ZXGD3107N8 SYNCHRONOUS MOSFET CONTROLLER IN SO-8 Description Features ZXGD3107N8 synchronous controller is designed for driving a MOSFET as an ideal rectifier. This is to replace a diode for increasing the power transfer efficiency. Proportional Gate Drive to Minimize Body Diode Conduction Low Standby Power with Quiescent Supply Current < 1mA 4.5V Operation Enables Low Voltage Supply 40V VCC Rating Proportional Gate drive control monitors the reverse voltage of the MOSFET such that if body diode conduction occurs, a positive voltage is applied to the MOSFET's GATE pin. Once the positive voltage is applied to the Gate, the MOSFET switches on allowing reverse current flow. The controllers' output voltage is then proportional to the MOSFET drain-source voltage and this is applied to the Gate via the driver. This action minimizes body diode conduction while enabling a rapid MOSFET turn-off as drain current decays to zero. 200V Drain Voltage Rating Operation up to 500kHz Critical Conduction Mode (CrCM) & Continuous Mode (CCM) Compliant with Eco-Design Directive Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony free. "Green" Device (Note 3) Applications Mechanical Data Flyback Converters in: AC-DC Adaptors Set-Top Boxes PoE Power Devices Resonant Converters in: Telecoms PSU Laptop Adaptors Computing Power Supplies - ATX and Server PSU Case: SO-8 Case Material: Molded Plastic. Green Molding Compound. UL Flammability Rating 94V-0 Moisture Sensitivity: Level 1 per J-STD-020 Terminals: Matte Tin Finish. Solderable per MIL-STD-202, Method 208 Weight: 0.074 grams (Approximate) Typical Configuration Transformer SO-8 Vout RBIAS RREF REF BIAS ZXGD3107 DRAIN GATE VCC GATE DNC GND BIAS DNC Vcc C1 GND VG DRAIN REF GND VD Top View Pin-Out Top View Synchronous Rectifier MOSFET Pin Name VCC DNC BIAS DRAIN REF GND GATE Pin Function Power Supply Do Not Connect Bias Current Drain Sense Reference Current Power Ground Gate Drive Ordering Information (Note 4) Product ZXGD3107N8TC Notes: Marking ZXGD3107 Reel Size (inches) 13 Tape Width (mm) 12 Quantity Per Reel 2,500 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated's definitions of Halogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green" products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. 4. For packaging details, go to our website at http://www.diodes.com/products/packages.html. Marking Information ZXGD 3107 YY WW ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 ZXGD = Product Type Marking Code, Line 1 3107 = Product Type Marking Code, Line 2 YY = Year (ex: 17 = 2017) WW = Week (01 to 53) 1 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Functional Block Diagram Vcc ZXGD3107N8 ZXGD3107 + Gate drive amplitude control Diff - amp DRAIN + - Hi volt comparator Turn-on/off control Driver GATE Threshold voltage control REF BIAS GND Pin Number Pin Name Pin Function and Description 1 VCC Power supply This supply pin should be closely decoupled to ground with a ceramic capacitor. 2, 6 DNC Do not connect Leave pin floating. 3 BIAS Bias Connect this pin to VCC via RBIAS resistor. Select RBIAS to source 0.56mA into this pin. Refer to Table 1 and 2, in Application Information section. 4 DRAIN 5 REF Drain sense Connect directly to the synchronous MOSFET drain terminal. Reference Connect this pin to VCC via RREF resistor. Select RREF to source 1.23mA into this pin. Refer to Table 1 and 2, in Application Information section. 7 GND Ground Connect this pin to the synchronous MOSFET source terminal and ground reference point. 8 GATE Gate drive This pin sinks and sources the ISINK and ISOURCE current to the synchronous MOSFET Gate. ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 2 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Absolute Maximum Ratings (@TA = +25C, unless otherwise specified.) Characteristic Supply Voltage, Relative to GND Drain Pin Voltage Gate Output Voltage Gate Driver Peak Source Current Gate Driver Peak Sink Current Reference Voltage Reference Current Bias Voltage Bias Current Symbol VCC VD VG ISOURCE ISINK VREF IREF VBIAS IBIAS Value 40 -3 to 200 -3 to VCC + 3 4 9 VCC 25 VCC 100 Unit V V V A A V mA V mA Unit Thermal Characteristics (@TA = +25C, unless otherwise specified.) Characteristic Symbol RJL Value 490 3.92 655 5.24 720 5.76 785 6.28 255 191 173 159 55 RJC 45 TJ TSTG -40 to +150 -50 to +150 (Note 5) (Note 6) Power Dissipation Linear Derating Factor PD (Note 7) (Note 8) Thermal Resistance, Junction to Lead (Note 5) (Note 6) (Note 7) (Note 8) (Note 9) Thermal Resistance, Junction to Case (Note 10) Thermal Resistance, Junction to Ambient Operating Temperature Range Storage Temperature Range RJA mW mW/C C/W C/W C/W C ESD Ratings (Note 11) Characteristic Electrostatic Discharge - Human Body Model Electrostatic Discharge - Machine Model Notes: Symbol Value Unit JEDEC Class ESD HBM ESD MM 1,500 200 V V 1C B 5. For a device surface mounted on minimum recommended pad layout FR-4 PCB with high coverage of single sided 1oz copper, in still air conditions; the device is measured when operating in a steady-state condition. 6. Same as note (5), except pin 1 (VCC) and pin 7 (GND) are both connected to separate 5mm x 5mm 1oz copper heatsinks. 7. Same as note (6), except both heatsinks are 10mm x 10mm. 8. Same as note (6), except both heatsinks are 15mm x 15mm. 9. Thermal resistance from junction to solder-point at the end of each lead on pin 1 (VCC) or pin 7 (GND). 10. Thermal resistance from junction to top of the case. 11. Refer to JEDEC specification JESD22-A114 and JESD22-A115. ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 3 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Max Power Dissipation (W) Thermal Derating Curve 0.8 15mm x 15mm 0.7 10mm x 10mm 0.6 0.5 5mm x 5mm 0.4 Minimum Layout 0.3 0.2 0.1 0.0 0 20 40 60 80 100 120 140 160 C) Junction Temperature ( ( C) Derating Curve ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 4 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Electrical Characteristics (@TA = +25C, unless otherwise specified.) VCC = 10V; RBIAS = 18k (IBIAS = 0.56mA); RREF = 7.5k (IREF = 1.23mA) Characteristic Input Supply Supply to GND Voltage Supply to GND Voltage Drain to GND Voltage Quiescent Current Gate Driver Gate Peak Source Current Gate Peak Sink Current Detector under DC Condition Turn-off Threshold Voltage Gate Output Voltage Symbol Min Typ Max Unit VCC(ON) VCC(OFF) VD IQ 40 40 200 -- -- -- -- 1.79 -- -- -- -- V V V mA VD = -100mV @ ICC = 10A VD = 1V @ ICC = 10A ID = 1A VD 0mV ISOURCE ISINK -- -- 2 7 -- -- A Capacitive load: CL = 20nF VT VG(OFF) -20 -- 5.0 8.0 -10 0.2 7.8 9.4 0 0.6 -- -- -- -- -- -- 70 175 15 20 -- -- -- -- VG Switching Performance Turn-on Propagation Delay Gate Rise Time Turn-off Propagation Delay Gate Fall Time tD(RISE) tR tD(FALL) tF mV V ns Test Condition VG = 1V VD 1V VD = -50mV VD = -100mV Capacitive load only Rise and fall measured 10% to 90% Refer to application test circuit below Test Circuit for Switching Performance Flyback transformer Magnetising inductance = 820H Vcc = 10V Output load RBIAS 18K RREF 7.5K REF BIAS Vcc ZXGD3107 DRAIN GATE GND VG C1 1uF Test conditions Switching frequency = 100kHz Continuous conduction mode VD MOSFET Qg(tot) = 82nC RDS(on) = 15m ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 5 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Typical Electrical Characteristics (@TA = +25C, unless otherwise specified.) 