DEIC420 20 Ampere Low-Side Ultrafast RF MOSFET Driver Features Description • Built using the advantages and compatibility of CMOS and IXYS HDMOSTM processes • Latch-Up Protected • High Peak Output Current: 20A Peak • Wide Operating Range: 8V to 30V • Rise And Fall Times of <4ns • Minimum Pulse Width Of 8ns • High Capacitive Load Drive Capability: 4nF in <4ns • Matched Rise And Fall Times • 32ns Input To Output Delay Time • Low Output Impedance • Low Quiescent Supply Currentt TheDEIC420 is a CMOS high speed high current gate driver specifically designed to drive MOSFETs in Class D and E HF RF applications at up to 45MHz, as well as other applications requiring ultrafast rise and fall times or short minimum pulse widths. The DEIC420 can source and sink 20A of peak current while producing voltage rise and fall times of less than 4ns, and minimum pulse widths of 8ns. The input of the driver is compatible with TTL or CMOS and is fully immune to latch up over the entire operating range. Designed with small internal delays, cross conduction/current shoot-through is virtually eliminated in the DEIC420. Its features and wide safety margin in operating voltage and power make the DEIC420 unmatched in performance and value. Applications • • • • • • • • Driving RF MOSFETs Class D or E Switching Amplifier Drivers Multi MHz Switch Mode Power Supplies (SMPS) Pulse Generators Acoustic Transducer Drivers Pulsed Laser Diode Drivers DC to DC Converters Pulse Transformer Driver The DEIC420 is packaged in DEI's low inductance RF package incorporating DEI's patented (1) RF layout techniques to minimize stray lead inductances for optimum switching performance. For applications that do not require the power dissipation of the DEIC420, the driver is also available in a 28 pin SOIC package. See the IXDD415SI data sheet for additional information. The DEIC420 is a surface-mount device, and incorporates patented RF layout techniques to minimize stray lead inductances for optimum switching performance. (1) DEI U.S. Patent #4,891,686 Figure 1 - DEIC420 Functional Diagram Copyright © DIRECTED ENERGY, INC. 2001 First Release DEIC420 Absolute Maximum Ratings Parameter Supply Voltage All Other Pins Value 30V -0.3V to VCC + 0.3V Power Dissipation TAMBIENT ≤25 oC TCASE ≤25 oC Storage Temperature 2W 100W -65oC to 150oC Soldering Lead Temperature (10 seconds maximum) Parameter Maximum Junction Temperature Value 150oC -40oC to 85oC Thermal Impedance (Junction To Case) θJC 0.13oC/W Operating Temperature Range 300oC Electrical Characteristics Unless otherwise noted, TA = 25 oC, 8V ≤ VCC ≤ 30V . All voltage measurements with respect to DGND. DEIC420 configured as described in Test Conditions. Symbol Parameter VIH High input voltage VIL Low input voltage VIN Input voltage range IIN Input current VOH High output voltage VOL Low output voltage ROH Output resistance @ Output high Output resistance @ Output Low Peak output current ROL IPEAK IDC fMAX Continuous output current Maximum frequency (1) tR Rise time tF Fall time tONDLY PWmin On-time propagation (1) delay Off-time propagation (1) delay Minimum pulse width VCC Power supply voltage ICC Power supply current tOFFDLY (1) Test Conditions Min Typ Max 3.5 0V ≤ VIN ≤ VCC Units V 0.8 V -5 VCC + 0.3 V -10 10 µA VCC - .025 V 0.025 V IOUT = 10mA, VCC = 15V 0.4 0.6 Ω IOUT = 10mA, VCC = 15V 0.4 0.6 Ω VCC = 15V 20 A 4 A 45 MHz 3 4 3 3.5 32 38 ns ns ns ns ns CL=4nF Vcc=15V 29 35 ns FWHM CL=1nF Vcc=15V +3V to +3V CL=1nF Vcc=15V 8 9 15 30 ns ns V 3 10 10 mA µA µA CL=4nF Vcc=15V CL=1nF CL=4nF CL=1nF CL=4nF CL=4nF Vcc=15V VOH=2V to 12V Vcc=15V VOH=2V to 12V Vcc=15V VOH=12V to 2V Vcc=15V VOH=12V to 2V Vcc=15V 8 VIN = 3.5V VIN = 0V VIN = + VCC 1 0 (1) Refer to Figures 3a and 3b Specifications Subject To Change Without Notice 2 DEIC420 Lead Description - DEIC420 SYMBOL FUNCTION VCC Supply Voltage IN Input OUT Output GND Power Ground DESCRIPTION Positive power-supply voltage input. These leads provide power to the entire chip. The range for this voltage is from 8V to 30V. Input signal-TTL or CMOS compatible. Driver Output. For application purposes, this lead is connected, directly to the Gate of a MOSFET The system ground leads. Internally connected to all circuitry, these leads provide ground reference for the entire chip. These leads should be connected to a low noise analog ground plane for optimum performance. Note 1: Operating the device beyond parameters with listed “absolute maximum ratings” may cause permanent damage to the device. Typical values indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. The guaranteed specifications apply only for the test conditions listed. