Ampro Corporation 486E manual Power Requirements, Backup Battery, Cooling Requirements

Product Reference

Power Requirements

The Little Board/486e CPU operates on +5VDC (±5%). The ±9V RS-232 voltages are generated on board. The exact power requirement of the Little Board/486e CPU system depends on several factors such as:

!Amount of installed DRAM

!Number of installed byte-wide memory devices

!Peripheral connections

!MiniModule products (if installed)

!Other expansion boards attached to the PC/104 bus

For example: AT keyboards draw power from the motherboard, and there can be some loading from the serial and parallel ports. Consult the specifications in Chapter 3 for the basic power requirements of your model.

If a switching power supply is used it must regulate properly with the system load. Some switching power supplies do not regulate properly unless they are loaded to some minimum value. If this is the case, consult the manufacturer for information regarding additional loading or use another supply or another type of power source such as a linear supply, or batteries.

Backup Battery

With only the real-time clock drawing current, the backup battery on the Little Board/486e should last 10 years. If it supplies only the clock, replace the battery every 10 years as a routine maintenance procedure.

Cooling Requirements

Adequate airflow should be provided to maintain an ambient temperature at or below 70°C within the case. For Extended Temperature Qualified products, the temperature must remain at or below 85°C. Little Board/486e CPU uses a 486DX/System Logic Chip rated at 3.3V to minimize power drain. In addition a heat sink is provided for the CPU. The majority of the current draw and heat generated come from the:

!486 CPU

!DRAM

!video controller

!486DX/System Logic Chip

2–7