PA94

PA94 High Voltage Power Operational Amplifiers RoHS COMPLIANT FEATURES • • • • High Voltage— 900V (±450V) High Slew Rate — 500V/µs Output Current— 100mA Programmable Current Limit APPLICATIONS • • • • High Voltage Instrumentation Programmable Power Supplies up to ±430V Mass Spectrometers Semiconductor Measurement Equipment DESCRIPTION The PA94 is a high voltage, MOSFET operational amplifier designed as a low cost solution for driving con‐ tinuous output currents up to 100mA and pulse currents up to 200mA into capacitive loads. The safe operat‐ ing area (SOA) has no second breakdown limitations and can be observed for all load types by choosing an appropriate current limiting resistor. The MOSFET output stage is biased AB for linear operation. External compensation provides flexibility in choosing bandwidth and slew rate for the application. Apex Microtech‐ nology’s Power SIP uses a minimum of board space allowing for high density circuit boards. The Power SIP is electrically isolated. Isolating thermal washers (TW13) prevent arcing from pins to heatsink. Figure 1: Equivalent Schematic 12 +VS R1A C2 R1B Q1 R3 Q3 Q2 R4 Q4 6 Q6 4 Q5 Q15A 1 –IN R9 R11 2 +IN www.apexanalog.com Q8 R7 7 OUT R10 R12 R20 ICL 8 Q11 Q29 Q21 R19 Q29 –VS 10 C C1 Q15B C C2 Q14 Q30 R27 © Apex Microtechnology Inc. All rights reserved Oct 2018 PA94U Rev R PA94 TYPICAL CONNECTION Figure 2: Typical Connection RF 100k +V S * 100nF RC CC RF +V S + RC 1k PA94 -V S RCL V OUT CC CL RL -V S * Use 10μF per Amp of Output Current. 2 * 100nF PA94U Rev R PA94 PINOUT AND DESCRIPTION TABLE Figure 3: External Connections Pin Number Name Description 1 ‐IN The inverting input. 2 +IN The non‐inverting input. 4, 6 CC Compensation capacitor connection. Select value based on Phase Compensation. See applicable section. 7 OUT The output. Connect this pin to load and to the feedback resistors. 8 CL Connect to the current limit resistor. Output current flows into/out of this pin through RCL. The output pin and the load are connected to the other side of RCL. 10 ‐VS The negative supply rail. 12 +VS The positive supply rail. PA94U Rev R 3 PA94 SPECIFICATIONS Unless otherwise noted: TC = 25°C, DC input specifications are ± value given. Power supply voltage is typical rating. CC = 4.7pF. ABSOLUTE MAXIMUM RATINGS Parameter Symbol Supply Voltage, total Output Current, source, sink, peak, within SOA Power Dissipation, continuous @ TC = 25°C Input Voltage, differential Input Voltage, common mode 1 Min Max Units +VS to ‐VS 900 V IOUT 200 mA PD 30 W VIN (Diff) ‐20 +20 V VCM ‐VS +VS V 260 °C 150 °C ‐55 +125 °C ‐40 +85 °C Temperature, pin solder, 10s max. Temperature, junction 2 TJ Temperature Range, storage Operating Temperature Range, case TC 1. Although supply voltages can range up to ± 450V the input pins cannot swing over this range. The input pins must be at least 30V from either supply rail but not more than 450V from either supply rail. See text for a more complete description of the common mode voltage range. 2. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dis‐ sipation to achieve high MTTF. CAUTION 4 The PA94 is constructed from MOSFET transistors. ESD handling procedures must be observed. The substrate contains beryllia (BeO). Do not crush, machine, or subject to temperatures in excess of 850°C to avoid toxic fumes. PA94U Rev R PA94 INPUT Parameter Test Conditions Min Offset Voltage, initial Typ Max Units 0.5 5 mV 15 50 µV/°C Offset Voltage vs. Supply 10 25 µV/V Offset Voltage vs. Time 75 Bias Current, initial 200 Offset Voltage vs. Temperature Full temp range µV/kh 2000 pA Bias Current vs. Supply 4 Offset Current, initial 50 Input Impedance, DC 1011 Ω 4 pF Input Capacitance Common Mode Voltage Range 1 VS = ±450V ±VS ∓ 30 Common Mode Rejection, DC VCM = ±90V 80 Noise 10 kHz bandwidth, RIN = 1 kΩ pA/V 500 pA V 98 dB 2 µV RMS 1. Although supply voltages can range up to ± 450V the input pins cannot swing over this range. The input pins must be at least 30V from either supply rail but not more than 450V from either supply rail. See text for a more complete description of the common mode voltage range. GAIN Parameter Min Typ 94 115 dB Gain Bandwidth Product @ 1 MHz RL = 5 kΩ 140 MHz Power Bandwidth RL = 5 kΩ 300 kHz Phase Margin, AV = 100 Full temp range 60 ° Open Loop @ 15 Hz Test Conditions RL = 5 kΩ Max Units OUTPUT Parameter Voltage Swing Test Conditions IOUT = 70mA Current, continuous Typ ±VS ∓ 24 ±VS ∓ 20 100 Slew Rate, AV = 100 CC =2.2pF Settling Time, to 0.1% Resistance PA94U Rev R Min 500 Max Units V mA 700 V/µs 2V Step 1 µs no load 100 Ω 5 PA94 POWER SUPPLY Parameter Test Conditions Voltage 1 Min Typ Max Units ±50 ±300 ±450 V 17 24 mA 120 µA