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| SP7120/22 2 or 3 Channel Low Dropout High Side Linear LED Driver FEATURES * * * * * * * * LED Driver for common cathode parallel connected LEDs Ultra Low Dropout Voltage of 150mV No EMI, no switching noise Integrated current matching PWM and Analog brightness control Enable/Shutdown control Shutdown current < 1A Lead Free, RoHS Compliant Package: Small footprint SOT23-6 * * * * APPLICATIONS Mobile Phones PDA, DSC, MP3 players Handheld Computers Keypads and display backlight GENERAL DESCRIPTION The SP712X driver's family provides a simple solution for a matched current source for any color common cathode LED configuration. The common cathode connection allows the user to increase the LED power dissipation by having the cathodes heat-sinked to the ground plane of the circuit board. The SP7120 may drive two LEDs or one LED at twice the current with two channels connected in parallel. The SP7122 can drive three LEDs or one LED at three times the current. The factory preset current values are 15mA (version A), 20mA (version B), or 25mA (version C) per channel. In shutdown mode (EN pin is LOW), the supply current drops to 40nA typical. The SP712x drivers are available in a small footprint 6-pin SOT23-6 package. APPLICATION SCHEMATIC C1 1nF SP7120 Powering 2 LEDs Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 1 ABSOLUTE MAXIMUM RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended period may affect reliability. RECOMMENDED OPERATING CONDITIONS Ambient operating temperature ...... -40 to+85 C Vcc, VLED1, VLED2, and EN to GND -0.3V to 6V Junction Temperature............................+150 C o Operating Temperature.................-40 to +85 C Storage Temperature...............-65 to +150 C C Package Thermal resistance JA .......190 C/W ESD Level...........................................2kV HBM ESD Level...........................................200V MM ESD Level EN.............................1.5kV HBM Lead Temperature (Soldering, 10 sec) ...300 C ELECTRICAL CHARACTERISTICS Specifications are at TA=25C, Vcc = 2.7 to 5.5, ENABLE =Vcc Parameter Vcc Shutdown Current 1 VLED Dropout Voltage, Vd 1 VLED Dropout voltage, Vd Version A LED Current per Version B Channel Version C Version A Version B Quiescent Version C Current Version A Version B Version C 6 LED to LED Current Matching 2 LED Current Accuracy 3 LED Current Line Regulation 4 LED Current Load Regulation LED Current Thermal Regulation 5 EN ON Voltage (HIGH) EN OFF Voltage (LOW) EN Input Bias Current EN Switching Frequency EN ON Minimum Pulse Width Min 2.7 Typ 0.04 160 140 15 20 25 0.5 0.7 0.86 0.6 0.9 0.99 0.8 Max 5.5 1 200 180 Units V A mV mV mA Conditions EN = LOW Vcc = 5.5V, ILED = 20mA Vcc = 5.5V, ILED = 15mA VD = 300mV VD = 300mV VD = 300mV SP7120 at VD = 300mV 0.7 1.1 1.7 0.8 1.2 1.9 3 .25 1.0 mA SP7122 at VD = 300mV % % %/V %/mA 0 %/ C V V A kHz s Vcc = 5.5V, VD > 300mV 300mV 0.01 2 0 2 Vcc 0.8 5 20 15 3 VEN = Vcc = 5.5V 1) Difference between Vcc voltage and LED anode voltage at which ILED current drops 10% from nominal value 2) ILED Current Variations from specified value 3) ILED Current Variations per volt Vcc change for any given temperature 4) ILED Current Variations at VD change from 0.3V to 1.0V 5) EN input voltage should not exceed Vcc voltage at any condition 6) This condition is part of the LED current accuracy and it shall not exceed that specification Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 2 PIN ASSIGNMENTS 6 5 4 SP7120 SOT23-6 1 2 3 Pin Name Vcc GND EN NC LED3 LED2 LED1 SP7120 1 2 3 4 5 6 SP7122 1 2 3 4 5 6 Pin Description Power input pin. Bypass Vcc to GND with 1nF capacitor as close to VIN as possible Ground pin Enable pin. Device is active if EN is logic HIGH No Connect should be left floating Connect anode of LED3 Connect anode of LED2 Connect anode of LED1 BLOCK DIAGRAM VLED3 VLED2 VLED1 VCC Rset Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 3 OUTPUT CURRENT SELECTION TABLE Part Number SP7120A SP7120B SP7120C SP7122A SP7122B SP7122C Output Current per channel Number of Channels 2 2 2 3 3 3 Comments Channels can be combined for higher output current Channels can be combined for higher output current Channels can be combined for higher output current Channels can be combined for higher output current Channels can be combined for higher output current Channels can be combined for higher output current 15mA 20mA 25mA 15mA 20mA 25mA CIRCUIT DESCRIPTION The SP712X drivers are regulated current sources with an enable input. The SP7120 and SP7122 have factory preset LED current at three programmed levels: 15mA, 20mA or 25mA (versions A, B, and C respectively). The SP712X circuit consists of enable, bandgap reference, and current amplifier circuit blocks. Enable circuit block provides the enable and PWM function for the SP712x. The bandgap reference provides a stable voltage source from which the output current is derived. ENABLE The SP712X drivers have a low current shutdown function. In shutdown mode, the part draws less than 1A current maximum. The part can be set into shutdown mode using the EN pin (EN = LOW). The enable pin cannot be left floating. There are no predefined internal states, so leaving this pin open will cause the part to operate incorrectly. PWM Dimming The SP712X drivers allow LED-dimming control by applying PWM signaling to EN pin. The acceptable frequency range of this signal is 100Hz to 20 kHz. The minimum ON time that is required for the Enable pin is 15s. Thus for a 2kHz PWM signal, the acceptable duty cycle range is 3% to 100%. To find the minimum PWM duty cycle the following steps are needed: Example For a 2kHz signal the minimum duty cycle