19-2615; Rev 0; 10/02
MAX1945 Evaluation Kit
General Description
The MAX1945 evaluation kit (EV kit) is a fully assembled
and tested surface-mount circuit board that contains a
high-efficiency step-down switching-regulator circuit for
applications requiring on-board postregulation. The cir-
cuit utilizes a MAX1945R regulator featuring
鹵4%
voltage
margining and is configured for a 1.8V output voltage.
The circuit provides up to 6A of current. A 2.6V to 5.5V
DC source can be utilized to power the circuit鈥檚 input.
The MAX1945R IC features an internal power MOSFET
switch and an internal synchronous rectifier. The
MAX1945 EV kit provides connections for the SYNC
input. It also provides an output to synchronize another
MAX1945 EV kit clock 180 degrees out-of-phase. Pulse-
width modulated (PWM) operation at 500kHz allows the
use of tiny surface-mount components.
o
0.970in x 0.840in Circuit Footprint
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2.6V to 5.5V Input Range
o
Output Voltage
1.8V/2.5V Preset
0.8V to 0.85x VIN Adjustable
o
Provides Up to 6A Output Current
o
鹵4% Voltage Margining
o
Internal Power Switch and Synchronous Rectifier
o
500kHz/1MHz PWM Selectable Switching
Frequency
o
SYNC Input: Synchronizes from 400kHz to 1.2MHz
TTL/CMOS Clock
o
SYNC Output: Drives 2nd MAX1945 Switching 180
Degrees Out-of-Phase
Features
Evaluates: MAX1945
Component List
DESIGNATION QTY
C1
1
DESCRIPTION
100碌F
鹵20%,
8V polymer capacitor
(7.3 x 4.3)
Panasonic EEFUE0K101R
180碌F
鹵20%,
4V polymer capacitor
(7.3 x 4.3)
Panasonic EEFUE0G181R
0.1碌F
鹵10%,
10V X7R ceramic
capacitors (0603)
AVX 0603ZC104KAT
0.22碌F
鹵10%,
6.3V X7R ceramic
capacitor (0603)
AVX 06036C224KAT
100pF
鹵5%,
50V COG ceramic
capacitor (0603)
TDK C1608COG1H101JT
1碌F
鹵10%,
16V X7R ceramic
capacitor (1206)
TDK C3216X7R1C105KT
100mA, 30V Schottky diode (SOD-523)
Central Semiconductor CMOSH-3
Scope probe connector
FCI 33JR135-1
2-pin headers
o
All Surface-Mount Components
o
Fully Assembled and Tested
Ordering Information
PART
MAX1945EVKIT
TEMP RANGE
0擄C to +70擄C
IC PACKAGE
28 TSSOP-EP*
C2
1
*EP
= Exposed pad.
C3, C6, C7
3
Quick Start
Required Equipment
The following equipment is required before beginning:
鈥?/div>
One 2.6V to 5.5V power supply capable of providing 5A
鈥?/div>
One voltmeter
The MAX1945 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:
C4
1
C5
1
C8
1
1.8V Output Voltage (Nominal)
1) Verify that jumpers JU1 (CTL1) and JU2 (CTL2) do
not have shunts across their respective pins.
2) Verify that a shunt is across the pins of jumper JU3
(SYNC).
3) Verify that jumper JU4 (FBSEL, 1.8V) has a shunt
installed across pins 2 and 3.
4) Connect the voltmeter to the VOUT and PGND
pads.
D1
J1
JU1, JU2, JU3
1
1
3
________________________________________________________________
Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
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