MP400FC

MP400FC RoHS Power Operational Amplifiers COMPLIANT FEATURES • • • • • • • • • Low Cost Wide Common Mode Range Standard Supply Voltage Single Supply: 10V to 50V SMPS input Output Current: 150 mA Continuous Output Voltage 50V to 340V (single supply) 350 V/µs Slew Rate 200 kHz Power Bandwidth On-board Power Supply APPLICATIONS • • • • Piezoelectric Positioning and Actuation Electrostatic Deflection Deformable Mirror Actuators Chemical and Biological Stimulators DESCRIPTION The MP400FC combines a high voltage, high speed precision power op amp with a supply voltage boost function in an integrated thermally conductive module. The voltage boost function uses a switch mode power supply (SMPS) to boost the input power supply voltage. This allows the user the benefits of using a standard 12 V or 24 V bus without the need to design a high voltage supply to power the op amp. The SMPS voltage is adjustable from 50-350 V, allowing for op amp output voltages up to 340 V. External phase compensation provides the user with the flexibility to tailor gain, slew rate and bandwidth for a specific application. The unique design of this amplifier provides extremely high slew rates in pulse applications while maintaining low quiescent current. The output stage is well protected with a user defined current limit. Safe Operating Area (SOA) must be observed for reliable operation. Figure 1: Equivalent Schematic 21 Vin (10V to 50V) 15 14 13 12 22 23 25 Vbias 24 L1 D1 Q2 SMPS CONTROLLER 8 Vboost L2 R8 R7 6 LFin R17 36 Cc+ 1 Out R14 R15 C6 AMP 2 Ilim C8 34 Rset www.apexanalog.com 4 +Vs 37 Cr+ R19 42 Cc38 Cr- 26 27 28 29 30 31 32 33 35 40 39 41 Analog -IN +IN -Vs Power GND GND © Apex Microtechnology Inc. All rights reserved Aug 2017 MP400U Rev G MP400FC TYPICAL CONNECTION Figure 2: Typical Connection RF VSMPS 100nF 10µF VIN VBIAS CN RN CBOOST VB Q2D PGND SMPS CONTROLLER RSET NC ON‐BOARD SMPS RSET +VS RCL LFIN VOUT CL RIN VIN OUT ‐IN +CC + +CC +IN ‐VS MP400 RL CC AGND ‐CC ‐CC CC 2 MP400U Rev G MP400FC PINOUT AND DESCRIPTION TABLE Figure 3: External Connections (from backplate) Unused pins should be left open. This is mandatory for pins 3, 5, 7, 9, 11 and 16. Pin Number Name Description 1 OUT The output. Connect this pin to load and to the feedback resistor. 2 CL Connect to the current limit resistor, and then the OUT pin. Output current flows into/out of this pin through RCL. 4 +Vs The positive supply rail. Leave open when using on-board SMPS. 6 LFIN The supply filter. When using the on-board SMPS, connect this pin to VB to power the amplifier. This filters the SMPS current through a 47 μH inductor. The current to this pin can not exceed 200 mA. See applicable section. 8 VB This is the output of the high voltage SMPS and typically is tied to pin 6, LFIN. Other loads can be added to this pin as long as the maximum output power of the SMPS is not exceeded. For proper operation, an external high voltage, low ESR capacitor must be connected to this pin. See applicable section. 12, 13, 14, 15 Q2D Drain node of the SMPS MOSFET switch. An external RC snubber may be connected from this node to power ground to reduce or eliminate overshoot and ringing at switch turn off, reducing switching noise on the SMPS. 21, 22, 23, 25 Vin Input voltage pins for the on-board high voltage switch mode power supply. Supply with 10-50 V. 24 Vbias Input voltage pin for the boost controller circuitry. This pin is typically tied to VIN. MP400U Rev G 3 MP400FC 4 Pin Number Name Description 26-33 PGND Power ground. SMPS switching circuits are referenced to ground through these pins. 34 RSET SMPS voltage set resistor connecton. The 'Set Resistor' is connected from this pin to PGND to set the SMPS voltage. Select value based on desired VBOOST. See applicable section. 35 AGND Analog ground for amplifier circuit. AGND and PGND are connected at one point on the unit. Avoid external connections between AGND and PGND. 36, 37 +CC Positive compensation capacitor connection. Select value based on Phase Compensation. See applicable section. 38, 42 -CC Negative compensation capacitor connection. Select value based on Phase Compensation. See applicable section. 39 +IN The non-inverting input. 40 -IN The inverting input. 