19-3253; Rev 0; 4/04
MAX8513 Evaluation Kit
General Description
The MAX8513 evaluation kit (EV kit) demonstrates the
MAX8513’s standard application circuit. This EV kit
operates from 9V to 16V, generating three positive
output voltages.
The MAX8513 EV kit includes a voltage-mode synchro-
nous step-down controller and two positive regulator
gain blocks. The main synchronous step-down controller
provides a 3.3V output with 2A output current. The posi-
tive regulator gain blocks use an external n-channel
MOSFET pass transistor to generate 2.5V with 1.5A out-
put current from the main 3.3V output, and an external
pnp pass transistor to generate 12V with 0.100A output
current using a coupled inductor from the step-down
converter. The EV kit operates at 1.4MHz switching
frequency, allowing the use of ceramic capacitors.
The MAX8513 EV kit can be reconfigured for other
input voltage ranges or output voltages by selecting
appropriate external components. The EV kit circuit
features adjustable soft-start, current-limit, input
power-fail detect (PFI), power-on reset (POR), power-
fail output (PFO) and configurable power sequencing.
Operation up to 1.4MHz allows the use of tiny sur-
face-mount components and improves data rate in
DSL applications by reducing noise interference.
♦
Input Voltages
9V to 16V
♦
Output Voltages
3.3V Output at 2A (Step-Down DC-DC Converter)
2.5V Output at 1.5A (First LDO Regulator)
12V Output at 0.100A (Second LDO Regulator)
♦
Adjustable Outputs
♦
Configurable Power-Up Sequencing for Outputs
♦
Adjustable Soft-Start and Foldback Current Limit
♦
Adjustable Input Power-Fail Circuit
♦
Switching Frequency Up to 1.4MHz
♦
Capable of Synchronizing to an External Clock
♦
Open-Drain POR and PFO Outputs
♦
Surface-Mount Components
♦
Fully Assembled and Tested
Features
Evaluates: MAX8513
Ordering Information
PART
MAX8513EVKIT
TEMP RANGE
0°C to +70°C
IC PACKAGE
28 QSOP
Component List
DESIGNATION QTY
C1, C8, C15
3
DESCRIPTION
1µF
±20%,
16V X5R ceramic
capacitors (0805)
TDK C2012X5R1C105MT
10µF
±20%,
35V X5R ceramic
capacitor (1210)
Taiyo Yuden GMK325F106ZH
0.1µF
±10%,
25V X7R ceramic
capacitors (0603)
Murata GRM188R71E104K
47µF
±20%,
6.3V X7R ceramic
capacitor (1210)
Taiyo Yuden JMK325BJ476MM
4700pF
±5%,
50V X7R ceramic
capacitor (0603)
TDK C1608X7R1H472KT
DESIGNATION QTY
C6
1
DESCRIPTION
10µF
±20%,
6.3V X5R ceramic
capacitor (1206)
Taiyo Yuden JMK316BJ106ML
1µF ±10%, 25V X7R ceramic
capacitors (1206)
TDK C3216X7R1E105K
2.2µF
±10%,
10V X5R ceramic
capacitor (0805)
TDK C2012X5R1A225K
680pF ±5%, 50V C0G ceramic
capacitor (0603)
Murata GRM1885C1H681J
47pF
±5%,
50V C0G ceramic
capacitor (0603)
TDK C1608C0G1H470JT
C2
1
C7, C18
2
C3, C9, C13
3
C10
1
C4
1
C11
1
C5
1
C12
1
________________________________________________________________
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.