14 VCC = 15V 12 VCC = 12V 10 VCC = 10V VG Gate Voltage (V) VG Gate Voltage (V) 14 8 6 VCC = 5V 4 2 Capacitive load only 0 -100 -80 -60 -40 -20 VCC = 15V 12 VCC = 12V 10 VCC = 10V 8 6 4 2 VCC = 5V Capacitive load and 50k pull down 0 -100 0 -80 Transfer Characteristic o T A = 125 C 6 VCC = 10V RBIAS=18k 2 RREF=9.1k 50k pull down 0 -100 -80 -60 -40 -20 0 Switching Time (ns) 0 0 VCC = 10V -5 RBIAS=18k RREF=7.5k -10 VG = 1V 50k pull down -15 -20 -25 -30 -50 0 50 100 150 Temperature ( C) Turn-off Threshold Voltage vs Temperature Transfer Characteristic 180 230 220 210 200 190 180 170 160 150 140 130 tON = tD(RISE) + tR VCC = 10V RBIAS=18k RREF=7.5k tOFF = tD(FALL) + tF CL=10nF 35 30 -50 -20 o VD Drain Voltage (mV) -25 0 25 50 75 o 100 125 150 Supply Current (mA) VG Gate Voltage (V) o T A = 25 C Turn-off Threshold Voltage (mV) o T A = -40 C 4 -40 Transfer Characteristic 10 8 -60 VD Drain Voltage (mV) VD Drain Voltage (mV) 160 RBIAS=18k 140 RREF=7.5k 100 VCC = 12V VCC = 10V 80 60 40 20 0 VCC = 5V 0 2 4 6 8 10 12 14 16 18 20 22 Capacitance (nF) Switching vs Temperature Document number: DS37887 Rev. 2 - 2 f=500kHz 120 Temperature ( C) ZXGD3107N8 VCC = 15V Supply Current vs Capacitive Load 6 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Typical Electrical Characteristics (Cont.) (@TA = +25C, unless otherwise specified.) 10 10 VG 8 VCC=10V 6 VD Voltage (V) Voltage (V) 8 RBIAS=18k RREF=7.5k 4 CL=10nF RL=0.1 2 0 VCC=10V 6 4 RBIAS=18k VG VD RREF=7.5k CL=10nF RL=0.1 2 0 -2 -100 0 100 200 -2 -200 300 -100 Time (ns) 0 100 200 300 Time (ns) Switch On Speed Switch Off Speed Time (ns) tON = tD(RISE) + tR 100 tOFF= tD(FALL) + tF VCC=10V RBIAS=18k RREF=7.5k RL=0.1 10 1 10 Gate Drive Current (A) 4 ISOURCE 2 0 -2 VCC=10V -4 RBIAS=18k -6 CL=10nF RREF=7.5k ISINK RL=0.1 -8 0 100 200 400 600 Time (ns) Capacitance (nF) Gate Drive Current Switching vs Capacitive Load VCC=10V VCC=10V 8 RBIAS=18k Supply Current (mA) Peak Drive Current (A) 10 -ISINK RREF=7.5k 6 RL=0.1 4 ISOURCE 2 0 1 10 RBIAS=18k 100 RREF=7.5k RL=0.1 CL=10nF CL=3.3nF 10 100 Gate Current vs Capacitive Load Document number: DS37887 Rev. 2 - 2 CL=33nF CL=1nF Capacitance (nF) ZXGD3107N8 CL=100nF 7 of 14 www.diodes.com 1 10 100 1000 10000 100000 Frequency (Hz) Supply Current vs Frequency April 2017 (c) Diodes Incorporated ZXGD3107N8 Application Information The purpose of the ZXGD3107N8 is to drive a MOSFET as a low-VF Schottky diode replacement in isolated AC-DC converter. When combined with a low RDS(ON) MOSFET, the controller can yield significant power-efficiency improvement, while maintaining design simplicity and incurring minimal component count. Figure 1 shows the typical configuration of ZXGD3107N8 for synchronous rectification in a low output voltage flyback converter. +Vout Transformer + In Rref Rbias REF Csnub Rsnub DRAIN BIAS Vcc ZXGD3107 GATE C1 GND Rd G Dsnub D S - Vout Synchronous MOSFET PWM controller CCM/CrCM/DCM - In Figure 1. Typical Flyback Application Schematic Threshold Voltage and Resistor Setting Proper selection of external resistors RREF and RBIAS is important for optimum device operation. RREF and RBIAS supply fixed current into the REF and BIAS pins of the controller. IREF and IBIAS combines to set the turn-off threshold voltage level, VT. In order to set VT to -10mV, the recommended IREF and IBIAS are 1.23mA and 0.56mA respectively. The values for RREF and RBIAS are selected based on the VCC voltage. If the VCC pin is connected to the power converter's output, the resistors should be selected based on the nominal converter's output voltage. Table 1 provides the recommended resistor values for different VCC voltages to achieve a VT of -10mV. Supply, VCC Bias Resistor, RBIAS Reference Resistor, RREF 5V 9.6k 4k 10V 18k 7.5k 12V 24k 9.6k 15V 30k 12k Table 1. Recommended Resistor Values for Different VCC Voltages ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 8 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Application Information (Cont.) Functional Descriptions The operation of the device is described step-by-step with reference to the timing diagram in Figure 2. 