PAD112 Thaler Corporation, PAD112 Datasheet - Page 4

• Manufacturer Part Number: PAD112
• Description: High Voltage Operational Amplifier
• Manufacturer: Thaler Corporation

HIGH VOLTAGE OPERATIONAL AMPLIFIER
When developing an application circuit it is wise to begin with
power supply voltages as low as possible while checking for
circuit functionality. Increase supply voltages slowly as
confidence in the application circuit increases. Always use a
“hands off” method whereby test equipment probes are
attached only when power is off.
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.
circuit that can be used to implement a four-wire current limit
configuration or, in combination with some external
components can be configured to implement a fold-over current
limit circuit. The four-wire current limit configuration insures
that parasitic resistance in the output line, Rp, does not affect
the programmed current limit setting. See Figure 1. The sense
voltage for current limit is 0.65V. Thus:
Where I
value of the current limit sense resistor.
In addition, the sense voltage has a temperature coefficient
approximately equal to
reduces the available current as the voltage across the output
transistors increases to help insure that the SOA of the output
transistors is not exceeded. Refer to Application Circuits for
details on how to connect the current limit circuitry to
implement either a four-wire current limit or current limit with
a fold-over function. The PAD112 is also compatible with the
precision PAD123 Current Limit Accessory Module. See
Figure 4 and the datasheet for the PAD123 for further details.
the four corners of the amplifier. Once the amplifier is seated,
secure the module with the provided
4.7 in oz [3.8 N cm] max. See “Dimensional Information” for
a detailed drawing. It is recommended that the heat sink be
grounded to the system ground. This can easily be done by
providing a grounded circuit board pad around any of the holes
for the mounting studs.
Thaler Corp 2015 N Forbes Blvd Tucson AZ 85745 USA Phone [phone] or [phone] Fax [phone] Web Site:
The operating voltages of the PAD112 are potentially deadly.
The PAD112 relies on its fan for proper cooling of the
The current limiting function of the PAD112 is a versatile
The amplifier is supplied with four 4-40 M/F hex spacers at
L
MOUNTING THE AMPLIFIER
is the value of the limited current and R
CURRENT LIMIT
SAFETY FIRST
COOLING FAN
–
I
L
2.2mV/
=
. 0
65
R
S
V
o
C. The fold-over function
4-40 nuts and torque to
S
is the
to ground 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 amplifier when the substrate temperature reaches 110
When the substrate cools down 10
enabled once again. The thermal shutdown feature is
activated either by amplifier overloads or a failure of the fan
circuit.
turned “off” and remains “off” as long as pin 7 is low.
When pin 7 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 7 indicates the temperature is
in the normal range. A “low” (ground) indicates a shutdown
condition. See Application Circuits for details on how to
implement an external shutdown circuit and how to monitor
the shutdown status when temperature is in the normal
range. A “low” (ground) indicates a shutdown condition.
See Application Circuits for details on how to implement
an external shutdown circuit and how to monitor the
shutdown status.
compensation capacitor, C
and 5. The compensation capacitor must be an NPO type
capacitor rated for the full supply voltage (150V). On page
2, under Amplifier Pinout and Connections, you will find a
table that gives recommended compensation capacitance
value for various circuit gains and the resulting slew rate for
each capacitor value. Consult also the small signal response
and phase response plots for the selected compensation
value in the Typical Performance Graphs section. A
compensation
recommended.
An analog output voltage is provided (pin 6, TMP) relative
The temperature monitoring circuit automatically turns off
When pin 7 ( SD ) is taken low (ground) the amplifier is
The PAD112 must be phase compensated. The
TEMPERATURE REPORTING
PHASE COMPENSATION
EXTERNAL SHUTDOWN
THERMAL SHUTDOWN
capacitor
T = (2.127 ─ V) (92.42)
OPERATING CONSIDERATIONS
C
, is connected between pins 4
less
than
o
C the amplifier is
100pF
o
C. The output
www.Thaler.com
is
PAD112
o
not
C.
4