9-740; Rev ; /04 General Description The MAX748 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that contains a boost switching regulator and two charge-pump voltage-regulator circuits. The boost switching circuit is configured for a +0V output that provides up to 00mA of current from a supply voltage of +.7V to +5.5V. The positive charge-pump circuit is configured for a +5V output that provides >0mA of current. The negative charge-pump circuit is configured for a -5V output and provides >0mA of current. Power for either or both s can be provided from the +.7VDC to +5.5VDC source or from the boost switching-regulator output. The MAX748 EV kit demonstrates low-quiescent current and high efficiency (over 86%) for maximum battery life. Operation at MHz allows the use of tiny surface-mount components. The MAX748 TSSOP package (.mm max) with low-profile external components allows this circuit to be less than.mm high. The MAX748 EV kit can also be used to evaluate the MAX779 IC. DESIGNATION QTY DESCRIPTION C, C6, C7, C8, C C, C4, C5, C6, C, C 5 6.µF, 0V X7R ceramic capacitors (0) Taiyo Yuden LMK5BJ5KD 0.µF, 6V X7R ceramic capacitors (060) Taiyo Yuden EMK07BJ04MA Features +.7V to +5.5V Input Range (as Configured) Output Voltages +0V Output at 00mA (Boost Switching) +5V Output >0mA (Positive Charge-Pump Regulator) -5V Output >0mA (Negative Charge-Pump Regulator) Outputs Are Adjustable with Resistors >85% Efficiency Internal MOSFET Switches 0.µA (typ) IC Shutdown Current MHz Boost Switching Frequency, 500kHz Charge-Pump Switching Frequency Low Profile Evaluates MAX779 (Component Replacement Required) Surface-Mount Components Fully Assembled and Tested PART MAX748EVKIT Ordering Information TEMP RANGE 0 C to +70 C IC PACKAGE 6 TSSOP Component List DESIGNATION QTY DESCRIPTION C0 C 0 Not installed (0805) C4 C9, C0 0 0.5µF, 5V X7R ceramic capacitor (06) Taiyo Yuden TMK6BJ54MD Not installed, ceramic capacitors (060) C 0 C7, C5, C4 C8 C9 Not installed (R) Sprague 59D6X006RT recommended µf, 6V X7R ceramic capacitors (06) Murata GRM9R7C05K 470pF, 50V C0G ceramic capacitor (060) Murata GRM885CH47IJ 0.µF, 0V X7R ceramic capacitor (060) Taiyo Yuden LMK07BJ4KA D.0A, 0V Schottky diode (S-flat) Toshi b a C RS 0 or N i hon E P 0QY 0 D, D 00mA, 5V Schottky diodes (SOT) Fairchild BAT54S D4, D5 0 Not installed (SOT) L 6.8µH inductor Coilcraft LPO506IB-68 R 48kΩ ±% resistor (0805) R 549kΩ ±% resistor (0805) R, R4, R6 49.9kΩ ±% resistors (0805) R5 00kΩ ±% resistor (0805) Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at -888-69-464, or visit Maxim s website at www.maxim-ic.com.
Component List (continued) DESIGNATION QTY DESCRIPTION R7 0 Not installed (0805) R8, R9 MΩ ±5% resistors (0805) U MAX748EUE (6-pin TSSOP) JU, JU4, JU5 -pin headers None Shunts (JU, JU4, JU5) None MAX748 PC board None MAX748 data sheet None MAX748 EV kit data sheet Quick Start The MAX748 EV kit is fully assembled and tested. Perform the following steps to verify board operation for a +0V output. Do not turn on the power supply until all connections are completed: ) Connect a +.7VDC to +5.5VDC power supply to the pad. Connect the supply ground to the pad. ) Connect a voltmeter to the V pad. ) Verify that shunts JU (SHDN) are across pins and and that shunts JU4 (SUPP) and JU5 (SUPN) are across pins and. 4) Turn on the power supply and verify that the main output (V) is +0V. 5) Verify that the negative charge-pump regulator output (VN) is -5V. 6) Verify that the positive charge-pump regulator output (VP) is +5V. For instructions on selecting the feedback resistors for other s, see the Output Voltage Selection section. The input voltage range is +.7V to +5.5V when selecting the. Detailed Description The MAX748 EV kit contains a boost switching regulator and two regulating charge pumps. The EV kit operates from a +.7V to +5.5V input voltage range. The boost switching regulator provides up to 00mA with a +0V output. The positive charge-pump regulator generates a +5V output and can provide >0mA of current. The negative charge-pump regulator generates -5V output and can provide >0mA of current. Jumper options allow either