 |
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
|
| If you can't view the Datasheet, Please click here to try to view without PDF Reader . |
|
|
| Datasheet File OCR Text: |
| MAX1705 Evaluation Kit _______________General Description The MAX1705 evaluation kit (EV kit) is a step-up switching regulator for battery-powered systems operating from 1 to 3 NiCd/NiMH cells or 1 Li-Ion cell. The EV kit accepts a +0.9V to +4.5V input and converts it to a 4.5V step-up output and a 3.3V linear-regulator output. It provides low quiescent current, high-efficiency pulsefrequency-modulation operation for maximum battery life, and a high-power, fixed-frequency pulse-widthmodulation mode. The MAX1705 features a built-in, low-dropout linear post-regulator that reduces high-frequency ripple. The MAX1705 EV kit is a fully assembled and tested surface-mount circuit board. It can also be used to evaluate the MAX1706. ____________________________Features o +0.9V to +4.5V Input Range o High-Power Output: 4.5V or Adjustable o Dual Outputs: Step-Up and Linear Regulator o 200mA Max Linear-Regulator Output Current o Optional Track Mode for Highest Efficiency o Low-Noise, 3.3V or Adjustable Output Voltage o High-Efficiency Step-Up Converter: Up to 96% o Up to 850mA Total Output Current o Internal 300kHz Oscillator o Internal MOSFET and Synchronous Rectifier o 1A Shutdown Current o Power-Good Output o Surface-Mount Components o Fully Assembled and Tested Evaluates: MAX1705/MAX1706 ____________________Component List DESIGNATION QTY C1 1 DESCRIPTION 22F, 25V tantalum capacitor Sprague 593D226X0025D2W or AVX TPSD226M025R0200 220F, 10V low-ESR tantalum capacitor Sprague 594D227X0010D2T, Sprague 593D227X0010D2W, or AVX TPSE227M010R0100 0.1F ceramic capacitor 22F, 6.3V tantalum capacitor Sprague 595D226X06R3B2T 0.33F ceramic capacitors 22pF ceramic capacitor Open Schottky diode Motorola MBR0520L 10H inductor Sumida CDR74B-100 267k, 1% resistor 100k, 1% resistors 165k, 1% resistor Open 0 resistor 100k, 5% resistors MAX1705EEE (QSOP-16) 2-pin headers 3-pin header Shunt MAX1705 PC board C8 1 C3 C4 C5, C7, C9 C6 C2 D1 L1 R1 R2, R4 R3 R5 R6 R7, R8, R9 U1 JU1, JU2, JU3 JU4 None None 1 1 3 1 0 1 1 1 2 1 0 1 3 1 3 1 1 1 ______________Ordering Information PART TEMP. RANGE BOARD TYPE MAX1705EVKIT 0C to +70C Surface Mount Note: To evaluate the MAX1706, request a MAX1706EEE free sample with the MAX1705 EV kit. ______________Component Suppliers SUPPLIER AVX Coilcraft Coiltronics Dale-Vishay Motorola Sprague Sumida Vishay/Vitramon PHONE (803) 946-0690 (847) 639-6400 (561) 241-7876 (402) 564-3131 (602) 303-5454 (603) 224-1961 (847) 956-0666 (203) 268-6261 FAX (803) 626-3123 (847) 639-1469 (561) 241-9339 (402) 563-6418 (602) 994-6430 (603) 224-1430 (847) 956-0702 (203) 452-5670 Note: Please indicate that you are using the MAX1705 when contacting these component suppliers. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 MAX1705 Evaluation Kit Evaluates: MAX1705/MAX1706 _________________________Quick Start The MAX1705 evaluation kit (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. 1) Connect a +2.4V power supply to the VIN pad. The ground connects to the GND pad. 2) Connect voltmeters, if any, to the POUT and VOUT pads. 3) Turn on the power supply and verify that POUT is 4.5V and VOUT is 3.3V. 4) Apply the loads, if any. 5) For other output voltages, refer to the Setting the Output Voltages section in the MAX1705/MAX1706 data sheet for instructions on selecting the feedback resistors. Table 1. Jumper JU1 Functions SHUNT LOCATION On Off ONA PIN Connected to GND Connected to POUT MAX1705 OUTPUT Shutdown mode, VOUT = 0V, POUT = VIN - VDIODE MAX1705 enabled, VOUT = 3.3V, POUT = 4.5V Switching Mode The two-pin header JU2 selects either PFM or PWM switching mode. Table 2 lists the selectable jumper options. Table 2. Jumper JU2 Functions SHUNT LOCATION On CLK/SEL PIN Connected to GND Connected to POUT SWITCHING MODE PFM mode, ITOTAL = 120mA at 2.4V input Fixed PWM mode (300kHz), ITOTAL = 450mA at 2.4V input _______________Detailed Description The MAX1705 EV kit is designed to supply both power and low-noise circuitry in portable RF and dataacquisition instruments. It combines a linear regulator, step-up switching