MAX13253 Evaluation Kit
Evaluates: MAX13253
General Description
The MAX13253 evaluation kit (EV kit) is a fully assembled
and tested PCB that demonstrates the MAX13253 low-
EMI push-pull transformer driver. The EV kit operates
from a single 3.0V to 5.5V supply and the on-board
1CT:1.3CT turns-ratio transformer sets the output voltage.
The EV kit provides up to 90% overall efficiency at
5V with up to 4.5W output power using a push-pull
isolated DC-DC converter. Undervoltage lockout,
current limiting, and thermal shutdown provide for a robust
isolated supply. The surface-mount transformer provides
galvanic isolation with the output powered from a push-pull
rectifier circuit, reducing the output-voltage ripple.
The EV kit circuit is configured as a push-pull rectifier, with
an output voltage that follows the input voltage. The EV kit
is also configurable for other topologies including bipolar
outputs and full-wave rectification.
Features and Benefits
● Up to 90% Efficiency
● Push-Pull Rectified Output
● 3.0V to 5.5V Operating Voltage Range
● Configurable Bipolar Outputs or Full-Wave Rectifier
● Internal or External Clock Operation
● Selectable Spread-Spectrum Option for Controlled EMI
● Proven PCB Layout
● Fully Assembled and Tested
Ordering Information
appears at end of data sheet.
Component List
DESIGNATION
C1, C2
QTY
2
DESCRIPTION
1µF ±10%, 25V X7R ceramic
capacitors (0603)
Murata GRM188R71E105K
10µF ±10%, 25V X7R ceramic
capacitors (1206)
Murata GRM31CR71E106K
Not installed, ceramic capacitor
(1206)
Red LED (1206)
30V, 2A Schottky diodes (SMA)
Diodes Inc. B230A-13-F
Not installed, Schottky diodes
(SMA)
3-pin headers
U1
—
—
*EP
= Exposed pad.
PHONE
972-987-3900
650-903-3800
770-436-1300
www.diodes.com
www.haloelectronics.com
www.murata-northamerica.com
WEBSITE
1
5
1
DESIGNATION
J2, J5
R1
R2
R3
TX1
QTY
2
1
1
1
1
DESCRIPTION
2-pin headers
560Ω ±5% resistor (0603)
0Ω ±5% resistor (0603)
1kΩ ±5% resistor (0603)
1CT:1.3CT turns-ratio transformer
(8 Gull Wing)
Halo TGM-H240V8LF
1A spread-spectrum push-pull
transformer driver (10 TDFN-EP*)
Maxim MAX13253ATB+
Shunts
PCB: MAX13253 EVALUATION
KIT
C3, C5
C4
D1
D2, D3
D4, D5
J1, J3, J4
2
0
1
2
0
3
Component Suppliers
SUPPLIER
Diodes Incorporated
Halo Electronics, Inc.
Murata Electronics, North America, Inc.
Note:
Indicate that you are using the MAX13253 when contacting these component suppliers.
19-6624; Rev 0; 3/13
MAX13253 Evaluation Kit
Evaluates: MAX13253
Quick Start
Required Equipment
● MAX13253 EV kit
● 5.0V, 2A DC power supply
● Electronic load capable of 1A
● Ammeter
● Voltmeter
10) Verify that the voltmeter reads approximately 5.5V.
Detailed Description
The MAX13253 EV kit is a low-EMI, isolated push-pull
DC-DC converter that provides an unregulated output
with respect to the isolated ground. The maximum load is
limited by the device and winding ratio of the transformer.
The device is an integrated primary-side controller and
push-pull driver for isolated power-supply circuits. The
device contains an on-board oscillator, protection circuitry,
and internal MOSFETs to provide up to 1A of current
to the transformer’s primary winding. The device can
be operated using the internal pin-selectable oscillator,
or driven by an external clock to synchronize multiple
devices.
The device operates from a single-supply voltage and
includes UVLO and an active-low enable input for
controlled startup. If the input voltage at V
DD
falls below
2.55V, or the
EN
input is pulled above 2.0V, the device
shuts down and T1 and T2 are high impedance.
Procedure
The EV kit is fully assembled and tested. Follow the steps
below to verify board operation.
Caution: Do not turn on
the power supply until all connections are completed.
1)
2)
3)
Verify that jumpers J1–J5 are in their default
positions, as shown in Table 1.
Set the DC power supply to 5.0V.
Set the electronic load to 500mA and disable the
output.
4) Connect the voltmeter between the +VOUT and
SGND PCB pads on the EV kit.
5)
Connect the ammeter between the +VOUT PCB pad
on the EV kit and the positive terminal on the electronic
load. The negative terminal on the electronic load is
connected to the SGND PCB pad on the EV kit.
Connect the power supply between the VDD and
GND PCB pads on the EV kit.
Clock Source
The device has two modes of operation, internal oscillator
or external clock.
Using the Internal Oscillator and Spread-Spectrum
Functionality
The device includes an internal oscillator with a guaranteed
50% duty cycle. To use the internal oscillator, place a shunt
across pins 1-2 on jumper J2. Place a shunt across pins
1-2 on jumper J3 to set the T1/T2 switching frequency to
600kHz (typ). Place a shunt across pins 2-3 on J3 to set
the T1/T2 switching frequency to 250kHz (typ).