charge pump to be fed power from or V. Component Suppliers SUPPLIER PHONE FAX Coilcraft 847-69-6400 847-69-469 Fairchild 408-8-000 408-8-0 Murata 84-7-4 84-8-0490 Sprague Sumida 60-4-96 708-956-0666 60-4-40 708-956-070 Taiyo Yuden Toshiba 408-57-450 949-455-000 408-57-459 949-859-96 Note: Please indicate that you are using the MAX748/MAX779 when contacting these component suppliers. The boost switching-regulator can be adjusted from +.7V to +V with resistors. The positive charge-pump regulator s output can be adjusted up to +5V, and the negative regulator can be adjusted to -5V with resistors. The MAX748 EV kit charge-pump circuits feature PC board pads for a positive voltage tripling and negative voltage doubling output circuits. The MAX748 EV kit can evaluate the MAX779 IC after replacing several components. See the Evaluating the MAX779 section. Jumper Selection Shutdown Mode The MAX748 EV kit features a shutdown mode that reduces the MAX748 quiescent current, preserving battery life. The -pin jumper (JU) selects the shutdown mode for the MAX748. Table lists the selectable jumper options. Positive Charge-Pump Regulator Feedback In the MAX748 EV kit, jumper JU selects which positive charge pump will be regulated: VP, a voltage doubler, or VPA, a voltage tripler. Table lists the positive charge-pump regulator jumper options. Negative Charge-Pump Regulator Feedback In the MAX748 EV kit, jumper JU selects which negative charge pump will be regulated: VN or VNA, a voltage doubler. Table lists the negative regulator jumper options. Positive Voltage Source The MAX748 EV kit features an option to choose which voltage source feeds the positive charge-pump regulator circuit. Jumper JU4 selects the input voltage source for the MAX748 s SUPP pin. Table 4 lists the options.
Table. Jumper JU Functions Table. Jumper JU Functions (PC trace shorts ) (cut open trace across, short across ) SHDN to to R to VP to VPA Table. Jumper JU Functions (PC trace shorts ), (cut open trace across, short across ) R5 to VN to VNA MAX748 OUTPUT MAX748 enabled, V = +0V Shutdown mode, V = P IN - V DIODE Regulate VP, doubler Regulate VPA, tripler Regulate VN, -5V Regulate VNA, negative doubler Negative Voltage Source The MAX748 EV kit features an option to choose which voltage source feeds the negative charge-pump regulator circuit. Jumper JU5 selects the input voltage source for the MAX748 s SUPN pin. Table 5 lists the options. Output Voltage Selection Boost Switching-Regulator Output Voltages The MAX748 EV kit s boost switching-regulator output is set to +0V by feedback resistors (R, R). To generate s other than +0V (+.7V to +V), select different external voltage-divider resistors (R, R). The ceramic capacitors (C7, C8, C0) are rated to +0V. To set the voltage >+0V, use higher-voltagerated capacitors. Refer to the Output Voltage Selection section in the MAX748 data sheet for instructions on selecting the resistors. The input voltage range will be +.7V to V when selecting other s. Positive Charge-Pump Output Voltages The MAX748 EV kit s positive charge-pump regulator output is set to +5V by feedback resistors (R, R4). To generate s other than +5V, select different external voltage-divider resistors (R, R4). Refer to the Output Voltage Selection section in the MAX748 data sheet for instructions on selecting the resistors. See Table 4 for the jumper selection of input voltage ranges. Check that the capacitor voltage rating is adequate for the configuration. Positive Tripler Charge-Pump Output Voltages The MAX748 EV kit features a positive charge-pump voltage tripler circuit. Three components (C0, C, D4) must be installed and jumper JU modified to utilize the tripler circuit. Capacitors C0 and C should be 0.