General Description
The MAX5015 evaluation kit (EV kit) is a fully assembled
and tested circuit board that contains a 50W forward
converter in the industry standard half-brick footprint.
The circuit is configured for a +5.0V output voltage and
provides up to 10A of current. Power for the circuit can
be provided from either a +36V to +72V or -36V to -72V
DC source.
High efficiency of 86% is achieved at 5A using a single
transistor, forward converter topology providing output
power up to 50W. The surface mount transformer pro-
vides galvanic isolation and has a reset winding to
recover magnetic energy. Galvanic isolation up to
1500V is achieved by an optocoupler and surface-
mount transformer.
Operation at 280kHz allows the use of small magnetics
and output capacitors.
Warning: The MAX5015 EV kit is designed to operate
with high voltages. Dangerous voltages are present on
this EV kit and on equipment connected to it. Users
who power up this EV kit or power the sources connect-
ed to it must be careful to follow safety procedures
appropriate to working with high-voltage electrical
equipment.
Under severe fault or failure conditions, this EV kit may
dissipate large amounts of power, which could result in
the mechanical ejection of a component or of compo-
nent debris at high velocity. Operate this kit with care to
avoid possible personal injury.
Features
♦+36V to +72V or -36V to -72V Input Range
♦+5V Output at 10A
♦VOUT Regulation better than 0.1% over Line and
Load
♦86% Efficiency at 48V Input and 5V/5A Output
♦Half-Brick Module Footprint and Pinout
♦Short-Circuit Protection
♦275kHz Switching Frequency
♦Designed for 1500V Isolation
♦Soft-Start
♦Fully Assembled and Tested
♦Remote ON/OFF
♦Remote Sense
Evaluates: MAX5015
MAX5015 Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
19-2053; Rev 1; 4/02
Component List
Ordering Information
Component Suppliers
Component List continued on next page.
PART TEMP. RANGE IC PACKAGE
MAX5015EVKIT
0°C to +70°C SO-8
SUPPLIER PHONE FAX
Central
Semiconductor 516-435-1110 516-435-1824
Coiltronics 561-752-5000 561-742-0134
Dale-Vishay 402-564-3131 402-563-6418
General
Semiconductor 631-847-3000 631-847-3236
International
Rectifier 310-322-3331 310-322-3332
Murata 814-237-1431 814-238-0490
Sanyo USA 619-661-6835 619-661-1055
Taiyo Yuden 408-573-4150 408-573-4159
TDK 847-803-6100 847-390-4405
DESIGNATION QTY DESCRIPTION
C1, C15 2
0.1µF, 10%, 50V, X7R ceramic
capacitors (0805)
Taiyo Yuden UMK212BJ104KG
C2 1 0.01µF, 10%, 50V, X7R ceramic
capacitor (0805)
C3 0 Not installed (0805)
C4, C5, C6 3
0.68µF, 100V, X7R ceramic
capacitors (1812)
TDK C4532X7R2A684K
C7, C13, C14 3
560µF, 6.3V electrolytic
capacitors (8 x 11.5)
Sanyo 6MV560WX
C8 1
0.047µF, 10%, 50V, X7R ceramic
capacitor (0805)
Taiyo Yuden UMK212BJ473KG
C9 1
10µF, 20%, 16V, X5R ceramic
capacitor (1210)
Taiyo Yuden EMK325BJ106MN
Note: Please indicate that you are using the MAX5015 when
contacting these component suppliers.
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.
Evaluates: MAX5015
MAX5015 Evaluation Kit
2 _______________________________________________________________________________________
Component List (continued)
DESIGNATION
QTY
DESCRIPTION
C10 1
0.1µF, 10%, 16V, X7R ceramic
capacitor (0603)
Taiyo Yuden EMK107BJ104KA
C11 1
0.33µF, 10%, 35V, X7R ceramic
capacitor (0805)
Taiyo Yuden GMK212BJ334KG
C12 1
0.001µF, 200V, X7R ceramic
capacitor (0603)
Murata GRM39-X7R102K200
C16 1
0.0047µF, 250VAC, X7R ceramic
capacitor (3045)
Murata GHM3045-X7R472K-GC
C17 1 0.022µF, 10%, 25V, X7R
ceramic capacitor (0603)
D1 0 Not installed 15V, 150mW zener
diode (S-mini)
D2 0 Not installed 3V 150mW zener
diode (S-mini)
D3 1 80V, 100mA Schottky diode
(S-mini)
D4 1
40V, 20A Schottky diode
(TO-220AB)
General Semiconductor
SBL2040CT
D5 1
250V, 250mA high-voltage
switching diode (SOD-123)
Central Semiconductor
CMHD2003
L1 1 4.7µH, 21.5A inductor
Coiltronics, HC2-4R7
N1 1
200V, 18A N-channel MOSFET
(TO-220AB)
International Rectifier IRF640N
Q1 0 Not installed NPN transistor
(SOT23)
R1, R10 0 Not installed (0805)
R3 1 20Ω ±5% resistor (1206)
DESIGNATION QTY DESCRIPTION
R5 1 240kΩ ±5% resistor (0805)
R6 1
0.1Ω ±1% power resistor (1206)
Dale Electronics, Inc.
