PAD128 Thaler Corporation, PAD128 Datasheet - Page 4

• Manufacturer Part Number: PAD128
• Description: High Power Operational Amplifier
• Manufacturer: Thaler Corporation

HIGH POWER OPERATIONAL AMPLIFIER
The PAD128 relies on its fan for proper cooling of the
amplifier. Make sure that air flow to the fan and away from the
heat sink remains unobstructed. The cooling method used is
impingement cooling, which means that cool air is pushed into
the heat sink and warm air is exhausted through the spaces
between the heat sink fins.
The amplifier is supplied with four 4-40 M/F hex spacers at the
four corner of the amplifier. Since the male threaded ends of
the spacers extend beyond the amplifier pins the spacers
provide a convenient alignment tool to guide the insertion of
the amplifier pins into the circuit board. Once the amplifier is
seated secure the module with the provided 4-40 nuts and
torque to 4.7 in oz [3.8 N cm] max. See “Dimensional
Information” for a detailed drawing.
An analog output voltage is provided (pin 24, TMP) relative to
ground (pin 25) and proportional to the temperature in degrees
C. The slope is approximately -10.82mV/
voltage follows the equation:
Where V is the TMP output voltage and T is the substrate
temperature in degrees C.
This high impedance output circuit is susceptible to capacitive
loading and pickup from the output of the amplifier. When
monitoring TMP filter the voltage as shown in Figure 3. See
Applications Circuits.
The temperature monitoring circuit automatically turns off the
output transistors when the substrate temperature reaches
110
enabled once again. The thermal shutdown feature is activated
either by amplifier overloads or a failure of the fan circuit.
When pin 26 ( SD ) is taken low (ground) the output stage is
turned “off” and remains “off” as long as pin 26 is low. When
pin 26 is monitored with a high impedance circuit it also
functions as a flag, reporting when the amplifier is shut down.
A “high” (+5V) on pin 26 indicates the temperature is in the
normal range. A “low” (ground) indicates a shutdown
condition. See Application Circuits for details on how to
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C. When the substrate cools down 10
TEMPERATURE REPORTING
MOUNTING THE AMPLIFIER
EXTERNAL SHUTDOWN
THERMAL SHUTDOWN
T = (2.127 ─ V) (92.42)
COOLING FAN
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C the output is
C. The output
implement an external shutdown circuit and how to monitor
the shutdown status.
The PAD128 does not have a current limiting circuit built
in. However, a Current Limit Accessory Module, model
PAD121, is available if the current limiting function is
needed for the application. See the PAD121 data sheet and
Application Circuits for a typical connection diagram.
Rail to rail input and output operation is implemented by
adding two additional external power supplies to the
amplifier circuit. One power supply is set to be +Vs+10V
and is connected to the +Vcc pin. The other additional
power supply is set to be –Vs-10V and is connected to the
–Vcc pin. See Figure 4 in Application Circuits. An
accessory module, model PAD130, provides a convenient
compact power supply for this purpose. See the data sheet
for the PAD130. See also application note AN10, The Rail
to Rail Advantage.
The PAD128 must be phase compensated to operate
correctly. The compensation capacitor, C
between pins 4 and 5. On page 6, Typical Performance
Graphs, you will find plots for small signal response and
phase response using compensation values of 100pF and
470pF. The compensation capacitor must be an NPO type
capacitor rated for the full supply voltage (100V). On page
2, under Amplifier Pinout and Connections, a table gives
recommended compensation capacitance values for various
gains and the resulting slew rate for each capacitor value.
RAIL TO RAIL OPERATION
PHASE COMPENSATION
CURRENT LIMIT
OPERATING CONSIDERATIONS
C
, is connected
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PAD128
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