Precision Analog Systems (954) 587-0668 / www.precisionanalog.com
I. INTRODUCTION
GENERAL DESCRIPTION
The PAS 9406/AMP provides twenty four channels of voltage amplification on
a 1U x 19” rack mountable panel. Two PCBs with 12 channels each are
mounted on the panel. Different types of amplifier boards can be mounted in
the different locations on the panel to tailor the amplifier to your application.
The integrated circuit amplifier used in this design is the OPA551 by Texas
Instruments. This amplifier can use power supply voltages from +/- 4 Volts to
+/- 30 Volts. The output current rating is 200 mAmps continuous. These
amplifiers can be used to significantly boost the output voltage and current
drive capability of a standard analog output card.
The board provides an offset voltage that can be connected to specific
channels to give them a different voltage transfer characteristic. In one case a
speed sensor was being simulated with the amplifier. When 0.0 Volts was
input to the card, the amplifier would output 1.4 Volts. When 3.8 Volts was
input to the card, the amplifier would output 2.8 Volts. This type of transfer
function is only possible by adjusting both the gain and offset of the amplifier
circuit. Not all of the amplifier circuits need to be connected to the offset
voltage. Jumpers are used to either select the offset voltage or 0.0 volts of
offset. Custom versions of the card are available, so the customer can select
any gain and offset required for each channel.
The amplifiers on this board use solder on heat sinks to increase the power
dissipation. The OPA551 provides thermal shutdown and output current
limiting to fully protect the amplifier. Each application that involves high
current and voltage needs to be evaluated to make sure the amplifiers power
dissipation is not exceeded. See the power dissipation calculation section
near the end of this manual.
