19-0689; Rev 0; 12/06 MAX15015A Evaluation Kit The MAX15015A evaluation kit (EV kit) is a fully assembled and tested PCB that evaluates the MAX15015A PWM/PFM step-down converter, which integrates a high-side switch and an LDO regulator. The MAX15015A EV kit operates over a wide inputvoltage range of 4.5V to 40V and provides up to 1A at the 3.3V output. The LDO regulator provides up to 50mA at the preset 5V output. The MAX15015A features undervoltage lockout, overcurrent, and thermalshutdown protection. The MAX15015A normally operates as a PWM converter and automatically switches to PFM mode at light loads to improve efficiency. The MAX15015A switching frequency is preset to 500kHz and features a SYNC input to provide external frequency synchronization for sensitive applications. The EV kit provides PCB pads to evaluate the SYNC and ENABLE features of the MAX15015A. The EV kit board can also be used to evaluate the MAX15015B. The MAX15015A can operate over the automotive temperature range of -40C to +125C. Features o 3.3V, 1A, 500kHz Step-Down Converter o 5V, 50mA LDO Regulator o LDO Voltage Adjustable Up to 11V o Independent Turn On/Off Control for Step-Down Converter (EN_SW) o Regulator Power-On Reset with Adjustable Timeout Period o 84% High Efficiency at VIN = 12V and IOUT = 1A o Automatic PWM/PFM Mode o Overcurrent and Thermal-Shutdown Protection o Fully Assembled and Tested Ordering Information PART TEMP RANGE MAX15015AEVKIT+ 0C to +70C* IC PACKAGE 36 TQFN-EP** +Denotes a lead-free and ROHS-complaint EV kit. *This limited temperature range is for the EV kit PCB only. **EP = Exposed paddle. Component List DESIGNATION QTY 10F 10%, 50V X5R ceramic capacitor (2220) Murata GRM55DR61H106K C10 1 1F 10%, 25V X7R ceramic capacitor (0805) TDK C2012X7R1E105K 5 0.1F 10%, 50V X7R ceramic capacitors (0603) TDK CI608X7R1H104K C11 1 10F 10%, 16V X7R ceramic capacitor (1206) Murata GRM31CR61C106K C3 1 0.22F 10%, 50V X7R ceramic capacitor (0805) Murata GRM21BR71H224K C12 1 220pF 5%, 50V X7R ceramic capacitor (0603) TDK C1608X7R1H221J C7 1 47F 20%, 6.3V X5R ceramic capacitor (1206) TDK C3216X5RUJ476M C14 1 4700pF 10%, 50V X7R ceramic capacitor (0603) Murata GRM188R71H472K C8, C13 2 0.033F 10%, 50V X7R ceramic capacitors (0603) Murata GRM188R71H333K D1 1 150mA, 100V Schotky diode (SOD-123) Vishay BAT46W 1 1 0.47F 10%, 10V X7R ceramic capacitor (0603) TDK CI608X7R1A474K D2 C9 2A, 60V Schotky diode (SMB) Diode Inc. B260 DESIGNATION QTY C1 1 C2, C4, C5, C6, C15 DESCRIPTION DESCRIPTION Component List continued on next page. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 Evaluates: MAX15015A/MAX15015B General Description MAX15015A Evaluation Kit Evaluates: MAX15015A/MAX15015B Component List (continued) Quick Start Recommended Equipment DESIGNATION QTY JU1, JU2, JU3 3 2-pin headers DESCRIPTION L1 1 27H, 2.8A inductor Sumida CDRH124NP-270MC R1, R2 2 332k 1% resistors (0603) Procedure R3 0 Not installed, resistor (0603) R4, R11 2 10k 5% resistors (0402) R5 1 1 5% resistor (0603) R6 1 2.26k 1% resistor (0603) The MAX15015A EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are completed. R7 1 4.53k 1% resistor (0603) R8 1 133 1% resistor (0603) R9 1 7.5k 1% resistor (0603) R10 1 61.9k 1% resistor (0603) R12 1 63.4k 1% resistor (0603) TP1 1 PC mini red test point U1 1 MAX15015AATX+ (36-pin, 6mm x 6mm x 0.8mm, TQFN) -- 3 Shunts (JU1, JU2, JU3) -- 1 MAX15015AEVKIT+ PCB * 40V adjustable, 2A power supply * Electronic load capable of sinking up to 1A * Three digital voltmeters 1) Connect the positive terminal of the electronic load to the VOUT PCB pad on the EV kit board. Connect the ground terminal of the electronic load to the PGND PC pad. 2) Connect digital voltmeters across the VIN and PGND pads, VOUT and PGND PC pads, and the LDO_OUT and GND pads. 3) Verify that shunts are installed on jumpers JU1 and JU2 (step-down converter and LDO outputs enabled). 4) Verify that a shunt is not installed at jumper JU3 (LDO_OUT set to 5V). 5) Connect the power supply's positive terminal to the VIN PCB pad on the EV kit. Connect the powersupply ground terminal to the PGND PC pad. 6) Turn on the power supply. 