CPC1580 Optically Isolated Gate Drive Circuit INTEGRATED CIRCUITS DIVISION Features Description • • • • • • • The CPC1580 optical gate driver provides isolated control of a discrete power MOSFET transistor without the need of an external power supply. Control of the power MOSFET transistor is accomplished by the application of sufficient input LED current to activate the driver circuitry. Drives External Power MOSFET Low LED Current (2.5mA) Requires No External Power Supply Load Voltages up to 65V High Reliability Small 8-pin Surface Mount Package 3750Vrms Input/Output Isolation On the load side, an external storage capacitor and an internal bootstrap diode enable the internal photovoltaic and gate driver circuitry to provide fast output switching characteristics by supplying the charge necessary to satisfy the MOSFET’s bias requirements. Applications • • • • • • Industrial Controls Instrumentation Medical Equipment Isolation Electronic Switching I/O Subsystems Appliances Provided in a small 8-pin package, the CPC1580 provides 3750Vrms of input-to-output isolation. Approvals Ordering Information • UL recognized component: File # E76270 Part Description CPC1580P 8-Pin Flatpack (50/Tube) CPC1580PTR 8-Pin Flatpack (1000/Reel) Figure 1. CPC1580 DC Application Circuit Diagram CPC1580 1 4 NC CST 8 VCAP 7 LOAD VD NC +VLOAD 5 LED + LED - 2 3 VG 6 VS DS-CPC1580-R01 www.ixysic.com Q1 -VLOAD 1 INTEGRATED CIRCUITS DIVISION CPC1580 1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Package Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 General Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.8 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 3 3 3 3 4 4 5 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Device Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 LED Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Storage Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Transistor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.1 Transistor Switching Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 6 7 7 5. CPC1580 Over-Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1 Other Protection Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Application Switching Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6.1 Resistive Load Losses: The Ideal Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.2 Inductive/Resistive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.3 Capacitive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6.4 dV/dt Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Design Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8. Manufacturing Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Moisture Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.2 ESD Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Reflow Profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 Board Wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 CPC1580P Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6 CPC1580PTR Tape and Reel Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 www.ixysic.com 12 12 12 12 12 13 13 R01 INTEGRATED CIRCUITS DIVISION CPC1580 1. Specifications 1.1 Package Pinout 1.3 Absolute Maximum Ratings CPC1580P Pinout N/C LED + LED N/C 1 8 2 7 3 6 4 5 Absolute maximum electrical ratings are at 25°C. Parameter Rating Units Blocking Voltage (VDS) 65 VP Reverse Input Voltage 5 V Input Control Current 50 mA 1 A 150 mW 500 mW 3750 Vrms Operational Temperature -40 to +110 °C Storage Temperature -40 to +125 °C VCAP VL1 VL2 Peak (10ms) VG Input Power Dissipation 1 Output Power Dissipation 2 Isolation Voltage (Input to Output) 1.2 Pin Description Pin# Name 1 N/C Description Not connected 2 LED + Positive input to LED 3 LED - Negative input to LED 4 N/C Not connected 5 VG Output, MOSFET Gate Control 6 VL2 -Load Voltage DC, ± Load Voltage AC 7 VL1 +Load Voltage DC, ± Load Voltage AC 8 VCAP Storage Capacitor 1 Derate linearly 1.33mW/°C 2 Derate linearly 6.0mW/°C Absolute maximum ratings are stress ratings. Stresses in excess of these ratings can cause permanent damage to the device. Functional operation of the device at conditions beyond those indicated in the operational sections of this data sheet is not implied. 