MIC3201 High Brightness LED Driver with High-Side Current Sense General Description Features The MIC3201 is a hysteretic step-down, constant-current, 6.0V to 20V input voltage range High-Brightness LED (HB LED) driver capable of driving High efficiency (>90%) up to four, 1A LEDs. It provides an ideal solution for 5% LED current accuracy interior/exterior lighting, architectural and ambient lighting, High-side current sense LED bulbs, and other general illumination applications. Dedicated dimming control input The MIC3201 operates with an input voltage range from Hysteretic control (no compensation ) 6V to 20V. The hysteretic control gives good supply rejection and fast response during load transients and 1A internal power switch PWM dimming. The high-side current sensing and on-chip Up to 1MHz switching frequency current sense amplifier delivers LED current with 5% Adjustable constant LED current accuracy. An external high-side current sense resistor is 5V on board regulator used to set the output current. Over temperature protection The MIC3201 offers a dedicated PWM input (DIM) which enables a wide range of pulsed dimming. A high switching 40C to +125C junction temperature range frequency operation up to 1MHz allows the use of smaller Available in an 8-Pin ePAD SOIC package external components minimizing space and cost. The MIC3201 operates over a junction temperature range Applications of -40C to +125C and is available in an 8-pin ePAD Architectural, industrial, and ambient lighting SOIC package. LED bulbs Datasheets and support documentation can be found on Indicators and emergency lighting Micrels web site at: www.micrel.com. Street lighting Channel letters 12V lighting systems (MR-16 bulbs, under cabinet lighting, garden/pathway lighting) Typical Application MIC3201 Step-down LED Driver Circuit Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC3201 (1) Ordering Information Part Number Marking Junction Temp. Range Package Lead Finish MIC3201YME MIC3201YME -40C to +125C 8-Pin ePAD SOIC Pb-Free Note: 1. YME is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 8-Pin ePAD SOIC (ME) Pin Description Pin Number Pin Name Pin Function 1 VCC Voltage Regulator Output. The V pin supplies the power to the internal circuitry. The VCC in CC the output of a linear regulator which is powered from VIN. A 1F ceramic capacitor is recommended for bypassing and should be placed as close as possible to the VCC and AGND pins. Do not connect to an external load. 2 CS Current Sense Input. The CS pin provides the high-side current sense to set the LED current with an external sense resistor. 3 VIN Input Power Supply. VIN is the input supply pin to the internal circuitry and the positive input to the current sense comparator. Due to the high frequency switching noise, a 10F ceramic capacitor is recommended to be placed as close as possible to VIN and the power ground (PGND) pin for bypassing. Please refer to layout recommendations. 4 AGND Ground pin for analog circuitry. Internal signal ground for all low power sections. 5 EN Enable Input. The EN pin provides a logic level control of the output and the voltage has to be 2.0V or higher to enable the current regulator. The output stage is gated by the DIM pin. When the EN pin is pulled low, the regulator goes to off state and the supply current of the device is greatly reduced (below 1A). In the off state, the output drive is placed in atri-state condition, where MOSFET is in an off or non-conducting state. Do not drive the EN pin above the supply voltage. 6 DIM PWM Dimming Input. The DIM pin provides the control for brightness of the LED. A PWM input can be used to control the brightness of LED. DIM high enables the output and its voltage has to be at least 2.0V or higher. DIM low disables the output, regardless of EN high state. 7 PGND Power Ground pin for Power FET. Power Ground (PGND) is the ground path for the high current hysteretic mode. The current loop for the power ground should be as small as possible and separate from the Analog ground (AGND) loop. Refer to the layout considerations for more details. 8 LX Drain of Internal Power MOSFET. The LX pin connects directly to the inductor and provides the switching current necessary to operate in hysteretic mode. Due to the high frequency switching and high voltage associated with this pin, the switch node should be routed away from sensitive nodes. EP GND Connect to PGND. February 2011 2 M9999-021011-B