19-2611; Rev 0; 10/02
MAX1875 Evaluation Kit
General Description
Features
ꢀ 8V to 18V Input Voltage Range
The MAX1875 evaluation kit (EV kit) demonstrates a low-
cost application circuit. This dual-PWM synchronous DC-
to-DC converter operates from unregulated AC adapters
and generates precision, low-voltage rails for broad-
band gateways, digital TVs, cable modems, and set-
top boxes.
ꢀ 1.8V and 3.3V Adjustable Output Voltages
ꢀ 3.5A Output Current (1.8V Output)
ꢀ 3.5A Output Current (3.3V Output)
ꢀ Lossless Foldback Current Limit
ꢀ 100kHz Switching Frequency
The MAX1875 EV kit provides dual 1.8V and 3.3V output
voltages from an 8V to 18V input voltage range. It delivers
up to 3.5A output current for the 1.8V output and the 3.3V
output, with greater than 90% efficiency. Both converters
operate 180 degrees out-of-phase to reduce input ripple
current. The EV kit operates at 100kHz switching frequency.
ꢀ RST Output with 140ms Delay
(MAX1876/MAX1858 only)
ꢀ 180 Degree Out-of-Phase Operation
ꢀ 24-Pin QSOP Package
This EV kit is a fully assembled and tested circuit
board. It also allows evaluation of other output voltages
in the 0.75V to 15V range.
ꢀ Low-Cost Components
ꢀ Fully Assembled and Tested
The MAX1875 EV kit can also be used to evaluate the
MAX1876 and MAX1858.
Ordering Information
PART
TEMP RANGE
IC PACKAGE
MAX1875EVKIT
0°C to +70°C
24 QSOP
Component List
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
27µH 5A power inductor
L2
1
390µF, 25V aluminum electrolytic
capacitors Sanyo 25MV390AX
C1, C4
2
N1A, N1B,
N2A, N2B
Dual N-channel MOSFETs 8-pin SO
Fairchild FDS6990A
2
C5, C6, C12
3
1
1
0.1µF ceramic capacitors (0805)
0.39µF ceramic capacitor (0805)
0.33µF ceramic capacitor (0805)
C7
C8
D2–D5
R1
0
1
2
1
1
1
1
1
1
1
1
2
1
1
2
1
2
1
Not installed (open)
8.06k
10k
1% resistor (0805)
1% resistors (0805)
1% resistor (0805)
1% resistor (0805)
5% resistor (0805)
5% resistor (0805)
1% resistor (0805)
1% resistor (0805)
5% resistor (0805)
5% resistor (0805)
5% resistors (0805)
1% resistor (0805)
1% resistor (0805)
R2, R4
R3
C9, C10, C11,
C13, C14
5
470µF, 10V aluminum electrolytic
capacitors Sanyo 10MV470AX
23.2k
60.4k
2.7k
2k
R5
C17
C18
1
1
2200pF ceramic capacitor (0805)
1500pF ceramic capacitor (0805)
R6
R7
0.22µF, 16V X5R ceramic capacitor
(0805) Taiyo Yuden EMK212BJ224KG
C19
C20
1
1
R8
49.9k
69.8k
100k
20
R9
4.7µF, 10V X5R ceramic capacitor
(1206) Taiyo Yuden LMK316BJ475ML
R10
R11
0.22µF, 50V X7R ceramic capacitor
(0805) Taiyo Yuden UMK212BJ224MG
or TDK C2012X7R1H224M
R12, R13
R14
3.9
C21
1
154k
84.5k
R15
C22, C23
2
0
0.01µF ceramic capacitors (0805)
Not installed (open)
JU1, JU2
U1
3-pin headers
C2, C3, C15
MAX1875EEG 24-pin QSOP
Shunts
100mA, 30V dual Schottky diode 23-pin
SOT Central Semiconductor CMPSH-3A
D1
L1
1
1
None
None
MAX1875 PC board
15µH 5A power inductor
________________________________________________________________ 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.