1.4 ESD Rating ESD Rating (Human Body Model) 1000 V 1.5 Recommended Operating Conditions Parameter Symbol Min Max Units Load Voltage VL 15 65 V Input Control Current IF 2.5 10 mA Forward Voltage Drop VF 1 1.4 V Operating Temperature TA -40 +110 °C R01 www.ixysic.com 3 INTEGRATED CIRCUITS DIVISION CPC1580 1.6 General Conditions Unless otherwise specified, minimum and maximum values are guaranteed by production testing. Typical values are characteristic of the device at 25°C, and are the result of engineering evaluations. They are provided for informational purposes only, and are not part of the manufacturing testing requirements. Unless otherwise noted, all electrical specifications are listed for TA=25°C. 1.7 Electrical Specifications Parameter Conditions Symbol Min Typ Max Units Load Side Characteristics Gate Voltage IF=2.5mA 8.2 IF=5mA IF=10mA 7.5 VGS 8.7 12 9.1 V IF=2.5mA -40°C<TA<110°C Capacitor Voltage Gate Drive Capability - 14.4 10V<VDS<65V VCAP VDS-0.8 - VDS-0.2 IF=2.5mA, VGS=0V, VCAP=15V IG_source 2 3.6 7 0.35 0.47 IG_sink 0.16 0.22 0.06 0.09 IF=0mA, VGS=8V, VCAP=8V IF=0mA, VGS=4V, VCAP=4V IF=0mA, VGS=2V, VCAP=2V Turn-On Delay 4.2 mA VDS=48V, VGS=4V, CVG=4nF IF=2.5mA IF=5mA ton 1 IF=10mA Turn-Off Delay 1 V 48 140 16 40 7 20 s VDS=48V, VGS=2V, CVG=4nF IF=2.5mA IF=5mA 150 toff1 40 IF=10mA 175 400 s 600 s A 195 VDS=48V, VGS=1V, CVG=4nF IF=2.5mA IF=5mA 240 toff2 40 IF=10mA 290 VDS=65V IDS Forward Voltage Drop IF=5mA Input Dropout Current VGS=1V Reverse Bias Leakage Current Off-State Leakage Current 270 - - 1 VF 1 1.27 1.4 V IF 0.2 0.7 1 mA VR=5V IR - - 10 A - CI/O - 3 - pF LED Characteristics Common Characteristics Input to Output Capacitance 4 www.ixysic.com R01 INTEGRATED CIRCUITS DIVISION CPC1580 1.8 Performance Data 7.5 Gate Source Current vs. Temperature (IF=5mA, VCAP=15V) VGS=2V 7.0 IG_source (mA) 6.5 VGS=4V 6.0 5.5 5.0 4.5 4.0 3.5 -40 0.30 -20 0 80 100 Gate Sink Current vs. Temperature (IF=0mA, VGS=VCAP) 0.25 IG_sink (mA) 20 40 60 Temperature (ºC) VGS=4V 0.20 0.15 VGS=2V 0.10 LED Forward Voltage Drop (V) 0.05 -40 0 20 40 60 Temperature (ºC) 80 100 LED Forward Voltage Drop vs. Temperature (IF=5mA) 1.40 1.35 1.30 1.25 1.20 1.15 1.10 1.05 1.00 -40 R01 -20 -20 0 20 40 60 80 Temperature (ºC) www.ixysic.com 100 120 5 INTEGRATED CIRCUITS DIVISION CPC1580 2. Introduction The CPC1580 Isolated Gate Driver uses an efficient optocoupler design to provide remote gate drive current to a MOSFET, while providing 3750Vrms of isolation between the LED control current input and the MOSFET gate drive output. The CPC1580 is used in conjunction with a MOSFET transistor for remote switching of DC loads (Figure 1) and two MOSFETS and a diode at low-frequency AC rates (Figure 2) where isolated power is unavailable. By selecting a few external components, the charge capacitor and resistors, the designer has control over the operating parameters of the CPC1580 circuit, and can customize the circuit to accommodate the requirements of a wide selection of MOSFETs. The designer just needs to know the MOSFET total gate charge (QG), and with this information a capacitor can be chosen. The capacitance of the storage capacitor, CST, should be greater than or equal to QG. 3. Functional Description The CPC1580 is operational when sufficient input control current is flowing, the LED is turned on, and the gate current is flowing. The LED illuminates the photovoltaics (converts light into electrical power, or photocurrent), which provides current to turn on the NPN bipolar transistor. The NPN transistor then allows for charge to go to the gate of the MOSFET. When an external storage capacitor is added to the CPC1580, the photocurrent that is produced turns on the NPN bipolar transistor and provides the charge (I x t = Q) plus the charge of the capacitor to turn on the MOSFET rapidly. If sufficient input control current is not flowing, the LED is turned off, and gate current is not flowing. The LED is off due to the VF<< the minimum forward voltage required and not enough current being applied. This turns on the PNP bipolar transistor, which provides a path for QG to discharge to VS. When VL is first applied, the external storage capacitor begins to charge. The value of the storage capacitor should be equal to or greater than the MOSFET gate capacitance: this will ensure proper operation. The charge is sent through a bootstrap diode to prevent the charge from escaping and discharging through a turned-on MOSFET. The input control current is applied, then the charge is transferred from the storage capacitor through the NPN bipolar transistor, 6 along with the charge from the photovoltaics, to the MOSFET gate to accomplish a rapid turn-on. After the capacitor has discharged and the MOSFET has turned on, the photocurrent from the input optocoupler continues to flow into the gate to keep the MOSFET turned on. When the input control current is removed, the gate current stops flowing and the PNP bipolar transistor is on and is discharging the MOSFET gate. The MOSFET is now off. At this point, the capacitor begins to recharge for the next turn-on cycle. 