41 -Vs The negative supply rail. This pin is typically connected to AGND. However, an external negative supply voltage can be connected to this pin. All Others NC No connection. MP400U Rev G MP400FC SPECIFICATIONS All Min/Max characteristics and specifications are guaranteed over the Specified Operating Conditions. Typical performance characteristics and specifications are derived from measurements taken at typical supply voltages and TC = 25°C. +VS and –VS denote the positive and negative supply voltages to the output stage. ABSOLUTE MAXIMUM RATINGS Parameter Symbol Max Units +VSMPS to GND 50 V +Vs to -Vs 350 V Output Current, peak within SOA IO 200 mA Power Dissipation, Internal, DC, Amplifier PD 14.2 W POUT, SMPS 67 W Supply Voltage, Total, SMPS Supply Voltage, Total, Amplifier Output Power, SMPS Input Voltage, differential Min VIN (Diff) -16 +16 V Vcm -VS +VS V 225 °C 150 °C -40 +105 °C -40 +85 °C Input Voltage, common mode Temperature, pin solder, 10s max. Temperature, junction 1 TJ Temperature Range, storage TC Operating Temperature Range, case 1. Long term operation at the maximum junction temperature will result in reduced product life. Derate power dissipation to achieve high MTTF. AMPLIFIER INPUT Parameter Test Conditions Min Offset Voltage, initial Offset Voltage vs. Temperature 0 to 85°C (Case) Typ Max 8 40 -63 Offset Voltage vs. Supply Units mV µV/°C 32 µV/V 8.5 200 pA Offset Current, initial 12 400 pA Input Resistance, DC 106 Ω Common Mode Voltage Range, pos. +VS - 2 V Common Mode Voltage Range, neg. -VS + 5.5 V 118 dB 418 µV RMS Bias Current, initial 1 Common Mode Rejection, DC Noise 90 700 kHz bandwidth 1. Doubles for every 10oC of temperature increase. MP400U Rev G 5 MP400FC AMPLIFIER GAIN Parameter Test Conditions Open Loop @ 15 Hz Min Typ 89 120 dB 1 MHz Gain Bandwidth Product @ 1 MHz Max Units Power Bandwidth, 300 VP-P +VS = 160 V, −VS = -160 V 200 kHz Phase Margin Full temp range 50 ° AMPLIFIER OUTPUT Parameter Test Conditions Min Typ Voltage Swing IO = 10 mA |VS| - 2 Voltage Swing IO = 100 mA |VS| - 8.6 Voltage Swing IO = 150 mA |VS| - 10 Current, continuous, DC 150 Slew Rate 100 Max Units V |VS| - 12 V V mA 350 V/µs Settling Time, to 0.1% 2 V Step 1 µs Resistance, No load RLIM = 6.2 Ω 44 Ω Current, quiescent, amplifier only 0.2 0.7 2.5 mA Min Typ Max Units 10 50 V 46.75 365 V SMPS Parameter Test Conditions Input Voltage, VIN SMPS Output Voltage, VB SMPS Output Current, IS VB = 10x VIN Output Voltage Tolerance VB ≤ 10x VIN, IS ≤ 150 mA, RSET = 1% 150 mA +/-2 Voltage Boost 6.5 10 % x input V THERMAL Parameter Test Conditions Min Typ Max Units 8.8 °C/W Resistance, DC, junction to case Full temp range, f300 V. Refer to Apex Application Note 21. Figure 40: Typical Application THEORY OF OPERATION The MP400 is designed specifically as a high speed pulse amplifier. In order to achieve high slew rates with low idle current, the internal design is quite different from traditional voltage feedback amplifiers. Basic op amp behaviors like high input impedance and high open loop gain still apply. But there are some notable differences, such as signal dependent supply current, bandwidth and output impedance, among others. The impact of these differences varies depending on application performance requirements and circumstances. These different behaviors are ideal for some applications but can make designs more challenging in other circumstances. MP400U Rev G 17 MP400FC SUPPLY CURRENT AND BYPASS CAPACITANCE A traditional voltage feedback amplifier relies on fixed current sources in each stage to drive the parasitic capacitances of the next stage. These currents combine to define the idle or quiescent current of the amplifier. By design, these fixed currents are often the limiting parameter for slew rate and bandwidth of the amplifier. Amplifiers which are high voltage and have fast slew rates typically have high idle currents and dissipate notable power with no signal applied to the load. At the heart of the MP400 design is a signal dependent current source which strikes a new balance between supply current and dynamic performance. With small input signals, the supply current of the MP400 is very low, idling at less than 1 mA. With large transient input signals, the supply currents increase dramatically to allow the amplifier stages to respond quickly. The Pulse Response plot in the typical performance section of this datasheet describes the dynamic nature of the supply current with various input transients. Choosing proper bypass capacitance requires careful consideration of