PRELIMINARY FEAURES LED Drivers for parallel connected LEDs Ultra Low Dropout Voltage of 0mV () No EMI, no switching noise Integrated current matching PWM and Analog brightness control Enable/Shutdown control Shutdown current < µa Small footprint SC-70 Package,, Low Dropout LED Driver for any Color LED P/N Channels Steady State Current Per LED 4 40mA 3 40mA 80mA Pin SC70 APPLICAIONS Next Generation Mobile Phones PDA, DSC, MP3 players Handheld Computers LCD Display Modules Keyboard Backlight LED Displays DESCRIPION he SP7X driver family provides a simple solution for a matched current source any color LED. he current in the LEDs can be programmed by an external resistor. he Individual LED currents are 00 x ISE, where ISE is the current through the external resistor connected to the pin. he is capable of driving four LEDs, while the can drive three LEDs. he is designated to drive two high current LEDs. should always be connected to an LED in order to have the other LEDs driven with a matched current to. he SP7 /A and have Enable pins. When these devices are disabled, the supply current drops to 0.0µA typical. he SP7X driver family is available in a small footprint -pin SC-70 package. YPICAL APPLICAION SCHEMAIC N/C 3 4 Now Available in Lead Free Packaging V CONROL I SE R SE ENABLE
ABSOLUE MAXIMUM RAINGS hese 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. V, V, V LED3, V LED4 and EN Voltage to...-0.3v to V Voltage to....0.v Output Current (I OU )...40mA Power Dissipation per Package - -pin SC-70 at A =8 C...90mW Junction emperature...+0 C Storage emperature... - C to +0 C ESD Level...4kV HBM ESD Level...kV CDM ELECRICAL CHARACERISICS Specifications are at A = C, = 3.3 to., ENABLE =, denotes the specifications which apply over the full operating temperature range, unless otherwise specified. PARAMEER P / N M IN. YP. MAX. UNIS LED Cathode Voltage 0.3 0. 0. V Ambient emperature -40 0 8 º C PARAMEER P / N M IN. YP. MAX. UNIS CONDIIONS Output Current Multiplication Ratio (Note ) LED Current I Per Diode) L ED ( 40 00 0 I SE V LED = 00µ A = 300mV I = 00µ A SE = 0mV V LED 0 ma I = 00µ A SE = 0mV I SE V LED V LED = 00µ A = 300mV Output Current Multiplication Ratio in Saturation /A 3 43 0 I = µ A SE V LED =.V SP74A 730 870 00 LED to LED Current Matching -3 0. 8 3 % No Load Peak Efficiency 90 % Current in OFF Mode 0.0 µ A V EN = 0V Min. ENABLE "ON Voltage" (Note ) 3 V I SE = = 3V 0µ A Max. ENABLE "OFF Voltage" (Note ) 0. V Note : Output current Multiplication Ratio (I LED /I SE ) is not linear. For actual ratio and I LED please refer to typical performance characteristics @ page 4 and page. Note : ENABLE "ON" is V where I > 0mA @ V = 0.3V. ENABLE "OFF" is V where I < µa @ V > 0.3V.
PIN DESCRIPION Pin No. PIN NAME DESCRIPION Sets LED Current Connect to Cathode of LED 3 NC Connect to Cathode of LED 4 Ground LED4 LED3 Connect to Cathode of LED LED3 Connect to Cathode of LED Chip /Disable Device Shutdown LED Current SP7 / SP74 Active SHDN he LED current in Shutdown mode is controlled by the EN pin, or cathode voltage. LED current fall time is typically 0.µs. SP7A / SP74A Passive SHDN he LED current in Shutdown mode is only controlled by the EN pin, and is independent of cathode voltage. LED current fall time is typically.µs. PINOU 3 3 Pin SC70 Pin SC70 4 LED4 LED3 4 LED3 N/C 3 Pin SC70 4 3
SP74 YPICAL PERFORMANCE CHARACERISICS Set Current (µa) SP74 ISE versus Voltage - Vcathode=V 00.0 80.0 0.0 40.0 00.0 80.0 0.0 40.0 0.0 0.00 0.0 0.40 0.0 0.80.00.0.40.0.80 Pin Voltage (V) SP74 LED Current versus Enable Voltage 8.0.0 4.0.0 0.0 8.0.0 4.0.0 0.0 0.0 0. 0.4 0. 0.8.0..4..8.0..4..8 3.0 VEN Voltage (V) 8.0.0 4.0.0 0.0 8.0.0 4.0.0 SP74 ILED vs Set Resistor and Cathode Voltage (Vcontrol = 3V) Vk=00mV Vk=0mV Vk=00mV Vk=0mV Vk=300mV Vk=0mV 0 0 30 40 0 0 70 80 90 00 Set Resistor (kohms) SP74 LED Current Vs emperature 30 Iset = 00uA, Vcathode = 0mV 0 0 0-40 - 0 3 0 8 emperature ( C) SP74 LED Current vs. LED Cathode Voltage 3 30 0 0 For Iset = 0uA For Iset = ua 0 0. 0.4 0. 0.8 LED Cathode Voltage (V) Control Voltage ransient Response Enable Voltage ransient Response [ ] [ ] Voltage LED Current (V/div) (0mA/div) ENABLE Voltage LED Current (V/div) (0mA/div) ime (µs/div) ime (µs/div) 4
