FCC Part 15 Modular Certification Rules Baseline Guidelines
FCC Part 15 modular rules allow pre-certified radios in host devices provided shielding, power regulation, labeling, and antenna limits match grant guidelines.
Internal Power Regulation
Meaning
Circuit architecture within a module stabilizes input voltage to protect sensitive radio frequency components from fluctuations. Utilizing internal power regulation allows a module to operate consistently across a range of battery levels or power supply qualities. It filters out high-frequency noise generated by the host processor or switching regulators.
Voltage Stability
Low-dropout regulators or switching converters sit at the entry point of the module power rail. When internal power regulation is active, the radio frequency output power stays flat even as the input voltage drops toward the lower limit of the specification. This mechanism prevents frequency drifting and transmission errors during sudden current spikes.
Design Rule
Regulated power is a mandatory requirement for modular approval in several major jurisdictions. By including internal power regulation, the module manufacturer proves that the radio behavior is independent of the host power quality. This decoupling allows the module to carry its own FCC or RED certification into a variety of different host products.
Operational Boundary
Efficiency is a primary consideration for small enclosures. Because internal power regulation dissipates heat during the voltage conversion process, the system must account for this thermal rise. Excess heat can shorten the lifespan of flash memory or affect the oscillator frequency.
A designer calculates the worst-case power consumption to verify the thermal pad on the bottom of the module can transfer enough energy to the motherboard ground plane. If the input voltage is much higher than the internal operating voltage, the regulator must work harder and generate more heat.