A Product Line of Diodes Incorporated ZXGD3104N8 SYNCHRONOUS MOSFET CONTROLLER IN SO8 Description Features The ZXGD3104 is intended to drive MOSFETS configured as ideal diode replacements. The device is comprised of a differential amplifier detector stage and high current driver. The detector 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. • • • 5-25V Vcc range Operating up to 250kHz Suitable for Discontinuous Mode (DCM), Critical Conduction Mode (CrCM) and Continuous Mode (CCM) operation Turn-off propagation delay 15ns and turn-off time 20ns. Proportional Gate Drive Detector threshold voltage -10mV Standby current 5mA “Lead-Free”, RoHS Compliant (Note 1) Halogen and Antimony free. “Green” Device (Note 2) Qualified to AEC-Q101 Standards for High Reliability Applications • • • • • • • • Mechanical Data Once the positive voltage is applied to the Gate the MOSFET switches on. The detectors’ output voltage is then proportional to the MOSFET Drain-Source voltage and this is applied to the Gate via the driver. This action provides a rapid MOSFET turn off at zero Drain current. Flyback Converters in: o ≥90W Laptop Adaptors • • • • • • • 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 SO-8 DNC DRAIN REF BIAS GATEL GND GATEH VCC Top View Pin-Out Ordering Information (Note 3) Product ZXGD3104N8TC Notes: Marking ZXGD3104 Reel size (inches) 13 Tape width (mm) 12 Quantity per reel 2,500 1. No purposefully added lead 2. Diodes Inc’s “Green” Policy can be found on our website at http://www.diodes.com 3. For packaging details, go to our website at http://www.diodes.com Marking Information ZXGD 3104 YY WW ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 ZXGD 3104 YY WW 1 of 13 www.diodes.com = Product Type Marking Code, Line 1 = Product Type Marking Code, Line 2 = Year (ex: 11 = 2011) = Week (01 - 53) November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Functional Block Diagram Pin No. Name Description and function Do not connect 1 DNC 2 REF 3 GATEL 4 GATEH Leave pin floating. Reference This pin is connected to VCC via resistor, RREF. Select RREF to source 2.16mA into this pin. Refer to Table 1, in Application Information section. Gate turn off This pin sinks current, ISINK, from the synchronous MOSFET Gate. Gate turn on This pin sources current, ISOURCE, to the synchronous MOSFET Gate. Power Supply 5 VCC This is the supply pin. It is recommended to decouple this point to ground closely with a ceramic capacitor. 6 GND 7 BIAS 8 DRAIN Ground This is the ground reference point. Connect to the synchronous MOSFET Source terminal. Bias This pin is connected to VCC via resistor, RBIAS. Select RBIAS to source 3mA into this pin. Refer to Table 1, in Application Information section. Drain connection This pin connects directly to the synchronous MOSFET Drain terminal. ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 2 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Maximum Ratings @TA = 25°C 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 25 -3 to 180 -3 to VCC + 3 2.5 7 VCC 25 VCC 100 Unit V V V A A V mA V mA Value 490 Unit Thermal Characteristics @TA = 25°C unless otherwise specified Characteristic Symbol (Note 4) Power Dissipation Linear derating factor 3.92 655 (Note 5) PD (Note 6) Thermal Resistance, Junction to Ambient Thermal Resistance, Junction to Lead Operating Temperature Range Storage Temperature Range Notes: 720 mW mW/°C 5.76 785 (Note 7) (Note 4) (Note 5) (Note 6) (Note 7) (Note 8) 5.24 6.28 RθJA RθJL TJ TSTG 255 191 173 159 135 -40 to +150 -50 to +150 °C/W °C/W °C 4. For a device surface mounted on minimum recommended pad layout FR4 PCB with high coverage of single sided 1oz copper, in still air conditions; the device is measured when operating in a steady-state condition. 5. Same as note (4), except pin 5 (VCC) and pin 6 (GND) are both connected to separate 5mm x 5mm 1oz copper heatsinks. 6. Same as note (5), except both heatsinks are 10mm x 10mm. 7. Same as note (5), except both heatsinks are 15mm x 15mm. 8. Thermal resistance from junction to solder-point at the end of each lead on pin 5 (VCC) and pin 6 (GND). ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 3 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 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 Junction Temperature (°C) Derating Curve ESD Rating Characteristic Value ESD for Human Body Model 2000 ESD for Machine Model 300 ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 4 of 13 www.diodes.com Unit V November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Electrical Characteristics @TA = 25°C unless otherwise specified VCC = 19V; RBIAS = 6.3kΩ; RREF = 8.5kΩ Characteristic Input and Supply Quiescent current Gate Driver Turn-off Threshold Voltage (Note 9 & 10) (Note 9 & 10) Gate output voltage (Note 9 & 11) Symbol Min Typ Max Unit IQ - 5.16 - mA VD ≥ 0V VT VG(off) -16 0 12.5 17 -10 0.73 14 18 0 1.0 VCC VCC mV VG = 1V VD ≥ 1V VD = -50mV VD = -100mV 175 11 335 530 35 250 15 480 760 50 325 20 625 990 65 VG Switching Performance for QG(tot) = 124nC (Note 12) Turn-on propagation delay td(rise) Turn-off propagation delay td(fall) Gate rise time tr Gate fall time tf Notes: V Test Condition - ns Refer to switching From 10% of VG to 10V waveforms in Fig. 1 From 10% to 90% of VG Continuous Conduction Mode 9.GATEH connected to GATEL 10.RH = 100kΩ, RL = O/C 11.RL = 100kΩ, RH = O/C 12. refer to test circuit below ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 5 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Descriptions of the normal operation The operation of the controller is described step-by-step with reference to the timing diagram in Figure 1. 