19-2516; Rev 0; 10/05
MAX1953 Evaluation Kit
General Description
The MAX1953 evaluation kit (EV kit) demonstrates two low-
cost, buck-controller application circuits. The MAX1953
application circuit features an adjustable current limit. The
1MHz switching frequency renders a small footprint. The
MAX1954 application circuit operates from a 3V to 13.2V
input voltage range and is adjustable independent of the
supply voltage. The MAX1954 switches at 300kHz and
boasts 93% efficiency with the supplied components.
This EV kit comes with the MAX1953 and MAX1954 evalu-
ation circuits fully assembled and tested.
♦
Low-Cost Current-Mode Controllers
♦
Fixed-Frequency Pulse-Width Modulation (PWM)
♦
0.8V (min) Output Voltage
♦
Operates from Low 3V Input Voltage
♦
MAX1953
1MHz Switching Frequency
Small Component Size, Low Cost
Adjustable Current Limit
♦
MAX1954
3V to 13.2V Input Voltage
93% Efficiency
300kHz Switching Frequency
♦
Shutdown Feature
♦
All n-Channel MOSFET Design for Low Cost
♦
No Current-Sense Resistor Needed
♦
Internal Digital Soft-Start
♦
Surface-Mount Components
♦
Thermal-Overload Protection
♦
Small 10-Pin µMAX
®
Package
♦
MAX1953/MAX1954 Circuit Fully Assembled and
Tested
Features
Evaluates: MAX1953/MAX1954
Component List
DESIGNATION
C1, C12
QTY
2
DESCRIPTION
1µF, 10V X7R ceramic capacitors
(0603)
TDK C1608X7R1A105K
0.22µF, 10V X7R ceramic capacitor
(0603)
Kemet C0603C224M8RAC
22µF, 16V X5R ceramic capacitor
(1210)
TDK C3225X5R1C226K
Not installed
180µF, 2V, 9mΩ SP capacitor
Panasonic EEFSX0D181R
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
capacitors (0603)
Taiyo Yuden EMK107BJ104KA
Not installed (0603)
1500pF
±10%,
50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H152K
C2
1
C3
C4
C5
1
1
1
Ordering Information
PART
MAX1953EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
10 µMAX
C6
1
C7
1
Recommended Equipment
•
•
•
•
Digital multimeter (DMM)
Ammeter (optional)
Power supply 1: 3V
DC
to 14V
DC
at 3A
Power supply 2: 3V
DC
to 6V
DC
at 100mA
C8, C18
C9, C19
C10
2
2
1
Component List continued on next page.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________
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.
MAX1953 Evaluation Kit
Evaluates: MAX1953/MAX1954
Component List (continued)
DESIGNATION
C11
C14
C15
QTY
1
1
1
DESCRIPTION
22µF
±20%,
6.3V X5R ceramic
capacitor (1206)
Taiyo Yuden JMK316 BJ226ML
Not installed (0402)
270pF
±5%,
50V C0G ceramic
capacitor (0402)
Taiyo Yuden UMK105 CG271JW
10µF
±10%,
6.3V X5R ceramic
capacitors (0805)
Taiyo Yuden JMK212 BJ106KG
4700pF
±10%,
50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H472K
Schottky diodes (SOT23-F)
Central Semiconductor CMPSH1-4
2-pin headers
Sullins PTC36SAAN
(36-pin strip, cut to size as needed)
3-pin header
Sullins PTC36SAAN
(36-pin strip, cut to size as needed)
DESIGNATION
L1
L2
QTY
1
1
DESCRIPTION
2.7µH, 6.6A, 12mΩ inductor
Coilcraft DO3316P-272HC
1µH, 3.6A, 20mΩ inductor
TOKO 817FY-1R0M
Dual n-channel MOSFETs, 20V,
7.5A, 0.018Ω (SO-8)
Fairchild FDS6890A
7.15kΩ
±1%
resistor (0603)
8.06kΩ
±1%
resistors (0603)
82kΩ
±5%
resistor (0603)
Not installed (0603)
2Ω
±5%
resistors (0603)
10.2kΩ
±1%
resistor (0603)
27kΩ
±5%
resistor (0603)
Maxim MAX1954EUB
Maxim MAX1953EUB
Shunts
Sullins STC02SYAN
Digi-key S9000-ND
N1, N2
R1
R2, R7
R3
R4, R9
R5, R10
R6
R8
U1
U2
—
2
1
2
1
2
2
1
1
1
1
4
C16, C17
2
C20
1
D1, D2
2
JU1, JU2, JU4
3
JU3
1
Component Suppliers
SUPPLIER
Central Semiconductor
Coiltronics
Fairchild Semiconductor
Kemet
Murata
Taiyo Yuden
TOKO
TDK
COMPONENT
Diodes
Inductors
MOSFETs
Capacitors
Capacitors
Capacitors
Inductors
Capacitors
PHONE
516-435-1110
561-752-5000
408-721-2181
864-963-6300
770-436-1300
408-573-4150
800-745-8656
847-803-6100
WEBSITE
www.centralsemi.com
www.coiltronics.com
www.fairchildsemi.com
www.kemet.com
www.murata.com
www.t-yuden.com
www.toko.com
www.component.tdk.com
Note:
Indicate you are using the MAX1953/MAX1954 when contacting these component suppliers.
Quick Start
The MAX1953/MAX1954 application circuits are fully
assembled and tested. Follow the steps below to verify
board operation.
3) Connect the positive lead of power supply 2 to the
VIN pad and connect the negative lead of the
power supply to GND.
4) Connect the positive lead of power supply 1 to the
HSD pad, and connect the negative lead on the
power supply to the GND pad.
