ADM00940 Microchip

MAQ3203 High-Brightness LED Driver Controller with High-Side Current Sense General Description The MAQ3203 is a hysteretic, step-down, constant- current, High-Brightness LED (HB LED) driver. It provides an ideal solution for interior/exterior lighting, architectural and ambient lighting, LED bulbs, and other general Features illumination applications. AEC-Q100 qualified The MAQ3203 is well suited for lighting applications 4.5V to 42V input voltage range requiring a wide-input voltage range. The hysteretic control High efficiency ( >90%) gives good supply rejection and fast response during load 5% LED current accuracy transients and PWM dimming. The high-side current sensing and on-chip current-sense amplifier delivers LED Dither enabled for low EMI current with 5% accuracy. An external high-side current- High-side current sense sense resistor is used to set the output current. Dedicated dimming control input The MAQ3203 offers a dedicated PWM input (DIM) which Hysteretic control (no compensation ) enables a wide range of pulsed dimming. A high-frequency Up to 1.5MHz switching frequency switching operation up to 1.5MHz allows the use of smaller Adjustable constant LED current external components minimizing space and cost. The Over-temperature protection MAQ3203 offers frequency dither feature for EMI control. 40C to +125C junction temperature range The MAQ3203 operates over a junction temperature from 40C to +125C and is available in an 8-pin SOIC Applications package. The MAQ3203 is AEC-Q100 qualified for Automotive lighting automotive applications. Industrial lighting Datasheets and support documentation are available on Micrels web site at: www.micrel.com. Typical Application MAQ3203 Step-Down LED Driver Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MAQ3203 Ordering Information (1) Part Number Marking Junction Temperature Range Package PWM MAQ3203YM MAQ3203YM 8-Pin SOIC Dither 40C to +125C Note: 1. YM is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 8-Pin SOIC (M) (Top View) Pin Description Pin Number Pin Name Pin Function Voltage Regulator Output. The V pin supplies the power to the internal circuitry. The VCC is the CC output of a linear regulator which is powered from VIN. A 1F ceramic capacitor is recommended for 1 VCC bypassing and should be placed as close as possible to the VCC and AGND pins. Do not connect to an external load. Current-Sense Input. The CS pin provides the high-side current sense to set the LED current with an 2 CS external sense resistor. 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 3 VIN 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. 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 5 EN (below 1A). In the off state, during this period 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. PWM Dimming Input. The DIM pin provides the control for brightness of the LED. A PWM input can 6 DIM 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. Power Ground Pin for Power FET. Power Ground (PGND) is for the high-current switching with 7 PGND 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. Gate-Drive Output. Connect to the gate of an external N-channel MOSFET. The drain of the external MOSFET connects directly to the inductor and provides the switching current necessary to operate in 8 DRV 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. April 20, 2015 Revision 1.2 2