regulator, N-channel power MOSFET, P-channel synchronous rectifier, precision reference, and low-battery comparator in a single, tiny 16-pin QSOP. The switching DC-DC converter boosts an input from one or two cells to a 4.5V output. An on-chip linear regulator also provides a low-noise 3.3V output. The EV kit operates in a constant-frequency (300kHz), low-noise pulse-width-modulation (PWM) mode with 450mA total output current capability at VIN = 2.4V. A low-quiescent-current standby pulse-frequency-modulation (PFM) mode offers a total output current up to 120mA and reduces quiescent power consumption to 500W. Off Tracking Mode Connecting the TRACK input to POUT implements a tracking mode that sets the step-up converter output to 300mV above the linear-regulator output, improving efficiency. In tracking mode, feedback for the step-up converter is derived from the OUT pin. Connect TRACK to GND for normal operation. The two-pin header JU3 selects the tracking mode. Table 3 lists the selectable jumper options. Table 3. Jumper JU3 Functions SHUNT LOCATION On Off TRACK PIN Connected to POUT Connected to GND TRACKING MODE Tracking mode; POUT is 300mV above VOUT Normal operation Shutdown Mode The MAX1705 EV kit features a shutdown mode that reduces quiescent supply current to 7A (1A for the IC plus 6A for the feedback resistors) to preserve battery life. During shutdown, the reference, the low-battery comparator, and all feedback and control circuitry are turned off. The step-up converter's output drops to within a Schottky diode drop below the input, and the linear-regulator output is turned off. The two-pin header JU1 selects shutdown mode. Table 1 lists the selectable jumper options. Power-Good Output The MAX1705 has an on-chip comparator for powergood detection. This comparator can be used to detect a low battery voltage at the input or low-voltage output. The MAX1705 EV kit is supplied with the comparator's 2 _______________________________________________________________________________________ MAX1705 Evaluation Kit Evaluates: MAX1705/MAX1706 VIN 0.9V TO 4.5V L1 10H 14 R9 100k ON/OFF R7 100k PWM/PFM JU3 R8 100k JU2 JU1 11 15 ONB LX PGND POUT OUT CLK/SEL 13 C1 22F 25V POUT 4.5V C2 OPEN R1 267k 1% C3 0.1F R2 100k 1% VOUT 3.3V MBRO520L ONA 12 16 6 C7 0.33F C8 220F 10V U1 MAX1705 FB 7 9 4 LDO TRACK 3 C5 0.33F 2 10 5 REF LBN LBO GND FBLDO LBP 8 1 R4 100k 1% 3 JU4 R6 SHORT R5 OPEN 2 1 VIN R3 165k 1% C6 22pF C4 22F 6.3V C9 0.33F PWRGD Figure 1. MAX1705 EV Kit Schematic Diagram LBN input connected to the reference, and the LBP input connected to GND through R6 (0). LBP can be connected to an external resistor-divider, R5-R6, to set the comparator threshold. PWRGD, an open-drain output, is low when LBN > LBP. Refer to the Low-Battery Comparator section of the MAX1705/MAX1706 data sheet for instructions on selecting R5 and R6. The three-pin header JU4 selects input or output detection. Remove R6 and refer to the Low-Battery Comparator section of the MAX1705/MAX1706 data sheet to determine R5 and R6. Table 4 lists the selectable jumper options. Evaluating the MAX1706 The MAX1705 EV kit can also be used to evaluate the MAX1706. Simply replace the MAX1705EEE with the MAX1706EEE and replace the 10H inductor, L1, with a 22H inductor (Sumida CD74B-220). Table 4. Jumper JU4 Functions SHUNT LOCATION 1 and 2 2 and 3 PWRGD OUTPUT Detects low-battery voltage input Detects low-voltage output _______________________________________________________________________________________ 3 MAX1705 Evaluation Kit Evaluates: MAX1705/MAX1706 1.0" Figure 2. MAX1705 EV Kit Component Placement Guide-- Component Side 1.0" Figure 3. MAX1705 EV Kit PC Board Layout--Component Side 1.0" Figure 4. MAX1705 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. 4 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 (c) 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. |
Price & Availability of MAX1705EVKIT-MAX1706EVKIT
 |
|
|
|
|
All Rights Reserved © IC-ON-LINE 2003 - 2022 |
| [Add Bookmark] [Contact Us] [Link exchange] [Privacy policy] |
|
Mirror Sites : [www.datasheet.hk]
[www.maxim4u.com] [www.ic-on-line.cn]
[www.ic-on-line.com] [www.ic-on-line.net]
[www.alldatasheet.com.cn]
[www.gdcy.com]
[www.gdcy.net] |