Second Generation egan FETs are Lead Free and Offer Improved Performance Alex Lidow, CEO, Efficient Power Conversion Corporation

Transcription

1 Second Generation egan FETs are Lead Free and Offer Improved Performance Alex Lidow, CEO, Efficient Power Conversion Corporation EFFICIENT POWER CONVERSION Since March, 11 Efficient Power Conversion Corporation (EPC) has launched the first five part numbers in a family of second generation enhancement mode gallium nitride (egan) FETs. In August, 11 EPC introduced a V, mω FET and a V, 1 mω FET. All of these new products are lead free, halogen free, RoHS compliant, and have significant improvements in their overall performance. These initial lead free products join the family of egan FETs introduced in March,. Additional lead free products are planned for introduction later in 11. Table 1 shows a comparison of key characteristics between the first generation and second generation V, V and V egan FETs [1,, 3,,,, 7,, 9, ]. In addition to the improvements shown in Table 1, there are several other areas of performance that have been enhanced in this new generation. Table 1 Part Number Package (mm) RoHS & Halogen Free T J(MAX) ( C) V DS V GS (max) Max R GS Q G typ Q G max Q GS typ Q GS max Q GD typ Q GD max Q OSS typ Q OSS max V TH typ Q RR I D (A) Pulsed I D (A) New! New! New! New! New! EPC1 LGA.1x1. No N/A 3. N/A. N/A 1. N/A EPC1 LGA.1x1. Yes EPC1 LGA 1.7x. No N/A 1 N/A. N/A. N/A 1. EPC1 LGA 1.7x. Yes EPC1 LGA.1x1. No 1 7. N/A 3 N/A 3.3 N/A 3 N/A 1. 1 EPC1 LGA.1x1. Yes EPC LGA 3.x1. No 1 7. N/A 1. N/A 3. N/A N/A 1. 1 EPC LGA 3.x1. Yes EPC1 LGA 1.7x.9 No N/A.37 N/A.9 N/A N/A EPC1 LGA 1.7x.9 Yes EPC1 Compared with EPC1 The four figures on the following page compare the V, A EPC1 (Figure 1) with the prior-generation EPC1 (Figure ) typical output and transfer characteristics. The new generation product performs significantly better at higher currents. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE 1

2 9 7 V GS = V = 3 GS C 1 C V DS = 3V V GS Gate-to-Source Voltage (V) Figure 1: EPC1(RoHS) typical output and transfer characteristics 9 7 V GS = V = 3 GS 7 Figure Transfer : Transfer Characteristics Characteristics C 1 C V DS = 3V V GS Gate-to-Source Voltage (V) Figure : EPC1 typical output and transfer characteristics In addition to less conduction loss at higher current, the new-generation EPC1 has improved R DS(ON) at lower gate-source voltages (see Figures 3 and comparisons below). This allows the user to realize the low R DS(ON) capability of the FETs with greater margin between the applied gate voltage and the V GS(MAX) of V. V GS necessary for significant conduction current has also increased, thereby reducing turn off time and increasing dv/dt immunity RFigure DS(ON) vs. 3: RV DS(on) GS for vs Various V GS for Various Currents Current I D = A I D = A I D = A I D = A I D = A I D = A I D = A I D = A Figure 3: EPC1 R DS(ON for various current levels. These RoHS parts are fully enhanced at A with V on the gate. Figure : EPC1 R DS(ON for various current levels. These older generation parts require V applied to the gate to be fully enhanced at A. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE

3 EPC1 Compared with EPC1 The EPC1 is a V, 33 A FET. The new generation product has been upgraded to an operating temperature of 1 C compared with 1 C for the prior generation, allowing the user more operating headroom. The graphs below compare the EPC1 (Figure ) with the prior-generation EPC1 (Figure ) typical output and transfer characteristics. As with the V FET discussed above, the new generation V product performs significantly better at higher currents and increased V GS necessary for significant current conduction. The new-generation EPC1 also has improved R DS(ON) at lower gate-source voltages (see comparisons in Figures 7 and ). 1 V GS = V = 3 GS 1 C 1 C V DS = 3V V GS Gate-to-Source Voltage (V) Figure : EPC1 (RoHS) typical output and transfer characteristics 1 V GS = 9 7 Figure Transfer : Characteristics C 1 C V DS = 3 V Figure : EPC1 (RoHS) typical output and transfer characteristics RFigure DS(ON) vs. 3: RV DS(on) GS for vs Various V GS for Various Currents Current I D = A I D = A I D = A I D = A 1 I D = A I D = A I D = A I D = A Figure 7: EPC1 R DS(ON) for various current levels. These RoHS parts are fully enhanced at A with V on the gate Figure : EPC1 R DS(ON) for various current levels. These older generation parts require V applied to the gate to be fully enhanced at A. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE 3