4. Device Configuration 4.1 LED Resistor LED resistor selection should comply with the recommended operating conditions. This will provide reliability to the design, and should help with temperature. The CPC1580 is capable of being operated at up to the maximum ratings, but this is not recommended. It will shorten the life-span of the device and could cause temperature problems that will produce inaccuracies. The reason for using a higher IF current is to provide for faster turn-on. Proper design will have to be used to decide on the needs of the application. The equation used to calculate the resistor value: RLED = • • • • VIN - VF IF IF = Input Control Current VIN = Input Power Source VF = Forward Voltage Drop of LED RLED = Input Resistor connected to LED 4.2 Storage Capacitor Selection The storage capacitor (CST) enables the part to turn on quickly by holding a reservoir of charge to be transferred to the gate of the MOSFET. The turn-off cycle does not depend on the storage capacitor. The equation used to calculate the value of the charge storage capacitor is: www.ixysic.com CST > QG VLOAD - VCAP (FARADS) R01 INTEGRATED CIRCUITS DIVISION CPC1580 Where VCAP > 15V and QG is the total gate charge (listed in the MOSFET data sheet). The storage capacitor needs to deliver enough charge to the gate without going below the 15V required for switching the MOSFET. This means that VLOAD must equal, at a minimum, 15.7V. The part can operate at a lower voltage, but the MOSFETs will be turned on slowly. The proper selection of a capacitor is important. The rated voltage should be at least two to three times the VCAP . The extra margin is important because some capacitors lose capacitance when operated at their full rated voltages. When selecting a capacitor, be sure to add in their tolerance because of capacitor drift. For example: • CST = 1F, 20% tolerance; VCAP = 15V • 1F x 20% = 0.2F • 1F + 0.2F = 1.2F Capacitance drift can also be due to temperature and the dielectrics used. Therefore, the required capacitor value is 12F or next higher value, and the capacitor voltage rating must be at least 30 volts. It is recommended to go higher in the voltage rating if engineering restraints permit, such as 50V. Temperature requirements for capacitors are application-specific. The designer must know the intended operating temperature when selecting capacitors. The information given above should be applied to other capacitors discussed in this data sheet. The CPC1580 can deliver 32nC at the rated operating speed and will operate with much larger loads (>4F) with slower turn-on and turn-off times. Note: Care must be taken to minimize any capacitor-to-ground leakage current path between pins 7 and 8 (MOSFET gate current) and between pins 5 and 6. Leakage currents will discharge the storage capacitor and, even though the device is already on, will become a load to the photocurrent, which keeps the gate voltage on. The gate voltage will be reduced if >500nA of leakage is present, therefore the combined impedance from pin 8 to pin 7, pin 5, and pin 6, capacitor current, and MOSFET current must be >20M over the temperature rating of the part. 4.3 Transistor Selection The CPC1580 charges and discharges an external MOSFET transistor. The selection of the MOSFET is determined by the user to meet the specific power requirements for the load. The CPC1580 output voltage is listed in the specifications, but as mentioned earlier, there must be little or no gate leakage. Another parameter that plays a significant role in the selection of the transistor is the gate drive voltage available from the part. The CPC1580 uses photovoltaic cells to collect the optical energy generated by the LED; to generate more voltage, the photovoltaic diodes are stacked. The voltage change of the photovoltaic stack reduces with increased temperature. The user must select a transistor that will maintain the load current at the maximum temperature, given the VGS in Section 1.7, the CPC1580 Table of Electrical Specifications. The example circuits shown in Figure 1 and Figure 3 use “logic level” MOSFETs for each design to maintain the load described. 