Three memory modules placed on a circuit board.

Rediscovering Signal Chain µModule®︎

Building a whole signal chain that fits perfectly on a particular system is a common challenge in this industry. What if we had a solution that could simplify your journey in the complex landscape of signal chain integration? In this blog, we will revisit and have a deeper look at Analog Devices (ADI) precision signal chain uModules.

uModule Portfolio
Figure 1. uModule Portfolio

What are Precision Signal Chain uModules?

Precision signal chain μModule® (micromodule) utilizes heterogeneous integration to provide a complete solution to precision data conversion. This means that we combine our various signal chain products, along with several critical passive components, to create a single device using the system-in-package (SiP) technology. This set of solutions, focused on precisely converting analog to digital signals, brought about a whole signal chain packaged in a single chip.

Precision Signal Chain uModule

Figure 2. Precision Signal Chain uModule

Understanding the Need for Precision Signal Chain uModules

Now that we know about precision signal chain uModules, let us also talk about the significant benefits of using these data conversion solutions.

1.   Space Saving and Board Density

The greatest advantage of using uModules is the amount of board area saved compared with its discrete-solution equivalent. A standard signal chain design involves discrete components in each stage (i.e., amplifier, voltage reference, ADC, etc.). These components, placed one by one on the board, take up most of the footprint. But with ADI's precision uModules, these signal chain blocks are already combined in a single package — allowing the customers to tuck in more components and save up board space, without sacrificing their performance requirements. Space reduction of uModules can even reach up to 11x, aligning with the current demand on precision data acquisition applications: high-channel-density, compact board design, and less component count for the whole system.

uModule Space Saving Comparison
Figure 3. Space Saving

2.   iPassives Technology

Integrated passives, simply iPassives, are incorporated as well in the uModule to further improve signal chain performance, particularly gain drift, and offset drift. iPassives technology can achieve precise matching since the passives came from the same die: denoting that they are manufactured at the same time, under the same conditions, with the same material set.1 

ADI’s iPassives Technology

Figure 4. ADI iPassives Technology

Figure 5 shows an inverting op-amp circuit, with its gain set up using the two resistors, R1 and R2. The spread in gain highly depends on the resistor choices, as emphasized in the color coding in Figure 6. For instance, red-colored "Discrete Resistors" from different batches would result in a widespread gain. On the other extreme are the white-colored "Nested Passive Resistors on a Single Die" showing a narrow distribution with a very tight spread in gain. Choosing passive resistors on a single die would result in more accurate gains across devices, giving a suitable condition for the entire signal chain.

Inverting Op-Amp Configuration with Gain Setup using Two Resistors

Figure 5. Inverting Op-Amp Configuration with Gain Setup using Two Resistors

Resistor ChoicesEquivalent Distribution
Figure 6. Resistor Choices and Equivalent Distribution

Moreover, since the passives came from the same die, interconnect parasitics are minimized, thus, addressing a common pain point of data acquisition applications. Aside from resistors, other primary passive components using this technology include capacitors, inductors, and diodes.

3.   Component selection and reduced total cost of ownership

Using a uModule transfers the design burden from the designer to the device. Individual precision products inside the uModule are proficiently handpicked, optimized, and laid out from ADI's wide portfolio. Having the right components integrated with the uModule eliminates problems associated with the supply chain in system-level design. Customers can therefore avoid design iterations and worry less about having out-of-stock parts.

Secondary costs are significantly diminished compared to a discrete signal chain solution, as shown in Figure 4. Temperature-dependent error sources are reduced with iPassives Technology, minimizing the need for parametric drift calibration. Field support costs are less due to fewer discrete components, PCB interconnects, and solder joints. The consistent performance and high manufacturing yield of a uModule also reduce manufacturing-related costs (i.e., technical support, pick-and-place costs, and assembled PCB yield loss).

Reduced Total Cost of Ownership

Figure 7. Reduced Total Cost of Ownership

4.   Guaranteed performance and faster time to market

The uModule datasheet limits cover the entire signal chain, including the performance variation over environmental conditions and the batch-to-batch variation. This advantage helps customers leverage their time to market, with less time spent on debugging and characterization of the signal chain performance. Similarly, customers can easily assess the functionality of the uModule through the evaluation board, which incorporates an onboard power solution and is accompanied by ADI's evaluation software — Analysis, Control, Evaluation (ACE). Having this plug-and-play solution allows customers to focus on validating new sections of their system, with faster prototyping and time-to-market.

Considering a Precision Signal Chain uModule into a Bigger System…

Moving up the stack with uModules walks us a step further in addressing design challenges and bringing our solutions to the Intelligent Edge. The “ADAQ” family, or simply the signal chain uModule “flavors” encompassing a wide range of applications in precision data conversion are accessible through Analog Devices.


[1] Use of Integrated Passives in Micromodule SIPs