APEX PA19

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FEATURES
• VERY FAST SLEW RATE — 900 V/µs
• POWER MOS TECHNOLOGY — 4A peak rating
• LOW INTERNAL LOSSES — 2V at 2A
• PROTECTED OUTPUT STAGE — Thermal Shutoff
• WIDE SUPPLY RANGE — ±15V TO ±40V
APPLICATIONS
8-PIN TO-3
PACKAGE STYLE CE
• VIDEO DISTRIBUTION AND AMPLIFICATION
• HIGH SPEED DEFLECTION CIRCUITS
• POWER TRANSDUCERS UP TO 5 MHz
• MODULATION OF RF POWER STAGES
• POWER LED OR LASER DIODE EXCITATION
TYPICAL APPLICATION
DESCRIPTION
The PA19 is a high voltage, high current operational amplifier optimized to drive a variety of loads from DC through the
video frequency range. Excellent input accuracy is achieved
with a dual monolithic FET input transistor which is cascoded
by two high voltage transistors to provide outstanding common
mode characteristics. All internal current and voltage levels
are referenced to a zener diode biased on by a current source.
As a result, the PA19 exhibits superior DC and AC stability
over a wide supply and temperature range.
High speed and freedom from second breakdown is assured
by a complementary power MOS output stage. For optimum
linearity, especially at low levels, the power MOS transistors
are biased in a class A/B mode. Thermal shutoff provides
full protection against overheating and limits the heatsink
requirements to dissipate the internal power losses under
normal operating conditions. A built-in current limit of 0.5A
can be increased with the addition of two external resistors.
Transient inductive load kickback protection is provided by
two internal clamping diodes. External phase compensation
allows the user maximum flexibility in obtaining the optimum
slew rate and gain bandwidth product at all gain settings. A
heatsink of proper rating is recommended.
This hybrid circuit utilizes thick film (cermet) resistors, ceramic
capacitors, and silicon semiconductor chips to maximize reliability, minimize size, and give top performance. Ultrasonically
bonded aluminum wires provide reliable interconnections at all
operating temperatures. The 8-pin TO-3 package is hermetically sealed and electrically isolated. The use of compressible
thermal washers and/or improper mounting torque will void
the product warranty. Please see “General Operating Considerations”.
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TYPICAL
APPLICATION
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This fast power driver utilizes the 900V/µs slew rate of the
PA19 and provides a unique interface with a current output
DAC. By using the DAC’s internal 1KΩ feedback resistor,
temperature drift errors are minimized, since the temperature
drift coefficients of the internal current source and the internal
feedback resistor of the DAC are closely matched. Gain of
VOUT to IIN is –6.5/mA. The DAC’s internal 1K resistor together
with the external 500Ω and 110Ω form a “tee network” in the
feedback path around the PA19. This effective resistance
equals 6.5KΩ . Therefore the entire circuit can be modeled as
6.5KΩ feedback resistor from output to inverting input and a
5mA current source into the inverting input of the PA19. Now
we see the familiar current to voltage conversion for a DAC
where VOUT = –IIN x RFEEDBACK.