4.3.1 Transistor Switching Characteristics The primary characteristics of the application switching are ton, toff, tRISE, tFALL, and the recovery time of the storage capacitor, tCHG. These parameters are dependent on the MOSFET selection and need to be reviewed in light of the application requirements. The CPC1580 turns on the MOSFET transistor to the specified VGS after the ton delay. Similarly the toff delay is the amount of time until the LED is turned off and the capacitive load discharges to the level in the CPC1580 specification. For MOSFETs with larger or smaller required gate charge the ton and toff will be proportionately faster and slower, but it is not a linear relationship. To calculate the nominal rise time of the transistor's drain voltage, VD: tRISE,VD ~ (SECONDS) IG_SINK To calculate the nominal fall time of the transistor's drain voltage, VD: tFALL,VD ~ R01 VLOAD • CRSS www.ixysic.com VLOAD • CRSS IG_SOURCE (SECONDS) 7 INTEGRATED CIRCUITS DIVISION CPC1580 Where CRSS is the MOSFET gate-drain capacitance (averaged over the switching voltage range) found in the MOSFET data sheet, IG_SINK is the gate sinking current of the CPC1580, and IG_SOURCE is the gate driving ability. The maximum value of tRISE is limited by the CPC1580 unloaded discharge characteristic and should be reviewed in light of the final application component selections if critical. ROVP and COVP are optional over-voltage protection elements that are present in the application circuit diagram (see Figure 3). The term inside the logarithm reflects the discharge and recharge voltage on CST. For practical circuit component selection, this can be simplified as described above. Use this information to calculate the maximum switching frequency in Section 7 below. The value for the charge time, tCHG, is due to external component selection. The storage capacitor charge recovery time (seconds) is computed as: tCHG ~ - (400 + ROVP) • (CST + COVP) • ln ( (VLOAD - VFINAL) • CST QG Note: The CPC1580 is ideal to use where remote power is otherwise unavailable. If the LED is also powered remotely, care must be taken to ensure that parasitic transient signals are reliably filtered from the input control signal. Large transient currents will mutually couple energy between cables and a simple R-C filtering of the CPC1580 input may be sufficient to suppress false turn-on. ) Which reduces to: tCHG ~ - (400 + ROVP) • (CST + COVP) • 3 Figure 2. CPC1580 AC Application Circuit CPC1580 1 4 * 8 VCAP NC CST 7 LED - 2 +/- VLOAD Q1 5 LED + LOAD VD NC VG Q2 3 6 +/- VLOAD VS * Minimum Blocking Voltage = 100V 5. CPC1580 Over-Voltage Protection Over-voltage protection is generally required for the CPC1580 because of parasitic inductance in the load, wires, board traces, and axial leads of protectors. Purely resistive loads or loads with low voltage switching may be able to rely on the transistor to handle any parasitic energy and thereby not require 8 protection for the CPC1580. For very low inductance loads and traces, over-voltage suppression may be handled with a simple R-C filter consisting of ROVP and COVP, or by use of a free-wheeling diode (see Figure 3). For more moderate load inductance, or remote switching of a load (i.e. through a long cable) a voltage suppressor can be used. For heavily inductive loads only a free-wheeling diode, DOVP, connected www.ixysic.com R01 INTEGRATED CIRCUITS DIVISION CPC1580 across the load element is recommended, see Figure 3. The consequence of increasing the gate-drain effective capacitance is reduced dV/dt tolerance. The energy not consumed in switching losses must be absorbed by the over-voltage protection element. Most protective devices are designed to withstand certain peak power, in the case of a Transient Voltage Suppressor (TVS); or maximum avalanche energy, in the case of a MOSFET. Understanding the switching losses and load dynamics is absolutely essential. When used in a circuit with an inductive load, precautions must be taken to prevent damage to the circuit from inductively generated voltage spikes. The circuit shown in Figure 3 includes such protection across the inductive load. 5.1 Other Protection Techniques One simple way to reduce the amount of stored inductive energy is to increase the energy dissipated in the switch. This can be accomplished by adding a larger capacitor in parallel with the gate-drain connection of the MOSFET, however care must be taken so that the rise time and peak current do not exceed the Safe Operating Area (SOA) rating of the transistor. Switching loads with higher inductance characteristics requires consideration of other circuit protection techniques, device ratings, or protector types. Of paramount importance is that the designer know the characteristics of the load being switched. Figure 3. CPC1580 Over-Voltage Protection for Inductive Loads DOVP CPC1580 1 4 CST 8 VCAP NC ROVP 7 VD NC ZLOAD +VLOAD COVP RLED VIN+ VIN- 5 2 VG LED + 3 LED - Q1 6 -VLOAD VS 6. Application Switching Losses During the transition intervals, the application and load components change energy states and, in the process, incur switching