the dynamic supply currents. High frequency ceramic capacitors of 0.1 µF or more should be placed as close as possible to the amplifier supply pins. The inductance of the routing from the supply pins to these ceramic capacitors will limit the supply of peak current during transients, thus reducing the slew rate of the MP400. The high frequency capacitance should be supplemented by additional bypass capacitance not more than a few centimeters from the amplifier. This additional bypass can be a slower capacitor technology, such as electrolytic, and is necessary to keep the supplies stable during sustained output currents. Generally, a few microfarads is sufficient. SMALL SIGNAL PERFORMANCE The small signal performance plots in the typical performance section of this datasheet describe the behavior when the dynamic current sources described previously are near the idle state. The selection of compensation capacitor directly affects the open loop gain and phase performance. Depending on the configuration of the amplifier, these plots show that the phase margin can diminish to very low levels when left uncompensated. This is due to the amount of bias current in the input stage when the part is in standby. An increase in the idle current in the output stage of the amplifier will improve phase margin for small signals although will increase the overall supply current. Current can be injected into the output stage by adding a resistor, RBIAS, between pins 42 and 4. The size of RBIAS will depend upon the application but 500 µA (50 V V+ supply/100K) of added bias current shows significant improvement in the small signal phase plots. Adding this resistor has little to no impact on small signal gain or large signal performance as under these conditions the current in the input stage is elevated over its idle value. It should also be noted that connecting a resistor to the upper supply only injects a fixed current and if the upper supply is fixed and well bypassed. If the application includes variable or adjustable supplies, a current source diode could also be used. These two terminal components combine a JFET and resistor connected within the package to behave like a current source. As a second stability measure, the MP400 is externally compensated and performance can be optimized to the application. Unlike the RBIAS technique, external phase compensation maintains the low idle current but does affect the large signal response of the amplifier. Refer to the small and large signal response plots as a guide in making the tradeoffs between bandwidth and stability. Due to the unique design of the MP400, two symmetric compensation networks are required. The compensation capacitor CC must be rated for a working voltage of the full operating supply voltage (+VS to –VS). NPO capacitors are recommended to maintain the desired level of compensation over temperature. 18 MP400U Rev G MP400FC LARGE SIGNAL PERFORMANCE As the amplitude of the input signal increases, the internal dynamic current sources increase the operation bandwidth of the amplifier. This unique performance is apparent in its slew rate, pulse response, and large signal performance plots. Recall the previous discussion about the relationships between signal amplitude, supply current, and slew rate. As the amplitude of the input amplitude increases from 1 VP-P to 15 VP-P, the slew rate increases from 50 V/µs to well over 350 V/µs. Notice the knee in the Rise and Fall times plot, at approximately 6 VP-P input voltage. Beyond this point the output becomes clipped by the supply rails and the amplifier is no longer operating in a closed loop fashion. The rise and fall times become faster as the dynamic current sources are providing maximum current for slewing. The result of this amplifier architecture is that it slews fast, and allows good control of overshoot for large input signals. This can be seen clearly in the large signal Transient Response plots. CURRENT LIMIT For proper operation, the current limit resistor, RLIM, must be connected as shown in the typical connection diagram. For maximum reliability and protection, the largest resistor value should be used. The maximum practical value for RLIM is about 12 Ω. However, refer to the SOA curve to assist in selecting the optimum value for Rlim in the intended application. Current limit may not protect against short circuit conditions