mic4802 Micrel Semiconductor, mic4802 Datasheet

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mic4802

Manufacturer Part Number
mic4802
Description
Manufacturer
Micrel Semiconductor
Datasheet
General Description
The MIC4802 is a high efficiency White LED (WLED)
driver designed to drive a single LED up to 800mA. The
MIC4802 constant current driver is designed to drive high
power LED’s in various lighting applications. The MIC4802
provides the highest possible efficiency as this architecture
has no switching losses present in traditional charge
pumps or inductive boost circuits. It features a typical
dropout of 280mV at 800mA. This allows the LEDs to be
driven directly from the voltage source eliminating
switching noise/losses present with the use of boost
circuitry. The high accuracy (±1% Typical) current
regulated
illumination under all conditions. The brightness is
controlled through an Ultra Fast PWM™ Control interface
operating down to less than 1% duty cycle.
The MIC4802 is available in the 8-pin SOIC Epad package
with a junction temperature range of -40°C to +125°C.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
____________________________________________________________________________________________________________
Typical Application
Ultra Fast PWM is a trademark of Micrel, Inc.
January 2011
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
WLED
channel
ensures
uniform
High Current Lighting Schematic
display
Features
• High Efficiency (no Voltage Boost losses)
• Ultra Fast PWM™ control (200Hz to 500kHz)
• Input voltage range: 3.0V to 5.5V
• Dropout of 280mV at 800mA
• Programmable LED current with external resistor
• Current accuracy of ±1% typical
Applications
• Bill board displays
• Marquee displays
• Instrument displays
• Architectural lighting
408
) 944-0800 • fax + 1 (408) 474-1000 •
High Efficiency 800mA Single Channel
Ultra Fast PWM™ Control
Linear WLED Driver with
MIC4802
http://www.micrel.com
M9999-013111-B

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mic4802 Summary of contents

Page 1

... The brightness is controlled through an Ultra Fast PWM™ Control interface operating down to less than 1% duty cycle. The MIC4802 is available in the 8-pin SOIC Epad package with a junction temperature range of -40°C to +125°C. Datasheets and support documentation can be found on Micrel’ ...

Page 2

... LED1 driver input. Connect LED anode to VIN and cathode to this pin. All D1 pins must be connected to the LED. EPAD HS PAD Heat sink pad. Not internally connected. Connect to ground. January 2011 Temperature Range –40°C to +125°C 8-Pin Epad SOIC (ME) (Top View) 2 MIC4802 Package 8-Pin EPAD SOIC M9999-013111-B ...

Page 3

... ....................................... ........................ –40°C to +125°C J EPAD SOIC-8L (θ )..........................................41°C/W JA ≤ 125°C; unless noted. J Min Typ 747 830 280 4.1 0.01 1.2 0. 0 MIC4802 IN IN Max Units 913 mA 500 mV 5 µA 0 µA 60 µs µs µs µs µ M9999-013111-B ...

Page 4

... RSET (kΩ) RSET Voltage vs. LED Current 1.4 1.38 1.36 1.34 1.32 1.3 1.28 1.26 VIN = 5V 1.24 0 200 400 600 800 1000 1200 1400 LED CURRENT (mA) 4 MIC4802 Dropout Voltage vs. LED Current 500 450 400 350 300 250 200 150 100 50 VIN = 200 400 600 800 1000 1200 1400 ...

Page 5

... Micrel Inc. Functional Characteristics January 2011 5 MIC4802 M9999-013111-B ...

Page 6

... Micrel Inc. Functional Diagram Functional Description The MIC4802 is a single channel linear LED driver with a maximum 800mA current capability. The LED driver is designed to maintain proper current regulation with LED current accuracy of ±10%. The dropout is 280mV at 800mA. The low dropout of the linear drivers allows the ...

Page 7

... EN The EN pin is equivalent to the enable pin for the linear drivers on the MIC4802. It can also be used for dimming applying a PWM signal. See the PWM Dimming Interface in the Application Information section for details. Pulling the EN low for more than 40ms puts the MIC4802 into a low I sleep mode ...

Page 8

... WLED current response when a PWM signal is applied to the END pin (1) From the low I sleep mode higher PWM frequencies above 15kHz Q require a logic high enable signal for 60μs to first enable the MIC4802 . prior to PWM dimming LED Current vs. PWM Duty Cycle 900 ...

Page 9

... Figure 8. PWM Signal at 50% Duty Cycle (I Figure 9. PWM Signal at 80% Duty Cycle (I January 2011 Thermal Consideration The MIC4802 thermal considerations involve calculating the junction temperature based on the voltage drop across the package and the LED current. The voltage drop across the package is equal to the voltage at D1 with respect to ground times the LED current ...

Page 10

... Micrel Inc. MIC4802 Typical Application Circuit Bill of Materials Item Part Number C1608X5R0J225K 06036D225KAT2A C1 GRM188R60J225KE19D VJ0603G225KXYAT LED R42180 R CRCW06036K19FKEA SET U1 MIC4802YME Notes: 1. TDK: www.tdk.com 2. AVX: www.avx.com 3. Murata: www.murata.com 4. Vishay: www.vishay.com 5. Seoul Semi: http://www.acriche.com/en 6. Micrel, Inc.: www.micrel.com January 2011 Manufacturer (1) TDK (2) AVX Ceramic Capacitor, 2.2µ ...

Page 11

... Micrel Inc. Layout Recommendations January 2011 Top Layer Bottom Layer 11 MIC4802 M9999-013111-B ...

Page 12

... 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 January 2011 8-Pin SOIC (ME) indemnify Micrel for any damages resulting from such use or sale. © 2010 Micrel, Incorporated. 12 http://www.micrel.com M9999-013111-B MIC4802 ...

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