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 inde-
pendent 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.
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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 µMAX
®
Package
Assembled and Tested
Evaluates: MAX1954A
Ordering Information
µMAX is a registered trademark of Maxim Integrated Products, Inc.
PART
MAX1954AEVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
10 µMAX
Component List
DESIGNATION
C1
QTY
1
DESCRIPTION
22µF, 16V X5R ceramic capacitor
(1210)
TDK C3225X5R1C226K
0.22µF, 10V X7R ceramic capacitor
(0603)
Kemet C0603C224M8RAC
1µF, 10V X7R ceramic capacitor
(0603)
TDK C1608X7R1A105K
180µF, 2V, 9mΩ 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
0.1µF
±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)
2.7µH, 6.6A, 12mΩ inductor
Coilcraft DO3316P-272HC
Dual n-MOSFET 20V, 7.5A, 0.018Ω
(8-pin SO)
Fairchild FDS6890A
7.15kΩ
±1%
resistor (0603)
8.06kΩ
±1%
resistor (0603)
82kΩ
±5%
resistor (0603)
2Ω
±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 neg-
ative 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 10
3
x ((V
OUT
/ 0.8) - 1)
Note that V
OUT
cannot exceed V
IN
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 out-
put, 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
22µF
D1
CMPSH1-4
N1
FDS6890A
N
C8
0.1µF
LX
C4
180µF
C5
OPEN
C10
OPEN
L1
2.7µH
VOUT
+1.5V AT 5A
GND
HSD
IN
C2
0.22µF
C3
1µF
BST
DH
R5
OPEN
U1
MAX1954A
COMP/SHDN
JU2
C7
R3
470pF 82kΩ
C6
18pF
DL
N
R4
2Ω
C9
1500pF
R1
7.15kΩ
PGND
GND
FB
R2
8.06kΩ
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
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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