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19-3351; Rev 0; 7/04
MAX1954A Evaluation Kit
General Description
The MAX1954A evaluation kit (EV kit) demonstrates the MAX1954A buck controller application circuit. The EV kit generates a 1.5V output voltage at load currents up to 5A from a 10.8V to 13.2V input voltage range independent of the IC supply voltage. The MAX1954A switches at 300kHz and has better than 90% efficiency with the supplied components. The EV kit comes fully assembled and tested.
Features
Current-Mode Controller 300kHz Fixed-Frequency PWM 0.8V Minimum Output Voltage 10.8V to 13.2V Input Voltage Range >90% Efficiency Output Shutdown Mode All n-Channel MOSFET Design for Low Cost No Current-Sense Resistor Needed Foldback Short-Circuit Protection Thermal-Overload Protection Small 10-Pin MAX(R) Package Assembled and Tested
Evaluates: MAX1954A
Ordering Information
MAX is a registered trademark of Maxim Integrated Products, Inc.
PART MAX1954AEVKIT TEMP RANGE 0C to +70C IC PACKAGE 10 MAX
Component List
DESIGNATION C1 QTY 1 DESCRIPTION 22F, 16V X5R ceramic capacitor (1210) TDK C3225X5R1C226K 0.22F, 10V X7R ceramic capacitor (0603) Kemet C0603C224M8RAC 1F, 10V X7R ceramic capacitor (0603) TDK C1608X7R1A105K 180F, 2V, 9m SP capacitor Panasonic EEFSX0D181R Not installed (0603) 18pF 5%, 50V C0H ceramic capacitor (0402) Taiyo Yuden UMK105CH180JW 470pF 10%, 50V X7R ceramic capacitor (0402) Taiyo Yuden UMK105BJ471KW 0.1F 10%, 16V X5R ceramic capacitor (0603) Taiyo Yuden EMK107BJ104KA 1500pF, 50V X7R ceramic capacitor (0603) TDK C1608X7R1H152K DESIGNATION C10 D1 QTY 0 1 DESCRIPTION Not installed (0603) Schottky diode (SOT23-F) Central Semiconductor CMPSH1-4 2-pin headers Sullins PTC36SAAN (36-pin strip, cut to size as needed) 2.7H, 6.6A, 12m inductor Coilcraft DO3316P-272HC Dual n-MOSFET 20V, 7.5A, 0.018 (8-pin SO) Fairchild FDS6890A 7.15k 1% resistor (0603) 8.06k 1% resistor (0603) 82k 5% resistor (0603) 2 5% resistor (0603) Not installed (0603) MAX1954AEUB Shunts
C2
1
JU1, JU2
2
C3
1
L1
1
C4 C5 C6
1 0 1
N1 R1 R2 R3 R4 R5 U1 None
1 1 1 1 1 0 1 2
C7
1
C8
1
C9
1
________________________________________________________________ Maxim Integrated Products
1
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.
MAX1954A Evaluation Kit Evaluates: MAX1954A
Component Suppliers
SUPPLIER Central Semiconductor Coilcraft Fairchild Semiconductor Kemet Taiyo Yuden TDK COMPONENT Diodes Inductors MOSFETs Capacitors Capacitors Capacitors PHONE NUMBER 516-435-1110 800-322-2645 408-721-2181 864-963-6300 408-573-4150 81-3-5201-7200 WEBSITE www.centralsemi.com www.coilcraft.com www.fairchildsemi.com www.kemet.com www.t-yuden.com www.component.tdk.com
Note: Indicate you are using the MAX1954A when contacting these manufacturers.
Recommended Equipment
* * * * * 15V at 1A DC variable power supply 5V at 100mA power supply Digital multimeter (DMM) 5A load Ammeter (optional)
Detailed Description
Evaluating Other Output Voltages
The MAX1954A EV kit comes preset to a 1.5V output voltage. The output of the MAX1954A is adjustable down to 0.8V. To adjust the output voltage, place a 1% resistor at R1 with a value corresponding to the equation:
Quick Start
The MAX1954A application circuit is fully assembled and tested. Follow these steps to verify board operation: 1) Preset the DC power supplies to 12V and 5V. Turn off the power supplies. Do not turn on the power supplies until all connections are complete. 2) Remove the shunt from JU1 and JU2. 3) Connect the positive lead of the 5V power supply to the VIN pad on the EV kit and connect the negative lead of the power supply to the GND pad on the EV kit. 4) Connect the positive lead of the 12V power supply to the VHSD pad on the EV kit and connect the negative lead of the power supply to the GND pad on the EV kit. 5) Connect the positive lead of the DMM to the VOUT pad on the EV kit and connect the negative lead of the DMM to the GND pad on the EV kit. 6) Turn on the power supplies. 7) Verify that the voltage at VOUT is 1.5V 2.5%. 8) Connect a 5A load between VOUT and GND. 9) Verify that the voltage at VOUT is 1.5V 2.5%.
R1 = 8.06 x 103 x ((VOUT / 0.8) - 1) Note that VOUT cannot exceed VIN and is limited by the maximum duty cycle of the MAX1954A. Refer to the MAX1954A data sheet for information on selecting output inductor, capacitor, and compensation components to optimize the circuit for different output voltages.
Using a Single Power Supply
If the input source is between 3V to 5.5V, install a shunt on JU1 (to connect VHSD and VIN), and connect the power supply between the VHSD pad and the GND pad on the EV kit. Refer to the MAX1954A data sheet for information on selecting the inductor, capacitors, and compensation components for optimum performance.
Jumper Settings
Jumper JU1 Function (HSD Control)
Connect HSD to IN when using input voltages lower than 5.5V. Place a shunt on JU1 to connect HSD to IN.
Jumper JU2 Function (Output Shutdown Mode)
The MAX1954A features an output shutdown mode to minimize the quiescent current. To shut down the output, place a shunt between pins 1 and 2 on JU2. For normal operation remove the shunt from JU2.
2
_______________________________________________________________________________________
MAX1954A Evaluation Kit Evaluates: MAX1954A
VHSD +10.8V TO +13.2V VIN +3.0V TO +5.5V
JU1 C1 22F D1 CMPSH1-4 N1 FDS6890A N C8 0.1F LX C4 180F C5 OPEN C10 OPEN L1 2.7H VOUT +1.5V AT 5A
GND
HSD IN C2 0.22F C3 1F BST DH
R5 OPEN
U1 MAX1954A
COMP/SHDN JU2 C7 R3 470pF 82k C6 18pF
DL
N
R4 2 C9 1500pF
R1 7.15k
PGND
GND FB
R2 8.06k
Figure 1. MAX1954A EV Kit Schematic
Figure 2. MAX1954A EV Kit Component Placement Guide-- Top Silkscreen
Figure 3. MAX1954A EV Kit PC Board Layout--Component Side 3
_______________________________________________________________________________________
MAX1954A Evaluation Kit Evaluates: MAX1954A
Figure 4. MAX1954A EV Kit PC Board Layout--Layer 2
Figure 5. MAX1954A EV Kit PC Board Layout--Layer 3
Figure 6. MAX1954A 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) 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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