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| 19-1888; Rev 0; 12/00 MAX1765 Evaluation Kit General Description The MAX1765 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that contains two separate switching-regulator and linear-regulator circuits. Both circuits are configured for a +3.3V DC-DC output, which provides up to 800mA of current. They also contain a low-dropout (LDO) linear regulator that is configured for a +2.85V output and provides up to 500mA at the output. The two circuits differ only in their package type: the low-power circuit (left side) uses a 16-pin QSOP that can dissipate up to 696mW, while the high-power circuit (right side) uses a 16-pin TSSOP-EP that can dissipate up to 1700mW. The MAX1765 features an internal N-channel MOSFET switch and a P-channel synchronous rectifier, and a pin-selectable forced pulse-width modulation (PWM) mode. The MAX1765 EV kit demonstrates low quiescent current and high efficiency (up to 96%) for maximum battery life. Operation at 1MHz allows the use of tiny surface-mount components. o Output Voltages +3.3V Output at 800mA (DC-DC) +2.85V Output at 500mA (LDO) o Both Outputs Are Adjustable with External Resistors o Two Complete Circuits (Both Package Types) o 1A IC Shutdown Current o 1MHz PWM Switching Frequency (for Small, Surface-Mount Components) o Programmable Operating Mode o Built-In 500mA LDO Linear Regulator o Fully Assembled and Tested Features o Operation from Inputs as Low as 0.7V Evaluates: MAX1765 Ordering Information PART MAX1765EVKIT *Exposed paddle TEMP. RANGE 0C to +70C IC PACKAGE 16 QSOP, 16 TSSOP-EP* Component List DESIGNATION QTY* C1, C11 C2, C12 C3, C7, C13, C17, C21, C22 C4, C14 C5, C15 C6, C16 C8, C18 C9, C19 C10, C20 D1 2 2 6 2 2 2 2 0 0 0 DESCRIPTION 33F, 16V low-ESR electrolytic caps (POSCAP) Sanyo 16TPC33M 100F, 6.3V low-ESR electrolytic caps (POSCAP) Sanyo 6TPC100M 1F, 10V X5R ceramic caps (0805) Taiyo Yuden LMK212BJ105MG 0.1F, 50V X5R ceramic caps (0805) Taiyo Yuden UMK212BJ104KG 0.68F, 10V X5R ceramic caps (0805) Taiyo Yuden LMK212BJ684KG 4.7F, 6.3V X5R ceramic caps (0805) Taiyo Yuden JMK212BJ475KG 0.22F, 25V X7R ceramic caps (1206) Taiyo Yuden TMK316BJ224KF Not installed (0805) Not installed (POSCAP D2) Not installed Nihon EP10QY03 (recommended for low-voltage startup) DESIGNATION QTY* D2 JU1-JU4, JU7-JU10 JU5, JU11 L1, L2 R1, R9 R2, R8 R3, R4, R6, R7, R10, R11, R13, R14 R5, R12 U1 U2 None None None None 1 8 2 2 2 2 0 2 1 1 10 1 1 1 DESCRIPTION 1A, 30V Schottky diode Nihon EP10QY03 3-pin headers 2-pin headers 3.3H inductors Coilcraft DO1606T-332 165k 1% resistors (0805) 100k 1% resistors (0805) Not installed (0805) 4.7 5% resistors (0805) MAX1765EEE (16 QSOP) MAX1765EUE (16 TSSOP-EP) Shunts (JU1-JU5, JU7-JU11) MAX1765 PC board MAX1765 data sheet MAX1765 EV kit data sheet *Quantities are for both circuits. ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. MAX1765 Evaluation Kit Evaluates: MAX1765 Component Suppliers SUPPLIER Coilcraft Nihon USA Sanyo USA Taiyo Yuden PHONE 847-639-6400 661-867-2555 619-661-6835 408-573-4150 FAX 847-639-1469 661-867-2698 619-661-1055 408-573-4159 Note: Please indicate that you are using the MAX1765 when contacting these component suppliers. Quick Reference The MAX1765 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. Both circuits require a +1.1V to +3.2V input voltage range. The LDO linear regulators can be powered from the switching regulator output (POUT) or an external DC voltage source. The circuits differ in their package type. The low-power circuit (left side) features a 16-pin QSOP, while the high-power circuit (right side) features a thermally enhanced 16-pin TSSOP-EP. The switching regulators' output voltages can be adjusted from +2.5V to +5.5V with external resistors. The MAX1765 EV kit permits jumper-selectable operational modes: normal (heavy-load PWM/light-load PFM) mode, track mode, forced PWM mode, and forced PWM mode with the internal oscillator synchronized to an external clock. Low-Power Circuit (Left Side) 1) Connect a voltmeter to the POUT pad. 2) Verify that shunts JU1 (ONA), JU2 (CLK/SEL), and JU4 (ONL) are across pins 1 and 2 and that shunt JU3 (TRACK) is across pins 2 and 3. Verify that a shunt is on jumper JU5. 