® PRELIMINARY SP7611A/7612/7614 Low Dropout LED Driver for any Color LED N/C FEATURES ■ LED Drivers for parallel connected LEDs ■ Ultra Low Dropout Voltage of 150mV (SP7614) ■ No EMI, no switching noise ■ Integrated current matching ■ PWM and Analog brightness control ■ Enable/Shutdown control ■ Shutdown current < 1µA ■ Small footprint SC-70 Package 3 CTRL LED1 2 1 SP7614 6 Pin SC70 4 5 6 GND LED2 ON/OFF Now Available in Lead Free Packaging APPLICATIONS ■ Next Generation Mobile Phones ■ PDA, DSC, MP3 players ■ Handheld Computers ■ LCD Display Modules ■ Keyboard Backlight ■ LED Displays DESCRIPTION The SP761X driver family provides a simple solution for a matched current source any color LED. The current in the LEDs can be programmed by an external resistor. The Individual LED currents are 200 x ISET, where ISET is the current through the external resistor connected to the CTRL pin. The SP7611A is capable of driving four LEDs, while the SP7612 can drive three LEDs. The SP7614 is designated to drive two high current LEDs. LED1 should always be connected to an LED in order to have the other LEDs driven with a matched current to LED1. P/N SP7611A SP7612 SP7614 Channel 4 3 2 IBIAS 160 120 160 IBIAS/LED 40 40 80 The SP7612 and SP7614 have Enable pins. When these devices are disabled, the supply current drops to 0.01µA typical. The SP7611A, SP7612 and SP7614 drivers are available in a small footprint 6-pin SC-70 package. TYPICAL APPLICATION SCHEMATIC VIN I SET V CONTROL RSET LED1 CTRL LED2 ® SP7614 ENABLE Date: 6/30/04 ON/OFF GND SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 1 © Copyright 2004 Sipex Corporation 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 periods of time may affect reliability. VLED1, VLED2, VLED3, VLED4 and EN Voltage to GND......................................................................................-0.3V to 6V CTRL Voltage to GND . .........................................................................................................................................0.5V Output Current (IOUT).............................................................................................................................................80mA Power Dissipation per Package - 6-pin SC-70 at TA =85°C...............................................................................190mW Junction Temperature.........................................................................................................................................+150°C Storage Temperature.......................................................................................................................... -55°C to +150°C ESD Level.......................................................................................................................................................................................................4kV HBM ESD Level.......................................................................................................................................................................................................1kV CDM ELECTRICAL CHARACTERISTICS Specifications are at TA=25°C, VIN =3.3to 5.5, ENABLE =VIN, ♦ denotes the specifications which apply over the full operating temperature range, unless otherwise specified. PARAMETER LED Cathode Voltage P/N MIN. SP7611A SP7612 0.3 SP7614 0.15 SP7614 -40 Ambient Temperature PARAMETER P/N Output Current Multiplication Ratio (Note 1) MIN. TYP. MAX. UNITS 0.5 1 V 20 85 ºC MAX. UNITS SP7611A SP7612 CONDITIONS ♦ ISET = 100µA VSAT = 300mV SP7614 ♦ ISET = 100µA VSAT = 150mV SP7611A SP7612 ♦ ISET= 100µA VSAT = 