Overview
Designed for harsh environment applications, the Aitech P221 is a versatile and reliable 6U VME power
supply providing VME systems with an exceptionally wide input voltage range and all standard VME
outputs and assures excellent load and line regulation.

The P221 input power voltage can vary from 16 Vdc to 36 Vdc, with a drop to 14 Vdc for up to 45 seconds,
and fully complies MIL STD 704A and D for 28 Vdc operation. For ultimate EMI reduction, an input line
filter is used to reduce the input reflected ripple.

The power supply asserts four VME 64X compliant voltages, each featuring an extended holdup time of
50 ms. The four outputs are provided by three DC-to-DC converters, with a total power rating of up to 175 W, and feature a minimum of 500 V isolation from input to output, thus eliminating any possibility of ground loops.

All outputs are individually protected against short-circuit and overvoltage. The power supply asserts all
three VME 64x compliant control signals, namely SYSRST, SYSFAIL and ACFAIL. The 5 Vdc output
carries sense lines for remote sensing.

The power supply provides temperature measurements and alarms, as well as DC fan output controlled by
temperature. In addition the P221 is equipped with a sophisticated BIT logic that monitors inputs and
outputs, the temperatures, the fan status, and provides the VME and BIT status signals.

In addition, the P221 features four visible LEDs to show proper output voltages and an external ON/OFF
signal for remote shutdown.