SP74A YPICAL PERFORMANCE CHARACERISICS Set Current (µa) SP74A Current versus Voltage (Vcontrol = open) Iset (ua) 00.0 80.0 0.0 40.0 00.0 80.0 0.0 40.0 0.0 0.00 0.0 0.40 0.0 0.80.00.0.40.0.80 Pin Voltage (V) SP74A LED Current versus LED Cathode Voltage Iset=uA Iset=0uA 4.0 40.0 3.0 30.0.0.0 0.0.0 0.0 0.0 0. 0. 0.3 0.4 0. 0. 0.7 0.8 0.9.0...3.4 Cathode Voltage (V) SP74A ILED vs Set Resistor and Cathode Voltage - VCONROL=3V Vk=00mV Vk=0mV Vk=300mV 8.0 Vk=0mV.0 4.0.0 Vk=00mV 0.0 8.0.0 Vk=0mV 4.0.0 0 0 30 40 0 0 70 80 90 00 Set Resistor (k Ohms) 9.0 7.0.0 3.0.0 9.0 7.0.0 3.0.0 -.0 SP74A LED Current versus Enable Voltage, Vk=0mV ILED (ma) 0.0 0. 0.4 0. 0.8.0..4..8.0..4..8 3.0 VEN Voltage (V) I (ua) 00.0 90.0 80.0 70.0 0.0 0.0 40.0 30.0 0.0 0.0 I (ua) Control Voltage ransient Response Enable Voltage ransient Response LED Voltage LED Current (V/div) (0mA/div) [ ] Voltage LED Current (V/div) (0mA/div) [ ] Voltage (V/div) ime (µs/div) ENABLE Voltage (V/div) ime (µs/div)
APPLICAION INFORMAION SEING HE LED CURREN he current flowing into LEDs is approximately 00 times greater than the current I SE. he LED current is controlled by I CONROL and R SE according to the following formula : I LED = 00 X (V CONROL - V ) / R SE For V CONROL = 3V and a specified LED current, the R SE value can be evaluated using the diagram shown in the ypical Performance Characteristics section. For any other option, I SE vs. V. he LED's brightness can also be adjusted by driving ENABLE or the pin with a PWM signal. he driving signal frequency should be greater than 00Hz to avoid flickering, increasing to more than MHz, if necessary. LEDs are very sensitive to temperature. In most cases the maximum allowed junction temperature is 00ºC. he over temperature due to power dissipation is described by the following: j = A + Ø ja x I xv F where j is the LED junction temperature, A is the ambient temperature, Ø ja is the junction to ambient thermal resistance, I is the LED current and V F is the LED forward voltage. When the temperature rises and the cathode voltage increases, SP7X reduces the current through LEDs. Refer to "LED Current vs. LED Cathode Voltage" graph under the ypical Performance Characteristics section. APPLICAION NOES he ultra-low voltage drop across the SP7X series of LED drivers, allows the devices to drive white, blue, and other color LEDs in a wide range of input voltages. he driver can be used in many applications. Any of the SP7X series of LED drivers can be used in the applications presented in this document, due to their similar operation. Example : Drive low V F white or blue LEDs directly from single cell Li-ion When using white or blue low V F LEDs, and utilizing the drivers low voltage drop, only 3.4V in is needed for the full 0mA LED current. At 3.V, there is still ma typical current available for the LEDs. he single cell Liion 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, and not down to the full discharge level (.7V) before requesting the charger. V CONROL I SE LED4 LED3 R SE he SP7X driver's low dropout architecture can significantly improve the efficiency compared to using simple ballast resistors. he system efficiency, defined as the ratio between the LEDs power and the input supplied power can be calculated as follows: Efficiency = ( - V CAHODE) / he lower the V CAHODE, the higher the system efficiency. Efficiency can be further improved using a higher with more LEDs as shown in example 3. - DROP < 0.3V - V F (at 0mA) < 3.V (Low V F ) - (at 0mA) < - V DROP +V F = 3.4V - (at ma typical) ~ 3.V Key Advantages ) No boost circuit needed for the LCD or keyboard backlight ) Drivers directly connected to a Li-ion battery 3) No EMI, no switching noise, no boost efficiency lost, no capacitor, and no inductor
