MAX20051 [MAXIM]
MAX20051 Evaluation Kit;
| 型号： | MAX20051 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | MAX20051 Evaluation Kit |
| 文件： | 总7页 (文件大小：1675K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
General Description
The MAX20051 evaluation kit (EV kit) demonstrates the
MAX20051 and MAX20053, 2A synchronous buck LED
drivers with integrated MOSFETs.
Features and Benefits
● 4.5V to 65V Input Voltage
● Drives 1 to 16 LEDs
● 0A to 2A LED Current
The EV kit operates from a DC supply voltage from
4.5V to 65V and the switching frequency is fixed at
400kHz. Spread-spectrum mode (SSM) is enabled for
EMI improvement. The EV kit demonstrates both analog
and pulse-width modulation (PWM) dimming. The EV kit
also demonstrates short LED, open LED, and overtem-
perature-fault protection.
● Demonstrates Undervoltage-Lockout and Output-
Short Protection
● Demonstrates Current-Limit and Thermal-Shutdown
Feature
● Demonstrates 5V, 10mA LDO Output Capability
● Proven PCB Layout and Thermal Design
● Fully Assembled and Tested
The EV kit also comes with a MAX20053 IC, which can
be installed to evaluate the 2.1MHz switching frequency
device. Refer to the Evaluating the MAX20053 section for
more information.
Ordering Information appears at end of data sheet.
MAX20051 EV Kit Photo
19-7363; Rev 0; 10/14
Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
frequency average current-mode step-down LED driver.
The device uses high-side current regulation, meaning
a current-sense resistor is placed on the high side of the
LED string, and the voltage across the current-sense
resistor is sensed and used to regulate the LED current.
The device offers both analog and PWM dimming.
Quick Start
Required Equipment
●
●
●
●
MAX20051 EV kit
5V to 65V, 4A DC power supply
Two digital voltmeters (DVMs)
Analog Dimming
One series-connected HB LED string rated to no less
than 2.5A
The EV kit demonstrates the analog dimming feature of
the device. R6 and R7 form a resistor-divider between
VCC and AGND. R6 is a 10kΩ resistor and R7 is a 10kΩ
potentiometer, with the wiper shorted to the high side of
the potentiometer. Using a flat-blade screwdriver, turn the
wiper-adjustment pin clockwise to increase the voltage on
the REFI input. Turn the wiper-adjustment pin counter-
clockwise to decrease the voltage on the REFI input.
The REFI input allows for analog dimming of the HB LED
string. A REFI input voltage of 0.2V or less turns off the
LED driver. A REFI input voltage between 0.2V and 1.2V
provides linear dimming of the HB LED string. A REFI input
voltage greater than 1.2V sets the HB LED string current
to maximum current (based on the current-sense resistor).
●
●
Current probe to measure the HB LED current
Small flat-blade screwdriver to turn the potentiometer
wiper-adjustment pin
Procedure
The EV kit is fully assembled and tested. Follow the steps
below to verify board operation:
1) Connect the HB LED string anode to the LED+ PCB
pad and the cathode to the PGND PCB pad.
2) Connect the first DVM across the LED+ and PGND
PCB pads.
3) Connect the second DVM across the REFI test point
and AGND test point.
4) Connect the power supply to the VIN PCB pad and
the power supply’s ground to the PGND PCB pad.
5) Clip the current probe across the wire connecting the
HB LED string to the EV kit.
6) Turn on the power supply and set it to a voltage great-
er than the maximum HB LED string voltage, but less
than the 65V maximum input voltage.
Alternatively, the analog dimming input can be set with
a power supply. Remove R12 and connect the power
supply directly to the REFI test point to perform analog
dimming with a power supply. Be careful not to violate
the absolute maximum voltage rating of V
+ 0.3V
CC
(refer to the Absolute Maximum Ratings section in the
MAX20050–MAX20053 IC data sheet).
7) Use the screwdriver to turn the potentiometer until the
second DVM reads 1.2V.
8) Measure the HB LED current using the current probe
and verify that the current is 2A.
9) Verify that the first DVM shows the expected LED
string voltage.
10) Use the screwdriver to turn the potentiometer until the
second DVM reads 0.7V.
PWM Dimming
The EV kit demonstrates the PWM dimming feature of
the device. Connect a PWM signal to the PWM test point.
Vary the duty cycle to increase or decrease the intensity
of the HB LED string. The PWM input of the device has 2V
(max) rising threshold and a 0.8V (min) falling threshold
so it is compatible with 3.3V and 5V logic-level signals.
The PWM input is pulled up to V
10kΩ resistor on the EV kit.
through an external
CC
11) Measure the HB LED current using the current probe
and verify that the current is 1A.
Fault Indicator
Detailed Description of Hardware
The EV kit demonstrates the fault-protection features of
the device. The device offers shorted LED, open LED,
and overtemperature protection. The FLT output is an
open-drain, active-low fault indicator. Refer to the Fault
Pin Behavior section in the MAX20050–MAX20053 IC
data sheet for more information.
The MAX20051 EV kit demonstrates the MAX20051 2A
synchronous buck LED driver with integrated MOSFETs.