losses. The switching losses are manifested as heat in the application circuit and must be addressed by the designer to ensure that no one component exceeds its power rating. The designer must understand the details of the load behavior in order to adequately size and protect the application circuit. There are three general cases to observe: (1) purely resistive loads, R01 (2) inductive/resistive loads, and (3) loads with significant capacitance. Inductors and capacitors are energy storage elements that require special consideration for switching. During the switching periods, energy is conserved. Inductors turning off transfer their stored energy to MOSFET switching losses, to the capacitance of the load and application circuit, and to the protector. During the turn-on interval, the inductor energy is zero, and so the capacitive energy in the load and parasitic elements of the switching application must be www.ixysic.com 9 INTEGRATED CIRCUITS DIVISION CPC1580 6.3 Capacitive Loads dissipated by the MOSFET, in order for the load to change state. The energy absorbed by the MOSFET for loads that are more capacitive in nature occurs during the MOSFET turn-on as opposed to the turn-off. The energy absorbed by the MOSFET will be a function of the load, the TVS (or other protector), and the MOSFET drain capacitance. The MOSFET energy, EFALL, in Joules is: To calculate the stored inductive energy in Joules: EL = 1 • L • ILOAD2 2 6.1 Resistive Load Losses: The Ideal Case For purely resistive loads, the energy dissipated by changing states occurs primarily in the MOSFET. EFALL = The equation describing MOSFET energy dissipation during rise time, in Joules, is: ERISE > VLOAD2 • CRSS • IG_SINK ILOAD 6 = PLOAD 6 • tRISE The average power of the MOSFET for any load type in Watts is: PAVG = ILOAD2 • RDSAT • D + fSWITCH • (ERISE + EFALL) Where fSWITCH is the application switching frequency; RDSAT is the MOSFET’s on-resistance; D is the switch's operational duty cycle: D = ton/(ton+toff); and EFALL is MOSFET energy dissipation during fall time, in Joules. 6.2 Inductive/Resistive Loads If the load is resistive and inductive, and the inductance doesn't saturate, the load current during turn off, tRISE, in Amps is: ILOAD(t) = VLOAD RLOAD - IG_SINK LLOAD • CRSS • ( ) 2 LLOAD RLOAD • [ -R LOAD RLOAD LLOAD LLOAD • t • t-1+e ] and the MOSFET drain voltage during turn off, tRISE, in Volts is: VDRAIN(t) = IG_SINK CRSS • t The instantaneous power in the MOSFET will be the product of the two equations and the energy will be the integral of the power over time. 1 2 • (CTVS + COSS + CLOAD) • VLOAD2 COSS is the MOSFET output capacitance found in the data sheet. As mentioned earlier, the MOSFET switching losses occur at different times, either rising or falling, so loads with a combination of inductance and capacitance can also be calculated by the energy equations described above. 6.4 dV/dt Characteristics The application circuit shown in Figure 1 dissipates significant energy caused by large dV/dt events. Fault voltages across the MOSFET will turn it on for the same reason the part turns off slowly. For dV/dt events > IG_SINK/CRSS (from Equation 2) the application circuit will dissipate energy proportional to the CRSS and gFS (forward conductance) of the selected transistor. CRSS is a function of the transistor's on-resistance and current/power capability, so higher load designs are more sensitive. The CPC1580 provides an internal clamp to protect the gate of the MOSFET from damage in such an event. The part can withstand 100mA for short periods, like dV/dt transients. 7. Design Switching Frequency The maximum switching frequency is the last design value to be calculated, because the over-voltage protection and the storage capacitor play a significant role in determining the result. Inasmuch as those factors are already determined, the following gives a good approximation for the maximum switching frequency. The maximum switching frequency is a function of the gate charge of the MOSFET, the storage capacitor (CST), and ROVP. The maximum switching frequency relationship in Hz is: Where: 10 www.ixysic.com R01 INTEGRATED CIRCUITS DIVISION fMAX < CPC1580 1 -1 • (ton + toff + (tRISE,VD | tCHG) + tFALL,VD) M • M=3 (multiplication factor for temperature and process variations • ton and toff are CPC1580 data sheet parameters • tRISE, VD is the rise time of the drain voltage and tCHG is the charge time of the storage capacitor and the over-voltage protection circuitry as derived in Section 4.3: choose the greater of tRISE,VD or tCHG for the calculation • tFALL,VD is the fall time across the transistor There is no