1. The controller monitors the MOSFET Drain-Source voltage. 2. When, due to transformer action, the MOSFET body diode is forced to conduct there is approximately -0.8V on the Drain pin. 3. The detector outputs a positive voltage with respect to ground, 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 onresistance-induced Drain-Source voltage drop across the MOSFET. Proportional gate drive ensures that MOSFET conducts for majority of the conduction cycle and minimizes body diode conduction time. 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 is removed 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. Figure 1. Timing diagram for a critical conduction mode Flyback converter ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 6 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Typical Electrical Characteristics @TA = 25°C unless otherwise specified ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 7 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Continued - Typical Electrical Characteristics @TA = 25°C unless otherwise specified ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 8 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Application Information The purpose of the ZXGD3104 is to drive a MOSFET as a low-VF Schottky diode replacement in offline power converters. When combined with a low RDS(ON) MOSFET, it can yield significant power efficiency improvement, whilst maintaining design simplicity and incurring minimal component count. Figure 2 shows typical configuration of ZXGD3104 for synchronous rectification in a 19V output Flyback Adaptor. Figure 2. Example connections in Flyback power supply Figure 3 shows operating waveforms for ZXGD3104 driving a MOSFET with Qg(TOT) = 124nC in a 19V output Flyback converter operating in critical conduction mode. ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 9 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Typical waveforms Fig 3a: Critical conduction mode, operating for MOSFET with Qg(TOT) =124nC Fig 3b: Typical switching waveform Fig 3c: Close up of typical turn off waveform ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 10 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 Design considerations It is advisable to decouple the ZXGD3104 closely to VCC and ground due to the possibility of high peak gate currents with a 1μF X7R type ceramic capacitor C1 as shown in Figure 2. Also the ground return loop should be as short as possible. To minimize parasitic inductance-induced premature turn-off of the synchronous controller always keep the PCB track length between ZXGD3104’s Drain input and MOSFET’s Drain to less than 10mm. Low internal inductance SMD MOSFET packages are also recommended for high switching frequency power conversion to minimize MOSFET body diode conduction loss. The Gate pins should be as close to the MOSFET’s gate as possible. External gate resistors are optional. They can be inserted to control the rise and fall time which may help with EMI issues. The careful selection of external resistors RREF and RBIAS is important to the optimum device operation. Select a value for resistor RREF and RBIAS from Table 1 based on the desired Vcc value. This provides the typical ZXGD3104’s detection threshold voltage of -10mV. Table 1. Recommended resistor values for various supply voltages ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 VCC RBIAS RREF 5V 10V 12V 15V 19V 1.6 kΩ 3.3 kΩ 3.9 kΩ 5.1 kΩ 6.3 kΩ 2 kΩ 4.3 kΩ 5.1 kΩ 6.8 kΩ 8.5 kΩ 11 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 h x 45° Package Outline Dimensions DIM Inches Millimeters DIM Inches Min. Millimeters Max. Max. Min. Max. A 0.053 0.069 1.35 1.75 e A1 0.004 0.010 0.10 0.25 b 0.013 0.020 0.33 0.51 D 0.189 0.197 4.80 5.00 c 0.008 0.010 0.19 0.25 H 0.228 0.244 5.80 6.20 θ 0° 8° 0° 8° E 0.150 0.157 3.80 4.00 h 0.010 0.020 0.25 0.50 L 0.016 0.050 0.40 1.27 - - - - - 0.050 BSC Min. Max. Min. 1.27 BSC Suggested Pad Layout 1.52 0.060 7.0 0.275 4.0 0.155 0.6 0.024 1.27 0.050 mm inches ZXGD3104N8 Document Number DS35546 Rev. 1 – 2 12 of 13 www.diodes.com November 2011 © Diodes Incorporated A Product Line of Diodes Incorporated ZXGD3104N8 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). Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. 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