4 EPC1 Compared with EPC1 The EPC1 is a V, A FET. The new generation product has been upgraded to an operating temperature of 1 C compared with 1 C for the prior generation, allowing the user more operating headroom. The graphs below compare the EPC1 (Figure 9) with the prior-generation EPC1 (Figure ) typical output and transfer characteristics. As with the FETs discussed above, the new generation V product performs significantly better at higher currents and increased V GS necessary for significant current conduction. The new-generation EPC1 also has improved R DS(ON) at lower gate-source voltages (see comparisons in Figures 11 and 1). ID Drain Current (A) 3 1 V GS = ID Drain Current (A) 3 1 C 1 C V DS = 3 V Figure 9: EPC1 (RoHS) typical output and transfer characteristics ID Drain Current (A) 3 1 V GS = ID Drain Current (A) 1 C 1 C V DS = 3 V Figure : EPC1 typical output and transfer characteristics I D = A I D = A I D = 1 A I D = A 3 1 RFigure DS(ON) vs. 3: RV DS(ON) GS for vs Various V G for Various Currents Current I D = A I D = A I D = 1 A I D = A Figure 11: EPC1 R DS(ON) for various current levels. These RoHS parts are fully enhanced at 1 A with V on the gate Figure 1: EPC1 R DS(ON) for various current levels. These older generation parts require V applied to the gate to be fully enhanced at 1 A. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE

5 EPC Compared with EPC The four figures below compare the V, 1 A EPC (Figure 13) with the prior-generation EPC (Figure 1) typical output and transfer characteristics. Consistent with the three parts discussed above, the new generation V product also performs significantly better at higher currents. The EPC is also rated for A maximum ID (pulsed) compared with only A in the prior generation. Typical Figure 1: Output Typical Characteristics Output Characteristics V GS = Figure Transfer : Characteristics C 1 C V DS = 3 V Figure 13: EPC (RoHS) typical output and transfer characteristics. Note that the EPC is rated up to A pulsed. 3 1 V GS = 3 1 C 1 C V DS = 3 V Figure 1: EPC typical output and transfer characteristics Figure 3: R vs V for Various Current Figure : R vs V for Various Temperature In addition to a higher pulsed current rating and less conduction loss at higher current, the new-generation EPC has improved R DS(ON) at lower gate-source voltages (see Figure1 and 1 comparisons on the following page). This allows the user to realize the low R DS(ON) capability of the FETs with greater margin between the applied gate voltage and the V GS(MAX) of V. V GS necessary for significant conduction current has also increased, thereby reducing turn off time and increasing dv/dt immunity. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE

6 I D = A I D = A I D = A I D = A I D = A I D = A I D = A I D = A Figure 1: EPC R DS(ON) for various current levels. These RoHS parts are fully enhanced at A with V on the gate. Figure 1: EPC R DS(ON) for various current levels. These older generation parts require V applied to the gate to be fully enhanced at A. The dv/dt immunity is further improved in the second-generation EPC because of the significantly improved Miller ratio []. As can be seen in Table 1 above, the Miller ratio (Q GD /Q GS(VTH) ) has improved from a typical value of.3 down to a value of 1.3 for the EPC. EPC1 Compared with EPC1 The four figures below and on the following page compare the V, 3 A EPC1 (Figure 17) with the prior-generation EPC1 (Figure 1) typical output and transfer characteristics. Consistent with the four parts discussed above, the new generation V product also performs significantly better at higher currents. The EPC1 is also rated for 1 A maximum ID (pulsed) compared with only 1 A in the prior generation. 1 V GS = 1 C 1 C V D = 3 V Figure 17: EPC1 (RoHS) typical output and transfer characteristics. Note that the EPC1 is rated up to 1 A pulsed. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE

7 1 V GS = C 1 C V D = 3 V Figure 1: EPC1 typical output and transfer characteristics In addition to a higher pulsed current rating and less conduction loss at higher current, the new-generation EPC1 has improved R DS(ON) at lower gate-source voltages (see Figure 19 and comparisons below). This allows the user to realize the low R DS(ON) capability of the FETs with greater margin between the applied gate voltage and the V GS(MAX) of V. V GS necessary for significant conduction current has also increased, thereby reducing turn off time and increasing dv/dt immunity. 1 R DS(ON) vs. VDS(ON) GS for Various GS Currents I D = 3 A I D = A I D = A I D = 1 A I D = 3 A I D = A I D = A I D = 1 A Figure 19: EPC1 R DS(ON) for various current levels. These RoHS parts are fully enhanced at A with V on the gate. Figure : EPC1 R DS(ON) for various current levels. These older generation parts require V applied to the gate to be fully enhanced at A. The dv/dt immunity is further improved in the second-generation EPC1 because of the significantly improved Miller ratio [11]. As can be seen in Table 1 above, the Miller ratio (Q GD /Q GS (V TH )) has improved from a typical value of. down to a value of 1. for the EPC1. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE 7

8 New Technical Information The data sheets for the EPCXXX series of lead free egan FETs, starting with the EPC1, EPC1, EPC1, EPC and EPC1 have additional information to help the designer get the maximum performance from the product. Thermal resistance data is supplied for both DC and transient operation as shown in Figures 1 and below [1]. EPC1 and EPC1 Thermal Characteristics TYP R θjc Thermal Resistance, Junction to Case 1. C/W R θjb Thermal Resistance, Junction to Board 1 C/W R θja Thermal Resistance, Junction to Ambient (Note 1) C/W EPC Thermal Characteristics TYP R θjc Thermal Resistance, Junction to Case 1. C/W R θjb Thermal Resistance, Junction to Board 1 C/W R θja Thermal Resistance, Junction to Ambient (Note 1) C/W EPC1 and EPC1 Thermal Characteristics TYP R θjc Thermal Resistance, Junction to Case. C/W R θjb Thermal Resistance, Junction to Board 3 C/W R θja Thermal Resistance, Junction to Ambient (Note 1) C/W Note 1: RθJA is determinged with the device mounted on one square inch of copper pad, single layer oz. copper on FR board. See for details. Figure 1: Typical thermal resistance for EPC1, EPC1, EPC1, EPC and EPC1. ZθJB, Normalized Thermal Impedance, C/Watt 1 Duty Factors: Normalized Maximum Transient Thermal Impedance P DM t Single Pulse Notes: Duty Factor: D = t 1/t Peak T J = P DM x Z θjb x R θjb + T B t t p, Rectangular Pulse Duration, seconds Figure : Normalized ZθJB Curve Set for EPCXXX Products EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE

9 Assembly Considerations for Second Generation egan FETs There are three physical changes to the new generation of lead-free product. The first change is that there is a connection to the silicon substrate that has been brought to the surface (see Figures 3,, and ). It is advised that the substrate be connected to source potential to get the maximum dynamic performance from the device. The second change is the width of the solder bars. The EPC1, EPC1 and EPC1 all have μm wide solder bars compared with μm in the prior generation. The EPC and EPC1 both have a μm wide solder bar compared with μm in the prior generation. The third change is that the height of the solder bars has been increased from 7μm +/- to μm +/- for all the new generation parts. The added height allows for greater post-assembly clearance between the FET and the PCB. This clearance makes it easier to clean out foreign materials and avoids the harmful accumulation of particles. This terminal is connected to the substrate This terminal is connected to the substrate This dimension has been decreased to µm Figure 3: Magnified die photo of EPC1 or EPC1 indicating the solder bar that is connected to the silicon substrate and the decreased solder bar width. This dimension has been decreased to µm Figure : Magnified die photo of EPC indicating the solder bar that is connected to the silicon substrate and the decreased solder bar width. Summary The new-generation of egan FETs are lead free and halogen free and have improved electrical performance, matched with additional support documentation to help the system designer deliver leading edge egan FET based product faster and with less engineering effort. These products maintain backward compatibility with the prior generation of egan FETs from EPC [1]. This terminal is connected to the substrate This dimension has been decreased to µm Figure : Magnified die photo of EPC1 indicating the solder bar that is connected to the silicon substrate and the decreased solder bar width. This terminal is connected to the substrate This dimension has been decreased to µm Figure : Magnified die photo of EPC1 indicating the solder bar that is connected to the silicon substrate and the decreased solder bar width. EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE 9

10 [1] [] [3] [] [] [] [7] [] [9] [] [11] Johan Strydom, The egan FET-Silicon Power Shoot-Out: : Drivers, Layout, Power Electronics Technology, January 1, 11, [1] John Worman and Yanping Ma, Thermal Performance of EPC egan FETs, product-training/appnote_thermal_performance_of_egan_fets.pdf [13] EPC EFFICIENT POWER CONVERSION CORPORATION COPYRIGHT 11 PAGE