Alternative Components in the BOM

Managing the Components in your Design

During the design process your initial focus is on the functionality of the circuit - issues like meeting the timing requirements, the power budget, the mechanical constraints of the case, will completely occupy your thoughts. As the design settles, your focus will shift to the implementation challenges - can it be built at the required pricepoint, are the parts available to meet the supply deadline, and so on.

It is during this implementation-oriented phase that you begin to lock down the components, R1 is no longer just a 10K 1% 0402 resistor, now it becomes a Vishay 70201889, which can be sourced from a number of suppliers. If you started the design process by placing your components from the Altium Component Content Vault, then it's an easy path to an implementation-ready state, as each component is already coupled to detailed, real-time, manufacturer and supplier data. If you've worked from your own libraries, then you might call on the Supplier Search feature to help map each design component to a real-world part.

The best approach to rapidly assembling a detailed, accurate, price-sensitive, BOM-ready, list of components is to use Altium Designer's ActiveBom. Using real-time pricing, you can move through the component list and select the most appropriate manufacturer and supplier for each component. But then your purchasing officer pops his head in the door and announces - new company policy, we need all BOMs to include at least 1 alternative source for every component. Not only does this mean that availability mistakes in supplier databases can be quickly avoided, it also gives the company much-needed confidence that their new product can still be built if Acme component manufacturing goes belly up.

Altium Designer 16 sees the introduction of support for Alternative Parts in the BOM. Building on the existing ability to define alternative parts for multi-source components, like discretes, using the Solutions feature, you can now select an alternative, functionally equivalent component. As well functional equivalents, you can also split a set of multiple component into smaller groups, useful if you need to select an alternative for a sub-set of components.

Alternative parts can be included in the BOM as separate line items, by enabling the Include Alternative Items option.

Defining Alternative Parts

Main page: ActiveBOM

Alternative parts are configured in the ActiveBOM (*.BomDoc) included as part of your project.

Alternative Parts are defined in the ActiveBOM, via the right-click menu.

Support for alternative parts feature can be broken down into the following three areas:

Alternative Manufacturer/Supplier

There is often a multitude of alternatives available for discrete and generic components. Resistors, capacitors, diodes, even transistors and op-amps, are available from multiple manufacturers, through multiple suppliers. To identify alternative Manufacturers/Suppliers, set the Rank for your preferred choices. The first two ranked solutions can be included as detail for any part in the Bill of Materials for BOM report generation dialog, by enabling the Solution 1 and Solution 2 checkboxes in the selection column.

Use the Rank feature to nominate preferred alternative manufacturer/supplier for discrete parts, two can be included in the BOM.

Alternative Functionally Equivalent Part

As the designer, you know your design inside out. That means you know that a particular component can be replaced by an alternative part, which might not be identical, but for your design is functionally equivalent. To select a functionally equivalent alternative part, right-click on the part in the BomDoc and select Add Alternative Item from the context menu. The Choose BOM Vault Component dialog will open, browse and locate the required alternative.

In the BOM Catalog tab of the BomDoc, the alternative will appear as a separate line below the existing solution, click the + symbol to display the detail of the alternative part.

To include the alternative part, enable the Include Alternative Items checkbox in the Bill of Materials for BOM report generation dialog. The alternative part will appear in the component grid below the original part.

Right-click to add a functionally equivalent part as an alternative, here an ARM Cortex-M3 with 10K internal RAM has been selected.

Alternative Group

As you organize alternatives for your discretes, you might also want to break a particular component into a number of groups. For example, you have a large number of 10K resistors, and a large production run. To ensure supply, you'd like to break this down and source the 10K resistors from 4 different suppliers when the BOM is processed. This can be done by splitting that part into four groups, with each group assigned a different Manufacturer/Supplier using the Rank feature.

Another situation where you might want to split a component into groups is when your design includes a component that requires a specific component from a specific manufacturer, but there are also other components that do not require the same restriction to a specific manufacturer. This can be achieved by creating a group for the special-case component to lock it to its specific manufacturer, and then assign the remaining components to the other group.

To split a component into groups, right-click on the part in the BomDoc and select the Split Item (Add Alternatives Group) command from the context menu. The Edit Alternative Group dialog will open, name the Alternative Group and enable the checkbox for each component you want in that group.

In the BOM Catalog tab of the BomDoc, the Alternative Group will be shown as a new line below the existing solution, with the group name appended to the solution's Description. Note that how the Group is displayed in the BomDoc is different to how an Alternative Equivalent Parts are displayed, because here you are effectively breaking down a single, larger group of identical parts, into a number of smaller groups. Each smaller group is then displayed as a separate line entry in the BomDoc and also in the BOM.

Define an Alternative Group, then assign specific components to it.

Including Alternative Parts in the BOM

To include Alternative Parts in the BOM, the Bill of Materials must use the BomDoc as its Data Source.

The Alternative Parts feature requires the BomDoc to be the Data Source for the BOM.

To display the alternative manufacturer/supplier details in the BOM, enable the required Solution checkboxes in the Bill of Materials for BOM Document dialog.

Enable the required Solutions checkboxes to include alternative manufacturer/supplier detail for purchasing.

To display the alternative functionally equivalent parts in the list of components, enable the Include Alternative Items checkbox in the Bill of Materials for BOM Document dialog.

Enable the Include Alternative Items checkbox to display the alternative part below the original part.

To cluster like-components, drag the DesignItemID or the LibRef label from the All Columns list on the left of the dialog, into the Grouped Columns region. Include the Alternative Group Name label to separate out those entries that belong to an Alternative Group.

To separate the alternative groups, include the Alternative Group Name in the Grouped Columns region.