APEX MICROTECHNOLOGY CORPORATION TELEPHONE (520) 690-8600 FAX (520) 888-3329 ORDERS (520) 690-8601 EMAIL prodlit@apexmicrotech.com
24-PIN PSOP
PACKAGE STYLE DF
EQUIVALENT SCHEMATIC
(ONE OF TwO cHANNELS)
EXTERNAL CONNECTIONS
For C
C
values, see graph on page 3.
Note: C
C
must be rated for full supply voltage.
* Supply bypassing required. See general Operating Con-
siderations.
FEATURES
RoHS COMPLIANT
SURFACE MOUNT PACKAGE
MONOLITHIC MOS TECHNOLOGY
LOW COST
HIGH VOLTAGE OPERATION--350V
LOW QUIESCENT CURRENT TYP.--2.2mA
NO SECOND BREAKDOWN
HIGH OUTPUT CURRENT--20 mA PEAK
APPLICATIONS
TELEPHONE RING GENERATOR
PIEZO ELECTRIC POSITIONING
ELECTROSTATIC TRANSDUCER & DEFLECTION
DEFORMABLE MIRROR FOCUSING
DESCRIPTION
The PA243 is a dual high voltage monolithic MOSFET op-
erational amplifier achieving performance features previously
found only in hybrid designs while increasing reliability. This
approach provides a cost-effective solution to applications
where multiple amplifiers are required. Inputs are protected
from excessive common mode and differential mode volt-
ages. The safe operating area (SOA) has no secondary
breakdown limitations and can be observed with all type
loads by choosing an appropriate current limiting resistor.
External compensation provides the user flexibility in choosing
optimum gain and bandwidth for the application.
The PA243DF is packaged in a 24 pin PSOP (JEDEC
MO-166) package. The heatslug of the PA243DF package is
isolated in excess of full supply voltage.
TYPICAL APPLICATION
Low Cost 660v p-p piezo Drive
A single PA243 amplifier operates as a bridge driver for a piezo
transducer providing a low cost 660 volt total drive capability.
The R
N
C
N
network serves to raise the apparent gain of A2 at
high frequencies. If R
N
is set equal to R the amplifiers can be
compensated identically and will have matching bandwidths.
See application note 20 for more details.
A
PA243
B
PA243
20R
PIEZO
TRANSDUCER
20R
R
N
20R
C
N
R
VIN
175
+175
175
+175
R
CL
R
CL
180
180
10pF
10pF
W
I
LIM
OUT
-IN
+IN
+V
S
-V
S
C
C
2
C
C
1
Q2
D4
Q11
Q7
Q1
Q15
Q12
Q5
Q9
Q14
Q13
Q10
Q6
Q4
Q3
Q8
D2
D3
D1
D5
C
C
*
*
*
*
C
C
R
CL
R
CL
+Vsa
NC
La
COMPa
COMPa
OUTa
NC
-INb
+INb
-Vsb
-Vsa
NC
NC
+INa
-INa
NC
OUTb
COMPb
COMPb
ILb
NC
+Vsb
24
1
+
-
+
-
A
B
APEX MICROTECHNOLOGY CORPORATION 5980 NORTH SHANNON ROAD TUcSON, ARIZONA 85741 USA APPLIcATIONS HOTLINE: 1 (800) 546-2739
2
pArAMeter
test CoNDitioNs
1
MiN
tYp
MAX
UNits
iNpUt
OFFSET VOLTAGE, initial
25
40
mV
OFFSET VOLTAGE, vs. temperature
3
Full temperature range
100
500
V/C
OFFSET VOLTAGE, vs supply
3
V/V
OFFSET VOLTAGE, vs time
70
130
V/kh
BIAS CURRENT, initial
50
200
pA
BIAS CURRENT, vs supply
2
pA/V
OFFSET CURRENT, initial
50
200
pA
INPUT IMPEDANCE, DC
10
11
INPUT CAPACITANCE
6
pF
COMMON MODE, voltage range
+V
S
14
V
COMMON MODE, voltage range
-V
S
+12
V
COMMON MODE REJECTION, DC
V
CM
= 90V DC
84
94
dB
NOISE, broad band
10kHz BW, R
S
= 1K
50
V RMS
NOISE, low frequency
1-10 Hz
125
V p-p
GAiN
OPEN LOOP at 15Hz
R
L
=
5K
90
96
dB
BANDWIDTH, gain bandwidth product
3
MHz
POWER BANDWIDTH
280V p-p
30
kHz
oUtpUt
VOLTAGE SWING
I
O
= 40mA
V
S
12
V
S
10
V
CURRENT, peak
3
120
mA
CURRENT, continuous
60
mA
SETTLING TIME to .1%
10V step, A
V
= 10
2
s
SLEW RATE
C
C
= 3.3pF
30
V/s
RESISTANCE
4
, 1mA
R
CL
=
0
150
RESISTANCE
4
, 40 mA
R
CL
= 0
5
power sUppLY
VOLTAGE
50
150
175
V
CURRENT, quiescent
2.2
2.5
mA
tHerMAL
RESISTANCE, junction to case
AC, single amplifier
F > 60Hz
6
7
C/W
DC, single amplifier
F < 60Hz
9
11
C/W
AC, both amplifiers
5
3.3
4.0
C/W
DC, both amplifiers
5
5.0
6.0
C/W
RESISTANCE, junction to air
6
Full temperature range
25
C/W
TEMPERATURE RANGE, case
Meets full range specifications
25
+85
C
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
PA243
ABSOLUTE MAXIMUM RATINGS
SUPPLY VOLTAGE, +V
S
to V
S
350V