300mV ♦ ISET = 100µA VSAT = 150mV % ♦ No Load % ♦ VIN = 3V 1 µA ♦ VEN = 0V 3 V ♦ ISET = 150µA V ♦ 140 LED Current ILED (Per Diode) TYP. 200 260 20 mA SP7614 LED to LED Current Matching -3 0.8 Peak Efficiency 3 90 Current in OFF Mode 0.01 Min. ENABLE "ON Voltage" SP7612 SP7614 Max. ENABLE "OFF Voltage" SP7612 SP7614 0.5 Note 1: Output current Multiplication Ratio (ILED/ISET) is not linear. For actual ratio and ILED please refer to typical performance characteristics @ page 4. Date: 6/30/04 SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 2 © Copyright 2004 Sipex Corporation PIN DESCRIPTION PIN NAME Pin No. DESCRIPTION SP7611A SP7612 SP7614 1 CTRL CTRL CTRL Sets LED Current 2 LED2 LED2 LED1 Connect to Cathode of LED 3 LED1 LED1 NC Connect to Cathode of LED 4 GND GND GND Ground 5 LED4 LED3 LED2 Connect to Cathode of LED LED3 Connect to Cathode of LED 6 ON/OFF ON/OFF Chip ON/OFF/Disable PINOUT LED1 3 LED2 2 CTRL LED1 1 3 CTRL LED2 2 1 SP7611A SP7612 6 Pin SC70 6 Pin SC70 4 5 6 4 5 6 GND LED4 LED3 GND LED3 ON/OFF N/C 3 CTRL LED1 2 1 SP7614 6 Pin SC70 Date: 6/30/04 4 5 6 GND LED2 ON/OFF SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 3 © Copyright 2004 Sipex Corporation TYPICAL PERFORMANCE CHARACTERISTICS ISET versus CTRL Voltage Vk=1V LED Current versus Enable Voltage Vk=150mV 200.0 18.000 180.0 16.000 14.000 LED Current (mA) Set Current (µA) 160.0 140.0 120.0 100.0 80.0 60.0 40.0 20.0 0.0 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 12.000 10.000 8.000 6.000 4.000 2.000 0.000 1.80 VEN Voltage (V) CTRL Pin Voltage (V) ILED vs Set Resistor and Cathode Voltage Vk=200mV Vk=250mV SP7614 LED Current vs. LED Cathode Voltage Vk=300mV 20.0 35 18.0 30 Vk=150mV 14.0 LED Current (mA) LED Current (mA) 16.0 12.0 Vk=100mV 10.0 8.0 Vk=50mV 6.0 4.0 2.0 10 20 30 40 50 60 70 80 90 For Iset = 50uA 25 20 For Iset = 25uA 15 10 100 Set Resistor (kOhms) 5 0 0.2 0.4 0.6 0.8 1 LED Cathode Voltage (V) PWM LED Current vs. Temperature Iset=100uA, Vcathode=150mV 25 ILED(mA) 24 23 22 21 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 Temperature (C) Control Voltage Transient Response T [ ] LED Current (20mA/div) LED Current (20mA/div) [ Enable Voltage Transient Response CTRL Voltage (1V/div) CTRL Voltage (1V/div) T T Time (1µs/div) Date: 6/30/04 T ] T T Time (1µs/div) SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 4 © Copyright 2004 Sipex Corporation APPLICATION INFORMATION SETTING THE LED CURRENT APPLICATION NOTES The current flowing into LEDs is approximately 200 times greater than the current ISET. The LED current is controlled by ICONTROL and RSET according to the following formula: The ultra-low voltage drop across the SP761X series of LED drivers, allow the devices to drive white, blue, and other color LEDs in a wide range of input voltages. The driver can be used in many applications. Although, only the SP7611A is shown in all three examples, any of the SP762X series of LED drivers can be used in the applications presented in this document, due to their similar operation. ILED = 200 X (VCONTROL - VCTRL) / RSET For VCONTROL = 3V and a specified LED current, the RSET value can be evaluated using the diagram shown in the Typical Performance Characteristics section. For any other option, ISET vs. VCTRL. The LED's brightness can also be adjusted by driving ENABLE or the CTRL pin with a PWM signal. The driving signal frequency should be greater than 100Hz to avoid flickering, increasing to more than 1MHz, if necessary. Example 1: Drive low VF white or blue LEDs directly from single cell Li-ion When using white or blue low VF LEDs, and utilizing the drivers low voltage drop, only 