mic3287 Micrel Semiconductor, mic3287 Datasheet
mic3287
Available stocks
Related parts for mic3287
mic3287 Summary of contents
Page 1
... LED driving applications. With a maximum output voltage of 24V and a switch current of over 350mA, the MIC3287 drives a string white LEDs in series, ensuring uniform brightness and eliminating several ballast resistors. The MIC3287 implements a constant frequency 1.2MHz PWM current-mode control scheme ...
Page 2
... MIC3287 Ordering Information Marking Overvoltage Part Number Code Protection MIC3287YD5 WGAA MIC3287-24YD6 WHAA MIC3287-24YML WLA Pin Configuration FB GND VIN TSOT-23-5 (YD5) Pin Description Pin Number Pin Number Pin Number TSOT-23-5 TSOT-23-6 8-Pin MLF ...
Page 3
... OUT 3.6V 300mA 0V 10V EN SW TURN ON TURN OFF V = 10V EN MIC3287-24YD6 MIC3287-24YML Hysteresis , and the ambient temperature The maximum allowable power dissipation will result in excessive Micrel, Inc. (2) ) .........................................2.8V to 5.5V IN (4) ) ...................................V OUT IN ) ............ –40°C to +125°C J (5) ) ....................................... 207°C/W ...
Page 4
... MIC3287 Typical Characteristics 3 Series White LED Efficiency 85 V =3. =3. =4. 10µ 0.22µF OUT WHITE LED CURRENT (mA) Frequency vs. Temperature 1.5 1.4 V =4. =3.6V IN 1.3 V =3.2V 1.2 IN 1.1 1.0 -40 -25 - TEMPERATURE (°C) Shutdown Current vs. Input Voltage ...
Page 5
... Functional Description The MIC3287 is a constant frequency pulse width modulated (PWM) current-mode step-up regulator. The block diagram is shown above. The MIC3287 is composed of an oscillator, slope compensation ramp generator, current amplifier, g ror amplifier, PWM generator, and a 350mA minimum bipolar output transistor. The oscillator generates a 1.2MHz clock. ...
Page 6
... MIC3287 External Component Selection The table below shows recommended inductor and output capacitor combinations for optimal performance. M9999-022106 Series LEDs L 2 22µH 15µH 10µH 6.8µH 4.7µH 3 22µH 15µH 10µH 6.8µH 4.7µH 4 22µH 15µH 10µH 6.8µH 4.7µH 6 Min C OUT 2.2µF 1µ ...
Page 7
... If the LEDs are disconnected from the circuit the case that an LED fails, the sense resistor will then pull the FB pin to ground. This will cause the MIC3287 to switch with a high duty- cycle, resulting in output over-voltage. This may cause the SW pin voltage to exceed its maximum voltage rating, damaging the IC and the external components ...
Page 8
... MIC3287 Package Information M9999-022106 5-Pin TSOT (YD5) 6-Pin TSOT (YD6) 8 Micrel, Inc. February 2006 ...
Page 9
... MIC3287 MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA + 1 (408) 944-0800 TEL 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. ...