6)
7) Turn on the power supply.
8) Enable the electronic load.
9) Verify that the ammeter reads approximately 500mA.
Table 1. Jumper Description Table
JUMPER
J1
J2
J3
J4
J5
*Default
position.
SHUNT POSITION
1-2
2-3*
Installed*
Not installed
1-2
2-3*
1-2
2-3*
Not installed*
Installed
EN
connected to V
DD
.
EN
connected to GND. Device enabled.
CLK connected to GND. Internal oscillator enabled.
CLK open. External oscillator enabled. Apply a clock signal to the CLK PCB pad on the EV kit.
HICLK connected to V
DD
. T1/T2 switch at 600kHz.
HICLK connected to GND. T1/T2 switch at 250kHz.
SPRD connected to V
DD
. Spread-spectrum functionality enabled.
SPRD connected to GND. Spread-spectrum functionality disabled.
+VOUT is not shorted to SGND.
+VOUT is shorted to SGND.
DESCRIPTION
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MAX13253 Evaluation Kit
Evaluates: MAX13253
The device features pin-selectable spread-spectrum
functionality on the internal oscillator for controlled EMI.
Use jumper J4 on the EV kit to enable or disable the
spread-spectrum functionality when the internal oscillator
is enabled. Place a shunt across pins 1-2 on J4 to enable
the ±4% frequency spread on the internal oscillator.
Place a shunt across pins 2-3 or leave J4 open to disable
spread spectrum.
The device can dissipate large amounts of power
during overcurrent limiting, causing the IC to enter thermal
shutdown. Ensure that the expected maximum operating
current is less than 1A for continuous operation.
Evaluating Other Transformer Configurations
Using the External Oscillator
When using the external clock, remove the shunt from J2
and apply a clock signal on the CLK PCB pad on the EV
kit. An internal flip-flop divides the external clock by two,
generating a switching signal with a guaranteed 50% duty
cycle. As a result, the T1/T2 outputs switch at one-half the
external clock frequency.
The device features overcurrent limiting to protect the
IC from excessive currents when charging large capaci-
tive loads or driving into short circuits. Current limiting
is achieved in two stages: internal circuitry monitors the
driver output current and detects when the peak current
rises above 2A. When the 2A limit is exceeded, internal
protection circuitry is immediately enabled, reducing the
output current and regulating it to the 1.4A (typ) current-
limit threshold. The device monitors the driver current
on a cycle-by-cycle basis, and the driver output current
is regulated to the current-limit threshold until the short
is removed.
The EV kit PCB layout provides an easy method to
reconfigure transformer TX1 secondary windings for other
configurations, including bipolar outputs and full-wave
rectifier. Use Table 2 to reconfigure the EV kit for the
appropriate output configuration.
Using the MAX13253EVKIT with Other
Transformers
The EV kit comes with the 1CT:1.3CT TGM-H240V8LF
transformer from Halo Electronics installed on TX1, but
the EV kit can also be used with other transformers. Table
3 is a list of available transformers from Halo Electronics
designed for the MAX13253 that have other winding-ratios
and/or higher isolation ratings. Contact Halo Electronics
to obtain samples of any of these transformers.
Note that the EV kit is designed for 4500V
RMS
isolation
operation, with 600 mils (15.24mm) spacing between the
primary ground (GND) and secondary ground (SGND)
planes. Test points GND and SGND are provided on
the PCB for probing the respective ground planes, or to
connect the GND and SGND planes together for
non-isolated evaluation of the circuit.
Overcurrent Limiting
Table 2. Output Configurations
CONFIGURATION
Full-wave rectifier
Bipolar outputs
Push-pull rectifier*
*Default
position.
D2
Installed
Installed
Installed
D3
Installed
Installed
Installed
D4
Installed
Installed
Not installed
D5
Installed
Installed
Not installed
C3
Installed
Installed
Installed
C4
0Ω resistor
Installed
Not installed
R2
Not installed
Installed
0Ω
Table 3. Available Transformers for the MAX13253
PART
TGM-H240V8LF
TGM-H260V8LF
TGM-H280V8LF
TGMR-H540V8LF
TGMR-H560V8LF
TGMR-H580V8LF
TURNS RATIO
1CT:1.3CT
1CT:2CT
1CT:2.67CT
1CT:1.375CT
1CT:2CT
1CT:2.67CT
ISOLATION VOLTAGE
1500V
RMS
1500V
RMS
1500V
RMS
4500V
RMS
4500V
RMS
4500V
RMS
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MAX13253 Evaluation Kit
Evaluates: MAX13253
Figure 1. MAX13253 EV Kit Schematic
1.0”
1.0”
Figure 2. MAX13253 EV Kit Component Placement Guide—
Component Side
Figure 3. MAX13253 EV Kit Component Placement Guide—
Solder Side
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MAX13253 Evaluation Kit
Evaluates: MAX13253
1.0”
1.0”
Figure 4. MAX13253 EV Kit PCB Layout—Component Side
Figure 6. MAX13253 EV Kit PCB Layout—PWR
1.0”
1.0”
Figure 5. MAX13253 EV Kit PCB Layout—GND
Figure 7. MAX13253 EV Kit PCB Layout—Solder Side
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