Evaluates: MAX MAX17016 Evaluation Kit. General Description. Features. Ordering Information. Component List

Transcription

1 General Description The MAX706 evaluation kit (EV kit) demonstrates the standard 0A application circuit of the MAX706. This DC-DC converter steps down high-voltage batteries to generate low-voltage core or chipset/ram bias supplies in notebook computers. The MAX706 EV kit provides a dynamically adjustable.5v/.05v output voltage from a 7V to 24V battery input range. It delivers up to 0A output current while achieving high efficiency. Programmed by a single resistor, the EV kit operates at 00kHz switching frequency and has superior line- and load-transient response. The EV kit is a fully assembled and tested printed circuit board (PCB). It also allows the evaluation of other dynamically adjustable output voltages by varying the external reference input, which can be realized by changing resistors R, R2, and R. Component List DESIGNATION QTY DESCRIPTION C, C2 2 C C4, C5 2 C6 0 C7 µf ±0%, X5R ceramic capacitors (0402) TDK C005X5R0J05K Taiyo Yuden LMK05BJ05KV 000pF ±0%, 50V ceramic capacitor (0402) TDK C005X7RH02K Murata GRM55R7H02K ±20%, 25V X5R ceramic capacitors (20) TDK C225X7RE06M Taiyo Yuden TMK25BJ06MM Not installed, 000µF, 50V aluminum electrolytic capacitor (6mm x 25mm) SANYO 50ME000AX 0.µF ±0%, 25V X7R ceramic capacitor (060) TDK C608X7RE04K Murata GRM88R7E04K C8, C9, C 0 Not installed, capacitors (060) Features 7V to 24V Input Range Dynamically Selectable.5V/.05V Output Voltage Dynamically Adjustable Output Voltage (0 to 0.9V IN Range) 0A Output Current (Continuous) 00kHz Switching Frequency Power-Good Output Indicator (PGOOD) Low-Profile, Surface-Mount Components Fully Assembled and Tested Ordering Information PART MAX706EVKIT+ +Denotes lead-free and RoHS compliant. TYPE EV Kit DESIGNATION QTY DESCRIPTION C0, C 2 C2, C5 C9 6 C4 D 0µF, 2V, 6mΩ polymer capacitors (D case) Panasonic EEFSX0DXR (6mΩ ESR,.9mm height) NEC TOKIN PSGD0E7M7 (7mΩ ESR, 2.8mm height) ±20%, X5R ceramic capacitors (0805) TDK C202X5R0J06M Murata GRM2BR6A06K µf ±0%, 25V X5R ceramic capacitor (060) Murata GRM88R6E05K Taiyo Yuden GDK07BJ05KA A, 0V Schottky diode (SMA case) Nihon ECQS0L Central Semiconductor CMSH- 40MA, lead free D2 Surface-mount LED, green (0805) EN, FBSENSE, GATE, PGOOD, REFIN, SKIP 6 Test points Keystone ; Rev 0; 5/07

2 Component List (continued) DESIGNATION QTY DESCRIPTION JU -pin header JU2 4-pin header JU 2-pin header L N N2 0.0µH,.25mΩ, 6A power inductor Würth Vishay/Dale IHLP4040DZERR0M n-channel, logic-level MOSFET (SOT2) Fairchild 2N7002 (Top Mark: 702) Central Semiconductor 2N7002 Not installed, n-channel MOSFET (DPAK) R, R kΩ ± resistors (060) R2 54.9kΩ ± resistor (060) R 97.6kΩ ± resistor (060) DESIGNATION QTY DESCRIPTION R4 kω ±5% resistor (060) R5 200kΩ ± resistor (060) R6 4.7Ω ±5% resistor (060) R7, R9 0 Not installed, resistors (060) R8 0Ω ±5% resistor (060) R0 40.2kΩ ± resistor (060) R2 0kΩ ± NTC resistor (060) Murata NCP8XH0F0RB R 00kΩ ±5%, resistor (060) R4 Not installed, W resistor (252) R5 5Ω ±5% resistor (060) U Shunts PWM controller (40 TQFN) Maxim MAX706ETL+ PCB: MAX706 Evaluation Kit+ Component Suppliers SUPPLIER PHONE WEBSITE Central Semiconductor Corp Fairchild Semiconductor Murata Electronics North America, Inc NEC TOKIN America, Inc Panasonic Corp SANYO Electric Co., Ltd Taiyo Yuden TDK Corp Vishay Würth Electronik GmbH & Co. KG Note: Indicate that you are using the MAX706 when contacting these component suppliers. Maxim Integrated 2

