MIC2287 (MLF™) Evaluation Board
1.2MHz PWM White LED Driver
General Description
The MIC2287 is a small 1.2MHz constant frequency
PWM white LED driver. The MIC2287 is available in
either a Thin SOT-23 or a 2mm x 2mm MLF™
package. High power densities in a very small size
are achieved using its internal 34V/500mA switch.
Requirements
The MIC2287 evaluation board requires an input
power source that is able to deliver greater than
500mA at 2.5V.
Precautions
The evaluation board does not have reverse polarity
protection. Applying a negative voltage to the V
IN
terminal may damage the device.
LED Current Setting
The LED current (I
LED
) is equal to the feedback
voltage (95mV typical) divided by the R1 resistance
value. To increase the LED current, the R1 resistor
value must be reduced. Conversely, to decrease the
LED current the R1 resistor value must be increased.
The LED current can be calculated as follows:
95mV
I
LED
=
R1
The evaluation board is preset for ~15mA of LED
current. The evaluation board can easily be modified
to yield the desired LED current by replacing the R1
resistor value.
The MIC2287 evaluation board is tailored for a Li-Ion
range input supply voltage. It should not exceed 10V
on the input.
Getting Started
1.
Connect an external supply to V
IN
. Apply
desired input voltage to the V
IN
(J1) and
ground (J2 and J6) terminals of the
evaluation board, paying careful attention to
polarity and supply voltage (2.5V≤V
IN
≤10V).
An ammeter may be placed between the
input supply and the V
IN
terminal to the
evaluation board. Ensure that the supply
voltage is monitored at the V
IN
terminal. The
ammeter and/or power lead resistance can
reduce the voltage supplied to the input.
2.
Enabling the MIC2287.
Apply a 1.5V or
greater voltage source to the enable (J3)
terminal.
MLF and
MicroLeadFrame
are a registered trademark of Amkor Technology.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax 1 (408) 474-1000 • http://www.micrel.com
M9999-052005
May 2005
(408) 955-1690
Micrel, Inc.
MIC2287 (MLF™) Evaluation Board
J1
V
IN
L1
10µH
D1
C1
1µF
J4
V
OUT
2
VIN
7
SW
1
LED1
LED2
LED3
J1
V
IN
L1
10µH
D1
C1
1µF
C2
1µF
2
VIN
SW
7
LED1
LED2
1
LED3
LED4
J4
V
OUT
C2
1µF
J3
EN
R2
OVP
U1
MIC2287-15BML
3
6
EN
FB
J3
EN
R2
R5
OVP
U1
MIC2287-34BML
3
6
EN
FB
PGND
8
AGND
4
PGND
8
4
LED5
AGND
LED5
J2
GND
J6
DAC
R1
J5
GND
J6
DAC
R1
J2
GND
J5
GND
3 LED Configuration
6 LED Configuration
Bill of Material
MIC2287 Evaluation Board
Part Number
GRM185R61A105KE36D
C1
C1608X5R1A105K
GRM216R61E105KA12D
VJ0805Y105KXXAT
C2
C2012X5R1E105K
D1
CMDSH-3
LQH32CN100K33
L1
VLF3010AT-100MR49
LED1→6
TLMW3101-GS08
R1
CRCW06036R34FRT1
R2
CRCW06032002FRT1
R3
CRCW06031001FRT1
R4
CRCW06032002FRT1
Ref Des
R5
U1
CRCW06030000FRT1
MIC2287BML-15BML
MIC2287BML-34BML
Description
1µF 10V
Ceramic Capacitor, Size 0603
1µF 10V
Ceramic Capacitor, Size 0603
1µF 25V
Ceramic Capacitor, Size 0805
1µF 25V
Ceramic Capacitor, Size 0805
1µF 25V
Ceramic Capacitor, Size 0805
100mA 30V Schottky Diode
10µH 450mA Inductor
10µH 490mA Inductor
20mA White LED
6.34Ω Resistor, Size 0603
20kΩ Resistor, Size 0603
1kΩ Resistor, Size 0603
20kΩ Resistor, Size 0603
0Ω Resistor, Size 0603 (For 3 LEDs)
OPEN (For 6 LEDs)
1.2MHz PWM White LED Driver w/ 15V OVP
1.2MHz PWM White LED Driver w/ 34V OVP
Manufacturer
Murata
TDK
Murata
Vishay
TDK
Central Semi
Murata
TDK
Vishay
Vishay
Vishay
Vishay
Vishay
Vishay
Micrel
Micrel
Notes:
1.
2.
3.
4.
5.
Murata:
www.murata.com
TDK:
www.tdk.com
Vishay:
www.vishay.com
Central Semiconductor:
www.centralsemi.com
Micrel, Inc.:
www.micrel.com
May 2005
2
M9999-052005
(408) 955-1690
Micrel, Inc.
MIC2287 (MLF™) Evaluation Board
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is
assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to
the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where
malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or
systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be
reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support
appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages
resulting from such use or sale.
© 2005 Micrel, Inc.
May 2005
4
M9999-052005
(408) 955-1690
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