EQUIVALENT SCHEMATIC
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EXTERNAL CONNECTIONS
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APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
1
PA19 • PA19A
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +VS to –VS
OUTPUT CURRENT, within SOA
POWER DISSIPATION, internal
INPUT VOLTAGE, differential
INPUT VOLTAGE, common mode
TEMPERATURE, pin solder — 10 sec
TEMPERATURE, junction1
TEMPERATURE, storage
OPERATING TEMPERATURE RANGE, case
SPECIFICATIONS
PARAMETER
TEST CONDITIONS 2
INPUT
OFFSET VOLTAGE, initial
OFFSET VOLTAGE, vs. temperature
OFFSET VOLTAGE, vs. supply
OFFSET VOLTAGE, vs. power
BIAS CURRENT, initial
BIAS CURRENT, vs. supply
OFFSET CURRENT, initial
INPUT IMPEDANCE, DC
INPUT CAPACITANCE
COMMON MODE VOLTAGE RANGE3
COMMON MODE REJECTION, DC
TC = 25°C
TC = 25°C to +85°C
TC = 25°C
TC = 25°C to +85°C
TC = 25°C
TC = 25°C
TC = 25°C
TC = 25°C
TC = 25°C
TC = 25°C to +85°C
TC = 25°C to +85°C, VCM = ±20V
GAIN
OPEN LOOP GAIN at 10Hz
OPEN LOOP GAIN at 10Hz
GAIN BANDWIDTH PRODUCT at 1MHz
POWER BANDWIDTH, AV = 100
POWER BANDWIDTH, AV = 1
TC = 25°C, RL = 1KΩ
TC = 25°C, RL = 15Ω
TC = 25°C, CC = 2.2pF
TC = 25°C, CC = 2.2pF
TC = 25°C, CC = 330pF
OUTPUT
VOLTAGE SWING3
VOLTAGE SWING3
VOLTAGE SWING3
SETTLING TIME to .1%
SETTLING TIME to .01%
SLEW RATE, AV = 100
SLEW RATE, AV = 10
TC = 25°C, IO = 4A
TC = 25°C to +85°C, IO = 2A
TC = 25°C to +85°C, IO = 78mA
TC = 25°C, 2V step
TC = 25°C, 2V step
TC = 25°C, CC = 2.2pF
TC = 25°C, CC = 22pF
POWER SUPPLY
VOLTAGE
CURRENT, quiescent
TC = 25°C to +85°C
TC = 25°C
THERMAL
RESISTANCE, AC, junction to case4
RESISTANCE, DC, junction to case
RESISTANCE, junction to air
TEMPERATURE RANGE, case
TC = 25°C to +85°C, F > 60Hz
TC = 25°C to +85°C, F < 60Hz
TC = 25°C to +85°C
Meets full range specifications
MIN
PA19
TYP
±.5
10
10
20
10
.01
5
1011
6
±VS–15 ±VS–12
70
104
74
±VS–5
±VS–3
±VS–1
600
±15
–25
80V
5A
78W
40V
±VS
300°C
150°C
–65 to 155°C
–55 to 125°C
MAX
MIN
PA19A
TYP
*
*
±.25
5
*
*
5
*
3
*
*
*
*
±3
30
200
100
111
78
100
3.5
250
*
±VS–4
±VS–2
±VS–.5
.3
1.2
900
650
*
*
*
800
±35
100
±40
120
1.2
1.6
30
1.3
1.8
+85
*
*
MAX
UNITS
±.5
10
mV
µV/°C
µV/V
µV/W
pA
pA/V
pA
MΩ
pF
V
dB
50
25
*
*
*
*
*
dB
dB
MHz
MHz
kHz
*
*
*
*
*
*
*
V
V
V
µs
µs
V/µs
V/µs
*
*
*
*
V
mA
*
*
*
*
*
°C/W
°C/W
°C/W
°C
*
NOTES: * The specification of PA19A is identical to the specification for PA19 in applicable column to the left.
1. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF.
2. The power supply voltage for all specifications is the TYP rating unless noted as a test condition.
3. +VS and –VS denote the positive and negative supply rail respectively. Total VS is measured from +VS to –VS.
4. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
CAUTION
The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or
subject to temperatures in excess of 850°C to avoid generating toxic fumes.
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
2
PA19 • PA19A
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TYPICAL PERFORMANCE
GRAPHS
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APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
3
OPERATING
CONSIDERATIONS
PA19 • PA19A
Please read Application Note 1 "General Operating Considerations" which covers stability, supplies, heat sinking,
mounting, current limit, SOA interpretation, and specification
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
Q2 (and Q25) limit output current by turning on and removing gate drive when voltage on pin 2 (pin 7) exceeds .65V differential from the positive (negative) supply rail. With internal
resistors equal to 1.2Ω, current limits are approximately 0.5A
with no external current limit resistors. With the addition of
external resistors current limit will be:
.65V
ILIM =
+.54A
RCL
To determine values of external current limit resistors:
.65V
RCL =
ICL - .54A
PHASE COMPENSATION
At low gain settings, an external compensation capacitor is
required to insure stability. In addition to the resistive feedback
network, roll off or integrating capacitors must also be considered when determining gain settings. The capacitance values
listed in the external connection diagram, along with good
high frequency layout practice, will insure stability. Interpolate
values for intermediate gain settings.