WSL-1206 0.1Ω ±1%
R7 1 1Ω ±5% resistor (0805)
R8 1 499Ω ±1% resistor (0805)
R9 1 150Ω ±5% resistor (0805)
R11 1 25.5kΩ ±1% resistor (0805)
R12 1 8.25kΩ ±1% resistor (0805)
R13 1 4.75kΩ ±1% resistor (0805)
R15 1 3.32kΩ ±1% resistor (0805)
R16, R17 2 51Ω ±5% resistors (0805)
T1 1
170µH 1:0.857: 0.357:0.357 turn
transformer (12-pin Gull Wing)
Coiltronics CTX03-14856
U1 1 MAX5015ESA (8 SO)
U2 1
70V 100% to 200% CTR
phototransistor (8-pin SO)
QT Optoelectronics MOC207
U3 1
1.24V precision shunt regulator
(SOT23)
Texas Instruments
TLV431AIDBV
None 1 Aluminum heatsink plate
Vista Industrial Products 5015
None 2 Nylon spacers, 1/4 x 5/8 nylon
None 2 Nylon screws, 4-40 x 1/4
None 2 Nylon screws, 4-40 x 1/2
None 2 Nylon screws, 6-32 x 3/8
None 2 TO-220AB Mica thermal
insulating pads
None 1 MAX5015 PC board
None 1 MAX5015 data sheet
None 1 MAX5015 EV kit data sheet
Evaluates: MAX5015
MAX5015 Evaluation Kit
_______________________________________________________________________________________ 3
Quick Start
The MAX5015 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.
Output
1) Connect a jumper wire from the VOUT pin to the
+SENSE pin.
2) Connect a jumper wire from the SGND pin to the
-SENSE pin.
3) Connect a voltmeter to the VOUT pin and SGND.
4) Connect a +36V to +72V power supply to the VIN+
pin. Do not exceed 100V input voltage.
Connect the power supply’s ground to the VIN- pin.
5) Turn on the power supply above +36V and verify
that VOUT provides +5V at the voltmeter.
For instructions on selecting the feedback resistors for
other output voltages, refer to the Evaluating other
Output Voltages section in this document.
Detailed Description
The MAX5015 EV kit is a 50W forward converter which
provides +5.0V and up to 10A at the output. The circuit
can be powered from a +36V to +72V or a -36V to -72V
DC source. The user must supply at least 220µF of
bulk storage capacitor at the input terminals (VIN+,
VIN-). The capacitor should be rated for 100V and be
able to carry 1.5A of ripple current.
The 50W forward converter achieves high efficiency by
using a single transistor topology. Current limiting pro-
tects the converter against short circuits at the output.
A current sense resistor (R6) senses the current
through the primary of the transformer (T1) and the
switching transistor (N1) and turns off the transistor
when the trip level of 500mV is reached. The surface-
mount transformer features a reset winding that, along
with diode (D5), recovers the magnetic energy stored in
the core and feeds it back to the input (VIN+). The
transformer provides galvanic isolation up to 1500V.
Shunt regulator (U3) along with feedback resistors (R11,
R12) provide voltage feedback to the primary side
through optocoupler (U2). Remote output voltage sens-
ing is provided by the +SENSE and -SENSE for accu-
rate output voltage regulation across the load. The soft-
start allows the output voltage to slowly ramp up in a
controlled manner within 20ms. The MAX5015 controller
switches at a fixed 275kHz frequency, and the duty
cycle is varied to control energy transfer to the output.
Shutdown
Shutdown Mode (Remote Control Method)
The MAX5015 EV kit features a pin to remotely shut-
down the forward converter. An open-collector/drain
transistor or relay contact must be connected to the
SHDN and VIN- pins of the EV kit. Table 1 lists the
options.
Evaluating Other Output
Voltages, Current Limits, and
Soft-Starts
VOUT Output Voltage
The MAX5015 EV kit’s output (VOUT) is set to +5.0V by
feedback resistors (R11, R12). To generate output volt-
ages other than +5.0V (+3.2V to +5.0V), select different
voltage-divider resistors (R11, R12). Resistor R11 is
typically chosen to be less than 25kΩ. Using the
desired output voltage, resistor R12 is then found by
the following equation:
R12 = [R11 / ((VOUT / VREF) - 1)] where VREF = 1.24V
The maximum output current should be limited to less
than 10A. The usable output voltage range for the EV kit
is +3.2V to +5.0V. Additionally, ICs U2, U3, and resistor
R9 limit the minimum output voltage (VOUT) to +3.2V.