Max Units 2.5 °C/W 4.2 °C/W Current, quiescent total Current, quiescent output stage only 1. Derate max supply rating 0.625 V/°C below 25°C case. No derating needed above 25°C case. THERMAL Parameter Test Conditions Resistance, AC, junction to case 1 Full temp range, F > 60 Hz Resistance, DC, junction to case Full temp range, F < 60 Hz Resistance, junction to air Full temp range Temperature Range, case Meets full range specifica‐ tions Min Typ 30 ‐25 °C/W +85 °C 1. Rating applies if the output current alternates between both output transistors at a rate faster than 60 Hz. 6 PA94U Rev R PA94 TYPICAL PERFORMANCE GRAPHS Figure 4: Power Derating Figure 5: Quiescent Current 1.08 25 Quiescent Current, I (X) /ŶƚĞƌŶĂůWŽǁĞƌŝƐƐŝƉĂƟŽŶ͕W;t) 30 T = TC 20 15 10 T = TA 5 0 0 1.04 1.00 0.96 0.92 0.88 25 50 75 100 125 0 150 400 800 600 1000 Total Supply Voltage, VS (V) Temperature, TC (°C) Figure 6: Small Signal Response Figure 7: Phase Response 120 -90 100 -120 CC = 2.2pF 80 Phase, ˇ;ΣͿ Open Loop Gain, A (dB) 200 CC = 4.7pF 60 CC = 22 pF 40 -180 CC = 4.7pF CC = 2.2pF 100 1k 10k 100k 1M Frequency, F (Hz) PA94U Rev R CC = 22 pF -210 20 0 10 -150 10M -240 1M 10M 20M Frequency, F (Hz) 7 PA94 Figure 9: Power Response 40 T C =1 25 °C C 16 25° 55°C TC = – 8 20 40 60 80 200 100 50 10k 4 0 100 Figure 10: Current Limit 20 Input Noise Voltage, VN ;Ŷsͬя,njͿ Current Limit, ICL (mA) 1M 2M Figure 11: Input Noise 200 120 100 70 50 30 20 5 10 20 50 100 150 Current Limit Resistor, RCL (ɏ) 8 100k Frequency, F (Hz) Output Current, IOUT (mA) 10 3 pF T C= 500 22 TC pF 2.2 C C= pF 4.7 C = 24 C 5° =8 C 32 Output Votlage, VOUT (VP-P) 900 C C= Voltage Drop From Supply, VS-VOUT (V) Figure 8: Output Voltage Swing 15 10 7 5 3 2 10 100 1k 10k 100k Frequency, F (Hz) PA94U Rev R PA94 SAFE OPERATING AREA (SOA) Figure 12: SOA KƵƚƉƵƚƵƌƌĞŶƚ&ƌŽŵнVSŽƌͲVS;ŵA) 250 ϭϬ Ϭŵ 150 ϮϬ 100  ͕d 50  ͕d  ͕d 25 C Ɛ =2 C 5° =8 C Ɛ Ϭŵ C 5° C =1 25 °C 15 10 5 50 WƵůƐĞƵƌǀĞƐΛ ϭϬйƵƚLJLJĐůĞDĂdž 100 200 500 1k ^ƵƉƉůLJƚŽKƵƚƉƵƚŝīĞƌĞŶƟĂů͕VS - VOUT (V) PA94U Rev R 9 PA94 GENERAL Please read Application Note 1 “General Operating Considerations” which covers stability, supplies, heat sinking, mounting, current limit, SOA interpretation, and specification interpretation. Visit www.apexana‐ log.com for Apex Microtechnology’s complete Application Notes library, Technical Seminar Workbook, and Evaluation Kits. TYPICAL APPLICATION Piezo positioning may be applied to the focusing of segmented mirror systems. The composite mirror may be composed of hundreds of elements, each requiring focusing under computer control. In such com‐ plex systems the PA94 reduces the costs of power supplies and cooling with its advantages of low cost and low quiescent power consumption while increasing circuit density with the SIP. Figure 13: Typical Application PHASE COMPENSATION Gain CC* ≥100 2.2pF ≥50 4.7pF ≥10 22pF * CC rated for full supply voltage INTERNAL POWER DISSIPATION AND HEATSINK SELECTION With the unique combination of high voltage and speed of the PA94, traditional formulas for heatsink selection will falsely lower the apparent power handling capability of this amplifier. To more accurately pre‐ dict operating temperatures refer to Apex Microtechnology Applications Note 1, General Operating Consider‐ ations, paragraph 7. Find total quiescent power (PDQ) by multiplying 0.024A by VSS (total supply voltage). Find output stage quiescent power (PDQOUT) by multiplying 0.00012 by VSS. 10 PA94U Rev R PA94 Calculate a heatsink rating which will maintain the case at 85°C or lower. TC – TA C R SA = -------------------------- – 0.1 -----PD + PD Q W Where: TC = maximum case temperature allowed TA = maximum ambient temperature encountered Calculate a heatsink rating which will maintain output transistor junctions at 150°C or lower. T J – T A –  PD + PD QOUT   R JC C R SA = ---------------------------------------------------------------------------------- – 0.1 -----PD + PD Q W Where: TJ = maximum junction temperature allowed. RØJC = AC or DC thermal resistance from the specification table. Use the larger heatsink of these two calculations. CURRENT LIMIT For proper operation, the current limit resistor (RCL) must be connected as shown in the typical connec‐ tion diagram. The minimum value is 3.5 ohm, however for optimum reliability the resistor value should be set as high as possible. The value is calculated as follows; with the maximum practical value of 30 ohms. 0.7V R CL    = ----------------I CL  A  COMMON MODE INPUT RANGE Operational amplifiers are usually designed to have a common mode input voltage range that approxi‐ mates the power supply voltage range. However, to keep the cost as low as possible and