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. CAUTION: These devices are sensitive to electrostatic discharge; follow proper ESD procedures when handling and assembling this component. Figure 2 - DEIC420 Package Photo And Outline Figure 3a - Characteristics Test Diagram Figure 3b - Timing Diagram 5V 90% INPUT 2.5V 10% 0V PWMIN tONDLY VIN Vcc 90% OUTPUT 10% 0V 3 tR tOFFDLY tF DEIC420 Typical Performance Characteristics Rise Time vs. Load Capacitance VCC = 15V, VOH = 2V To 12V Fall Time vs. Load Capacitance VCC = 15V, VOH = 12V To 2V Fig. 5 5 5 4 4 3 3 Fall Time (ns) Rise Time (ns) Fig. 4 2 2 1 1 0 0 0 1k 2k 3k 0 4k 1k 2k Fig. 6 Supply Current vs. Frequency Vcc=15V 6 3k 4k Load Capacitance (pF) Load Capacitance (pF) Supply Current vs. Load Capacitance Vcc=15V Fig. 7 10 4 nF 5 40 MHz 2 nF 30 MHz 1 nF CL = 0 Supply Current (A) Supply Current (A) 4 3 2 20 MHz 1 10 MHz 5 MHz 1 1 MHz 0.1 0k 0 10 20 30 40 1k Frequency (MHz) 50 3k 4k Propagation Delay Times vs. Junction Temperature CL = 4nF, VCC = 15V Fig. 9 Propagation Delay Times vs. Input Voltage CL=4nF VCC=15V Fig. 8 2k Load Capacitance (pF) 50 45 tONDLY tONDLY 40 30 tOFFDLY 35 tOFFDLY Time (ns) Propagation Delay (ns) 40 20 30 25 20 10 15 0 10 2 4 6 8 10 12 -40 Input Voltage (V) -20 0 20 40 60 Temperature (°C) 4 80 100 120 DEIC420 Fig. 10 50 Propagation Delay vs. Supply Voltage CL=4nF VIN=5V@100kHz 40 Propagation Delay (ns) tONDLY 30 tOFFDLY 20 10 0 8 10 12 14 16 18 Supply Voltage (V) Typical Output Waveforms Unless otherwise noted, all waveforms are taken driving a 1nF load, 1MHz repetition frequency, VCC=15V, Case Temperature = 25°C Figure 11 Figure 13 3ns Rise Time Figure 12 Figure 14 <8ns Minimum Pulse Width 5 3ns Fall Time 1MHz CW Repetition Frequency DEIC420 Figure 15 13.56MHz CW Repetition Frequency Figure 16 Figure 17 - High Frequency Gate Drive Circuit 6 50MHz Burst Repetition Frequency DEIC420 APPLICATIONS INFORMATION High Frequency Gate Drive Circuit the DEIC420 and whatever logic is driving it. All three of these paths should be as low in resistance and inductance as possible, and thus as short as practical. The circuit diagram in figure 17 is a circuit diagram for a very high switching speed, high frequency gate driver circuit using the DEIC420. This is the circuit used in the EVIC420 Evaluation Board,and is capable of driving a MOSFET at up to the maximum operating limits of the DEIC420. The circuit's very high switching speed and high frequency operation dictates the close attention to several important issues with respect to circuit design. The three key elements are circuit loop inductance, Vcc bypassing and grounding. Output Lead Inductance Of equal importance to supply bypassing and grounding are issues related to the output lead inductance. Every effort should be made to keep the leads between the driver and its load as short and wide as possible, and treated as coplanar transmission lines. In configurations where the optimum configuration of circuit layout and bypassing cannot be used, a series resistance of a few Ohms in the gate lead may be necessary to prevent ringing. Circuit Loop Inductance Referring to Figure 17, the Vcc to Vcc ground current path defines the loop which will generate the inductive term. This loop must be kept as short as possible. The output lead must be no further than 0.375 inches (9.5mm) from the gate of the MOSFET. Furthermore the output ground leads must provide a balanced symmetric coplanar ground return for optimum operation. Heat Sinking For high power operation, the bottom side metalized substrate should be placed in compression against an appropriate heat sink. The substrate is metalized for improved heat dissipation, and is not electrically connected to the device or to ground. Vcc Bypassing In order for the circuit to turn the MOSFET on properly, the DEIC420 must be able to draw up to 20A of current from the Vcc power supply in 2-6ns (depending upon the input capacitance of the MOSFET being driven). This means that there must be very low impedance between the driver and the power supply. The most common method of achieving this low impedance is to bypass the power supply at the driver with a capacitance value that is at least two orders of magnitude larger than the load capacitance. Usually, this is achieved by placing two or three different types of bypassing capacitors, with complementary impedance curves, very close to the driver itself. (These capacitors should be carefully selected, low inductance, low resistance, high-pulse current-service capacitors). Care should be taken to keep the lengths of the leads between these bypass capacitors and the DEIC420 to an absolute minimum. See the DEI technical note "DE-Series MOSFET and IC Mounting Instructions" on the DEI web site at www.directedenergy.com/apptech.htm for detailed mounting instructions. The package dimensions of the DEIC420 are identical to those of the DE-275 MOSFET. The bypassing should be comprised of several values of chip capacitors symmetrically placed on ether side of the IC. Recommended values are .01uF, .47uF chips and at least two 4.7uF tantalums. Grounding In order for the design to turn the load off properly, the DEIC420 must be able to drain this 20A of current into an adequate grounding system. There are three paths for returning current that need to be considered: Path #1 is between the DEIC420 and its load. Path #2 is between the DEIC420 and its power supply. Path #3 is between Directed Energy, Inc. An IXYS Company 2401 Research Blvd. Ste. 108, Ft. Collins, CO 80526 Tel: 970-493-1901; Fax: 970-493-1903 e-mail: [email protected] www.directedenergy.com 7 Doc #9200-0230 Rev 2