with supply voltages over 200 V. LAYOUT CONSIDERATIONS Care should be taken to position the RC / CC compensation networks close to the amplifier compensation pins. Long loops in these paths pick up noise and increase the likelihood of LC interactions and oscillations. SMPS OPERATION Figure 41: SMPS Output vs. RSET 100000 RSET (ё) 10000 1000 100 10 1 50 100 150 200 250 300 350 VBoost (V) MP400U Rev G 19 MP400FC The MP400FC is designed to operate off of a standard voltage rail. Typical values include 12 V, 24 V, or 48 V. The addition of the on-board SMPS eliminates the need to design or purchase a high voltage power supply. The only inputs required by the SMPS are the VIN source. Input and output filter capacitor, and boost voltage set resistor (RSET). The SMPS output can be adjusted between a minimum of 50 V to a maximum of 350 V. The voltage boost adjustment is independent of VIN. Adjustment to the boost level is made through a resistor from the RSET pin to ground. The resistor value is: 5 1.85  10 - – 615 R SET = -------------------------------------V BOOST – 49.95 Where VBOOST = desired SMPS voltage. Example: 1. Desired VBOOST = 160 V 2. RSET = 1k (1066 by equation) If RSET is open, VBOOST will be 50 V. If RSET is shorted to ground VBOOST will be limited to 350 V. Note that while the MP400 SMPS generates a positive voltage from 50 V to 350 V, the amplifier may operate from a variety of supply voltages. Symmetric, asymmetrical and single supply configurations can be used so long as the total supply voltage from +VS to -VS does not exceed 350 V. The amplifier performance graphs in this datasheet include some plots taken with symmetrical supplies, but those plots generally apply to all supply configurations. SMPS OUTPUT CAPACITOR An external SMPS output filter capacitor is required for proper operation. ESR considerations prevail in the choice of the output filter capacitor. Select the highest value capacitor that meets the following ESR requirement. The minimum value for CBOOST is 100 µF. dVoESR = ---------I LPK Where: dVo = The maximum acceptable output ripple voltage ILPK = Peak inductor current = (1/L) • VIN • ton L = 10-6 if the internal inductor is used. VIN = Input voltage of the application. ton= √(2 • Io • L • ((VBOOST + 0.6 - VIN)/(FSW • VIN2))) VBOOST= The boost supply voltage of the application. IO= The maximum continuous output current for the application. FSW= 100 kHz switching frequency of the MP400FC boost supply. 20 MP400U Rev G MP400FC SMPS INPUT CAPACITOR An external input capacitor is required. This capacitor should be at least 100 µF. THERMAL CONSIDERATIONS For reliable operation the MP400FC will require a heatsink for most applications. When choosing the heatsink the power dissipation in the op amp and the SMPS MOSFET switch (Q2) are both considered. The power dissipation of the op amp is determined in the same manner as any power op amp. The power dissipation of the MOSFET switch (Q2) is the sum of the power dissipation due to conduction and the switching power. 2 P D  Q2  =  I IN  pk   R DS  ON   D  +  I IN  pk   V IN  t r  F SW  Where: VIN = SMPS input voltage VB = SMPS output voltage IO = Total SMPS output current FSW = 100 kHz RDS(ON)= 0.621 Ω tr= 82 x 10-9s D= t1 • FSW t1 = 2  I O  10  10 –6  V B – V IN    -------------------------2-  F SW  V IN  VB  td I IN  pk  = ---------------------–6 10  10 VB t d = t 1   --------------------- – t 1 V B – V IN MP400U Rev G 21 MP400FC PACKAGE OPTIONS Part Number Apex Package Style Description MP400FC FC 42-pin DIP PACKAGE STYLE FC 22 MP400U Rev G MP400FC 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. Apex Microtechnology owns the copyrights associated with the information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Apex Microtechnology integrated circuits or other products of Apex Microtechnology. This consent does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale. APEX MICROTECHNOLOGY PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN PRODUCTS USED FOR LIFE SUPPORT, AUTOMOTIVE SAFETY, SECURITY DEVICES, OR OTHER CRITICAL APPLICATIONS. PRODUCTS IN SUCH APPLICATIONS ARE UNDERSTOOD TO BE FULLY AT THE CUSTOMER OR THE CUSTOMER’S RISK. Apex Microtechnology, Apex and Apex Precision Power are trademarks of Apex Microtechnology, Inc. All other corporate names noted herein may be trademarks of their respective holders. MP400U Rev G 23