for the PWM signal is Step 1: Determine the time period of the PWM frequency Where PWMf is the PWM frequency Step 2: take the minimum enable ON time; this is 15S for the SP712x parts %Minimum Duty cycle = 3% Fault Operation If one of LEDs is shorted, the voltage across The Sp712X for that LED pin will be Vcc, but that channel will still provide the nominal current value thus increasing power dissipation. If all channels are shorted, excessive power dissipation may damage the device. If an LED is open, the LED pin voltage will be pulled up to Vcc, and LED current will be reduced to 3mA for the other channels. (c) 2007 Sipex Corporation Jun29-07 RevD SP7120/22 Low Dropout LED Driver page 4 APPLICATION CIRCUITS Powering 1 high power LED IOUT up to 75mA with C version Powering 1 high power LED IOUT up to 50mA with C version C1 1nF SP7122 Powering 3 LED's C1 1nF SP7120 Powering 2 LEDs Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 5 BOARD LAYOUT AND GROUNDING To obtain the best performance from the SP712X, a printed circuit board with ground plane is required. High quality, low series resistance ceramic 1nF bypass capacitors should be used at the Vcc and GND pins. This capacitor must be located as close to the pins as possible. The traces connecting the pins and these capacitors must be kept short and should be made as wide as possible. TYPICAL PERFORMANCE SP7120A The quiescent current is part of the total output current IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 6 TYPICAL PERFORMANCE SP7120A The quiescent current is part of the total output current IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel IOUT is for 2 Channels 15mA per channel Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 7 TYPICAL PERFORMANCE SP7120A PWM Minimum duty cycle 15S 20kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 10mA/div PWM Low duty cycle 15S 5kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 8 TYPICAL PERFORMANCE SP7120A PWM High Duty Cycle 20kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div PWM 50% Duty Cycle 5kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div TYPICAL PERFORMANCE SP7122A The quiescent current is part of the total output current IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 9 TYPICAL PERFORMANCE SP7122A IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 10 TYPICAL PERFORMANCE SP7122A The quiescent current is part of the total output current IOUT is for 3 Channels 15mA per channel IOUT is for 3 Channels 15mA per channel 50% Duty Cycle 5Khz PWM CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div Low duty cycle 5Khz CH:1 PWM Signal CH2: Anode of LED CH4: LED current 10mA/div Minimum On time 15S 20kHz PWM CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div Jun29-07 RevD High Duty Cycle 20kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div (c) 2007 Sipex Corporation SP7120/22 Low Dropout LED Driver page 11 TYPICAL PERFORMANCE SP7122A PWM 50% Duty Cycle Single LED 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 20mA/div PWM Low Duty Cycle Single LED 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 20mA/div PWM Minimum on time 15S Single LED 20kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 20mA/div PWM 50% Single LED 20kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 20mA/div Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 12 TYPICAL PERFORMANCE SP7122B The quiescent current is part of the total output current IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channel Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 13 TYPICAL PERFORMANCE SP7122B IOUT is for 3 channels 20mA per channel IOUT is for 3 channels 20mA per channe PWM Minimum on time 15S 20kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div PWM High Duty Cycle 20kHz CH1: PWM Signal CH2: Anode of LED CH4: LED current 10mA/div PWM Low Duty Cycle 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 10mA/div PWM 50%Duty Cycle 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 10mA/div Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 14 TYPICAL PERFORMANCE SP7122B PWM Low Duty Cycle Single LED 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 50mA/div PWM 50% Duty Cycle Single LED 5kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 50mA/div PWM 50% Duty Cycle Single LED 20kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 50mA/div PWM Minimum Duty Cycle 15uS Single LED 20kHz CH1: PWM Signal CH2 Anode of LED CH4: LED current 50mA/div Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 15 PACKAGE: 6 PIN SOT23 Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 16 ORDERING INFORMATION Part Number SP7120AEK-L/TR SP7120BEK-L/TR SP7120CEK-L/TR SP7122AEK-L/TR SP7122BEK-L/TR SP7122CEK-L/TR Temp Range -40 to C +85 C -40 to C +85 C -40 to C +85 C -40 to C +85 C -40 to C +85 C -40 to C +85 C Package Type SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 SOT23-6 RoHS/ Lead Free Yes Yes Yes Yes Yes Yes Output # of Current per Channels Channel 15mA 20mA 25mA 15mA 20mA 25mA 2 2 2 3 3 3 JA (C/W) Moisture Sensitivity Level L1 @ 260C L1 @ 260C L1 @ 260C L1 @ 260C L1 @ 260C L1 @ 260C 190 190 190 190 190 190 Pack quantity is 2500 for SOT23-6 tape and reel. For further assistance: Email: WWW Support page: Sipex Application Notes: Sipexsupport@sipex.com http://www.sipex.com/content.aspx?p=support http://www.sipex.com/applicationNotes.aspx Solved by Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA95035 tel: (408) 934-7500 FAX: (408) 935-7600 TM Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others. Jun29-07 RevD SP7120/22 Low Dropout LED Driver (c) 2007 Sipex Corporation page 17 |
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