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1
FEATURES
VERY FAST SLEW RATE -- 900 V/s
POWER MOS TECHNOLOGY -- 4A peak rating
LOW INTERNAL LOSSES -- 2V at 2A
PROTECTED OUTPUT STAGE -- Thermal Shutoff
WIDE SUPPLY RANGE -- 15V TO 40V
APPLICATIONS
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
DESCRIPTION
The PA19 is a high voltage, high current operational ampli-
fier 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 reli-
ability, minimize size, and give top performance. Ultrasonically
bonded aluminum wires provide reliable interconnections at all
operating temperatures. The 8-pin TO-3 package is hermeti-
cally sealed and electrically isolated. The use of compressible
thermal washers and/or improper mounting torque will void
the product warranty. Please see "General Operating Con-
siderations".
TYPICAL APPLICATION
This fast power driver utilizes the 900V/s slew rate of the
PA19 and provides a unique interface with a current output
DAC. By using the DAC's internal 1K 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
V
OUT
to I
IN
is 6.5/mA. The DAC's internal 1K resistor together
with the external 500 and 110 form a "tee network" in the
feedback path around the PA19. This effective resistance
equals 6.5K . Therefore the entire circuit can be modeled as
6.5K 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 V
OUT
= I
IN
x R
FEEDBACK
.
EQUIVALENT SCHEMATIC
EXTERNAL CONNECTIONS
TYPICAL
APPLICATION
8-PIN TO-3
PACKAGE STYLE CE
APEX MICROTECHNOLOGY CORPORATION 5980 NORTH SHANNON ROAD TUCSON, ARIZONA 85741 USA APPLICATIONS HOTLINE: 1 (800) 546-2739
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ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +V
S
to V
S
80V
OUTPUT CURRENT, within SOA
5A
POWER DISSIPATION, internal
78W
INPUT VOLTAGE, differential
40V
INPUT VOLTAGE, common mode
V
S
TEMPERATURE, pin solder -- 10 sec
300C
TEMPERATURE, junction
1
150C
TEMPERATURE, storage
65 to 155C
OPERATING TEMPERATURE RANGE, case
55 to 125C
PA19
PA19A
PARAMETER
TEST CONDITIONS
2
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
INPUT
OFFSET VOLTAGE, initial
T
C
= 25C
.5
3
.25
.5
mV
OFFSET VOLTAGE, vs. temperature
T
C
= 25C to +85C
10
30
5
10
V/C
OFFSET VOLTAGE, vs. supply
T
C
= 25C
10
*
V/V
OFFSET VOLTAGE, vs. power
T
C
= 25C to +85C
20
*
V/W
BIAS CURRENT, initial
T
C
= 25C
10
200
5
50
pA
BIAS CURRENT, vs. supply
T
C
= 25C
.01
*
pA/V
OFFSET CURRENT, initial
T
C
= 25C
5
100
3
25
pA
INPUT IMPEDANCE, DC
T
C
= 25C
10
11
*
M
INPUT CAPACITANCE
T
C
= 25C
6
*
pF
COMMON MODE VOLTAGE RANGE
3
T
C
= 25C to +85C
V
S
15 V
S
12
*
*
V
COMMON MODE REJECTION, DC
T
C
= 25C to +85C, V
CM
= 20V
70
104
*
*
dB
GAIN
OPEN LOOP GAIN at 10Hz
T
C
= 25C, R
L
= 1K
111
*
dB
OPEN LOOP GAIN at 10Hz
T
C
= 25C, R
L
= 15
74
78
*
*
dB
GAIN BANDWIDTH PRODUCT at 1MHz T
C
= 25C, C
C
= 2.2pF
100
*
MHz
POWER BANDWIDTH, A
V
= 100
T
C
= 25C, C
C
= 2.2pF
3.5
*
MHz
POWER BANDWIDTH, A
V
= 1
T
C
= 25C, C
C
= 330pF
250
*
kHz
OUTPUT
VOLTAGE SWING
3
T
C
= 25C, I
O
= 4A
V
S
5 V
S
4
*
*
V
VOLTAGE SWING
3
T
C
= 25C to +85C, I
O
= 2A
V
S
3 V
S
2
*
*
V
VOLTAGE SWING
3
T
C
= 25C to +85C, I
O
= 78mA
V
S
1 V
S
.5
*
*
V
SETTLING TIME to .1%
T
C
= 25C, 2V step
.3
*
s
SETTLING TIME to .01%
T
C
= 25C, 2V step
1.2
*
s
SLEW RATE, A
V
= 100
T
C
= 25C, C
C
= 2.2pF
600
900
800
*
V/s
SLEW RATE, A
V
= 10
T
C
= 25C, C
C
= 22pF
650
*
V/s
POWER SUPPLY
VOLTAGE
T
C
= 25C to +85C
15
35
40
*
*
*
V
CURRENT, quiescent
T
C
= 25C
100
120
*
*
mA
THERMAL
RESISTANCE, AC, junction to case
4
T
C
= 25C to +85C, F > 60Hz
1.2
1.3
*
*
C/W
RESISTANCE, DC, junction to case
T
C
= 25C to +85C, F < 60Hz
1.6
1.8
*
*
C/W
RESISTANCE, junction to air
T
C
= 25C to +85C
30
*
C/W
TEMPERATURE RANGE, case
Meets full range specifications
25
+85
*
*
C
PA19 PA19A
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. +V
S
and V
S
denote the positive and negative supply rail respectively. Total V
S
is measured from +V
S
to V
S
.
4. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
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 850C to avoid generating toxic fumes.
CAUTION
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TYPICAL PERFORMANCE
GRAPHS
PA19 PA19A
APEX MICROTECHNOLOGY CORPORATION 5980 NORTH SHANNON ROAD TUCSON, ARIZONA 85741 USA APPLICATIONS HOTLINE: 1 (800) 546-2739
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OPERATING
CONSIDERATIONS
PA19 PA19A
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:
V
S
CAPACITIVE LOAD
INDUCTIVE LOAD
40V
.1F
11mH
30V
500F
24mH
20V
2500F
75mH
15V
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.
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 limit-
ing 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 150C. 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
GENERAL
Please read Application Note 1 "General Operating Con-
siderations" 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 remov-
ing gate drive when voltage on pin 2 (pin 7) exceeds .65V dif-
ferential from the positive (negative) supply rail. With internal
resistors equal to 1.2, current limits are approximately 0.5A
with no external current limit resistors. With the addition of
external resistors current limit will be:
.65V
I
LIM
=
+.54A
R
CL
To determine values of external current limit resistors:
.65V
R
CL
=
I
CL
- .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 consid-
ered 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)
The MOSFET output stage of this power operational ampli-
fier 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
for internal thermal delays. For a given application, the direc-
tion and magnitude of the output current should be calculated
or measured and checked against the SOA curves. This is
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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.
PA19U REV H FEBRUARY 1998 1998 Apex Microtechnology Corp.
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 reli-
ability of the device.
STABILITY
Due to its large bandwidth, the PA19 is more likely to oscil-
late 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 connec-
tions 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, capaci-
tor 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 500. Larger sumpoint
load resistances can be used with increased phase com-
pensation and/or by bypassing the feedback resistor.
3. Connect the case to any AC ground potential.
OPERATING
CONSIDERATIONS
PA19 PA19A
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