The device consists of a fully synchronous step-down
converter with integrated MOSFETs and is capable of
driving a series string of LEDs at up to 2A, with a minimum
number of external components. The device is a fixed-
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Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
switching frequency, L2 should be decreased to 4.7μH,
R5 should be increased to 3.92kΩ, and C8 should be
increased to 4700pF. The MAX20053 is only suitable for
applications where the maximum input voltage is less
than 40V.
Acoustic Noise
High input voltage can cause acoustic noise in
certain applications. The acoustic noise comes from the
electrostrictive effect of ferroelectric ceramics. If this is a
concern, consider using low acoustic-noise capacitors on
the output, such as the Murata GJ8 series capacitors or
Rubycon polymer multilayer (PML) capacitors.
Evaluating the MAX20050 and MAX20052
The MAX20050 and MAX20052 offer internal error-
amplifier compensation in a 12-pin TDFN-EP package.
To evaluate these devices, order the MAX20050 EV kit
instead.
Evaluating the MAX20053
The EV kit is capable of evaluating the MAX20053 with
some minor modifications. The MAX20053 has a switch-
ing frequency of 2.1MHz. To accommodate the higher
Component List
PART
QTY
DESCRIPTION
PART
QTY
DESCRIPTION
C1, C2,
C4, C6, C7
2.2µF ±10%, 100V X7R ceramic
capacitors (1210)
4.7µH ±20%, 6.2A inductor
Coilcraft MSS1278T-472ML
5
L1
1
22µF, 100V electrolytic capacitor
(Size F)
47µH ±20%, 2.9A inductor
Coilcraft MSS1278T-473ML
C3
C5, C10
C8
1
2
1
1
0
1
1
L2
1
R1, R2
R3, R4
R5
2
2
1
0.2Ω ±1% resistors (1206)
10Ω ±1% resistors (0603)
2.74kΩ ±1% resistor (0603)
0.1µF ±10%, 50V X7R ceramic
capacitors (0603)
0.01µF ±10%, 16V X7R ceramic
capacitor (0603)
R6, R13,
R14
3
10kΩ ±1% resistors (0603)
1µF ±10%, 25V X7R ceramic
capacitor (0603)
C9
10kΩ ±10% potentiometer
Bourns Inc. 3296W-1-103LF
R7
R12
U1
1
1
1
C11, C12,
C16
Not installed, ceramic capacitors
0Ω ±5% resistor (0603)
100pF ±5%, 50V C0G ceramic
capacitor (0603)
C18
D2
LED driver (14 TSSOP-EP*)
Maxim MAX20051AUD/V+
80V, 1A Schottky diode (SMA)
Diodes, Inc. B180A-13-F
LED driver (14 TSSOP-EP*)
Maxim MAX20053AUD/V+
—
—
1
1
D3
0
1
Not installed, Schottky diode
Inductor—PCB short
PCB: MAX20051 EVKIT
FB1
*EP = Exposed pad.
Component Suppliers
SUPPLIER
PHONE
WEBSITE
www.bourns.com
Bourns Inc.
951-781-5500
847-639-6400
805-446-4800
770-436-1300
Coilcraft Inc.
www.coilcraft.com
Diodes Incorporated
Murata Americas
www.diodes.com
www.murataamericas.com
Note: Indicate that you are using the MAX20051 when contacting these component suppliers.
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Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
L1
VIN
FB1
4.7UH
PC SHORT
2
3
C19
OPEN
C1
2.2UF
100V
C2
2.2UF
100V
C4
2.2UF
100V
C3
IN
IN
22UF
100V
12
BST
LED+
U1
C5
0.1UF
50V
L2
47UH
LED+
PGND
MAX20051AUD/V+
R1
1
PGND
PWM
13
LX
LX
01.%2
D3
OPEN
6
PWM
VCC
14
R14
10K
VCC
C6
2.2UF
100V
C7
2.2UF
100V
C11
OPEN
C12
OPEN
D2
1%
11
VCC
R3
R2
B180-13-F
4
CS+
C9
10
1UF
25V
01.%2
PGND
C18
1%
R4
R6
10K
1%
100PF
REFI
5
8
CS-
R12
0
10
REFI
10
1%
C10
0.1UF
50V
COMP
3
1
R5
2.74K
1%
2
R7
FLT
7
AGND EP
15
10K
C16
OPEN
9
VCC
C8
0.01UF
AGND
R13
10K
1%
FLT
Figure 1. MAX20051 EV Kit Schematic
1”
1”
Figure 2. MAX20051 EV kit Component Placement Guide—
Component Side
Figure 3. MAX20051 EV Kit PCB Layout —Component Side
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Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
1”
1”
Figure 4. MAX20051 EV Kit PCB Layout—AGND Layer 2
Figure 5. MAX20051 EV Kit PCB Layout—VCC Layer 3
1”
Figure 6. MAX20051 EV Kit PCB Layout—Solder Side
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Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
Ordering Information
PART
TYPE
EV kit
MAX20051EVKIT#
#Denotes RoHS compliant.
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Evaluates: MAX20051/MAX20053
MAX20051 Evaluation Kit
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
10/14
Initial release
—
For information on other Maxim Integrated products, visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2018 Maxim Integrated Products, Inc.
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