still meet the requirements of most applications the common mode input voltage range of the PA94 is restricted. The input pins must always be a least 30V from either supply voltage but never more than 450V. This means that the PA94 cannot be used in applications where the supply voltages are extremely unbalanced. For example, sup‐ ply voltages of +800V and –100V would not be allowed in an application where the non‐inverting pin is grounded because in normal operation both input pins would be at 0V and the difference voltage between the positive supply and the input pins would be 800V. In this kind of application, however, supply voltages +450V and ‐100V does meet the input common mode voltage range requirements since the maximum differ‐ ence voltage between the inputs pins and the supply voltage is 450V (the maximum allowed). The output has no such restrictions on its voltage swing. The output can swing within 24V of either supply voltage regardless of value so long as the total supply voltage does not exceed 900V. INPUT PROTECTION Although the PA94 can withstand differential input voltages up to ±20V, additional external protection is recommended. In most applications 1N4148 or 1N914 signal diodes are sufficient (D1, D2 in Figure 14A). In more demanding applications where low leakage or low capacitance are of concern 2N4416 or 2N5457‐ 2N5459 JFETs connected as diodes will be required (Q1, Q2 in Figure 14B). In either case the input differential voltage will be clamped to ±0.7V. This is sufficient overdrive to produce maximum power bandwidth. Note that this protection does not automatically protect the amplifier from excessive common mode input volt‐ ages. PA94U Rev R 11 PA94 Figure 14: Overvoltage Protection POWER SUPPLY PROTECTION Unidirectional zener diode transient suppressors are recommended as protection on the supply pins. 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 per‐ formance including power‐on overshoot and power‐off polarity reversal as well as line regulation. Conditions which can cause open circuits or polarity reversals on either power supply rail should be avoided or protected against. Reversals or opens on the negative supply rail are known to induce input stage failure. Unidirectional transzorbs prevent this, and it is desirable that they be both electrically and physically as close to the amplifier as possible. STABILITY The PA94 is stable at gains of 100 or more with a NPO (COG) compensation capacitor of 2.2pF. The com‐ pensation capacitor, Cc, in the external connections diagram must be rated at 1000V working voltage and mounted closely to pins 4 and 6 to prevent spurious oscillation. A compensation capacitor less than 2.2pF is not recommended. EXTERNAL COMPONENTS The compensation capacitor Cc must be rated for the total supply voltage. An NPO (COG) capacitor rated at 1kV is recommended. Of equal importance are the voltage rating and voltage coefficient of the gain setting feedback resistor. Typical voltage ratings of low wattage resistors are 150 to 250V. Up to 500 V can appear across the feedback resistor. High voltage rated resistors can be obtained. However a 1 MΩ feedback resistor composed of five 200k resistors in series will produce the proper voltage rating. CAUTIONS The operating voltages of the PA94 are potentially lethal. During circuit design develop a functioning cir‐ cuit at the lowest possible voltages. Clip test leads should be used for “hands off” measurements while trou‐ bleshooting. 12 PA94U Rev R PA94 PACKAGE OPTIONS PACKAGE STYLE DQ NEED TECHNICAL HELP? CONTACT APEX SUPPORT! For all Apex Microtechnology product questions and inquiries, call toll free 800-546-2739 in North America. For inquiries via email, please contact apex.support@apexanalog.com. International customers can also request support by contacting their local Apex Microtechnology Sales Representative. To find the one nearest to you, go to www.apexanalog.com IMPORTANT NOTICE Apex Microtechnology, Inc. has made every effort to insure the accuracy of the content contained in this document. However, the information is subject to change without notice and is provided "AS IS" without warranty of any kind (expressed or implied). Apex Microtechnology reserves the right to make changes without further notice to any specifications or products mentioned herein to improve reliability. This document is the property of Apex Microtechnology and by furnishing this information, Apex Microtechnology grants no license, expressed or implied under any patents, mask work rights, copyrights, trademarks, trade secrets or other intellectual property rights. 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