19-2613; Rev 0; 10/02
MAX1858 Evaluation Kit
General Description
The MAX1858 evaluation kit (EV kit) demonstrates the
MAX1858’s standard application circuit. This dual PWM
synchronous DC-to-DC converter generates outputs
down to 0.75V for core, I/O, and logic supplies.
The MAX1858 EV kit provides dual 1.8V and 2.5V output
voltages from an 8V to 20V input voltage range. It delivers
up to 10A output current for the 2.5V output and 10A for
the 1.8V output with greater than 90% efficiency. Both
converters operate 180 degrees out-of-phase to reduce
input ripple current. The EV kit operates at 600kHz
switching frequency and has superior line- and load-
transient response.
This EV kit is a fully assembled and tested circuit board.
It allows evaluation of other output voltages in the 0.75V
to 15V range. The MAX1858 EV kit can also be used to
evaluate the MAX1875 and MAX1876.
o
8V to 20V Input Voltage Range
o
1.8V and 2.5V Adjustable Output Voltages
o
10A Output Current (2.5V Output)
o
10A Output Current (1.8V Output)
o
Lossless Foldback Current Limit
o
600kHz Switching Frequency
o
RST
Output with 140ms Delay
o
180 Degrees Out-of-Phase Operation
o
24-Pin QSOP Package
o
Low-Profile Components
o
Fully Assembled and Tested
Features
Evaluates: MAX1858/MAX1875/MAX1876
Ordering Information
PART
MAX1858EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
24 QSOP
Component List
DESIGNATION
C1–C4
C5, C6, C22
C7
C8
C9–C16
C17, C18
QTY
4
3
1
1
8
2
DESCRIPTION
10µF, 25V ceramic capacitors (1812)
Taiyo Yuden TMK432BJ106KM or
TDK C4532X5R1E106M
0.1µF ceramic capacitors (0805)
0.01µF ceramic capacitor (0805)
0.0068µF ceramic capacitor (0805)
220µF, 4V, 40mΩ low-ESR capacitors
Sanyo 4TPC220M
100pF ceramic capacitors (0805)
0.22µF, 16V X5R ceramic capacitor
(0805)
Taiyo Yuden EMK212BJ224KG or
TDK2012X7R1H224KT
4.7µF, 10V X5R ceramic capacitor
(1206)
Taiyo Yuden LMK316BJ475ML
0.22µF, 50V X7R ceramic capacitor
(0805)
Taiyo Yuden UMK212BJ224MG or
TDK C2012X7R1H224M
100mA, 30V dual Schottky diode
Central Semiconductor CMPSH-3A
3A, 30V Schottky diodes
Nihon EC31QS03L
100mA, 30V Schottky diodes
Central Semiconductor CMSSH-3
N1–N4
R1
R2, R4, R5
R3
R6
R7
R8
R9
R10
R11
R12, R13
R14
R15
None
U1
None
DESIGNATION
JU1, JU2
L1, L2
QTY
DESCRIPTION
2
3-pin headers
1.1µH power inductors
2
Sumida CEP12D38-H-1R1 (18.1A,
6mΩ, 12.5mm x 12.5mm x 4.0mm)
N-channel MOSFETs 8-pin SO
4
International Rectifier IRF7811W or
Fairchild FDS6694
1
8.06kΩ ±1% resistor (0805)
3
1
1
1
1
1
1
1
2
1
1
2
1
1
10kΩ ±1% resistors (0805)
15kΩ ±1% resistor (0805)
8.2kΩ ±5% resistor (0805)
5.9kΩ ±5% resistor (0805)
97.6kΩ ±1% resistor (0805)
140kΩ ±1% resistor (0805)
100kΩ ±5% resistor (0805)
4.7Ω ±5% resistor (0805)
4.7Ω ±5% resistors (0603)
118kΩ ±1% resistor (0805)
84.5kΩ ±1% resistor (0805)
Shunts
MAX1858EEG 24-pin QSOP
MAX1858 PC board
C19
1
C20
1
C21
1
D1
D2, D3
D4, D5
1
2
2
________________________________________________________________
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.
MAX1858 Evaluation Kit
Evaluates: MAX1858/MAX1875/MAX1876
Component Suppliers
SUPPLIER
Central Semiconductor
Fairchild
International Rectifier
Nihon
Sanyo
Sumida
Taiyo Yuden
TDK
PHONE
516-435-1110
408-721-2181
310-322-3331
847-843-7500
619-661-6835
708-956-0666
408-573-4150
847-390-4373
FAX
516-435-1824
408-721-1635
310-322-3332
847-843-2798
619-661-1055
708-956-0702
408-573-4159
847-390-4428
WEBSITE
www.centralsemi.com
www.fairchildsemi.com
www.irf.com
www.niec.co.jp
www.sanyovideo.com
www.sumida.com
www.t-yuden.com
www.component.tdk.com
Note:
Please indicate that you are using the MAX1858 when contacting these component suppliers.
_________________________Quick Start
The following equipment is required before beginning:
• 8V to 20V power supply
• Electronic loads capable of sinking 10A each
• Digital multimeters (DMMs)
• 100MHz dual-trace oscilloscope
Follow these steps to verify board operation.
Do not
turn on the power supply until all connections are
completed:
1) Ensure that the circuit is connected correctly to the
supply and electronic loads before applying any
power. Set the electronic loads in resistive mode.
2) Verify that the shunts are across JU1 pins 1 and 2
and JU2 pins 1 and 2.
3) Turn on power supply.
4) Verify that the output voltages are 1.8V and 2.5V.
Evaluating Other Output Voltages
The EV kit outputs are programmed for 1.8V and 2.5V.
However, the output voltages can also be adjusted
between 1V and 15V by selecting R1/R2 and R3/R4
values. Select feedback resistors R2 and R4. R1 and
R3 are then given by:
R1 (or R3) = R2 (or R4) x [(V
OUT
/ V
FB
) - 1]
where V
FB
= 1V. Refer to the MAX1858 data sheet for
selection of output capacitors, inductors, and compen-
sation networks. For output voltages below 1V, refer to
Figure 6 in the MAX1858 data sheet.
Evaluating MAX1875/MAX1876
Replace U1 with the MAX1875/MAX1876.
Table 1. JU1 Functions (EN Mode Selection)
JU1
1 and 2
2 and 3
Not
Installed
EN PIN
Connected to VL
Connected to GND
Connected to
EN pad
MAX1858 OUTPUT
MAX1858 enabled, V
OUT1
=
1.8V and V
OUT2
= 2.5V
Shutdown mode, V
OUT1
=
0V and V
OUT2
= 0V
MAX1858 must be enabled by
an external signal
Table 2. JU2 Functions (SYNC Mode Selection)
JU2
1 and 2
SYNC PIN
Connected to VL
EFFECT
Used to sync up an additional
MAX1858. CKO is 2x DH1 and
phase shifted by 90 degrees.
Used to sync up an additional
single buck. CKO is the same
frequency and phase as DH1.
External clock is applied to
SYNC input (1100kHz to
1300kHz)
2 and 3
Connected to
GND
Connected to
SYNC pad
Not
Installed
2
_______________________________________________________________________________________
无线连接
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