7) Set the power-supply voltage to 12V. Component Suppliers SUPPLIER PHONE WEBSITE 8) Enable the 1A electronic load. 9) Verify that the voltmeters at VOUT and LDO_OUT measure 3.3V and 5V, respectively. Diodes Inc. 805-446-4800 www.diodes.com Detailed Description Murata 770-436-1300 www.murata.com Sumida 847-545-6700 www.sumida.com The MAX15015A EV kit evaluates the MAX15015A PWM/PFM step-down converter with an integrated high-side switch and LDO regulator. The MAX15015A EV kit operates over a wide input-voltage range of 4.5V to 40V and requires a 2A power supply. The MAX15015A EV kit step-down converter is configured to 3.3V and provides up to 1A (typ). The MAX15015A step-down converter switching frequency is set to 500kHz, and can be synchronized to a SYNC input signal operating below 600kHz. The MAX15015A normally operates as a PWM converter and automatically switches to PFM mode at light loads to improve efficiency. The EV kit features PCB pads to evaluate the SYNC, EN_SW, and the EN_SYS features of the MAX15015A. TDK 847-803-6100 www.component.tdk.com Vishay 203-268-6261 www.vishay.com Note: Indicate that you are using the MAX15015A when contacting these component suppliers. 2 _______________________________________________________________________________________ MAX15015A Evaluation Kit Jumper Selection Enabling VOUT and LDO_OUT The MAX15015A features input pads EN_SW and EN_SYS that can be used to enable the VOUT and LDO_OUT outputs. The EV kit also provides jumpers JU1 and JU2 to configure the EN_SW and EN_SYS, respectively. See Table 1 for jumpers JU1 and JU2 configurations. Table 1. EN_SYS and EN_SW Configuration EV KIT FUNCTION JU1 SHUNT POSITION JU2 SHUNT POSITION Not installed Not installed Off Off Not installed Installed Off Off Installed Not installed Off On Installed Installed On On VOUT LDO_OUT The MAX15015A EV kit shutdown current can be evaluated by removing jumper JU1. LDO_OUT Selection Jumper JU3 sets the linear regulator output voltage to 2.5V or 5V. See Table 2 for LDO jumper configuration. To configure LDO_OUT to other output voltages, refer to the Setting the LDO Linear Regulator Output Voltage section in the MAX15015A data sheet. Table 2. LDO Configuration (JU3) JU3 SHUNT POSITION SET_LDO PIN CONNECTION LDO_OUT OUTPUT VOLTAGE Not installed Connected to GND 5V Installed Connects to feedback resistors R10 and R12 2.5V Configuring the Output Voltage (VOUT) The MAX15015A EV kit step-down converter output voltage is configured to 3.3V by resistors R7 and R9. The EV kit's output voltage (VOUT) can be reconfigured in the range of 1.26V to 28V by replacing these resistors. To select a new value for resistor R7, refer to the Setting the Output Voltage section in the MAX15015A data sheet. Use the following equation to reconfigure the output voltage to the desired value: R7 = R9 VOUT 1.244 - 1 where VOUT is the desired output voltage in volts. Reconfiguring the MAX15015A EV kit for a new output voltage may require replacing inductor L1 and capacitors C1 and/or C7. To select a new value for inductor L1 and capacitors C1 and C7, refer to the Inductor Selection, Output Capacitor Selection, and Input Capacitor Selection sections, respectively, in the MAX15015A data sheet. Configuring the Undervoltage Lockout (UVLO) The MAX15015A step-down converter and LDO regulator turns on when the input voltage (VIN) is above the MAX15015A minimum 4.1V threshold (shunts on JU1 and JU2 must be installed). The converter turn-on threshold can be reconfigured to a desired value greater than 4.1V by selecting resistors R2 and R3. To reconfigure the converter's turn-on threshold, use the following equation: VEN _ SW R2 = R 3 x - 1 1 5 V . where VEN_SW is the desired turn-on threshold in volts. _______________________________________________________________________________________ 3 Evaluates: MAX15015A/MAX15015B The LDO regulator has a default 5V output and can be configured for a 2.5V output after installing the shunt on jumper JU3. An open-drain RESET output changes from low to high whenever the LDO voltage