Evaluates: MAX6397 MAX6397 Evaluation Kit General Description The MAX6397 evaluation kit (EV kit) demonstrates a high-voltage overvoltage protection circuit for applications that must survive load dump and high-voltage transient conditions. This EV kit is a fully assembled and tested surface-mount board. The EV kit supports high-output currents up to 5A, runs at voltages up to 72V, and can withstand temperatures ranging from -40°C to +105°C. Two alternate voltage inputs implement two different schemes for reversebattery protection. Connections to the on-chip linear regulator, capable of driving 100mA, and the power-good (POK) signal are also provided. Features ●● 5.5V to 72V Wide Supply Voltage Range ●● Up to 5A Output Current Capacity ●● Selectable Overvoltage Mode and OvervoltageLimiter Mode ●● Adjustable Overvoltage Threshold ●● 100V Reverse-Battery Protection ●● Always-On Linear Regulator Output ●● Power-Good Signal Output Quick Start Procedure The MAX6397 EV kit is fully assembled and tested. Follow these steps to verify operation. Do not turn on the power supply until all connections are completed. 1) Connect a DC power supply (0 to 20V or above, 5A or depending on load) to VIN1 and GND. 2) Connect a voltmeter or oscilloscope and a load (if desired) to OUT and GND. 3) Make sure the J2 shunt connects pins 1 and 2 (overvoltage-protect mode). The J4 shunt should connect pins 1 and 2. 4) Turn on the power supply and increase the input voltage. The output turns on when the input voltage reaches 5.5V. Increase the supply voltage further; the output turns off when the input voltage reaches 17V. 5) The above steps can be followed for a power supply connected to VIN2 or VIN3. The thresholds for turn on and turn off for inputs VIN2 and VIN3 are higher due to the voltage drop across the reverse-battery protection. 6) Check the linear regulator output and POK signal. Ordering Information PART MAX6397EVKIT 19-4003; Rev 2; 4/15 TYPE EV Kit Evaluates: MAX6397 MAX6397 Evaluation Kit Detailed Description The MAX6397 EV kit demonstrates a high-voltage overvoltage-protection circuit for applications that must survive load dump and high-voltage transient conditions. This EV kit can be configured in overvoltage mode or overvoltage limiter mode by setting jumper J2 (see Table 1 for the jumper settings), and can supply up to 5A of output current. The minimum output voltage in overvoltage-limiter mode depends on load current, output capacitance, and the MOSFET’s switching period. The MAX6397 EV kit comes with one 22μF capacitor at the output to supply the load during the time when the MOSFET is off. Connect the optional electrolytic capacitor C13 (150μF, 100V) to support load currents higher than 0.5A when the EV kit operates in overvoltage limiter mode. The MAX6397 EV kit has three positive power-supply inputs: VIN1, VIN2, and VIN3. Inputs VIN2 and VIN3 have diode-based and p-channel MOSFET-based reversebattery protections, respectively, and VIN1 bypasses all reverse-battery protections. Add capacitor C3 on the gate of MOSFET M1 to decrease the frequency of the sawtooth waveform. This process helps limit the device’s power dissipation. Linear Regulator Output and Power-Good Signal Overvoltage Mode Connections are also included for the linear regulator output and the power-good (POK) signal. The linear regulator supplies up to 100mA at 5V, limited by the ambient temperature, the input/output voltages, and the package power dissipation. The POK signal has a 100kΩ resistor (R3) to the regulator output. The linear regulator is always on regardless of the state of SHDN. In overvoltage mode, the MAX6397 monitors the input voltage and turns off the series-pass n-channel MOSFET (M1) when the input voltage exceeds the programmed threshold voltage. As soon as the input voltage drops below the overvoltage threshold, the MAX6397 charge pump fully enhances MOSFET M1 to turn the output back on. The voltage-divider formed by R1 and R2 sets the threshold voltage. The resistors provided in the MAX6397 EV kit set the threshold at 17V. If inputs VIN2 or VIN3 are used, this threshold is higher due to the voltage drop in D1 or M2. The overvoltage threshold can be adjusted by varying R1 or R2 using the equation below: V R1 OV − 1 × R2 = 1.215 where VOV is the desired overvoltage threshold. To maintain threshold accuracy, R2 must be less than 250kΩ. Since the EV kit ships with R2 set at 49.9kΩ, use the formula above to change the threshold by changing R1 only. Overvoltage-Limiter Mode In overvoltage-limiter mode, the MAX6397 monitors the output voltage instead of the input voltage. The output voltage is sensed through the same voltagedivider formed by R1 