OUTPUT CURRENT, continuous within SOA
60 mA
OUTPUT CURRENT, peak
120 mA
POWER DISSIPATION, continuous @ T
C
= 25C
12W
INPUT VOLTAGE, differential
16 V
INPUT VOLTAGE, common mode
V
S
TEMPERATURE, pin solder 10 sec
220C
TEMPERATURE, junction
2
150C
TEMPERATURE, storage
65 to +150C
TEMPERATURE RANGE, powered (case)
40 to +125C
CAUTION
The PA243 is constructed from MOSFET transistors. ESD handling procedures must be observed.
SPECIFICATIONS
NOTES: 1.
Unless otherwise noted T
C
= 25C, C
C
= 6.8pF. DC input specifications are value given. Power supply voltage is typical rat-
ing.
2.
Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation
to achieve high MTTF. For guidance, refer to heatsink data sheet.
3.
Guaranteed but not tested.
4.
The selected value of R
CL
must be added to the values given for total output resistance.
5.
Rating applies when power dissipation is equal in the two amplifiers.
6.
Rating applies with solder connection of heatslug to a minimum 1in
2
foil area of the printed circuit board.
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3
TYPICAL PERFORMANCE
GRAPHS
PA243
APEX MICROTECHNOLOGY CORPORATION 5980 NORTH SHANNON ROAD TUcSON, ARIZONA 85741 USA APPLIcATIONS HOTLINE: 1 (800) 546-2739
4
OPERATING
CONSIDERATIONS
PA243
GENERAL
Please read Application Note 1 "General Operating Consid-
erations" which covers stability, power 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.
PHASE COMPENSATION
Open loop gain and phase shift both increase with increas-
ing temperature. The PHASE COMPENSATION typical graph
shows closed loop gain and phase compensation capacitor
value relationships for four case temperatures. The curves
are based on achieving a phase margin of 50. Calculate
the highest case temperature for the application (maximum
ambient temperature and highest internal power dissipation)
before choosing the compensation. Keep in mind that when
working with small values of compensation, parasitics may
play a large role in performance of the finished circuit. The
compensation capacitor must be rated for at least the total
voltage applied to the amplifier and should be a temperature
stable type such as NPO or COG.
OTHER STABILITY CONCERNS
There are two important concepts about closed loop gain
when choosing compensation. They stem from the fact that
while "gain" is the most commonly used term,
(the feedback
factor) is really what counts when designing for stability.
1. Gain must be calculated as a non-inverting circuit (equal
input and feedback resistors can provide a signal gain of
-1, but for calculating offset errors, noise, and stability, this
is a gain of 2).
2. Including a feedback capacitor changes the feedback factor
or gain of the circuit. Consider Rin=4.7k, Rf=47k for a gain
of 11. Compensation of 4.7 to 6.8pF would be reasonable.
Adding 33pF parallel to the 47k rolls off the circuit at 103kHz,
and at 2MHz has reduced gain from 11 to roughly 1.5 and
the circuit is likely to oscillate.
As a general rule the DC summing junction impedance
(parallel combination of the feedback resistor and all input
resistors) should be limited to 5k ohms or less. The amplifier
input capacitance of about 6pF, plus capacitance of connecting
traces or wires and (if used) a socket will cause undesirable
circuit performance and even oscillation if these resistances
are too high. In circuits requiring high resistances, measure or
estimate the total sum point capacitance, multiply by Rin/Rf, and
parallel Rf with this value. Capacitors included for this purpose
are usually in the single digit pF range. This technique results
in equal feedback factor calculations for AC and DC cases. It
does not produce a roll off, but merely keeps
constant over
a wide frequency range. Paragraph 6 of Application Note 19
details suitable stability tests for the finished circuit.
