CPC1580P

Optically Isolated Gate Drive Circuit CPC1580 Features • • • • • • • 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 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. 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. Provided in a small 8-pin package, the CPC1580 provides 3750Vrms of input-to-output isolation. Applications • • • • • • Industrial Controls Instrumentation Medical Equipment Isolation Electronic Switching I/O Subsystems Appliances Approvals • UL recognized component: File # E76270 Ordering Information Part CPC1580P CPC1580PTR Description 8-Pin Flatpack (50/Tube) 8-Pin Flatpack (1000/Reel) Figure 1. CPC1580 Application Circuit Diagram CPC1580 1 4 NC NC 8 VCAP 7 CST V+ VD 5 LED + 2 VG Q1 LED - 3 6 VS V- DS-CPC1580 - R00G www.clare.com 1 CPC1580 1. Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Package Pinout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 General Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.7 Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3 3 3 3 4 4 5 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. External Part Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Storage Capacitor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Transistor Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Transistor Switching Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 7 7 4. CPC1580 Over-Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Other Protection Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Application Switching Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Resistive Load Losses: The Ideal Case. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Inductive/Resistive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Capacitive Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 dV/dt Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9 9 9 9 6. Design Switching Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Manufacturing Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Washing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Mechanical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Tape and Reel Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 11 11 11 11 2 www.clare.com R00G CPC1580 1. Specifications 1.1 Package Pinout 1.3 Pin Description Pin# 1 VCAP VD VS VG CPC1580P Pinout N/C LED + LED N/C 1 2 3 4 8 7 6 5 Name N/C LED + LED N/C VG VS VD VCAP Not connected Description Positive input to LED Negative input to LED Not connected Output, MOSFET Gate Control MOSFET Source Voltage MOSFET Drain Voltage Storage Capacitor 2 3 4 5 6 7 8 1.2 Absolute Maximum Ratings Parameter Blocking Voltage (VDS) Reverse Input Voltage Input Control Current Peak (10ms) Input Power Dissipation 1 Output Power Dissipation 2 Isolation Voltage (Input to Output) Operational Temperature Storage Temperature 1 2 1.4 ESD Rating Rating 65 5 50 1 150 500 3750 -40 to +110 -40 to +125 Units VP V mA A mW mW Vrms °C °C ESD Rating (Human Body Model) 1000 V Derate linearly 1.33mW/°C Derate linearly 6.0mW/°C Absolute maximum electrical ratings are at 25°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. R00G www.clare.com 3 CPC1580 1.5 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 1.6 Electrical Specifications 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. Parameter Load Side Characteristics Gate Voltage Conditions IF=2.5mA IF=5mA IF=10mA IF=2.5mA -40°C500nA 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 >20MΩ over the temperature rating of the part. 3. External Part Selection 3.1 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. 6 www.clare.com R00G CPC1580 3.2 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 1.6, the CPC1580 Table of Electrical Specifications. The example circuits shown in Figure 1 and Figure 2 use “logic level” MOSFETs for each design to maintain the load described. 3.2.1 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 by the CPC1580 unloaded discharge characteristic and should be reviewed in light of the final application component selections if critical. 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 QGATE ) Which reduces to: tCHG ~ - (400 + ROVP) • (CST + COVP) • 3 ROVP and COVP are optional over-voltage protection elements that are present in the application circuit diagram (see Figure 2). 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 6 below. 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. ~ VLOAD • CRSS IG_SINK (SECONDS) To calculate the nominal fall time of the transistor's drain voltage, VD: tFALL,VD ~ VLOAD • CRSS IG_SOURCE (SECONDS) 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 R00G www.clare.com 7 CPC1580 4. 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 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 2). 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 across the load element is recommended, see Figure 2. 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. 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. The consequence of increasing the gate-drain effective capacitance is reduced dV/dt tolerance. 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 2 includes such protection across the inductive load. 4.1 Other Protection Techniques 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 2. CPC1580 Over-Voltage Protection for Inductive Loads DOVP CPC1580 1 4 NC NC 8 VCAP 7 CST ROVP ZLOAD V+ VD COVP RLED VIN+ 5 2 LED + VG Q1 VIN- 3 LED - 6 VS V- 8 www.clare.com R00G CPC1580 5. 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, (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 dissipated by the MOSFET, in order for the load to change state. To calculate the stored inductive energy in Joules: EL = 1 2 • L • ILOAD2 5.2 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 • () LLOAD RLOAD 2 • [ -R LOAD RLOAD LLOAD • t-1+e LLOAD •t ] 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. 5.3 Capacitive Loads 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: EFALL = 1 2 • (CTVS + COSS + CLOAD) • VLOAD2 5.1 Resistive Load Losses: The Ideal Case For purely resistive loads, the energy dissipated by changing states occurs primarily in the MOSFET. The equation describing MOSFET energy dissipation during rise time, in Joules, is: ERISE > VLOAD2 • CRSS IG_SINK • ILOAD 6 = PLOAD 6 • tRISE 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. 5.4 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. 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. R00G www.clare.com 9 CPC1580 6. 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: FMAX < 1 -1 • (tON + tOFF + (tRISE,VD | tCHG) + tFALL,VD) M Where: • 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 3.2: 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. 10 www.clare.com R00G CPC1580 7. Manufacturing Information 7.1 Soldering For proper assembly, the component must be processed in accordance with the current revision of IPC/JEDEC standard J-STD-020. Failure to follow the recommended guidelines may cause permanent damage to the device resulting in impaired performance and/or a reduced lifetime expectancy. 7.3 Mechanical Dimensions 8 Pin Flatpack Package 2.540 ± 0.127 (0.100 ± 0.005) 6.350 ± 0.127 (0.250 ± 0.005) 9.398 ± 0.127 (0.370 ± 0.005) 2.159 TYP . (0.085 TYP .) 7.620 ± 0.254 (0.300 ± 0.010) 2.286 MAX. (0.090 MAX.) 7.2 Washing Clare does not recommend ultrasonic cleaning or the use of chlorinated hydrocarbons. Recommended PCB Land Pattern 2.54 (0.10) 0.635 ± 0.127 (0.025 ± 0.005) 0.65 (0.0255) 8.70 (0.3425) 0.203 (0.008) 8.077 ± 0.127 (0.318 ± 0.005) 9.652 ± 0.381 (0.380 ± 0.015) 2.159 TYP . (0.085 TYP .) Dimensions mm (inches) 1.55 (0.0610) 0.457 ± 0.076 (0.018 ± 0.003) 7.4 Tape and Reel Specification Tape and Reel Packaging for 8 Pin Flatpack Package W = 16.30 max (0.642 max) 330.2 DIA. (13.00 DIA.) 1 8 Bo = 10.30 (0.406) Top Cover Tape K0 = 2.70 (0.106) K1 = 2.00 (0.079) Top Cover Tape Thickness 0.102 MAX. (0.004 MAX.) P = 12.00 (0.472) Ao = 10.30 (0.406) Dimensions mm (inches) Embossed Carrier User Direction of Feed Embossment NOTE: Tape dimensions not shown comply with JEDEC Standard EIA-481-2 For additional information please visit our website at: www.clare.com Clare, Inc. 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 Clare’s Standard Terms and Conditions of Sale, Clare, Inc. 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 Clare’s product may result in direct physical harm, injury, or death to a person or severe property or environmental damage. Clare, Inc. reserves the right to discontinue or make changes to its products at any time without notice. Specification: DS-CPC1580-R00G ©Copyright 2007, Clare, Inc. All rights reserved. Printed in USA. 8/17/07 11