PA84 APEX PRECISION POWER, PA84 Datasheet - Page 4

• Manufacturer Part Number: PA84
• Description: IC, OP-AMP, 75MHZ, 180V/µs, TO-3-8
• Manufacturer: APEX PRECISION POWER

Specifications of PA84

• Op Amp Type: Precision
• No. Of Amplifiers: 1
• Bandwidth: 75MHz
• Slew Rate: 180V/µs
• Supply Voltage Range: ± 15V To ± 150V
• Amplifier Case Style: TO-3
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PA84 • PA84A • PA84S
GENERAL
ations" which covers stability, supplies, heat sinking, mounting,
current limit, SOA interpretation, and specification interpretation.
Visit www.Cirrus.com for design tools that help automate tasks
such as calculations for stability, internal power dissipation,
current limit and heat sink selection. The "Application Notes"
and "Technical Seminar" sections contain a wealth of informa-
tion on specific types of applications. Package outlines, heat
sinks, mounting hardware and other accessories are located
in the "Packages and Accessories" section. Evaluation Kits
are available for most Apex Precision Power product models,
consult the "Evaluation Kit" section for details. For the most
current version of all Apex Precision Power product data sheets,
visit www.Cirrus.com.
SAFE OPERATING AREA (SOA)
amplifier has two output limitations:
1. The internal current limit which limits maximum available
2. The second breakdown effect, which occurs whenever the
given application, the direction and magnitude of the output
current should be calculated or measured and checked against
the SOA curves. This is simple for resistive loads but more
complex for reactive and EMF generating loads. However,
the following guidelines may save extensive analytical efforts:
1. The following capacitive and inductive loads are safe:
2. Short circuits to ground are safe with dual supplies up to
3. Short circuits to the supply rails are safe with total supply
4
Please read Application Note 1 "General Operating Consider-
The bipolar output stage of this high voltage operational
The SOA curves combine the effect of these limits. For a
output current.
simultaneous collector current and collector-emitter voltage
exceeds specified limits.
±150V or single supplies up to 150V.
voltages up to 150V (i.e. ±75V).
30
50
40
35
25
20
150
SUPPLY TO OUTPUT DIFFERENTIAL VOLTAGE (V)
150V
125V
100V
75V
±V
SAFE OPERATING AREA CURVES
S
170
200
C(MAX)
SOA
1.2µF
6.0µF
12µF
ALL
250
L(MAX)
.7H
25H
90H
ALL
300
P r o d u c t I n n o v a t i o n F r o m
OUTPUT PROTECTION
to protect these amplifiers against flyback (kickback) pulses
exceeding the supply voltages of the amplifier when driving
inductive loads. For component selection, these external diodes
must be very quick, such as ultra fast recovery diodes with
no more than 200 nanoseconds of reverse recovery time. Be
sure the diode voltage rating is greater than the total of both
supplies. The diode will turn on to divert the flyback energy
into the supply rails thus protecting the output transistors from
destruction due to reverse bias.
pulse must be absorbed by the power supply. As a result, a
transient will be superimposed on the supply voltage, the
magnitude of the transient being a function of its transient
impedance and current sinking capability. If the supply voltage
plus transient exceeds the maximum supply rating or if the AC
impedance of the supply is unknown, it is best to clamp the
output and the supply with a zener diode to absorb the transient.
STABILITY
than lower bandwidth Power Operational Amplifiers such as
the PA83 or PA08. To prevent oscillations, a reasonable phase
margin must be maintained by:
1. Selection of the proper phase compensation capacitor and
2. Keeping the external sumpoint stray capacitance to ground
3. Connecting the amplifier case to a local AC common thus
FIGURE 1. PROTECTIVE,
Two external diodes as shown in Figure 1, are required
A note of caution about the supply. The energy of the flyback
Due to its large bandwidth the PA84 is more likely to oscillate
resistor. Use the values given in the table under external
connections and interpolate if necessary. The phase margin
can be increased by using a large capacitor and a smaller
resistor than the slew rate optimized values listed in the
table. The compensation capacitor may be connected to
common (in lieu of +V
bypassed to common. Because the voltage at pin 8 is only a
few volts below the positive supply, this ground connection
requires the use of a high voltage capacitor.
at a minimum and the sumpoint load resistance (input and
feedback resistors in parallel) below 500Ω. Larger sumpoint
load resistance can be used with increased phase compen-
sation (see 1 above).
preventing it from acting as an antenna.
INDUCTIVE LOAD
S
) if the positive supply is properly
–V
+V
S
S
PA84U