MP39 Apex Microtechnology Corporation, MP39 Datasheet - Page 4

• Manufacturer Part Number: MP39
• Description: Power Operational Amplifiers
• Manufacturer: Apex Microtechnology Corporation

GENERAL
Considerations" which covers stability, supplies, heat sinking,
mounting, current limit, SOA interpretation, and specifi cation
interpretation. Visit www.apexmicrotech.com for design tools
that help automate tasks such as calculations for stability,
internal power dissipation, current limit; heat sink selection;
Apex’s complete Application Notes library; Technical Seminar
Workbook; and Evaluation Kits.
CURRENT LIMIT
directly across the current limit sense resistor. For the current
limit to work correctly pin 24 must be connected to the
amplifi er output side and pin 23 connected to the load
side of the current limit resistor, R
1. This connection will bypass any parasitic resistances,
Rp, formed by sockets and solder joints as well as internal
amplifi er losses. The current limiting resistor may not be
placed anywhere in the output circuit except where shown
in Figure 1.
as follows:
BOOST OPERATION
are operated at higher supply voltages than the amplifi er's
high current output stage. +V
18-20) are connected to the high current output stage. An
additional 10V on the V
signal stages to drive the output transistors into saturation and
improve the output voltage swing for extra effi cient operation
when required. When close swing to the supply rails is not
required the +V
well as the –V
not be at a voltage lower than the V
This data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifi cations are subject to change without notice.
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4
MP39
Please read Application Note 1 "General Operating
The two current limit sense lines are to be connected
The value of the current limit resistor can be calculated
With the V
FIGURE 1. CURRENT LIMIT
INPUT
R i
B
feature the small signal stages of the amplifi er
B
B
and –V
and +V
30
29
MP39
23
B
S
S
pins is suffi cient to allow the small
pins. The boost voltage pins must
pins must be strapped together as
R
24
CL
S
= .7
(pins 12-14) and –V
15–17
I
LIMIT
S
CL
pins.
R
, as shown in Figure
f
MP39U REV. D OCTOBER 2002 © 2002 Apex Microtechnology Corp .
R
P
R
CL
S
R
(pins
L
BYPASSING
proper operation. Bypass the ±Vs pins with a aluminum
electrolytic capacitor with a value of at least 10µF per amp of
expected output current. In addition a .47µF to 1µF ceramic
capacitor should be placed in parallel with each aluminum
electrolytic capacitor. Both of these capacitors have to be
placed as close to the power supply pins as physically
possible. If not connected to the Vs pins (See BOOST
OPERATION) the V
.47µF to 1µF ceramic capacitor.
USING THE Iq PIN FUNCTION
AB biasing current from the output stage. Typically this would
remove 1-4 mA of quiescent current. The resulting decrease
in quiescent power dissipation may be important in some
applications. Note that implementing this option will raise the
output impedance of the amplifi er and increase crossover
distortion as well.
COMPENSATION
connected to pins 4 and 6. Unity gain stability can be achieved
at any compensation capacitance greater than 470 pF with at
least 60 degrees of phase margin. At higher gains more phase
shift can be tolerated in most designs and the compensation
capacitance can accordingly be reduced, resulting in higher
bandwidth and slew rate.
APPLICATION REFERENCES
following application notes.
Proper bypassing of the power supply pins is crucial for
Pin 25 (Iq) can be tied to pin 6 (Cc1) to eliminate the class
The external compensation components C
For additional technical information please refer to the
AN 1 General Operating Considerations
AN 11 Thermal Techniques
AN 38 Loop Stability with Reactive Loads
B
pins should also be bypassed with a
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
C
and R
C
are