Component Selection and Comparison Practical Selection Questions Selection

How do I select between an off-the-shelf module and a custom designed RF assembly?

Selecting between an off-the-shelf (OTS) module and a custom designed RF assembly balances the trade-offs of development cost and time versus production cost, performance optimization, and size/weight/power (SWaP). OTS module advantages include: no NRE (development) cost (the module is designed, tested, and qualified by the manufacturer), fast time to market (evaluation and integration take weeks to months versus months to years for a custom design), guaranteed specifications (the manufacturer warrants the module's performance), and available support (the manufacturer provides applications engineering assistance). OTS module disadvantages include: higher per-unit cost (the manufacturer's margin and overhead are included; OTS modules typically cost 2-5x more per unit than the equivalent custom assembly at production volumes), compromise specification (the module is designed for general use, not optimized for the specific application; it may not meet the exact performance requirements or may include unnecessary features that add cost and size), larger size (general-purpose modules include extra filtering, connectors, and features that increase size), and supply dependence (the user depends on the module manufacturer for ongoing supply and support). Custom design advantages include: optimized performance (designed specifically for the application requirements; can achieve higher performance in a smaller package), lower production cost at volume (no manufacturer margin; component cost only; break-even versus OTS typically occurs at 100-1000 units depending on the design complexity), intellectual property ownership (the custom design is the user's IP), and full supply chain control. Custom design disadvantages: significant NRE cost ($50K-$500K+ for a full custom RF module design), long development time (6-18 months from concept to qualified production), and design risk (the custom design may not meet specifications, requiring iteration).

Category: Component Selection and Comparison

Updated: April 2026

Product Tie-In: All Components

OTS vs. Custom RF Assembly Decision

The make-vs-buy decision for RF assemblies is one of the most impactful choices in an RF program. The wrong choice can either waste money (over-investing in a custom design for low volumes) or limit performance (using a generic module when a custom design is needed).

Decision Framework

Low volume (1-100 units): Almost always use OTS modules. The NRE for custom design cannot be amortized over such a small quantity. Exception: if no OTS module meets the performance requirement, custom design may be the only option
Medium volume (100-1000 units): Evaluate both options. Calculate the total cost including NRE. If the OTS per-unit cost × quantity > custom NRE + (custom per-unit cost × quantity): custom is cheaper. Performance and SWaP requirements may also drive the decision
High volume (1000+ units): Custom design is usually more cost-effective. The NRE is amortized across many units. Custom design also provides full supply chain control and optimization opportunity

Make vs Buy Parameters

Total cost comparison:
OTS: TC_OTS = C_module × N_units
Custom: TC_custom = NRE + C_custom_unit × N_units
Break-even: N_break = NRE / (C_module - C_custom_unit)
For NRE=$100K, C_module=$500, C_custom=$200:
N_break = $100K / $300 = 333 units

Common Questions

Frequently Asked Questions

What OTS modules are available?

Major OTS RF module suppliers: Mini-Circuits: broadest catalog of amplifiers, filters, mixers, attenuators, switches, and frequency synthesizers. Low to moderate performance. Very competitive pricing. Analog Devices (via Hittite Microwave acquisition): high-performance amplifiers, VCOs, PLLs, mixers, and digital attenuators. Qorvo: GaN PA modules, switches, and filters for defense and 5G. Marki Microwave: high-performance mixers and IF amplifiers. API Technologies / Richardson RFPD: integrated subsystem modules (receivers, transmitters, transceivers). Check these catalogs before starting a custom design.

What NRE should I expect?

Simple custom RF module (amplifier or filter on a small PCB): NRE $20-50K, 3-6 months development. Moderate custom module (multi-stage receiver or transmitter with digital control): NRE $50-150K, 6-12 months. Complex custom RF assembly (multi-function module with MMIC design, hermetic packaging, military qualification): NRE $200-500K+, 12-24 months. These estimates include: schematic and layout design, prototype fabrication (2-3 prototype iterations), testing and characterization, documentation, and production release. Military qualification testing (MIL-STD-810, MIL-STD-461) adds $50-200K to the NRE.

Can I start with OTS and switch to custom later?

Yes, this is a common and effective strategy. Phase 1: use OTS modules for the prototype and initial production. This gets the system into the field quickly with minimal NRE. Phase 2: once the system requirements are validated in the field, design a custom replacement that: reduces per-unit cost for volume production, optimizes performance based on field experience, and reduces SWaP. The key: design the Phase 1 system architecture to accommodate the custom replacement (use standard interfaces, document the requirements, and plan the transition).

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