3.4V in VIN is needed for the full 20mA LED current. At 3.1V, there is still 5mA typical current available for the LEDs. The single cell Li-ion is utilized in most applications like cell phones or digital still cameras. In most cases, the Li-ion battery voltage level only goes down to 3.0V voltage level, and not down to the full discharge level (2.7V) before requesting the charger. LEDs are very sensitive to temperature. In most cases the maximum allowed junction temperature is 100ºC. This temperature is the result of adding to the ambient temperature the over temperature due to power dissipation, is described by the following: VIN Tj = TA + ØjA x I xVF where Tj is the LED junction temperature, TA is the ambient temperature, ØjA is the junction to ambient thermal resistance, I is the LED current and VF is the LED forward voltage. I SET V CONTROL The SP7611AA to SP7614 are designed to reduce the current through LEDs, when the temperature rises and the cathode voltage increases, as can be seen from typical the "LED Current vs. LED Cathode Voltage" graph under the Typical Performance Characteristics section. LED3 LED2 LED1 ® SP7611 ENABLE ON/OFF GND - TDROP < 0.3V - VF (at 20mA) < 3.1V (Low VF) The SP761X driver's low dropout architecture can significantly improve the efficiency compared to using simple ballast resistors. - VIN (at 20mA) < - VDROP +VF = 3.4V - VIN (at 5mA typical) ~ 3.1V The system efficiency, defined as the ratio between the LEDs power and the input supplied power can be calculated as follows: Key Advantages 1) No boost circuit needed for the LCD or keyboard backlight Efficiency = (VIN - VCATHODE) / VIN 2) Drivers directly connected to a Li-ion battery The lower the VCATHODE , the higher the system efficiency. Efficiency can be further improved using a higher VIN with more LEDs as shown in example 3. Date: 6/30/04 RSET LED4 CTRL 3) No EMI, no switching noise, no boost efficiency lost, no capacitor, and no inductor SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 5 © Copyright 2004 Sipex Corporation APPLICATION INFORMATION - VDROP < 0.3V Example 2: Drive high VF white or blue LEDs from existing bus from 4.0V to 5.5V - VIN_MIN = N x VF + VDROP High VF white or blue LEDs have forward voltage drop in the range of 3.2V to 4.0V. To drive these LEDs with the maximum current of 20mA for maximum brightness, usually requires a boost circuit for a single cell Li-ion voltage range. In some cases, there is already a voltage bus in the system, which can be utilized. Due to the ultralow voltage drop of the SP761X series of LED drivers to drive high VF white or blue LEDs. The VIN needs to be only 300mV higher than the highest VF in the circuit. - VIN_MIN = N x VF + 5.5V Where VIN = Existing bus, boost Voltage Key Advantages 1) No need for current matching resistors and discrete transistor for brightness control LED Brightness Control VIN I SET V CONTROL RSET LED4 CTRL LED3 LED2 All of the SP761X LED Drivers feature analog and PWM controls to give designers flexible brightness control. These control methods can be applied to the circuit in two different ways, to provide more flexibility than any other solution. To determine the value of RSET , use the "ISET vs. VCRTL" graph under the Typical Performance Characteristics. LED1 ® 1. SP7611A SP7611 ENABLE ON/OFF GND VIN - TDROP < 0.3V - VF (at 20mA) < 3.3V to 4.0V (High VF) I SET VCONTROL 3V - VIN (at 20mA) = VDROP +VF = 3.6V to 4.3V RSET LED4 CTRL LED3 LED2 LED1 ® - VIN (at 5mA typical) ~ 3.3V SP7611 Where VIN = Existing bus = 3.3V to 4.3V ENABLE ON/OFF GND Key Advantages 1) No boost circuit needed for the LCD or keyboard