minimum switching frequency since the CPC1580 uses photovoltaic diodes to keep the output charged while LED current flows. R01 www.ixysic.com 11 INTEGRATED CIRCUITS DIVISION CPC1580 8. Manufacturing Information 8.1 Moisture Sensitivity All plastic encapsulated semiconductor packages are susceptible to moisture ingression. IXYS Integrated Circuits Division classified all of its plastic encapsulated devices for moisture sensitivity according to the latest version of the joint industry standard, IPC/JEDEC J-STD-020, in force at the time of product evaluation. We test all of our products to the maximum conditions set forth in the standard, and guarantee proper operation of our devices when handled according to the limitations and information in that standard as well as to any limitations set forth in the information or standards referenced below. Failure to adhere to the warnings or limitations as established by the listed specifications could result in reduced product performance, reduction of operable life, and/or reduction of overall reliability. This product carries a Moisture Sensitivity Level (MSL) rating as shown below, and should be handled according to the requirements of the latest version of the joint industry standard IPC/JEDEC J-STD-033. Device Moisture Sensitivity Level (MSL) Rating CPC1580 MSL 1 8.2 ESD Sensitivity This product is ESD Sensitive, and should be handled according to the industry standard JESD-625. 8.3 Reflow Profile This product has a maximum body temperature and time rating as shown below. All other guidelines of J-STD-020 must be observed. Device Maximum Temperature x Time CPC1580 260°C for 30 seconds 8.4 Board Wash IXYS Integrated Circuits Division recommends the use of no-clean flux formulations. However, board washing to remove flux residue is acceptable. Since IXYS Integrated Circuits Division employs the use of silicone coating as an optical waveguide in many of its optically isolated products, the use of a short drying bake could be necessary if a wash is used after solder reflow processes. Chlorine- or Fluorine-based solvents or fluxes should not be used. Cleaning methods that employ ultrasonic energy should not be used.. Pb 12 e3 www.ixysic.com R01 INTEGRATED CIRCUITS DIVISION CPC1580 8.5 CPC1580P Package 0 MIN / 0.102 MAX (0 MIN / 0.004 MAX) 2.540 ± 0.127 (0.100 ± 0.005) 6.350 ± 0.127 (0.250 ± 0.005) 7.620 ± 0.254 (0.300 ± 0.010) 9.398 ± 0.127 (0.370 ± 0.005) Pin 1 2.286 MAX. (0.090 MAX.) PCB Land Pattern 2.54 (0.10) 0.635 ± 0.127 (0.025 ± 0.005) 0.203 ± 0.013 (0.008 ± 0.0005) 9.652 ± 0.381 (0.380 ± 0.015) 8.70 (0.3425) 1.55 (0.0610) 0.65 (0.0255) 2.159 ± 0.025 (0.085 ± 0.001) 0.457 ± 0.076 (0.018 ± 0.003) 0.864 ± 0.120 (0.034 ± 0.004) Dimensions mm (inches) 8.6 CPC1580PTR Tape and Reel Specification 2.00 (0.079) 330.2 DIA. (13.00 DIA.) Top Cover Tape Thickness 0.102 MAX. (0.004 MAX.) Embossment W = 16.00 (0.63) 7.50 (0.295) Bo = 10.30 (0.406) K0 = 2.70 (0.106) K1 = 2.00 (0.079) Embossed Carrier 4.00 (0.157) P = 12.00 (0.472) Ao = 10.30 (0.406) User Direction of Feed Dimensions mm (inches) NOTES: 1. All dimensions carry tolerances of EIA Standard 481-2 2. The tape complies with all “Notes” for constant dimensions listed on page 5 of EIA-481-2 For additional information please visit our website at: www.ixysic.com IXYS Integrated Circuits Division makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication and reserves the right to make changes to specifications and product descriptions at any time without notice. Neither circuit patent licenses nor indemnity are expressed or implied. Except as set forth in IXYS Integrated Circuits Division’s Standard Terms and Conditions of Sale, IXYS Integrated Circuits Division assumes no liability whatsoever, and disclaims any express or implied warranty, relating to its products including, but not limited to, the implied warranty of merchantability, fitness for a particular purpose, or infringement of any intellectual property right. The products described in this document are not designed, intended, authorized or warranted for use as components in systems intended for surgical implant into the body, or in other applications intended to support or sustain life, or where malfunction of IXYS Integrated Circuits Division’s product may result in direct physical harm, injury, or death to a person or severe property or environmental damage. IXYS Integrated Circuits Division reserves the right to discontinue or make changes to its products at any time without notice. Specification: DS-CPC1580-R01 ©Copyright 2013, IXYS Integrated Circuits Division All rights reserved. Printed in USA. 7/11/2013 R01 www.ixysic.com 13