LDS8846-002-T2

LDS8846 4-Channel Ultra Low Dropout No Noise LED Driver FEATURES o Ultra-low dropout PowerLite™ Current Regulator* o o Drives up to 4 LEDs at 30 mA each PWM brightness control o o Power efficiency > 95% Low input noise & ripple o o Low current shutdown mode Load disconnect in shutdown mode o o Short circuit protection Thermal shutdown protection o Available in 4 x 4 x 0.8 mm and 3 x 3 x 0.8 mm 16-pin TQFN packages LED current is easily adjustable by an external resistor up to 30 mA per channel. The CTRL0, CTRL1, and CTRL2 logic inputs function as a LED enable and a PWM mode LED brightness control. APPLICATION o o Keypad and Display Backlight Cellular Phones o o Digital Still Cameras PDAs and Smartphones The driver supports a wide range of input voltages from 2.7 V to 5.5 V. The thermal and short circuit protection guarantee high device reliability. DESCRIPTION The device is available in a 16-lead TQFN 4 x 4 mm and 3 x 3 mm packages with a max height of 0.8 mm . The LDS8846 is a high efficiency ultra-low dropout current regulator that can drive up to four LEDs. The . TYPICAL APPLICATION CIRCUIT © 2009 IXYS Corp. Characteristics subject to change without notice 1 Doc. No. 8845DS, Rev. N1.6 LDS8846 ABSOLUTE MAXIMUM RATINGS Parameter V IN, LEDx voltage V OUT voltage EN, CTRL0, CTRL1, CTRL2 voltage Storage Temperature Range Junction Temperature Range Soldering Temperature (10s) ESD protection HBM Rating -0.3 to 6 -0.3 to 6 V IN + 0.7V -65 to +150 -40 to +125 300 2 Unit V V V °C °C °C kV NOTE: Stresses listed above may cause permanent damage to thje device. Functional operation of the device at these or any other conditio ns beyond those indicated in the “Recommended Operating Conditions” is not impiled. Exposure to abslute maximum rating conditions for extended periods may remain possibility to affect device reliability. RECOMMENDED OPERATING CONDITIONS Parameter Rating 2.7 to 5.5 -40 to +85 V IN Ambient Temperature Range Unit V °C ELECTRICAL OPERATING CHARACTERISTICS (Over recommended operating conditions unless specified otherwise) V IN = 3.6V, EN = High, TAMB = 25°C Name Conditions Quiescent Current Shutdown Current LED Current Typ Max Units ILED = 20mA per channel 1.3 1.5 mA EN = 0V RSET = 24k 0.1 1 µA RSET = 96k 2.7 < V IN < 5.5V To set value (ILED MAX - ILED MIN) / (ILED MAX + I LED MIN) LED Current Setting Range LED Current Accuracy LED Channel Matching Min 20 5 2 -8 -5 Current Sink Dropout Voltage* Short Circuit Output Current Limit EN, CTRL0, CTRL1, CTRL2 pins Leakage Current High Low High Low V OUT = 0V Input Voltage = V IN Input Voltage = 0 Logic Level Threshold PWM frequency PWM duty cycle Thermal Shutdown Thermal Hysteresis Under Voltage Lockout (UVLO) Threshold *) Voltage drop at led pin, at which LED current falls 10% below set value © 2009 IXYS Corp. Characteristics subject to change without notice 2 mA 3 30 +8 mA % 3 +5 % 20 30 mV 22 25 1 mA -1 1.3 0.4 100000 100 100 1 150 20 2.4 µA V Hz % °C V Doc. No. 8846DS, Rev. N1.6 LDS8846 CONTROL INPUTS FUNCTION Control Inputs CTRL2 CTRL1 CTRL0 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 LED4 OFF OFF OFF ON OFF OFF ON OFF Output States LED3 LED2 OFF OFF OFF ON ON OFF OFF OFF OFF ON ON ON ON ON OFF OFF LED1 ON OFF OFF OFF ON ON ON OFF TYPICAL CHARACTERISTICS 0 V IN = 3.6V, I OUT = 104 mA (4 LEDs at 26 mA each), CIN = COUT = 1 µF, Vf = 3.2 V, TAMB = 25 C Power Efficiency vs. Input Voltage LED Current vs. Temperature LED Current vs. Input Voltage Power-Up Delay Time EN V OUT ILED ( 4 LEDs) 50 mA/div © 2009 IXYS Corp. Characteristics subject to change without notice 3 Doc. No. 8846DS, Rev. N1.6 LDS8846 Power-Down Delay Time PWM Mode (1 kHz, 50 Duty Cycle) EN CRL0 V OUT V OUT ILED ILED (4 LEDs) (4 LEDs) 50 mA/div 50 mA/div PWM Mode (10 kHz, 50 Duty Cycle) PWM Mode (50 kHz, 50 Duty Cycle) CRL0 CRL0 V OUT VOUT ILED ILED (4 LEDs) (4 LEDs) 50 mA/div 50 mA/div I LED Current vs. Duty Cycle © 2009 IXYS Corp. Characteristics subject to change without notice ILED Current Error vs. Duty Cycle 4 Doc. No. 8846DS, Rev. N1.6 LDS8846 PIN DESCRIPTION Pin # Name 1 2 3 4 5 6 7 8 - 11 12 13 14 15 16 PAD EN CTRL0 CTRL1 CTRL2 ISET V OUT VIN NC PGND LED4 LED3 LED2 LED1 PAD Function Device Enable. Output Control Bit 0 (See Table Control Pin Function) Output Control Bit 1 (See Table Control Pin Function) Output Control Bit 2 (See Table Control Pin Function) LED current setting pin Output voltage to the LED anodes Input Voltage No internal connect Power Ground LED4 Cathode Terminal LED3 Cathode Terminal LED2 Cathode Terminal LED1 Cathode Terminal Connect to GND on the PCB PIN FUNCTION supply falls below the under-voltage threshold (2.2 V), all the LED channels are disabled, and the device enters shutdown mode. EN is a Device Enable. This pin is high impedance. There should be a pull down resistor