The voltage specification for SFP+ (Small Form-Factor Pluggable Plus) modules depends on the specific module and its design. Generally, SFP+ modules operate with a supply voltage in the range of 3.1 to 3.5 volts.

Here are some key points regarding the voltage of SFP+ modules:

1. Supply Voltage Range: The typical supply voltage range for SFP+ modules is between 3.1V and 3.5V. This voltage is used to power the electronics and components within the SFP+ module.

2. Power Consumption: SFP+ modules are designed to be power-efficient, and the supply voltage contributes to the overall power consumption of the module. Lower power consumption is often a key consideration in data center and networking environments.

3. Compatibility: When using SFP+ modules, it's crucial to ensure that the host equipment (such as switches or routers) provides the correct voltage within the specified range to power the modules correctly.

4. Manufacturer Specifications: The exact voltage specifications can vary between different SFP+ module manufacturers and models. Therefore, it's essential to refer to the datasheet or technical specifications provided by the manufacturer for precise details on voltage requirements.

Always check the documentation and specifications of the specific SFP+ modules you are using to ensure proper compatibility and operation within the specified voltage range. Using incorrect voltages can lead to unreliable operation and potential damage to the modules or the connected equipment.