3) Connect a +1.1VDC to +3.2VDC power supply to the PIN pad. Connect the supply ground to the GND pad. 4) Turn on the power supply and verify that the main output (POUT) is +3.3V. 5) Verify that the LDO linear regulator output (OUTL) is +2.85V. For instructions on selecting the feedback resistors for other output voltages, see the Evaluating Other Output Voltages section. Jumper Selection Shutdown Mode (Both Circuits) The MAX1765 EV kit features a shutdown mode that reduces the MAX1765 quiescent current to less than 1A (typ), preserving battery life. The 3-pin jumpers, JU1 and JU7, select the shutdown mode for the MAX1765. Table 1 lists the selectable jumper options. CLK/SEL Operating Mode (Both Circuits) Jumpers JU2 and JU8 control the CLK/SEL pin operating mode for the left and right circuits, respectively. Options include low-noise forced PWM mode, normal mode, and external clock source driving the CLK/SEL pin. The external clock source must operate in the 500kHz to 1200kHz range. Table 2 lists the CLK/SEL jumper options. Table 1. Jumper JU1, JU7 Functions SHUNT LOCATION 1, 2 2, 3 ONA PIN Connected to POUT Connected to GND MAX1765 OUTPUT MAX1765 enabled, POUT = +3.3V Shutdown mode, POUT = PIN - VDIODE High-Power Circuit (Right Side) 1) Connect a voltmeter to the POUT pad. 2) Verify that shunts JU7 (ONA), JU8 (CLK/SEL), and JU10 (ONL) are across pins 1 and 2 and that shunt JU9 (TRACK) is across pins 2 and 3. Verify that a shunt is on jumper JU11. 3) Connect a +1.1VDC to +3.2VDC power supply to the PIN pad. Connect the supply ground to the GND pad. 4) Turn on the power supply and verify that the main output (POUT) is +3.3V. 5) Verify that the LDO Linear Regulator output (OUTL) is +2.85V. For instructions on selecting the feedback resistors for other output voltages, see the Evaluating Other Output Voltages (Both Circuits) section. Table 2. Jumper JU2, JU8 Functions SHUNT LOCATION 1, 2 CLK/SEL PIN OPERATING MODE Forced PWM mode: PWM operation at all loads Normal mode: PFM at light load and PWM at heavy load PWM mode synchronized to external 500kHz to 1200kHz range clock Connected to POUT 2, 3 Connected to GND Detailed Description The MAX1765 EV kit contains two separate boost switching-regulator circuits that provide +3.3VDC output and linear regulators that provide +2.85V output. 2 None Clock connected to CLK/SEL pad _______________________________________________________________________________________ MAX1765 Evaluation Kit TRACK Operating Mode (Both Circuits) The MAX1765 EV kit features a track mode where POUT is set to +0.5V above the LDO linear regulator output voltage to improve efficiency. Use JU3 and JU9 to select track mode for either circuit. Table 3 lists the selectable jumper options. LDO Linear Regulator Shutdown Mode (Both Circuits) The MAX1765 EV kit features a shutdown mode for the built-in LDO linear regulator. The 3-pin jumpers, JU4 and JU10, disable and enable the left and right LDO linear regulators, respectively. Table 4 lists the selectable jumper options. LDO Linear Regulator Source Selection (Both Circuits) The MAX1765 EV kit allows each built-in LDO linear regulator to be powered from the boost switching regulator or an external voltage source. Jumpers JU5 and JU11 select the DC voltage source for the left and right LDO linear regulators, respectively. Table 5 lists the jumper options. Evaluating Lower Startup Input Voltages The MAX1765 EV kit can operate from DC supply voltages down to +0.7V. When PIN is below +1.1V, a Schottky diode is required to guarantee startup below 1.1V. A Shottky diode is supplied with the high-power circuit (right side), but the user must add it to the lowpower circuit (left side). Refer to the Selecting the Output Diode section in the MAX1765 data sheet for instructions on selecting D1. Evaluates: MAX1765 Evaluating Other Output Voltages (Both Circuits) The MAX1765 EV kit's boost switching regulator outputs are set to +3.3V by feedback resistors R1, R2, R8, and R9. To generate output voltages other than +3.3V (+2.5V to +5.5V), select different external voltage-divider resistors (R1, R2 left side and R8, R9 right side). Refer to Setting the Output Voltages section in the MAX1765 data sheet for instructions on selecting the resistors. Evaluating Other LDO Linear Regulator Output Voltages (Both Circuits) The MAX1765 EV kit's LDO linear regulator output (OUTL) has been set to +2.85V by shorting the FBL pin to ground. To generate output voltages other than +2.85V (+1.25V to +5V), cut open the PC board trace across resistor R4 or R10 for the left and right sides, respectively. Select different external voltage-divider resistors. Refer to the Setting the Output Voltages section in the MAX1765 data sheet for instructions on the resistors (R3, R4 left side or R10, R11 right side). Table 3. Jumper JU3, JU9 Functions SHUNT LOCATION 1, 2 2, 3 TRACK PIN Connected to POUT Connected to GND OPERATING MODE Track mode enabled Normal operation Table 4. Jumper JU4, JU10 Functions SHUNT LOCATION 1, 2 2, 3 ONL PIN Connected to POUT Connected to GND LDO OPERATING MODE Linear regulator enabled Linear regulator disabled Evaluating Other Current Limits (Both Circuits) The EV kit inductor current limit can be set from 400mA to 1250mA. The EV kit is factory configured for a 1250mA inductor current limit. To evaluate other current limits, cut open the PC board trace shorting R6 or R14 for the left and right sides, respectively. Resistors must be selected and installed to set the current limit. Refer to Setting the Switch Current Limit and Soft-Start section of the MAX1765 data sheet for selecting the resistors (R6, R7 left side or R13, R14 right side). Table 5. Jumper JU5, JU11 Functions LOCATION INL PIN Connected to POUT Connected to external DC source LDO POWER SOURCE POUT supplies the LDO linear regulator power External source supplies the LDO linear regulator power Enabling Soft-Start (Both Circuits) The MAX1765 soft-start feature will limit in-rush current during startup. To evaluate soft-start, cut open the PC board trace shorting R6 or R14 for the left and right sides, respectively. Install capacitor C9 or C19 and resistors R6 or R14. Refer to the Setting the Switch Current Limit and Soft-Start section in the MAX1765 data sheet for instructions on selecting C9 or C19 and R6 or R14 to activate soft-start. Installed None Note: INL must be powered to use the boost switching regulator circuit. If the LDO linear regulator is not used, INL must be connected to POUT (JU5 or JU11 installed) or a higher external source applied to the INL pad. _______________________________________________________________________________________ 3 MAX1765 Evaluation Kit Evaluates: MAX1765 PIN +0.7V TO +3.2V GND C1 33F 16V POUT +3.3V C2 100F 6.3V C3 1F 10V POUT GND L1 3.3H D1 (OPEN) 9 ONB LX 11 C10 (OPEN) POUT ONA 3 2 1 POUT CLK/SEL 1 2 3 JU2 PWM PFM 8 JU1 7 ONA 12 C4 0.1F U1 MAX1765 CLK/SEL OUT 6 R5 4.7 5% C5 0.68F R1 165k 1% R2 100k 1% 3 2 1 JU3 15 TRACK FB 5 +2.85V OUTL R3 (OPEN) R4 (SHORT PC TRACE) 3 C8 0.22F R6 (SHORT PC TRACE) 2 R7 (OPEN) C9 (OPEN) 16 REF OUTL 14 ISET ONL GND 4 FBL 1 C6 4.7F 6.3V C7 1F 10V GND INL PGND 10 13 1 2 JU4 3 C21 1F ONL JU5 INL POUT Figure 1. MAX1765 EV Kit Schematic (Left Side) 4 _______________________________________________________________________________________ MAX1765 Evaluation Kit Evaluates: MAX1765 PIN +0.7V TO +3.2V GND C11 33F 16V L2 3.3H D2 C12 100F 6.3V C13 1F 10V POUT +3.3V 9 ONB LX 11 C20 (OPEN) POUT GND POUT ONA 3 2 1 POUT CLK/SEL 1 2 3 JU8 PWM PFM 8 JU7 7 ONA 12 C14 0.1F U2 MAX1765 CLK/SEL OUT 6 C15 0.68F R12 4.7 5% R9 165k 1% R8 100k 1% 3 2 1 JU9 15 TRACK FB 5 +2.85V OUTL R11 (OPEN) R10 (SHORT PC TRACE) 3 C18 0.22F R14 (SHORT PC TRACE) 2 R13 (OPEN) C19 (OPEN) 16 REF OUTL 14 ISET ONL GND 4 FBL 1 C16 4.7F 6.3V C17 1F 10V GND INL PGND 10 13 1 2 3 JU10 C22 1F ONL JU11 INL POUT Figure 2. MAX1765 EV Kit Schematic (Right Side) _______________________________________________________________________________________ 5 MAX1765 Evaluation Kit Evaluates: MAX1765 1.0" Figure 3. MAX1765 EV Kit Component Placement Guide--Component Side 1.0" Figure 4. MAX1765 EV Kit PC Board Layout--Component Side 6 _______________________________________________________________________________________ MAX1765 Evaluation Kit Evaluates: MAX1765 1.0" Figure 5. MAX1765 EV Kit PC Board Layout--Solder Side 1.0" Figure 6. MAX1765 EV Kit Component Placement Guide--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. 7 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. |
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