19-1914; Rev 1; 1/01
MAX5003 Evaluation Kit
General Description
The MAX5003 evaluation kit (EV kit) provides a regulat-
ed 5V output voltage up to 1A while operating from a
+36V to +72V input voltage.
The MAX5003 EV kit is a fully assembled and tested
surface-mount printed circuit (PC) board. It comes with
the output voltage set to 5V. This EV kit is configured as
a flyback converter, and can easily be configured for
either isolated or nonisolated operation by selecting the
state of a mechanical switch. Additionally, for systems
in which the input and output ground references are not
at the same potential and for which isolation is not
desired, the user has the option to install a level-shifter
(not supplied) in the controller feedback loop.
WARNING:
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 connected 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.
o
5V at 1A Output
o
+36V to +72V Input Voltage Range
o
300kHz Switching Frequency
o
Can be Configured for -48V Input and +5V Output
o
Selectable Isolated or Nonisolated Operation
o
Proven PC Board Layout
o
Fully Assembled and Tested Surface-Mount Board
Features
Evaluates: MAX5003
Ordering Information
PART
MAX5003EVKIT
*With air flow.
TEMP. RANGE
0°C to +70°C*
IC PACKAGE
16 QSOP
Component List
DESIGNATION QTY
DESIGNATION
C1
C2, C3
C5
C6
C7
C8
C9
C10
C11, C13, C17
C12
C16
D1
D2
N1
Q1
1
2
1
1
1
1
1
1
3
1
1
1
1
1
0
DESCRIPTION
33µF, 100V electrolytic capacitor
Sanyo 100MV33CZ
22µF, 10V ceramic capacitors
Taiyo Yuden LMK432BJ226MM
2200pF ±10% ceramic capacitor
3900pF ±10% ceramic capacitor
0.01µF ceramic capacitor
10µF, 16V ceramic capacitor
Taiyo Yuden EMK325BJ106MN
100pF ±10% ceramic capacitor
0.47µF ceramic capacitor
0.1µF ceramic capacitors
390pF ±10% ceramic capacitor
4.7µF, 25V tantalum capacitor
AVX TAJB475M025
30V, 1A Schottky diode
Fairchild MBRS130L
Small-signal switching diode
Central Semiconductor CMSD4448
200V, 5.2A N-channel MOSFET
International Rectifier IRF620S
Not installed
1
DESIGNATION QTY
Q2
R1
R2
R3
R4, R22, R23
R5
R6
R7
R8, R15
R9
R10
R11
R12
R13
R14
R16, R17
R18
1
1
1
1
3
1
1
1
2
1
1
1
1
1
1
2
0
DESCRIPTION
2N3904-type NPN transistor
Central Semiconductor CMPT3904 or
equivalent
41.2kΩ ±1% resistor
17.4kΩ ±1% resistor
68kΩ ±5% resistor
1MΩ ±5% resistors
39kΩ ±5% resistor
51kΩ ±5% resistor
200kΩ ±5% resistor
43Ω ±5% resistors
0.11Ω ±1%, 1/4W resistor
Dale WSL-1206/0.11Ω/1%
100Ω ±5% resistor
100kΩ ±5% resistor
20kΩ ±5% resistor
1.3kΩ ±5% resistor
240kΩ ±5% resistor
24.9kΩ ±1% resistors
Not installed
________________________________________________________________
Maxim Integrated Products
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.
