The power consumption of QSFP28 (Quad Small Form-Factor Pluggable 28) transceiver modules can vary depending on the specific type of optics and features they support. QSFP28 modules are used for high-speed data transmission in data centers and telecommunications networks, typically for 100 Gigabit Ethernet (100GbE) applications and beyond.

As of my last knowledge update in January 2022, the power consumption for QSFP28 modules generally falls within the range of approximately 3.5 watts to 4.5 watts. However, it's important to note that this is a generalization, and the actual power consumption can vary based on the specific type of module, optics, and additional functionalities supported by the transceiver.

When selecting or deploying QSFP28 modules, it's crucial to refer to the datasheet or technical specifications provided by the module's manufacturer. The datasheet will provide detailed information on the power requirements, including the maximum power consumption under various operating conditions.

Advancements in technology and the introduction of new transceiver types may result in modules with different power profiles. Therefore, for the most accurate and up-to-date information on the power limit for a specific QSFP28 module, it's recommended to consult the manufacturer's documentation or reach out to the manufacturer directly.