µF (Taiyo Yuden, UMKBJ04MG recommended) with a voltage rating equal to or greater than the expected output voltage at VPA. Lower cost diodes with higher forward voltage drops can be used for D4, if enough voltage headroom is available. The shorted PC trace across pinholes and must be cut open and a jumper wire installed in pinholes and at jumper JU. Note: VPA will now be the regulated output. To generate a different voltage, select proper voltagedivider resistors (R, R4) while taking into consideration input voltages and jumper settings. Refer to the Output Voltage Selection section in the MAX748 data sheet for instructions on selecting the resistors. See Table 4 for jumper selection of input voltage ranges. Negative Charge-Pump Output Voltages The MAX748 EV kit s negative charge-pump regulator output is set to -5V by feedback resistors (R5, R6). To generate different voltages, select different external voltage-divider resistors (R5, R6) while taking into consideration input voltages and jumper settings. Refer to the Output Voltage Selection section in the MAX748 data sheet for instructions on selecting the resistors. See Table 5 for the jumper selection of input voltage ranges. Negative Doubler Charge-Pump Output Voltages The MAX748 EV kit features a negative charge-pump voltage doubler circuit. Three components (C, C, D5) must be installed and jumper JU modified to utilize the doubler circuit. Capacitors C and C should be 0.µF (Taiyo Yuden UMKBJ04MG recommended) with a voltage rating equal to or greater than the expected at VNA. Lower cost diodes with higher forward voltage drops can be used for D5 if enough voltage headroom is available. The shorted PC trace across pinholes and must be cut open and a jumper wire installed in pinholes and at jumper JU. To generate a different negative, select different external voltage-divider resistors (R5, R6) while taking into consideration input voltages and jumper settings. Refer to the Output Voltage Selection section in the MAX748 data sheet for instructions on selecting the
Table 4. Jumper JU4 Functions PART QTY V OUT = 5.V, V IN =.0V, I OUT = 50MA (MAX) resistors. See Table 5 for jumper selection of input voltage ranges. Evaluating the MAX779 MAX779 Reconfiguration The MAX748 EV kit can be reconfigured to evaluate the MAX779EUE. Replace the components listed in Table 6. The boost switching regulator output (V) +5.V and provides up to 50mA to 00mA of current, depending on the inductor value and output capacitance chosen. The positive and negative charge-pump outputs provide +9V (VP) and -4V (VN) at their outputs. Table 6 below lists the components that must be replaced to evaluate a MAX779. DESCRIPTION V OUT = 5.V, V IN =.0V, I OUT = 00MA (MAX) C4, C6 0.µF, 6V X7R ceramic capacitors (060) 0.µF, 6V X7R ceramic capacitors (060) C8 0.00µF, 0V X5R ceramic capacitor (060) 0.00µF, 0V X5R ceramic capacitor (060) C8 0 Open Open C9 0pF, 0V X5R ceramic capacitor (060) 470pF, 0V X5R ceramic capacitor (060) C, C7 L SUPP to to V Table 5. Jumper JU5 Functions SUPN to to V Table 6. Component List voltage source feeds positive Boost converter (V) feeds positive voltage source feeds negative Boost converter (V) feeds negative 4.7µF, 6.V X7R ceramic capacitors (0) 0µH, 0.A inductor Coilcraft LPO506IB-0 or Sumida CMD4D08-00 recommended 0µF, 6.V X7R ceramic capacitors (0) µh, 0.A inductor Sumida CMD4D08-0 or Coilcraft LPO506IB- recommended R 54kΩ ±% resistor (0805) 54kΩ ±% resistor (0805) R 09kΩ ±% resistor (0805) 09kΩ ±% resistor (0805) R5 58kΩ ±% resistor (0805) 58kΩ ±% resistor (0805) R7 0kΩ ±5% resistor (0805) 4kΩ ±5% resistor (0805) U MAX779EUE (6-pin TSSOP) MAX779EUE (6-pin TSSOP) 4
4 6 0 8 6 9 SHDN RDY 5 4 7 5 RDY VNA VNA VN -5V +.7V TO +5.5V C L D5 R C R V L C6 0.μF C7 μf VNA D JU R5 00kΩ UNLESS OTHERWISE NOTED, ALL RESISTORS ARE (0805) %. C.μF JU5 C6.μF R6 49.9kΩ JU R8 MΩ C 0.μF C8 470pF C4 0.5μF C9 0.μF L 6.8μH D V +0V V C.μF C7.μF C8.μF C TIN TPA INTG SUPN DRVN FBN REF U MAX748 LX FB P SUPP DRVP FBP R4 49.9kΩ C5 μf R 549kΩ R 48kΩ R 49.9kΩ R7 C9 JU4 C0 V C0 C4 0.μF D4 D R L R L V C 0.μF C5 0.μF V JU C C 0.μF VPA C4 μf VPA VPA VP +5V R9 MΩ Figure. MAX748 EV Kit Schematic 5
.0" Figure. MAX748 EV Kit Component Placement Guide Component Side.0" Figure. MAX748 EV Kit PC Board Layout Component Side.0" Figure 4. MAX748 EV Kit PC Board Layout Solder Side 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. 6 Maxim Integrated Products, 0 San Gabriel Drive, Sunnyvale, CA 94086 408-77-7600 004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.