rises to 92.5% of its regulated output. When LDO_OUT exceeds its rising threshold voltage, RESET remains low for the reset timeout period, and then goes high. The RESET signal can be monitored at test point TP1 on the EV kit and is pulled up to LDO_OUT by resistor R11. The reset timeout period is set by capacitor C8. The MAX15015A features configurable soft-start, independent undervoltage lockout (UVLO) for the stepdown converter and regulator, cycle-by-cycle current limit, hiccup-mode-output short-circuit protection, and thermal shutdown. The step-down converter UVLO is configurable by choosing the appropriate R2 and R3 resistor values. Evaluates: MAX15015A/MAX15015B MAX15015A Evaluation Kit Linear Regulator Operation The MAX15015A linear regulator operates in either a preset voltage mode or an adjustable mode. In preset voltage mode, LDO_OUT is 5V. Select the preset voltage mode by removing the shunt at JU3. In adjustable mode, LDO_OUT is set to 2.5V by resistors R10 and R12 (shunt installed at JU3). To reconfigure LDO_OUT voltage to a different voltage (1.5V to 11V ), replace resistors R10 and R12 with new values. Use the following equation to select a new resistor value: R10 = R12 VLDO _ OUT - 1 1.244 where VLDO_OUT is the desired LDO_OUT voltage. Synchronization Input (SYNC) The EV kit's SYNC PCB pad can be used to synchronize the MAX15015A switching frequency with an external digital-clock signal in the range of 400kHz to 600kHz. When SYNC is driven with an external digital clock, the MAX15015A synchronizes to the rising edge of the external clock. The square-wave clock source must provide the following signal qualities: * Logic-low = 0 to 0.8V * Input frequency = 400kHz to 600kHz. Refer to the MAX15015A data sheet for more information on the SYNC pin. * Duty cycle = 50% To use external synchronization, connect the external square-wave clock to the SYNC and GND pads. Compensation Network The MAX15015A IC provides the flexibility of externally compensating its internal error amplifier to achieve stability for various applications. The MAX15015A is compensated by choosing values for resistors R6-R9, and capacitors C12, C13, and C14. To reconfigure the compensation network for specific requirements, refer to the Compensation Design section in the MAX15015A data sheet. Evaluating the MAX15015B The MAX15015A EV kit board can also evaluate the MAX15015B step-down converter. The MAX15015A IC must be removed and replaced with the MAX15015B. When using the MAX15015B, LDO_OUT has a 3.3V default output (JU3 not installed). * Logic-high = 2.2V to 5.5V 4 _______________________________________________________________________________________ _______________________________________________________________________________________ SYNC EN_SW GND EN_SYS PGND VIN PGND JU1 VIN R3 OPEN SGND C10 1F C9 0.47F R1 332k 1% R2 332k 1% JU2 C1 10F 50V C2 0.1F R5 1 5 34 25 R4 10k 29 7 8 33 20 21 DRAIN DRAIN U1 1 2 3 9 12 14 16 19 24 26 27 30 35 31 COMP PGND 22 MAX15015A IN_SW 36 C4 0.1F N.C.N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. REG DVREG SGND SYNC EN_SW EN_SYS SS C3 0.22F 28 C+ C12 220pF 32 R6 C13 2.26k 0.033F 1% C- 23 C5 0.1F FB R7 4.53k 1% R8 133 1% IN_LDO SET_LDO LDO_OUT RESET CT LX LX BST R9 7.5k 1% C14 4700pF 13 10 11 4 6 18 17 15 C15 0.1F VIN C11 10F R10 61.9k 1% JU3 R12 63.4k 1% L1 27H VOUT R11 10k TP1 C8 0.033F D2 C6 0.1F D1 C7 47F 6.3V GND LDO_OUT PGND VOUT VOUT Evaluates: MAX15015A/MAX15015B VIN MAX15015A Evaluation Kit Figure 1. MAX15015A EV Kit Schematic 5 Evaluates: MAX15015A/MAX15015B MAX15015A Evaluation Kit Figure 2. MAX15015A EV Kit Component Placement Guide-- Component Side Figure 3. MAX15015A EV Kit PCB Layout--Component Side Figure 4. MAX15015A EV Kit PCB Layout--GND Layer 2 Figure 5. MAX15015A EV Kit PCB Layout--Power Layer 3 6 _______________________________________________________________________________________ MAX15015A Evaluation Kit Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 (c) 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. Evaluates: MAX15015A/MAX15015B Figure 6. MAX15015A EV Kit PCB Layout--Solder Side