5) Turn on power supply 1.
6) Turn on power supply 2.
MAX1954
1) Preset DC power supply 1 to 12V, and power sup-
ply 2 to 5V. Turn off the power supplies.
2) Verify that there is no shunt at JU1 and JU2.
2
_______________________________________________________________________________________
MAX1953 Evaluation Kit
7) Verify that the voltage at VOUT is ~1.5V.
8) Connect a 5A load between VOUT and GND.
9) Verify that the voltage at VOUT is ~1.5V.
Jumper Settings
JU2 and JU4 Functions
(Shutdown Mode)
The MAX1953/MAX1954 feature a shutdown mode to
minimize the quiescent current. To shut down the
MAX1953, place a shunt between pins 1 and 2 on JU4.
To shut down the MAX1954, place a shunt between
pins 1 and 2 on JU2.
Evaluates: MAX1953/MAX1954
MAX1953
1) Preset DC power supply 1 to 3.3V. Turn off the
power supply.
2) Ensure that there is a shunt between positions 1
and 2 at JU3.
3) Verify that there is no shunt at JU4.
4) Connect the positive lead of power supply 1 to the
VIN1 pad and connect the negative lead to the
GND1 pad.
5) Turn on the power supply.
6) Verify that the voltage at VOUT1 is ~1.8V.
7) Connect a 3A load between VOUT1 and GND1.
8) Verify that the voltage at VOUT1 is ~1.8V.
JU1 Function (HSD Control, MAX1954)
The HSD and IN pins on the MAX1954 can be connect-
ed when using input voltages lower than 5.5V. Place a
shunt on JU1 to connect the HSD and IN pins.
Setting the Current Limit (MAX1953)
Use JU3 to set the short-circuit current-limit threshold for
the MAX1953. Short JU3 between pins 1 and 2 for a
105mV threshold, between 2 and 3 for a 320mV threshold,
or remove the shunt from JU3 for a 210mV threshold.
Detailed Description
Evaluating Other Output Voltages
The MAX1953/MAX1954 application circuits come
assembled with output voltages of 1.8V and 1.5V,
respectively. The MAX1953/MAX1954 are capable of
adjustable output voltage settings from 0.8V to 0.86 x
V
IN
. To adjust the output voltage, place an 8.06kΩ ±1%
resistor at R2 (R5) and a 1% resistor at R1 (R4) with a
value corresponding to the equation:
R1 (R4) = 8.06 x 10
3
x ((V
OUT
/ 0.8) - 1)
V
OUT
can not exceed V
IN
.
The compensation network may need to be optimized
for each output voltage. Refer to the
Stability and
Compensation
section of the MAX1953/MAX1954/
MAX1957 data sheet for the method to calculate the
compensation components.
Input Capacitance Guidelines
An oscillation may occur in the input voltage when
using the MAX1953 EV kit that shows up on the output.
This is typically due to long input leads. An LC “tank”
circuit is formed with the inductance of the input leads
and the input capacitance. Use very short leads or add
a high equivalent series resistance (ESR) capacitor
(aluminum electrolytic or tantalum) at the input to stop
this oscillation. This “detunes” the LC tank circuit and
effectively stops the oscillation.
Using a Single Power Supply (MAX1954)
To use a single power supply with the MAX1954, the
power-supply voltage must be between 3V and 5.5V.
Connect the positive lead of the power supply to the
HSD pad on the EV kit, and connect the negative lead
of the power supply to the GND pad on the EV kit.
Install a shunt on JU1.
Table 1. JU3 Positions
SHUNT
LOCATION
Between 1 and 2
None
Between 2 and 3
ILIM
Connected to GND
Unconnected
Connected to IN
V
CS
(mV)
105
210
320
_______________________________________________________________________________________
3
MAX1953 Evaluation Kit
Evaluates: MAX1953/MAX1954
VHSD
+10.8V TO +13.2V
JU1
VIN
+3.0V TO +5.5V
GND
1
HSD
5
C2
0.22µF
C1
1µF
U1
MAX1954
JU2
C7
470pF
2
COMP/
SHDN
C6
18pF
4
GND
IN
DH
LX
DL
BST
10
8
9
6
C8
0.1µF
C3
22µF
D1
CMPSH1-4
N1
FDS6890A
R4
OPEN
C9
OPEN
N
L1
2.7µH
C5
180µF
VOUT
+1.5V AT 5A
C4
OPEN
N
R5
2Ω
C10
1500pF
R1
7.15kΩ
R3
82kΩ
PGND
7
FB
3
R2
8.06kΩ
VIN1
+3.0V TO +5.5V
C11
22µF
GND1
C12
1µF
5
3
JU3
2
1
1
ILIM
U2
MAX1953
DH
LX
DL
IN
BST
10
8
D2
CMPSH1-4
N2
FDS6890A
R9
OPEN
C18
0.1µF
9
6
N
R10
2Ω
C20
4700pF
R6
10.2kΩ
N
C19
L2
OPEN 1µH
VOUT1
+1.8V AT 3A
C16
10µF
C17
10µF
2
JU4
C15
270pF
R8
27kΩ
C14
OPEN
4
COMP/
SHDN
PGND
7
GND
FB
3
R7
8.06kΩ
Figure 1. MAX1953 EV Kit Schematic
4
_______________________________________________________________________________________
MAX1953 Evaluation Kit
Evaluates: MAX1953/MAX1954
Figure 2. MAX1953 EV Kit Component Placement Guide—
Component Side Silkscreen
Figure 3. MAX1953 EV Kit PC Board Layout—Component Side
_______________________________________________________________________________________
5
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