SAFE OPERATING AREA (SOA)
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The MOSFET output stage of this power operational amplifier has two distinct limitations:
1. The current handling capability of the MOSFET geometry
and the wire bonds.
2. The junction temperature of the output MOSFETs.
The SOA curves combine the effect of these limits and allow
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for internal thermal delays. For a 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. The following guidelines may save
extensive analytical efforts:
1. Capacitive and inductive loads up to the following maximums
are safe:
±VS
CAPACITIVE LOAD
INDUCTIVE LOAD
40V
30V
20V
15V
.1µF
500µF
2500µF
∞
11mH
24mH
75mH
100mH
2. Safe short circuit combinations of voltage and current are
limited to a power level of 100W.
3. The output stage is protected against transient flyback.
However, for protection against sustained, high energy
flyback, external fast-recovery diodes should be used.
SUPPLY CURRENT
The PA19 features a class A/B driver stage to charge and
discharge gate capacitance of Q7 and Q19. As these currents
approach 0.5A, the savings of quiescent current over that of a
class A driver stage is considerable. However, supply current
drawn by the PA19, even with no load, varies with slew rate
of the output signal as shown below.
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GENERAL
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OUTPUT LEADS
Keep the output leads as short as possible. In the video
frequency range, even a few inches of wire have significant
inductances, raising the interconnection impedance and limiting the output current slew rate. Furthermore, the skin effect
increases the resistance of heavy wires at high frequencies.
Multistrand Litz Wire is recommended to carry large video
currents with low losses.
THERMAL SHUTDOWN
The thermal protection circuit shuts off the amplifier when
the substrate temperature exceeds approximately 150°C. This
allows the heatsink selection to be based on normal operating
conditions while protecting the amplifier against excessive
junction temperature during temporary fault conditions.
Thermal protection is a fairly slow-acting circuit and therefore
does not protect the amplifier against transient SOA violations
(areas outside of the steady state boundary). It is designed to
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
4
PA19 • PA19A
OPERATING
CONSIDERATIONS
protect against short-term fault conditions that result in high
power dissipation within the amplifier. If the conditions that
cause thermal shutdown are not removed, the amplifier will
oscillate in and out of shutdown. This will result in high peak
power stresses, destroy signal integrity, and reduce the reliability of the device.
STABILITY
Due to its large bandwidth, the PA19 is more likely to oscillate than lower bandwidth power operational amplifiers. To
prevent oscillations a reasonable phrase margin must be
maintained by:
1. Selection of the proper phase compensation capacitor.
Use the values given in the table under external connections and interpolate if necessary. The phase margin can
be increased by using a larger capacitor at the expense of
slew rate. Total physical length (pins of the PA19, capacitor leads plus printed circuit traces) should be limited to a
maximum of 3.5 inches.
2. Keep the external sumpoint stray capacitance to ground
at a minimum and the sumpoint load resistance (input and
feedback resistors in parallel) below 500Ω. Larger sumpoint
load resistances can be used with increased phase compensation and/or by bypassing the feedback resistor.
3. Connect the case to any AC ground potential.
This data
sheet has been carefullyCORPORATION
checked and is believed
to be reliable,
however,
no responsibility
is assumed
for possible• inaccuracies
or omissions.
All specifications
subject to change without notice.
APEX
MICROTECHNOLOGY
• TELEPHONE
(520)
690-8600
• FAX (520)
888-3329
ORDERS (520)
690-8601
• EMAILare
prodlit@apexmicrotech.com
PA19U REV H FEBRUARY 1998
© 1998 Apex Microtechnology Corp.
5