UG:301

vicorpower.com

Applications Engineering: 800 927.9474

Page 2

The PI31xx operates over a wide range input, delivering 50 W or 60 W output power

depending on the individual model number. The PI31xx Series is available in a space

saving surface mountable 0.87” x 0.65” x 0.265” Power –System –in – a – Package (PSiP),

achieving ~50% space reduction versus alternative solutions.

The switching frequency of 900kHz allows for small input and output filter components

which further reduces the total size and cost of the overall system solution. The output

voltage is sensed and fed back to the internal controller using a proprietary isolated

magnetic feedback scheme which allows for high bandwidth and good common mode

noise immunity.

The PI31xx Series requires no external feedback compensation and offers a total

solution with a minimum number of external components. A rich feature set is

offered, including + 10%, -20% output voltage trim capability (depending on the model

number), remote enable, over-voltage protection, adjustable soft-start, over-current

protection with auto-restart to protect against both short circuit and overload and over

and under input voltage lockout. A unique temperature monitor and protection circuit

is included that provides an analog voltage proportional to the internal die temperature,

as well as over temperature shutdown, restart and over temperature fault alarm signal.

Board Connections

1. Connect Test Equipment

The negative terminal should be wired to –IN and the positive terminal should

connect to the positive terminal of the DMM wired as a DC Ammeter. Be sure

that the proper sized wires are used to allow minimum voltage drop for a

maximum input current of up to 4 A. Use ring lugs mated to the included

fasteners on the evaluation board. If your input power supply has remote sense

capability, it can be wired to the INN and INP test points if desired. Connect the

positive terminal of the DMM to the +IN lug on the evaluation board.

INP respectively.

both primary and secondary signals at the same time. If you do not have an

isolated differential amplifier, it is important to note that simultaneous

measurement of both primary and secondary referenced signals using an

oscilloscope with a grounded chassis is not recommended, as it will short circuit

the primary to secondary isolation barrier. Floating the oscilloscope is also not

recommended due to the large capacitance introduced by this long standing

practice. The best practice is to use an isolated differential amplifier or use an

oscilloscope with isolated channels. That is, the input returns are isolated from

each other and earth ground.

d. Connect the output DC DMM to the test points OUTN and OUTP. These test

points are done in a Kelvin type manner so that they have no high current

flowing in them.

e. Connect the DC Load to the output lugs OUT+ and OUT-. It is critical for this

connection to be low inductance.