MAX8513 Evaluation Kit
Evaluates: MAX8513
Component List (continued)
DESIGNATION QTY
C14
C16, C17, C21
C19
C20
1
0
0
1
DESCRIPTION
0.47µF
±10%,
16V X7R ceramic
capacitor (0805)
TDK C2012X7R1C474K
Not installed, capacitors (0805)
Not installed, capacitor (1206)
1000pF ±10%, 50V X7R ceramic
capacitor (0603)
Murata GRM188R71H102K
1000pF ±10%, 50V X7R ceramic
capacitor (0603)
TDK C1608X7RZH102K
100mA, 30V Schottky diodes
(SOD-523)
Central Semiconductor CMOSH-3
250mA, 75V ultra-high-speed diode
(SOT23)
Central Semiconductor CMPD4448
2-pin header
3-pin header
30V, 5.5A/8.5A dual n-channel
MOSFET (8-pin SO)
Fairchild FDS6984S
30V, 23A n-channel MOSFET (D-PAK)
International Rectifier IRLR2703
40V, 600mA pnp transistor (SOT23)
Central Semiconductor CMPT4403
13.3kΩ
±1%
resistor (0603)
8.06kΩ
±1%
resistor (0603)
6.8kΩ
±5%
resistor (0603)
560Ω
±5%
resistor (0603)
1.74kΩ
±1%
resistor (0603)
806Ω
±1%
resistors (0603)
10.7kΩ
±1%
resistor (0603)
U1
None
None
1
2
1
T1
1
R26, R27
R28
R29
R30
R
SENSE
0
1
1
1
1
DESIGNATION QTY
R8, R9, R22
R10
R11
R12
R13
R15
3
1
1
1
1
1
DESCRIPTION
100kΩ
±5%
resistors (0603)
68.1kΩ
±1%
resistor (0603)
12.4kΩ
±1%
resistor (0603)
1kΩ
±5%
resistor (0603)
11.3kΩ
±1%
resistor (0603)
10Ω
±5%
resistor (0805)
Not installed, 0.01Ω
±5%
current-sense resistor (1206)
IRC LRF 1206-01-R010-J
recommended
665kΩ
±1%
resistor (0603)
66.5kΩ
±1%
resistor (0603)
200Ω
±5%
resistors (0603)
20Ω
±5%
resistor (0603)
Not installed, resistor (0805)
Not installed, resistor (2010)
5.1Ω ±5%, 0.5W resistor (2010)
Panasonic ERJ-12ZYJ5R1U
Vishay CRCW2010 5.1 5% 100 R02
SEI Electronics RMC 1/2 5.1 5% A
Not installed, resistors (0603)
0Ω ±5% resistor (0603)
4.7Ω ±5% resistor (0603)
1.5kΩ ±5% resistor (1206)
0.02Ω
±5%
resistor (1206)
IRC LRF 1206-01-R020-J
Coupled inductor:
Primary 1.8µH/4.5A/0.01Ω
Secondary/primary = 20:6
Coiltronics CTX 03-16101 or
ICE ICA-1119
MAX8513EEI (28-pin QSOP)
Shunts (JU3, JU4)
MAX8513 PC board
R16
C22
1
0
R17
R18
R19, R20
R21
R23
R24
1
1
2
1
0
0
D1
1
D2
JU3
JU4
N1
1
1
1
1
R25
1
N2
Q1
R1
R2
R3
R4
R5
R6, R14
R7
1
1
1
1
1
1
1
2
1
2
_______________________________________________________________________________________
MAX8513 Evaluation Kit
Component Suppliers
SUPPLIER
Central Semiconductor
Cooper Coiltronics
Fairchild
ICE
International Rectifier
IRC
Kemet
Murata
SEI Electronics
Taiyo Yuden
TDK
PHONE
631-435-1110
561-752-5000
888-522-5372
703-257-7740
310-322-3331
361-992-7900
864-963-6300
770-436-1300
888-734-7347
800-348-2496
847-803-6100
FAX
631-435-1824
561-742-1178
N/A
703-257-7547
310-726-8721
361-992-3377
864-963-6322
770-436-3030
919-850-9504
847-925-0899
847-390-4405
WEBSITE
www.centralsemi.com
www.cooperet.com
www.fairchildsemi.com
www.icecomp.com
www.irf.com
www.irctt.com
www.kemet.com
www.murata.com
www.seielect.com
www.t-yuden.com
www.componet.tdk.com
Evaluates: MAX8513
Note:
Indicate that you are using the MAX8513 when contacting these component suppliers.
Quick Start
The MAX8513 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:
1) Verify that a shunt is not installed across jumper JU3
(EN/SYNC, enabled).
2) Verify that a shunt is across pins 1 and 2 of jumper
JU4 (SEQ, outputs tracking).
3) Connect a voltmeter to the VOUT1 pad and the
PGND pad.
4) Connect a 9VDC to 16VDC power supply to the VIN
pad.
5) Connect the supply ground to the PGND pad.
6) Turn on the power supply.
7) Verify that the main output (VOUT1) is 3.3V, the first
LDO regulator output (VOUT2) is 2.5V, and the sec-
ond LDO regulator (VOUT3) is 12V.
For instructions on selecting the feedback resistors for
other output voltages, see the
Evaluating Other Output
Voltages
section.
transistor to generate 12V with 0.100A output current
using a coupled inductor from the step-down converter.
The EV kit operates from a 9V to 16V input range, and a
DC source that provides the EV kit up to 2A of current.
The EV kit can be reconfigured for other input voltage
ranges up to 28V.
The MAX8513 EV kit features a coupled inductor (T1) to
store energy for the 3.3V output (VOUT1) and 12V output
(VOUT3). Resistors R1 and R2 set the output voltage for
the 3.3V step-down DC-DC converter. The output volt-
age can be adjusted from 1.25V to 5.5V. Refer to the
MAX8513 data sheet for more information on setting the
output voltage.
