PA46 Apex Microtechnology, PA46 Datasheet - Page 4

• Manufacturer Part Number: PA46
• Description: HIGH VOLTAGE POWER OPERATIONAL AMPLIFIER
• Manufacturer: Apex Microtechnology

PA46
GENERAL
erations" which covers stability, supplies, heat sinking, mount-
ing, current limit, SOA interpretation, and specification inter-
pretation. Visit www.apexmicrotech.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 information 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 product
models, consult the "Evaluation Kit" section for details. For the
most current version of all Apex product data sheets, visit
www.apexmicrotech.com.
CURRENT LIMIT
amplifiers current sense circuit by way of an internal tie to the
output drive (pin 5) and an external current sense line (pin 10).
A sense resistor R
current flowing from output drive.
typical value of output resistance and affects the total possible
swing since it carries the load current. The swing reduction, V
can be established V
INPUT PROTECTION
voltages up to the supply rails, differential voltages up to 16
volts and static discharge. Differential voltages exceeding 16
volts will be clipped by the protection circuitry. However, if
more than a few milliamps of current is available from the input
drive source, the protection circuitry could be destroyed. The
protection circuitry includes 300 ohm current limiting resistors
at each input. This security may be insufficient for severe
overdrive of the input. Adding external resistors to the applica-
tion which limits severe input overdrive current to 1mA, will
prevent damage.
STABILITY
for unity gain to be stable with capacitive loads of at least 10nF.
However, the low pass circuit created by the sum-point (–in)
capacitance and the feedback network may add phase shift
and cause instabilities. As a rule, the sum-point load resis-
tance (input and feedback resistors in parallel) should be 1k
ohm or less. Alternatively, use a bypass capacitor across the
feedback resistor. The time constant of the feedback resistor
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: [phone]
This data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifications are subject to change without notice.
Please read Application Note 1 "General Operating Consid-
Current limiting is achieved by developing 0.83V on the
with a maximum practical value of 16 . R
The PA46 inputs are protected against common mode
The PA46 has sufficient phase margin when compensated
R
CL
I
CL
CL
=
=
is used to relate this sense voltage to a
R
= I
0.83 – 0.05 * I
OUT
R
CL
*
0.83
+ 0.05
I
R
CL
CL
.
CL
PA46U REV. C FEBRUARY 2001 © 2001 Apex Microtechnology Corp.
CL
is added to the
R
and bypass capacitor combination should match the time
constant of the sum-point resistance and sum-point capaci-
tance.
be tailored to the application. The compensation network C
R
avoid noise coupling to these high impedance nodes.
SAFE OPERATING AREA (SOA)
fier has limitations from its channel temperature.
However, for protection against sustained, high energy flyback,
external fast-recovery diodes should be used.
SHUTDOWN
90 A is pulled from pin 3 to any voltage at least 3 volts less than
+V
BIAS CLASS OPTION FOR LOWER
QUIESCENT CURRENT
(C
This results in lower quiescent current, but also class C
biasing of the output stage.
C
The PA46 is externally compensated and performance can
The MOSFET output stage of this power operational ampli-
NOTE: The output is protected against transient flyback.
Pin 3 (SHDN) will shut off the output stage when at least
Normally pin 7 (I
CI
s
6.0
4.0
2.0
1.0
0.8
0.6
0.4
0.2
0.1
must be mounted closely to the amplifier pins 8 and 9 to
(ground, for example).
) the quiescent current in the output stage is disabled.
4
PULSE CURVES @ 10% DUTY CYCLE MAX
SUPPLY TO OUTPUT DIFFERENTIAL, V
6
8 10
SAFE OPERATING AREA
Q
) is left open. When pin 7 is tied to pin 8
20
40
60
CONSIDERATIONS
100
S
OPERATING
-V
O
(V)
200
C
-