PAD117 Thaler Corporation, PAD117 Datasheet - Page 4

• Manufacturer Part Number: PAD117
• Description: Rail To Rail Operational Amplifier
• Manufacturer: Thaler Corporation

RAIL TO RAIL OPERATIONAL AMPLIFIER
means that it works equally well with the input pins biased to
either supply rail or at any voltage in between. The most
common application utilizing this function is the single supply
voltage amplifier where the +IN pin and the –Vs supply pin are
grounded.
either supply voltage rail. As the load current increases the
maximum output swing is reduced, but at 15A output the swing
from the positive supply rail is less than 1V and less than 1.5V
from the negative supply rail. This does not include any voltage
drop due to the sensing voltage required for the current limit
circuit to operate.
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
of the current limit sense resistor.
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.
lower sense voltage may be desired. In this case the PAD117
can be operated with the PAD121 current limit accessory
module. See Figure 3 in the applications section and the
PAD121 data sheet for more details.
The PAD117 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 four corners of the amplifier. Since the male threaded ends
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The PAD117 is a rail to rail operational amplifier. This
With no load the output voltage of the PAD117 can swing to
The current limiting function of the PAD117 is a versatile
In addition, the sense voltage has a temperature coefficient
In some applications better current limiting protection and a
The amplifier is supplied with four 4-40 M/F hex spacers at
L
is the value of the limited current and R
MOUNTING THE AMPLIFIER
COMMON MODE RANGE
CURRENT LIMIT
OUTPUT SWING
COOLING FAN
–
I
L
2.2mV/
=
. 0
65
R
S
V
o
C. The fold-over function
S
is the value
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. 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.
relative to ground and proportional to the temperature in
degrees C. The slope is approximately -10.82mV/
output voltage follows the equation:
Where V is the TMP output voltage and T is the substrate
temperature in degrees C.
capacitive loading and pickup from the output of the
amplifier. When monitoring TMP filter the voltage as
shown in Figure 4. See Applications Circuits.
the output transistors when the substrate temperature
reaches 110
output is 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 8 is low.
When pin 8 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 8 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.
The PAD117 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.
An analog output voltage is provided (pin 6, TMP)
This high impedance output circuit is susceptible to
The temperature monitoring circuit automatically turns off
When pin 8 ( SD ) is taken low (ground) the output stage is
TEMPERATURE REPORTING
o
PHASE COMPENSATION
EXTERNAL SHUTDOWN
THERMAL SHUTDOWN
C. When the substrate cools down 10
T = (2.127 ─ V) (92.42)
OPERATING CONSIDERATIONS
C
, is connected
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PAD117
o
C. The
o
C the
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