The 2.5V LDO regulator circuit derives its power from
the 3.3V main output (VOUT1). An n-channel MOSFET
is used as the linear pass element for regulating the
2.5V output (VOUT2). Resistors R5 and R6 set the out-
put voltage for the 2.5V LDO regulator’s output. The
output voltage can be adjusted from 0.8V to 3.3V (45V
logic gate MOSFET). Refer to the MAX8513 data sheet
for more information on setting the output voltage.
Jumper JU5 and PC board pad SUP2 are provided to
enable an external voltage source to drive the gate of
N1. The voltage source must be 1V above N1’s fully-
enhanced gate-drive voltage plus the voltage at VOUT2.
The EV kit’s 12V LDO regulator circuit utilizes coupled
inductor T1 secondary winding and diode D2 to
increase the voltage available to the 12V output pass
transistor Q1. The 12V output linear pass element is a
pnp surface-mount transistor using the PC board for
heat dissipation.
Detailed Description
The MAX8513 EV kit includes a voltage-mode synchro-
nous step-down controller and two positive regulator gain
blocks. The main synchronous step-down controller pro-
vides a 3.3V output with 2A output current. The positive
regulator gain blocks use an external n-channel MOSFET
pass transistor to generate 2.5V with 1.5A output current
from the main 3.3V output, and an external pnp pass
_______________________________________________________________________________________
3
MAX8513 Evaluation Kit
Evaluates: MAX8513
Resistors R13 and R14 set the output voltage for the
12V LDO regulator output. The output voltage can be
adjusted from 0.8V to 27V (12V as configured). Refer to
the MAX8513 data sheet for more information on setting
the output voltage. The MAX8513 EV kit features sever-
al jumper options that are configurable for choosing the
shutdown and clock synchronizing mode (JU3) and
power-on sequencing of the outputs (JU4). The EV kit
can also be reconfigured for using a more accurate cur-
rent-sensing resistor (R16) after modifications (see the
Current-Limit Sensing Methods
section for a complete
description of the two methods and configurations).
Multifunction jumper JU3, along with resistor R7, can be
configured to enable the MAX8513 and to set the
switching frequency up to 1.4MHz for the 3.3V convert-
er. Jumper JU3 can also be configured for shutdown
mode that reduces the MAX8513 shutdown current to
less than 200µA (typ). All outputs are turned off in this
mode. When configured for synchronizing mode, an
external TTL/CMOS square-wave clock is used to syn-
chronize and set the switching frequency of the
MAX8513. The SYNC PC board pad is provided for
connecting the external clock (see Table 1 for more
information on the external clock).
The MAX8513 EV kit features a jumper (JU4) to select
the outputs’ power-up mode: an output tracking or an
output stagger-sequence mode. In output tracking
mode, VOUT1, VOUT2, and VOUT3 are turned on at the
same time. When configured for the output stagger-
sequence mode, once VOUT1 reaches 90% (2.9V),
then VOUT2 is softly turned on. Once VOUT2 reaches
90% (2.2V), VOUT3 is softly turned on. Individual soft-
start on VOUT2 and VOUT3 eliminates glitches on the
previous stages due to the charging output capacitors.
The EV kit circuit also includes soft-start and a config-
urable input power-fail circuit. Resistors R10 and R11
can be replaced to evaluate other input power-fail volt-
ages. Lastly, open-drain outputs with pullup resistors to
the 3.3V main output are available for the MAX8513
POR
and
PFO
pins of the MAX8513. These output sig-
nals are available on the EV kit’s
POR
and
PFO
pads.
Jumper Selection
Shutdown Control and Clock Synchronization
The MAX8513 EV kit has a multifunction jumper that
features a shutdown mode to reduce the MAX8513
shutdown current or synchronize to an external
TTL/CMOS clock source. The 2-pin jumper JU3 selects
the shutdown mode or clock synchronization and fre-
quency for the MAX8513. Table 1 lists the jumper
options.
The TTL/CMOS clock source must provide the following
signal qualities:
•
Output voltage:
Logic low = 0V to 0.8V
Logic high = 2.4V to 5.5V
• Output frequency = 1.4MHz ±30% (MAX8513 syn-
chronization range is 200kHz to 1.4MHz; refer to the
MAX8513 data sheet for more information.)
• Duty cycle = 200ns (min) pulse width (high or low)
Connect the external clock to the SYNC and GND
pads. Refer to the MAX8513 data sheet for selecting a
different switching frequency and choosing resistor R7.
Output Power-Up Sequence Control
The MAX8513 EV kit features two modes for powering
up the outputs: an output tracking or an output stagger-
sequence mode. The 3-pin jumper JU4 selects the
mode of operation for the EV kit’s outputs. Table 2 lists
the selectable jumper options.