1. The detector stage monitors the MOSFET drain-source voltage. 2. When, due to transformer action, the MOSFET body diode is forced to conduct there is a negative voltage on the drain pin due to the body diode forward voltage. 3. When the negative drain voltage crosses the turn-off Threshold voltage VT, the detector stage outputs a positive voltage with respect to ground after the turn-on delay time tD(FALL). This voltage is then fed to the MOSFET driver stage and current is sourced out of the GATE pin. 4. The controller goes into Proportional Gate drive control -- the Gate output voltage is proportional to the MOSFET on-resistance-induced drainsource voltage. Proportional Gate drive ensures that MOSFET conducts during majority of the conduction cycle to minimize power loss in the body diode. 5. As the drain current decays linearly toward zero, Proportional Gate drive control reduces the Gate voltage so the MOSFET can be turned off rapidly at zero current crossing. The Gate voltage falls to 1V when the drain-source voltage crosses the detection threshold voltage to minimize reverse current flow. 6. At zero drain current, the controller Gate output voltage is pulled low to VG(OFF) to ensure that the MOSFET is off. MOSFET Drain Voltage VD 1 VT Body Diode Conduction 2 3 90% MOSFET Gate Voltage 4 5 VG 90% 10% 6 10% td(rise) D(RISE) MOSFET Drain Current VVG(off) G(OFF) tfF ttrR td(fall) tD(FALL) ID 0A Figure 2. Timing Diagram for a Critical Conduction Mode Flyback Converter ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 9 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Application Information (Cont.) Gate Driver The controller is provided with single channel high-current Gate drive output, capable of driving one or more N-channel power MOSFETs. The controller can operate from VCC of 4.5V to drive both standard MOSFETs and logic level MOSFETs. The GATE pin should be as close to the MOSFET's Gate as possible. A resistor in series with GATE pin helps to control the rise time and decrease switching losses due to Gate voltage oscillation. A diode in parallel to the resistor is typically used to maintain fast discharge of the MOSFET's Gate. REF BIAS DRAIN VCC GATE GND Figure 3. Typical Connection of the ZXGD3107N8 to the Synchronous MOSFET When the VCC/VOUT exceeds the maximum VGSS of the MOSFET (typically 20V) then GATE drive voltage needs reducing. It is recommended to regulate the voltage on RBIAS as this fixes the max GATE output voltage level. The VCC pin can be directly driven from the VOUT up to a max of 40V, and if the converter's output voltage is higher than 40V then it is also recommended to tie the VCC pin to a series voltage regulator. Figure 4 shows an example for 24V converter output, using the ZXTR2012FF regulator transistor to give a regulated 12V for the MOSFET gate drive. Figure 4. Reduce GATE Drive Voltage to Less than the VGSS Max of the MOSFET using 12V Regulator Transistor ZXTR2012FF. ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 10 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Application Information (Cont.) Quiescent Current Consumption The quiescent current consumption of the controller is the sum of IREF and IBIAS. For an application that requires ultra-low standby power consumption, IREF and IBIAS can be further reduced by increasing the value of resistor RREF and RBIAS. Bias Current IBIAS Ref Current IREF Bias Resistor RBIAS Ref Resistor RREF Quiescent Current IQ 0.25 0.78 39.8k 11.9k 1.03mA 0.35 0.94 28.4k 9.8k 1.29mA 0.45 1.1 22.1k 8.4k 1.55mA 0.56 1.23 18k 7.5k 1.79mA 0.6 1.34 16.6k 6.9k 1.94mA 0.8 1.6 12.4k 5.8k 2.4mA Table 2. Quiescent Current Consumption for Different Resistor Values at VCC = 10V IREF also controls the Gate driver peak sink current whilst IBIAS controls the peak source current. At the default current value of I REF and IBIAS of 1.23mA and 0.56mA, the Gate driver is able to provide 2A source and 6A sink current. The Gate current decreases if IREF and IBIAS are reduced. Care must be taken in reducing the controller quiescent current so that sufficient drive current is still delivered to the MOSFET particularly for highswitching frequency application. Layout Guidelines When laying out the PCB, care must be taken in decoupling the ZXGD3107N8 closely to VCC and ground with 1F low-ESR, low-ESL X7R type ceramic bypass capacitor. If the converter's output voltage is higher than 40V, a series voltage regulator between the converter's output voltage and the VCC pin can be used to get a stable VCC voltage. GND is the ground reference for the internal high-voltage amplifier as well as the current return for the Gate driver. So the ground return loop should be as short as possible. Sufficient PCB copper area should be allocated to the VCC and GND pin for heat dissipation especially for highswitching frequency application. Any stray inductance involved by the load current may cause distortion of the drain-to-source voltage waveform, leading to premature turn-off of the synchronous MOSFET. In order to avoid this issue, drain-voltage sensing should be done as physically close to the drain terminals as possible. The PCB track length between the controller drain pin and MOSFET's terminal should be kept less than 10mm. MOSFET packages with low internal-wire-bond inductance are preferred for high-switching frequency power conversion to minimize body diode conduction. After the primary MOSFET turns-off, its drain voltage oscillates due to reverse recovery of the snubber diode. These high-frequency oscillations are reflected across the transformer to the drain terminal of the synchronous MOSFET. The synchronous controller senses the drain-voltage ringing, causing its Gate output voltage to oscillate. The synchronous MOSFET cannot be fully enhanced until the drain voltage stabilizes. In order to prevent this issue, the oscillations on the primary MOSFET can be damped with either a series resistor Rd to the snubber diode or an R-C network across the diode. Both methods reduce the oscillations by softening the snubber diode's reverse recovery characteristic. ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 11 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Application Information (Cont.) REF BIAS VCC DRAIN GATE GND Figure 5. Primary Side Snubber Network to Reduce Drain Voltage Oscillations ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 12 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. SO-8 E 1 b E1 h ) ides All s 9 ( R 0 e c 4 3 A .1 Q 45 7 SO-8 Dim Min Max Typ A 1.40 1.50 1.45 A1 0.10 0.20 0.15 b 0.30 0.50 0.40 c 0.15 0.25 0.20 D 4.85 4.95 4.90 E 5.90 6.10 6.00 E1 3.80 3.90 3.85 E0 3.85 3.95 3.90 e --1.27 h -0.35 L 0.62 0.82 0.72 Q 0.60 0.70 0.65 All Dimensions in mm A1 E0 L Gauge Plane Seating Plane D Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. SO-8 X1 Dimensions Value (in mm) C 1.27 X 0.802 X1 4.612 Y 1.505 Y1 6.50 Y1 Y C ZXGD3107N8 Document number: DS37887 Rev. 2 - 2 X 13 of 14 www.diodes.com April 2017 (c) Diodes Incorporated ZXGD3107N8 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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