3 Quick Start Recommended Equipment 7V to 24V power supply, battery, or notebook AC adapter DC bias power supply, 5V at 00mA Dummy load capable of sinking 0A Digital multimeter (DMM) 00MHz dual-trace oscilloscope Procedure The MAX706 EV kit is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on the power supply until all connections are completed. ) Ensure that the circuit is connected correctly to the power supplies and dummy load prior to applying any power. 2) Verify that the shunts are placed as follows: JUMPER SHUNT POSITION FUNCTION JU -2 EN high JU2-2 Forced PWM JU Not installed +.5V output ) Turn on battery power prior to +5V bias power; otherwise, the output undervoltage (UVP) FAULT latch sets, disabling the regulator until +5V power is cycled below the VCC POR (0.5V) or EN is toggled. 4) Observe the.5v output with the DMM and/or oscilloscope. Look at the LX switching node and MOSFET gate-drive signals while varying the load current. Detailed Description Jumper Settings Several jumper settings in the following tables illustrate some features of the MAX706 EV kit. Pulse-Skipping Control Input The MAX706 EV kit features a 4-pin jumper (JU2) for pulse-skipping control input. This four-level input determines the mode of operation under normal steadystate conditions and dynamic output-voltage transitions. The default configuration has a shunt installed at pins -2 for low-noise, forced-pwm mode. Table 2 lists the other selectable jumper options. Refer to the Modes of Operation section of the IC data sheet for a more detailed description. Table. Jumper JU Functions SHUNT POSITION *Default position. EN PIN -2* Connected to 2- Connected to GND Not installed Table 2. Jumper JU2 Functions SHUNT POSITION EN must be driven by an external signal connected to the EN test point SKIP PIN -2* Connected to - Connected to REF -4 Connected to GND MAX706 OUTPUT Enabled (VOUT =.5V/.05V) Shutdown mode (VOUT = 0V) Operation depends on the external EN signal levels OPERATIONAL MODE Low-noise mode, forced-pwm operation Pulse-skipping mode with forced-pwm during transitions Pulse-skipping mode without forced-pwm during transitions Shutdown Control Input The MAX706 EV kit features a -pin jumper (JU) that selects the shutdown control input. Table lists the selectable jumper options. Not installed *Default position. Open Ultrasonic mode without forced-pwm during transitions Maxim Integrated

4 External Gate The MAX706 EV kit features a 2-pin jumper (JU) that controls the gate of the external MOSFET (N). The external MOSFET can be controlled through the gate test point, to dynamically adjust the REFIN voltage by forcing N s drain to a low- or a high-impedance state. The default configuration has a shunt installed on only one pin of JU to provide a.5v output. Table lists the selectable jumper options. Table. Jumper JU Functions SHUNT POSITION Installed Not installed* *Default position. EXTERNAL GATE Connected to Pulled to GND by R MAX706 OUTPUT A logic-high on gate turns on the external MOSFET, effectively shorting R (VOUT =.05V through resistor-dividers R and R2) A logic-low on gate turns off the external MOSFET (VOUT =.5V through resistor-dividers R and R2 + R) Evaluating Other Dynamic Output Voltages The EV kit output is preset to.05v/.5v. However, the output voltage can also be adjusted between 0 and 2V (FB = OUT) by selecting R, R2, and R values. The MAX706 regulates FB to the voltage set at REFIN. By changing the voltage at REFIN, the MAX706 can be used in applications that require dynamic output voltage changes between multiple set points. Using the external gate signal, a resistor can be switched in and out of the REFIN resistor-divider, changing the voltage at REFIN. A logic-high on gate turns on the external n-channel MOSFET, forcing N s drain to a low-impedance state. A logic-low on gate disables the n-channel MOSFET, so N s drain is high impedance. The two output voltages (FB = OUT) are determined by the following equations: R2 VOUT (LOW ) = VREF R R2 + R2+ R VOUT (HIGH) = VREF R+ R2 + R where V REF = 2.0V. Setting V OUT with a Resistive Voltage-Divider at FB Connecting FB to a resistive voltage-divider allows for output voltages above the reference voltage (0.9V IN range). To get an output above 2V, install resistor R9 with a 0kΩ ± resistor and replace R8 with following equation: where V FB = V REFIN. V R8 OUT V FB = + R9 The switching frequency setting input should then be adjusted by replacing external resistor R5 (R TON ) according to the following equations: VFB TSW = C TON (R TON + 6.5k Ω) VOUT TSW = fsw where C TON = 6.26pF, f SW = 00kHz, and V FB = V REFIN under normal operating conditions. Refer to the MAX706 data sheet for selection of output capacitor and inductor values for output voltages greater than 2V. Transient Load Tester The MAX706 EV kit features an optional transient load tester consisting of a power MOSFET (N2), R4, and a termination resistor (R5). Refer to Application Note 752: Creating a Fast Load Transient, located at /AN752, for a more detailed discussion. Maxim Integrated 4

5 GATE PGOOD JU R 00kΩ EN REFIN D2 REF N 2 +5V R4 kω R 49.9kΩ R2 54.9kΩ R 97.6kΩ C µf JU 2 JU2 2 4 C 000pF SKIP REF 2 EN 6 SKIP 4 8 PGOOD VCC U MAX IN 9 IN 20 IN 2 IN 22 IN 2 IN 24 IN 25 IN 26 IN 4 EP 29 TON 0 BST 42 EP2 5 LX 6 LX 5 REF 4 REFIN N.C. 7 N.C. 27 N.C. N.C. 9 N.C. 40 N.C. AGND AGND FB ILIM EP C2 µf R6 4.7Ω R9 C C4 µf 25V R5 200kΩ C7 0.µF 25V D R7 C9 FBSENSE R 49.9kΩ C4 25V L.0µH C8 R8 0Ω R0 40.2kΩ C5 25V C6 C0 0µF 2V R2 0kΩ NTC REF +7V TO +24V C 0µF 2V IN C2 TP R5 5Ω C5 C6 VOUT 4 N2 R4 C7 C8 +.5V/+.05V, 0A C9 VOUT Figure. MAX706 EV Kit Schematic Maxim Integrated 5

6 .0.0 Figure 2. MAX706 EV Kit Component Placement Guide Component Side Figure. MAX706 EV Kit PCB Layout Component Side Maxim Integrated 6

7 .0.0 Figure 4. MAX706 EV Kit PCB Layout GND Layer 2 Figure 5. MAX706 EV Kit PCB Layout GND Layer Maxim Integrated 7

8 .0 Figure 6. MAX706 EV Kit PCB Layout Solder Side Figure 7. MAX706 EV Kit Component Placement Guide Solder Side For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim Integrated s website at. 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 Maxim Integrated Products, Inc. 8