MAX5003 Evaluation Kit
Evaluates: MAX5003
Component List (continued)
DESIGNATION QTY
R19
R20
R21
SW1
SW2
T1
U1
U2
U3
None
None
None
0
1
1
1
1
1
1
1
1
1
1
1
DESCRIPTION
Not installed
680Ω ±5% resistor
15Ω ±5% resistor
DPDT switch
SPDT switch
65µH, 8:1:2.5 transformer
Coiltronics CTX03-14502
MAX5003EEE (16-pin QSOP)
2.5V voltage reference
Motorola TL431BCD
Low-current optocoupler
QT Opto MOC217
MAX5003 PC board
MAX5003 data sheet
MAX5003 EV kit data sheet
Table 1. Switch/Jumper Functions
FUNCTION
Nonisolated,
Non-level-shifted Feedback
Mode (e.g., +48V input and
+5V output)
SWITCH/
JUMPER
SW1
SW2
JU1
SW1
SW2
JU1
SW1
SW2
JU1
POSITION
NON
DIR
Closed*
(default trace)
NON
LVL
Open (Cut)
ISO
LVL
Open (Cut)
Nonisolated, Level-Shifted
Feedback Mode (e.g.,
-48V input and +5V output)
Isolated Feedback Mode
(input and output supplies
isolated from one another)
*Default
setting
Component Suppliers
SUPPLIER
AVX
Central
Semiconductor
Coiltronics
Dale-Vishay
Fairchild
International
Rectifier
Motorola
QT Optoelectronics
Sanyo
Taiyo Yuden
PHONE
803-946-0690
516-435-1110
561-241-7876
402-564-3131
408-822-2000
310-322-3331
303-675-2140
408-720-1440
619-661-6835
408-573-4150
FAX
803-626-3123
516-435-1824
561-241-9339
402-563-6418
408-822-2102
310-322-3332
303-675-2150
408-720-0848
619-661-1055
408-573-4159
3) Verify that switch SW1 is set to the NON position and
SW2 is set to the DIR position. See Table 1 for a de-
scription of the switch settings.
4) Turn on the power and verify that the output voltage
is +5V.
5) Refer to the
Isolated Feedback
section to modify the
board for isolated operation. Refer to the
Nonisolated
Level-Shifted Feedback
section to modify the board
for operation with the input and output negative sup-
plies at different potentials.
Detailed Description
Feedback Mode Selection
Switch SW1 selects the feedback configuration (isolat-
ed or nonisolated). If SW1 is set to the NON position,
switch SW2 selects either direct feedback (for the case
in which the input and output share the same ground)
or level-shifted feedback. Switch SW2 is only effective
when nonisolated feedback is selected. Jumper JU1
determines whether the input and output ground refer-
ences are connected. Table 1 summarizes switch and
jumper functions.
Do not operate switches SW1 and
SW2 when power is applied to the EV kit because
the controller can be damaged.
Note:
Please indicate that you are using the MAX5003 when
contacting the above component suppliers.
Quick Start
The MAX5003 EV kit is fully assembled and tested.
Follow these steps to verify board operation in noniso-
lated mode.
Do not turn on the power supply until all
connections are completed.
1) Connect a +36V to +72V power supply to the pad
labeled VIN.
Do not exceed 100V input voltage.
The ground connects to the GND pad (-48V).
2) Connect a voltmeter and load (if any) to the +5V pad.
2
Isolated Feedback
To configure the MAX5003 EV kit for isolated operation,
turn off the power supply and cut the JU1 PC board
trace. Set the SW1 switch to the ISO position, and set
the SW2 switch to the LVL position (setting SW2 to the
_______________________________________________________________________________________
MAX5003 Evaluation Kit
LVL position disconnects the R1-R2 resistor-divider
from the MAX5003’s FB pin, as required for isolated
operation). Turn the power supply back on and verify
that the output voltage is still +5V. Note that for the iso-
lated configuration, the output ground and the input
ground may differ by as much as 500V.
Do not oper-
ate switches SW1 and SW2 when power is applied
to the EV kit because the controller can be dam-
aged.
high signal to turn on transistor Q2. For normal opera-
tion, the SHDN pad can be connected to ground or left
unconnected. Note that the logic-high signal used to
drive the SHDN pad is referenced to the negative side
of the input supply. For more details regarding under-
voltage lockout, refer to the MAX5003 data sheet.
Evaluates: MAX5003
Current Limiting
The MAX5003 EV kit has a current-limiting feature
implemented by current-sense resistor R9. The
MAX5003 turns off switching FET N1 when the voltage
at the CS pin reaches 100mV. Since R9 is a 0.11Ω
resistor, this limits the current in the transformer primary
to 0.91A peak, which corresponds to a typical output
short-circuit current of 4.5A. R10, a 100Ω resistor, is
connected between the current-sense resistor and the
CS pin to enable current-sense blanking after N1 is
turned on, as described in the MAX5003 data sheet.