CURRENT LIMIT
For proper operation, the current limit resistor, Rcl, must be
connected as shown in the external connection diagram. The
minimum value is 3.9 ohms, however for optimum reliability,
the resistor should be set as high as possible. The maximum
practical value is 110 ohms. Current limit values can be pre-
dicted as follows:
Ilimit = Vbe
Rcl
Where Vbe is shown in the CURRENT LIMIT typical
graph.
Note that +Vbe should be used to predict current through
the +Vs pin, -Vbe for current through the -Vs pin, and that they
vary with case temperature. Value of the current limit resistor
at a case temperature of 25 can be estimated as follows:
Rcl = 0.7
Ilimit
When the amplifier is current limiting, there may be spurious
oscillation present during the current limited portion of the nega-
tive half cycle. The frequency of the oscillation is not predictable
and depends on the compensation, gain of the amplifier, value
of the current limit resistor, and the load. The oscillation will
cease as the amplifier comes out of current limit.
SAFE OPERATING AREA
The MOSFET output stage of the PA243 is not limited by
second breakdown considerations as in bipolar output stages.
However there are still three distinct limitations:
1. Voltage withstand capability of the transistors.
2. Current handling capability of the die metalization.
3. Temperature of the output MOSFETS.
APEX MICROTECHNOLOGY CORPORATION TELEPHONE (520) 690-8600 FAX (520) 888-3329 ORDERS (520) 690-8601 EMAIL prodlit@apexmicrotech.com
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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.
PA243U REV D MARCH 2006 2006 Apex Microtechnology Corp.
These limitations can be seen in the SOA (see Safe Operat-
ing Area graphs). Note that each pulse capability line shows
a constant power level (unlike second breakdown limitations
where power varies with voltage stress). These lines are shown
for a case temperature of 25C and correspond to thermal re-
sistances of 5.2C/W for the PA243DF. Pulse stress levels for
other case temperatures can be calculated in the same manner
as DC power levels at different temperatures. The output stage
is protected against transient flyback by the parasitic diodes of
the output stage MOSFET structure. However, for protection
against sustained high energy flyback external fast-recovery
diodes must be used.
HEATSINKING
The PA243DF package has a large exposed integrated
copper heatslug to which the monolithic amplifier is directly
attached. The solder connection of the heatslug to a minimum
of 1 square inch foil area on the printed circuit board will result
in thermal performance of 25C/W junction to air rating of
the PA243DF. Solder connection to an area of 1 to 2 square
inches is recommended. This may be adequate heatsinking
but the large number of variables involved suggest temperature
measurements be made on the top of the package. Do not
allow the temperature to exceed 85C.
FIGURE
OVERVOLTAGE PROTECTION
Although the PA241 can withstand differential input voltages
up to 16V, in some applications additional external protection
may be needed. Differential inputs exceeding 16V will be
clipped by the protection circuitry. However, if more than a few
milliamps of current is available from the overload source, the
protection circuitry could be destroyed. For differential sources
above 16V, adding series resistance limiting input current to
1mA will prevent damage. Alternatively, 1N4148 signal diodes
connected anti-parallel across the input pins is usually sufficient.
In more demanding applications where bias current is impor-
tant, diode connected JFETs such as 2N4416 will be required.
See Q1 and Q2 in Figure 1. In either case the differential input
voltage will be clamped to 0.7V. This is sufficient overdrive to
produce the maximum power bandwidth.
OPERATING
CONSIDERATIONS
PA243
+Vs
-Vs
OUT
+Vs
-Vs
Z1
Z2
-IN
+IN
Q1
Q2
In the case of inverting circuits where the +IN pin is grounded,
the diodes mentioned above will also afford protection from
excessive common mode voltage. In the case of non-invert-
ing circuits, clamp diodes from each input to each supply will
provide protection. Note that these diodes will have substantial
reverse bias voltage under normal operation and diode leak-
age will produce errors.
Some applications will also need over-voltage protection
devices connected to the power supply rails. Unidirectional
zener diode transient suppressors are recommended. The
zeners clamp transients to voltages within the power sup-
ply rating and also clamp power supply reversals to ground.
Whether the zeners are used or not the system power sup-
ply should be evaluated for transient performance including
power-on overshoot and power-off polarity reversals as well
as line regulation. See Z1 and Z2 in Figure 1.
APPLICATION REFERENCES:
For additional technical information please refer to the fol-
lowing Application Notes:
AN1: General Operating Considerations
AN3: Bridge Circuit Drives
AN25: Driving Capacitive Loads
AN38: Loop Stability with Reactive Loads
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