APPLICAION INFORMAION Example : Drive high V F white or blue LEDs from existing bus from 4.0V to.v High V F LEDs have a forward voltage drop in the range of 3.V to 4.0V. In order to drive these LEDs with the maximum current of 0mA enabling maximum brightness, usually requires a boost circuit for a single cell Liion power supply. he ultra-low voltage drop of the SP7X series is capable of driving high V F white or blue LEDs with its ultra-low dropout feature. he needs to be only 300mV higher than the highest V F in the circuit. - V DROP < 0.3V - _MIN = N x V F + V DROP - _MIN = N x V F +.V Where = Existing bus, boost Voltage Key Advantages ) No need for current matching resistors and discrete transistors for brightness control. LED Brightness Control he SP7X LED Drivers feature analog and PWM controls to give designers flexible brightness control. o determine the value of R SE, use the "I SE vs. V CRL" graph under the ypical Performance Characteristics. V CONROL I SE LED4 LED3 R SE. - DROP < 0.3V - V F (at 0mA) < 3.3V to 4.0V (High V F ) - (at 0mA) = V DROP +V F = 3.V to 4.3V - (at ma typical) ~ 3.3V Where = Existing bus = 3.3V to 4.3V Key Advantages ) No boost circuit needed for the LCD or keyboard backlight ) Drivers utilizes existing bus 3) Ultra-low voltage drop provides the full 0mA LED current at the lowest possible voltage level. Example 3: Drive white, blue red, amber LEDs string In a boost circuit, or existing voltage bus, the SP7X series of LED drivers can be used to drive a whole string of LEDs and flexible brightness control - analog and/or PWM. I SE LED4 LED3 V CONROL 3V R SE - Analog Set V CONROL and R SE for LED current I LED = 00 x (V CONROL - V CNR ) / R SE - PWM V CONROL = PWM -Amplitude sets maximum LED current -Pulse width controls between 0 and maximum. SP7 N number of LEDs Per Branch V CONROL I SE R SE LED4 LED3 V CONROL I SE R SE ENABLE LED4 LED3 7
APPLICAION INFORMAION - Analog Set V CONROL and R SE for LED current 3. SP74 - PWM - -I LED = 00 x (V CONROL - V ) / R SE -Amplitude sets maximum LED current -Pulse width controls between 0 and maximum - PWM - Set V CONROL and R SE for LED current I LED ~ 00 x I SE = PWM -Amplitude has no effect on current -Pulse width controls between 0 and maximum I SE V CONROL R SE ENABLE VSS - Analog Set V CONROL and R SE for LED current I LED = 00 x (V CONROL - V ) / R SE - PWM - -Amplitude sets maximum LED current -Pulse width controls between 0 and maximum - PWM - Set V CONROL and R SE for LED current I LED ~ 00 x I SE = PWM -Amplitude has no effect on current -Pulse width controls between 0 and maximum 8
PACKAGE: PIN SC-70 D e N N/ + E E/ E/ E B B H SEE VIEW C INDEX AREA (D/ X E/) e N/ Ø b Gauge Plane Seating Plane 4X Ø L L VIEW C Ø L Dimensions in (mm) A PIN SC-70 JEDEC MO-03 (AB) Variation MIN NOM MAX - -.0 A A A A 0-0.0 0.70 0.90.00 A SIDE VIEW b 0. - 0.30 c 0.08-0. WIH PLAING b D.00 BSC E.0 BSC E. BSC c L L L Ø Ø 0. 0.3 0.4 0.4 REF 0. BSC 0º 4º 8º 4º - º BASE MEAL PIN SC-70 9
ORDERING INFORMAION Part Number emperature Range Package ype EC... -40 C to +8 C... Pin SC-70 EC/R... -40 C to +8 C... Pin SC-70 SP7EC... -40 C to +8 C... Pin SC-70 SP7EC/R... -40 C to +8 C... Pin SC-70 SP7AEC... -40 C to +8 C... Pin SC-70 SP7AEC/R... -40 C to +8 C... Pin SC-70 SP74EC... -40 C to +8 C... Pin SC-70 SP74EC/R... -40 C to +8 C... Pin SC-70 SP74AEC... -40 C to +8 C... Pin SC-70 SP74AEC/R... -40 C to +8 C... Pin SC-70 Available in lead free packaging. o order add "-L" suffix to part number. Example: SP74EC/R = standard; SP74EC-L/R = lead free /R = ape and Reel Pack quantity is 00 for SC70. Corporation ANALOG EXCELLENCE Sipex Corporation Headquarters and Sales Office 33 South Hillview Drive Milpitas, CA 903 EL: (408) 934-700 FAX: (408) 93-700 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. 0