backlight - Analog 2) Drivers utilizes existing bus Set VCONTROL and RSET for LED current 3) Ultra-low voltage drop provides the full 20mA LED current at the lowest possible voltage level. ILED = 200 x (VCONTROL - VCNTR) / RSET Example 3: Drive white, blue red, amber LEDs string - PWM Assuming boost circuit, or existing voltage bus, the SP761X series of LED drivers can be used to drive a whole string of LEDs and flexible brightness control analog and/or PWM. VCONTROL = PWM V -Amplitude sets maximum LED current -Pulse width controls between 0 and maximum 2. SP7612 IN VIN ‘N’number of LEDs Per Branch I SET V CONTROL RSET LED4 CTRL LED3 LED2 I SET LED1 V CONTROL ® SP7611 ENABLE ON/OFF RSET LED1 ® SP7612 GND ENABLE Date: 6/30/04 LED3 LED4 CTRL SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 6 ON/OFF GND © Copyright 2004 Sipex Corporation APPLICATION INFORMATION 3. SP7614 - Analog VIN Set VCONTROL and RSET for LED current - PWM -1 I SET -ILED = 200 x (VCONTROL - VCTRL) / RSET VCONTROL -Amplitude sets maximum LED current RSET LED1 CTRL LED2 ® SP7614 -Pulse width controls between 0 and maximum ENABLE ON/OFF VSS - PWM -2 Set VCONTROL and RSET for LED current - Analog ILED ~ 200 x ISET Set VCONTROL and RSET for LED current ON/OFF = PWM ILED = 200 x (VCONTROL - VCTRL) / RSET -Amplitude has no effect on current - PWM - 1 -Pulse width controls between 0 and maximum -Amplitude sets maximum LED current -Pulse width controls between 0 and maximum - PWM - 2 Set VCONTROL and RSET for LED current ILED ~ 200 x ISET ON/OFF = PWM -Amplitude has no effect on current -Pulse width controls between 0 and maximum Date: 6/30/04 SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 7 © Copyright 2004 Sipex Corporation PACKAGE: 6 PIN SC-70 D e1 N N/2 +1 H E/2 E1/2 B E E1 B 1 INDEX AREA (D/2 X E1/2) 2 SEE VIEW C N/2 e Ø1 b Gauge Plane Seating Plane 4X Ø1 L Ø L2 L1 VIEW C Dimensions in (mm) A - A1 0 - 0.10 A2 0.70 0.90 1.00 b 0.15 - 0.30 c 0.08 - 0.22 - A2 A 1.10 A1 D 2.00 BSC E 2.10 BSC E1 1.25 BSC L Date: 6/30/04 6 PIN SC-70 JEDEC MO-203 (AB) Variation MIN NOM MAX 0.26 0.36 SIDE VIEW b WITH PLATING c 0.46 L1 0.42 REF L2 0.15 BSC BASE METAL Ø 0º 4º 8º Ø1 4º - 12º 6 PIN SC-70 SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 8 © Copyright 2004 Sipex Corporation ORDERING INFORMATION Part Number Temperature Range Package Type SP7611AEC6 .............................................. -40°C to +85°C ......................................................... 6 Pin SC-70 SP7611AEC6/TR ........................................ -40°C to +85°C ......................................................... 6 Pin SC-70 SP7612EC6 ................................................ -40°C to +85°C ......................................................... 6 Pin SC-70 SP7612EC6/TR .......................................... -40°C to +85°C ......................................................... 6 Pin SC-70 SP7614EC6 ................................................ -40°C to +85°C ......................................................... 6 Pin SC-70 SP7614EC6/TR .......................................... -40°C to +85°C ......................................................... 6 Pin SC-70 Available in lead free packaging. To order add "-L" suffix to part number. Example: SP7614EC6/TR = standard; SP7614EC6-L/TR = lead free /TR = Tape and Reel Pack quantity is 2500 for SC70. Corporation ANALOG EXCELLENCE Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600 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. Date: 6/30/04 SP7611A/7612/7614 Low Dropout LED Driver for Any Color LED 9 © Copyright 2004 Sipex Corporation