and R2, so the equation given for overvoltage mode also applies to the threshold voltage in overvoltage limiter mode. During an input overvoltage transient in this mode, the MOSFET switches off until the output voltage falls to 95% of the threshold voltage, and then the MOSFET switches back on. This cycle repeats, generating a sawtooth waveform on the output. www.maximintegrated.com Jumper Selection To filter fast transients that may be present at the input from reaching the MAX6397, place a small resistor, R4, (10Ω, for example) on the board, and cut jumper J1. Three-pin jumper J2 selects between overvoltage mode and overvoltage limiter mode; do not leave this jumper unconnected. Three-pin jumper J3 controls the gate drive of p-channel MOSFET M3 used as a reverse- battery protection. Use J3 to disconnect resistor R5 when M3 is not used to avoid supply leakage through R5. Three-pin jumper J4 controls the SHDN pin of the MAX6397 and can enable or disable the MOSFET M1 enhancement. Table 1 lists the jumper options. Table 1. Jumper Function SHUNT POSITION AND FUNCTION JUMPER 1 and 2 J1 2 and 3 Shorted: RC input filter disabled* J2 Overvoltage mode* Overvoltage limiter mode J3 M2 gate drive is disabled* M2 gate drive is enabled J4 U1 is enabled* U1 is disabled *Default position. Maxim Integrated │ 2 Evaluates: MAX6397 MAX6397 Evaluation Kit Component List DESIGNATION QTY C1, C7 2 22µF, 100V aluminum electrolytic capacitors Vishay 222215364229 C2, C8–C12 0 Not installed, capacitors C3 0 Not installed, capacitor (1206) C4 1 10µF, 10V X7R ceramic capacitor Murata GRM31CR71A106KA01B or TDK C3216X7R1C106K C5 0 C6 C13 D1 DESIGNATION QTY D3 1 18V zener diode Central Semi CMPZ5248B or Diodes Inc. MMBZ5248BT D4 0 Not installed, optional TVS diode (DO-15) J1 0 Not installed, 2-pin header J2–J4 3 3-pin headers Not installed, capacitor (1206) M1 1 1 0.1µF, 100V X7R ceramic capacitor TDK C3216X7R2A104K or AVX 12061C104KAT2A 100V, 33A n-channel MOSFET International Rectifier IRF540NS or Fairchild FQB33N10 M2 1 R1 1 649kΩ ±1% resistor (0805) 0 Not installed, 150µF/100V electrolytic capacitor Vishay BC Components 118AHT-222211829151 or Epcos B41693A9157Q009 100V, 23A p-channel MOSFET International Rectifier IRF9540NS or Fairchild FQB22P10 R2 1 49.9kΩ ±1% resistor (0805) R3, R5 2 100kΩ ±1% resistors (0805) R4 0 Not installed, resistor (0805) R6 1 2.2MΩ ±1% resistor (0805) U1 1 High-voltage overvoltage-protection circuit (8 TDFN-EP*) Maxim MAX6397LATA-T — 1 PCB: MAX6397 EVALUATION KIT 1 D2 DESCRIPTION 1 8A/100V Schottky diode International Rectifier 8TQ100S-IS or STMicroelectronics STPS8H100G 60V, 600W TVS diode Diodes Inc. SMBJ54A or Fairchild SMBJ54A DESCRIPTION *EP = Exposed pad. Component Suppliers SUPPLIER PHONE WEBSITE AVX North America 864-967-2150 www.avx.com Central Semiconductor 631-435-1110 www.centralsemi.com Diodes Incorporated 805-446-4800 www.diodes.com ECS 714-895-6351 www.ecsconn.com EPCOS AG 732-906-4300 www.epcos.com International Rectifier 310-322-3331 www.irf.com Murata Americas 800-241-6574 www.murataamericas.com STMicroelectronics 408-452-8585 www.us.st.com TDK Corp. 847-803-6100 www.component.tdk.com Vishay 402-563-6866 www.vishay.com Note: Indicate you are using the MAX6397 when contacting these component suppliers. www.maximintegrated.com Maxim Integrated │ 3 www.maximintegrated.com GND VIN3 VIN2 VIN1 R5 100kΩ D3 18V 3 2 1 J3 1 J4 2 3 R6 2.2MΩ M2 IRF9540NS D1 8TQ100S-IS J1 D2 SMBJ54A C6 0.1µF 100V R2 49.9kΩ 4 GND OUT POK MAX6397 U1 REG C3 OPEN C10 OPEN GATE IN C2 OPEN 2 SHDN SET 3 1 J2 1 2 3 C1 22µF 100V R1 649kΩ R4 OPEN D4 OPEN 5 6 7 8 C11 OPEN M1 IRF540NS R3 100kΩ C7 22µF 100V C4 10µF 10V C8 OPEN C5 OPEN C9 OPEN C12 OPEN POK REG C13 OPEN GND OUT MAX6397 Evaluation Kit Evaluates: MAX6397 Figure 1. MAX6397 EV Kit Schematic Maxim Integrated │ 4 MAX6397 Evaluation Kit Evaluates: MAX6397 1.0’’ Figure 2. MAX6397 EV Kit Component Placement Guide—Component Side www.maximintegrated.com Maxim Integrated │ 5 MAX6397 Evaluation Kit Evaluates: MAX6397 1.0’’ Figure 3. MAX6397 EV Kit PCB Layout—Component Side www.maximintegrated.com Maxim Integrated │ 6 MAX6397 Evaluation Kit Evaluates: MAX6397 1.0’’ Figure 4. MAX6397 EV Kit PCB Layout—Solder Side www.maximintegrated.com Maxim Integrated │ 7 Evaluates: MAX6397 MAX6397 Evaluation Kit Revision History REVISION NUMBER REVISION DATE 2 4/15 PAGES CHANGED DESCRIPTION Deleted automotive reference in General Description and Detailed Description sections; moved Component List and Component Suppliers tables to page 3 and Quick Start section to page 1; added Revision History table 1, 2, 4, 8 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2015 Maxim Integrated Products, Inc. │ 8