 OHM 1/16W 1% 0402 SMDVishayCRCW0402240RFKED
1RES 470K OHM 1/16W 1% 0402 SMDVishayCRCW0402470KFKED
1Integrated Power Management UnitTITPS65217C ( RSLR )
1IC LDO VOLT REG 500MA 8-SOICTITL5209D ( R )
1AM3358B, SubArctic Cortex A8 Processor 15x15,1GHz, 2.1TIAM3358BZCZ100
1DDR3 Memory 4Gb,256Mx16MicronMT41K256M16TW-107:P-ND
3Ferrite Bead 150 Ohm 800mALaird-Signal IntegrityLaird-Signal Integrity

The equivalent discrete design to the OSD3358 has 21 unique line items that need to be set up and 128 individual placements that must be made. Depending on the quantity of boards assembled, the cost savings from using a System-In-Package can be significant.  This is seen in the quotes we received from our PCB assembly house outlined below.

Quantity of Boards Assembled10501005001000
Discrete Total Assembly Cost$232.92$798.53$1,364.27$5,338.09$9,850.89
Discrete Assembly Cost Per Board$23.29$15.97$13.64$10.68$9.85
OSD3358 Total Assembly Cost$26.61$107.39$163.50$561.11$865.80
OSD3358 Assembly Cost per Board$2.66$2.15$1.64$1.12$0.87
Total Savings$206.31$691.14$1,200.77$4,776.98$8,985.09
Saving Per Board$20.63$13.82$12.01$9.55$8.99

As you can see when assembling a low quantity of boards, 10, using a SiP instead of the discrete components saves $20.63 per board.  Even at larger volumes, 1,000 boards, the per board assembly cost savings is $8.99.  This translates into a total assembly cost savings of almost $9,000 by using the OSD3358 SiP instead of the discrete components.

Conclusion

When this article was written the 1K price for the OSD3358 was $25.  The cost of the 128 discrete components was ~$21.00.  If your cost analysis stopped here you would conclude the discrete solution is lower cost.

However, when you look at the total cost including assembly you get a different story.  To finish out the example started above we compared the cost to purchase the components and build 1,000 of each design.  The results are outlined in the table below.

 OSD3358128 Discrete partsSavings
Component cost per board$25.00$21.00
Total Component Cost $25,000.00 $21,000.00
Assembly Cost Per Board$0.87$9.85
Total Assembly Cost$865.80$9,850.89
Total Per Board Cost$25.87$30.85$4.98
Total Board Cost$25,865.80$30,850.89$4,985.09

The System-in-Package solution saves almost $5.00 per board and almost $5,000 on the total build.  This calculation doesn’t even include the savings from a lower cost PCB the System-In-Package solution allows, or the increased revenues from getting to market faster, or the savings from simplifying the supply chain and increasing reliability.

The moral of the story here is that when evaluating if a System-In-Package device is the right solution for you, make sure you look at the whole picture!

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