Current Limiting
The EV kit features current limiting for the transformer
primary current. The MAX5015 IC turns off the switch-
ing MOSFET (N1) when the voltage at the CS pin of the
device reaches 465mV. A current sense resistor (R6,
0.1Ω) limits the peak primary current to 4.65A (465mV /
0.1Ω= 4.65A). This will limit short-circuit current on the
secondary output (VOUT) to 13A typically. To evaluate
lower current limits, the current sense resistor (R6) must
Table 1. Shutdown Pin Function
(Remote Control)
SHDN PIN MAX5015 OUTPUT
Open MAX5015 Enabled,
VOUT = +5.0V
Pull low Shutdown mode,
VOUT = 0V
be replaced with a surface-mount resistor (1206 size)
as determined by the following equation:
R6 = VSENSE / ((NS/ NP) x (1.2 x IOUTMAX))
where VSENSE = 0.5V, NS= 5, NP= 14, and IOUTMAX =
maximum DC output current (10A as configured).
Soft-Start
The MAX5015 EV kit limits the ramp time to full current
limit and duty cycle with a soft-start feature. Capacitor
C2 (0.01µF), sets the ramp time to 20ms. To evaluate
other soft-start ramp times replace capacitor C2 with
another surface mount capacitor (0805 size) as deter-
mined by the following equation:
C2 (µF) = soft-start time (s) / (0.45s/µF)
Forward Converter
Waveforms
Evaluates: MAX5015
MAX5015 Evaluation Kit
4 _______________________________________________________________________________________
Figure 1. Efficiency vs. Output Current. VIN+ = 48V
0
20.0
10.0
50.0
40.0
30.0
80.0
70.0
60.0
90.0
0462 8 10 12 14
EFFICIENCY (%) vs. OUTPUT CURRENT (A)
OUTPUT CURRENT (A)
EFFICIENCY (%)
Figure 2. Output Voltage Transient at Power-Up. VIN+ = 48V,
IOUT = 5A
Figure 3. MOSFET N1, Drain-Source Voltage Waveform, VIN+
= 48V
1V/div
0
20V/div
0
1µs/div
4ms/div
Evaluates: MAX5015
MAX5015 Evaluation Kit
_______________________________________________________________________________________ 5
Figure 4. MAX5015 EV Kit Schematic
7
4
GND
CS
MAX5015
U1
NDRV
6
5
V+
VCC
VDD
OPTO
1
8
2
3
SS/SHDN
CS
VOUT
CS
N1
VOUT
SGND
C7
560µF
6.3V
C12
0.001µF
200V
C8
0.047µF
C6
0.68µF
C5
0.68µF
C4
0.68µF
R3
20Ω
R6
0.1Ω
1%
R1
OPEN
R8
499Ω
1%
R11
25.5kΩ
1%
R13
4.75kΩ
1%
R15
3.32kΩ
1%
R12
8.35kΩ
1%
R5
240kΩ
R10
SHORT
R9
150Ω
R16
51Ω
R17
51Ω
R7
1Ω
D1
OPEN
SHORT
COLLECTION TO EMITTER
L1
4.7µH
D5
VIN
VDD
D4
T1
3
32
1
Q1 4
5
6
1
12 3
1
2
11
9
8
1
2
2
3
D3
C2
0.01µF
C11
0.33µF
C1
0.1µF
C9
10µF
C10
0.1µF
C17
0.022µF
C3
OPEN
VIN+
+SENSE
VIN-
VDD
VCC
C13
560µF
6.3V
C14
560µF
6.3V
C16
0.0047µF
250VAC
C15
0.1µF
SHDN
6
7
D2
OPEN
U2
U3
5
3
5
1
2
4
-SENSE
VIN
Evaluates: MAX5015
MAX5015 Evaluation Kit
6 _______________________________________________________________________________________
Figure 7. MAX5015 EV Kit PC Board Layout—Inner Layer,
Ground Plane
Figure 5. MAX5015 EV Kit Component Placement Guide—
Component Side
Figure 8. MAX5015 EV Kit PC Board Layout—Inner Layer,
Power Plane
1.0"
1.0"
1.0"
Figure 6. MAX5015 EV Kit PC Board Layout—Component Side
1.0"
Evaluates: MAX5015
MAX5015 Evaluation Kit
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7
© 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Figure 10. MAX5015 EV Kit Component Placement Guide—
Solder Side
1.0"
Figure 9. MAX5015 EV Kit PC Board Layout—Solder Side
1.0"
