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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 TELEPHONE RING GENERATOR PIEZO ELECTRIC POSITIONING ELECTROSTATIC TRANSDUCER & DEFLECTION DEFORMABLE MIRROR FOCUSING
APPLICATIONS
24-PIN PSOP PACKAGE STYLE DF EQUIVALENT SCHEMATIC (ONE OF TwO cHANNELS)
+VS Q1 C C1 C C2 +IN -IN D1 D2 Q11 Q7 Q8 Q9 Q10 Q5 Q6 Q2 Q3 Q4 ILIM OUT
DESCRIPTION
The PA243 is a dual high voltage monolithic MOSFET operational 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 voltages. 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.
D4 D3
Q13 Q12 Q15 D5 -VS Q14
TYPICAL APPLICATION
R VIN 20R +175 10pF B PA243
RCL CC
20R 20R +175 10pF
EXTERNAL CONNECTIONS
* +Vsa NC La COMPa COMPa OUTa NC +INb -INb
1
+ -
24 A
-
-Vsa NC NC +INa -INa NC OUTb COMPb COMPb ILb NC +Vsb
*
A PA243
R CL
-175
-175
* -Vsb
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 RN CN network serves to raise the apparent gain of A2 at high frequencies. If RN is set equal to R the amplifiers can be compensated identically and will have matching bandwidths. See application note 20 for more details.
For CC values, see graph on page 3. Note: CC must be rated for full supply voltage. * Supply bypassing required. See general Operating Considerations.
APEX MICROTECHNOLOGY CORPORATION * TELEPHONE (520) 690-8600 * FAX (520) 888-3329 * ORDERS (520) 690-8601 * EMAIL prodlit@apexmicrotech.com
+
PIEZO 180 TRANSDUCER 180 W
R CL
RN CN
B
RCL CC
*
PA243
ABSOLUTE MAXIMUM RATINGS
ABSOLUTE MAXIMUM RATINGS SPECIFICATIONS
SPECIFICATIONS
pArAMeter iNpUt OFFSET VOLTAGE, initial OFFSET VOLTAGE, vs. temperature3 OFFSET VOLTAGE, vs supply OFFSET VOLTAGE, vs time BIAS CURRENT, initial BIAS CURRENT, vs supply OFFSET CURRENT, initial INPUT IMPEDANCE, DC INPUT CAPACITANCE COMMON MODE, voltage range COMMON MODE, voltage range COMMON MODE REJECTION, DC NOISE, broad band NOISE, low frequency GAiN OPEN LOOP at 15Hz BANDWIDTH, gain bandwidth product POWER BANDWIDTH oUtpUt VOLTAGE SWING CURRENT, peak3 CURRENT, continuous SETTLING TIME to .1% SLEW RATE RESISTANCE4, 1mA RESISTANCE4, 40 mA power sUppLY VOLTAGE CURRENT, quiescent tHerMAL RESISTANCE, junction to case AC, single amplifier DC, single amplifier AC, both amplifiers5 DC, both amplifiers5 RESISTANCE, junction to air6 TEMPERATURE RANGE, case test CoNDitioNs1
SUPPLY VOLTAGE, +VS to -VS OUTPUT CURRENT, continuous within SOA OUTPUT CURRENT, peak POWER DISSIPATION, continuous @ TC = 25C INPUT VOLTAGE, differential INPUT VOLTAGE, common mode TEMPERATURE, pin solder - 10 sec TEMPERATURE, junction2 TEMPERATURE, storage TEMPERATURE RANGE, powered (case)
MiN tYp 25 100 3 70 50 2 50 1011 6 94 50 125 96 3 30 VS-10 2 30 150 5 150 2.2 175 2.5 MAX 40 500 130 200 200
350V 60 mA 120 mA 12W 16 V VS 220C 150C -65 to +150C -40 to +125C
UNits mV V/C V/V V/kh pA pA/V pA pF V V dB V RMS V p-p dB MHz kHz V mA mA s V/s V mA
Full temperature range
VCM = 90V DC 10kHz BW, RS = 1K 1-10 Hz RL = 5K 280V p-p IO = 40mA 10V step, A V = -10 CC = 3.3pF RCL = 0 RCL = 0
+VS-14 -VS+12 84
90
VS-12 120 60
50
F > 60Hz F < 60Hz Full temperature range Meets full range specifications
-25
6 9 3.3 5.0 25
7 11 4.0 6.0 +85
C/W C/W C/W C/W C/W C
NOTES: 1. 2. 3. 4. 5. 6.
Unless otherwise noted TC = 25C, CC = 6.8pF. DC input specifications are value given. Power supply voltage is typical rating. 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. Guaranteed but not tested. The selected value of RCL must be added to the values given for total output resistance. Rating applies when power dissipation is equal in the two amplifiers. Rating applies with solder connection of heatslug to a minimum 1in2 foil area of the printed circuit board.
CAUTION
The PA243 is constructed from MOSFET transistors. ESD handling procedures must be observed.
APEX MICROTECHNOLOGY CORPORATION * 5980 NORTH SHANNON ROAD * TUcSON, ARIZONA 85741 * USA * APPLIcATIONS HOTLINE: 1 (800) 546-2739
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TYPICAL PERFORMANCE GRAPHS
PA243
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PA243
GENERAL
Please read Application Note 1 "General Operating Considerations" 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.
OPERATING CONSIDERATIONS
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 predicted 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 negative 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.
PHASE COMPENSATION
Open loop gain and phase shift both increase with increasing 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.
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 * 5980 NORTH SHANNON ROAD * TUcSON, ARIZONA 85741 * USA * APPLIcATIONS HOTLINE: 1 (800) 546-2739
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OPERATING CONSIDERATIONS
PA243
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-inverting 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 leakage 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 supply rating and also clamp power supply reversals to ground. Whether the zeners are used or not the system power supply 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.
These limitations can be seen in the SOA (see Safe Operating 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 resistances 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.
APPLICATION REFERENCES:
For additional technical information please refer to the following Application Notes: AN1: General Operating Considerations AN3: Bridge Circuit Drives AN25: Driving Capacitive Loads AN38: Loop Stability with Reactive Loads
FIGURE
+Vs Z1
-IN Q1 +IN Q2
+Vs OUT
-Vs
-Vs
Z2
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 important, 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.
This data sheet has been carefully checked and is believed to be reliable, however, no responsibility assumed for possible inaccuracies (520) 690-8601 * EMAIL subject to change without notice. APEX MICROTECHNOLOGY CORPORATION * TELEPHONE (520) 690-8600 * FAXis (520) 888-3329 * ORDERS or omissions. All specifications are prodlit@apexmicrotech.com PA243U REV D MARCH 2006 (c) 2006 Apex Microtechnology Corp.
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