Nonisolated Level-Shifted Feedback
To configure the MAX5003 EV kit for operation in a sys-
tem in which the negative terminal of the input power
supply is at a more negative potential than the negative
terminal of the output power supply (for example, in a
-48V input to +5V output application), first turn off the
power supply and cut the JU1 PC board trace. Set the
SW1 switch to the NON position, and set the SW2
switch to the LVL position. Locate parts R18, R19, and
Q1 (directly above jumper JU1 on the PC board).
Solder the following parts into the R18, R19, and Q1
locations: R18 = 36.5kΩ ±1% resistor (1206), R19 =
12.4kΩ ±1% resistor (1206), and Q1 = 60V 2N2907-
type PNP transistor (SOT23). Note that the initial DC
output voltage accuracy and the temperature variation
will be degraded in this configuration.
Do not operate
switches SW1 and SW2 when power is applied to
the EV kit because the controller can be damaged.
Layout Considerations
The MAX5003 EV kit layout is optimized for fast switch-
ing and high currents. The input and output power and
ground traces must both be as short and wide as pos-
sible to minimize unwanted parasitic inductance. This
board was not designed per UL spacing specifications.
Undervoltage Lockout
and Shutdown
The MAX5003 EV kit is configured to go into undervolt-
age lockout when VIN drops below 32V. The MAX5003
does not have a shutdown pin, but the undervoltage
lockout state is equivalent to a shutdown state. The
MAX5003 EV kit contains a shutdown function consist-
ing of an NPN switching transistor (Q2) that can pull the
VINDIV pin to ground. To place the MAX5003 in under-
voltage lockout, drive the SHDN pad with a +5V logic-
_______________________________________________________________________________________
3
Evaluates: MAX5003
MAX5003 Evaluation Kit
Figure 1. MAX5003 EV Kit Schematic
1
D2
3
VDD
C16
4.7µF
25V
7
VDD
8
V
DD
VDD
2
5
D1
3
15
C8
10µF
16V
C5
2200pF
2
4
FREQ
NDRV
1
N1
3
R19
OPEN
3
1
R18
OPEN
SW2
R2
17.4kΩ
1%
JU1
CUT HERE
2
R20
680Ω
R15
43Ω
R14
240kΩ
REF
7
CON
AGND
REF
COMP
FB
9
R6
51kΩ
MAXTON
R22
1MΩ
1
8
R7
200kΩ
C12
390pF
U2
TL431
2, 3
6, 7
NON
2
6
ISO
8
COMP
10
11
R13
1.3kΩ
6
5
U3
MOC217
7
1
2
R3
68kΩ
14
Q1
R8
43Ω
3
SW1-A
NON
1
ISO
5
C2
22µF
10V
C3
22µF
10V
ES
C13
0.1µF
V
CC
+5V
C17
0.1µF
16
11
12
T1
9
10
R21
15Ω
2
C1
33µF
100V
1
VINDIV
V+
R4
1MΩ
2
3
C9
100pF
R5
39kΩ
2
4
U1
MAX5003
5
SS
R10
100Ω
PGND
13
NOT INSTALLED
C10
0.47µF
R9
0.11Ω
1/4W
1%
R1
41.2kΩ
1%
GND
LVL DIR
6
C11
0.1µF
REF
CS
12
C7
0.01µF
R16
24.9kΩ
1%
C6
3900pF
R17
24.9kΩ
1%
GND (-48V)
VIN
Q2
SHDN
1
R11
100kΩ
R12
20kΩ
REF
REF
R23
1MΩ
4
_______________________________________________________________________________________
SW1-B
MAX5003 Evaluation Kit
Evaluates: MAX5003
1.0"
Figure 2. MAX5003 EV Kit Component Placement Guide—
Component Side
1.0"
1.0"
Figure 3. MAX5003 EV Kit PC Board Layout—Component Side
Figure 4. MAX5003 EV Kit PC Board Layout—Solder Side
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 _____________________
5
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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