Table 1. Jumper JU3 Functions
SHUNT
LOCATION
None
EN/SYNC PIN
Connected to
R22
EV KIT OPERATING
MODE
Enabled mode:
1.4MHz set by resistor
R7
Shutdown mode:
VOUT1, VOUT2,
VOUT3 = Disabled
Enabled and
synchronization
mode: synchronized
to an external clock
frequency
Table 2. Jumper JU4 Function
SHUNT
LOCATION
1 and 2
2 and 3
SEQ PIN
Connected to
MAX8513 VL pin
Connected to
GND
MAX8513 OUTPUTS
Output tracking mode
Output stagger
sequence mode
Installed
(high or low)
Connected to
GND
Connected to an
external
TTL/CMOS
clock source
None
4
_______________________________________________________________________________________
MAX8513 Evaluation Kit
SUP2 External Supply (N2 Gate Voltage)
The MAX8513 EV kit features two methods of providing
the VOUT2 linear pass MOSFET maximum gate volt-
age: the MAX8513 IN pin or an external voltage source
1V above the desired gate-drive voltage plus the volt-
age at VOUT2. The 2-pin jumper JU5 selects the gate-
drive source. Table 3 lists the selectable jumper
options.
Note: The MOSFET’s maximum V
GS
rating
must not be exceeded. The maximum voltage rating
of the MAX8513 SUP2 pin must not be exceeded.
12V LDO Regulator Output (VOUT3 Output)
The MAX8513 EV kit’s 12V LDO regulator output
(VOUT3) is set to 12V by feedback resistors R13 and
R14. To generate output voltages other than 12V (0.8V
to 27V), refer to the MAX8513 data sheet to select dif-
ferent voltage-divider resistors and the coupled induc-
tor turns ratio.
Evaluates: MAX8513
Evaluating Other Input Voltages and
Current-Limit Sensing Methods
VIN Input
The MAX8513 EV kit is factory configured for an input
voltage range of 9V to 16V at the VIN input. Higher
input voltages up to 28V can be evaluated once
capacitors C18 and C19 have been replaced with
appropriate voltage-rated capacitors. Additionally, for
lower input voltages, MOSFET N1 can be replaced with
a lower V
DS
-rated MOSFET to reduce cost. Coupled
inductor T1, input and output capacitors, and compen-
sation components should be evaluated also. Refer to
the MAX8513 data sheet for information on selecting
these components.
Current-Limit Sensing Methods
The MAX8513 EV kit features two methods for current-
limit sensing at the step-down DC-DC converter’s out-
put: a low-cost lossless method or a more accurate cur-
rent-sense resistor. By default the EV kit is configured
for the lossless method, which uses the coupled induc-
tor’s (T1) primary-side DC resistance, capacitor C14,
and resistors R19 and R20 to sense the output current.
Refer to the MAX8513 data sheet for additional informa-
tion on choosing other values for resistors R19 and R20
and capacitor C14. This low-cost method provides ade-
quate current-limit and short-circuit protection for most
applications.
The more accurate current-sense resistor method can
also be evaluated. To evaluate the current-sense resistor
method, cut open the PC board trace-shorting resistor
R16 and install resistor R
SENSE
(provided on the EV kit)
on to R16 pads. Move R19 and install it at resistor R26
pads. Remove resistor R28 and install it at R27 pads.
Table 3. Jumper JU5 Function
PC TRACE
SHORT
Shorted
(default)
SUP2 PIN
Connected to
MAX8513 IN pin
SUP2 SOURCE
VIN supply’s voltage
to the SUP2 pin
through R23
External voltage
source connected to
SUP2 pad and PGND
Cut Open
Connected to
SUP2 pad
Evaluating Other Output Voltages
Step-Down DC-DC Converter (VOUT1 Output)
The MAX8513 EV kit’s step-down DC-DC converter
main output (VOUT1) is set to 3.3V by feedback resis-
tors R1 and R2. To generate output voltages other than
3.3V (1.25V to 5.5V), select different voltage-divider
resistors (R1, R2). Additionally, coupled inductor T1,
input and output capacitors, and compensation compo-
nents should be evaluated. Refer to the MAX8513 data
sheet for information on selecting all these components.
2.5V LDO Regulator Output (VOUT2 Output)
The MAX8513 EV kit’s 2.5V LDO regulator output
(VOUT2) is set to 2.5V by feedback resistors R5 and
R6. To generate output voltages other than 2.5V (0.8V
to 3.3V ), select different voltage divider resistors (R5,
R6). This output must be limited to 1.5A because of the
coupled inductor’s (T1) primary-side current rating.
Lower output values cause additional power dissipation
at MOSFET N2. Refer to the MAX8513 data sheet to
adjust the compensation components when charging
the output voltage and maximum current.
_______________________________________________________________________________________
5
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