RT9301GJ8

RT9301 3-Channel Low Dropout RGB LED Driver General Description Features The RT9301 is a 3-Channel current source driver for RGB LED. It is easy to be designed in applications that need mixing RGB light source for multi-color output. z Input Voltage Range : 2.8V to 5.5V z Low 60/45mV Dropout at 20/15mA Individual Current Setting by External Resistor Individual On/Off Control by Baseband MPU Up to 50mA LED Bias Current Simple LED Brightness Control 5%(max.) LED Current Matching Low 0.1uA Shutdown Current UVLO Protection RoHS Compliant and 100% Lead (Pb)-Free z z z z z z z Applications z Ordering Information z RT9301 z WDFN-8L 3x3 is in W-Type z Richtek products are : 8 7 6 5 2 3 4 RoHS compliant and compatible with the current require- ` Suitable for use in SnPb or Pb-free soldering processes. LED3 ments of IPC/JEDEC J-STD-020. TSOT-23-8 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. GND ` ISET2 z (TOP VIEW) ISET3 Note : Pin Configurations ISET1 Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) z VIN Package Type J8 : TSOT-23-8 QW : WDFN-8L 3x3 (Green Only) Mobile phone, Smart Phone Multi-color LED Backlight Camera Flash White LED LCD Display Modules Keypad Backlight LED1 The RT9301 features very low dropout and under voltage lockout protection. It is available in a space-saving TSOT-23-8 and WDFN-8L 3x3 packages. LED2 The RT9301 also provide users with great flexibility and device performance. It uses externals resistor to set the bias current for three LEDs, which are matched to 5%(max.). Users can adjust the output current from 2mA to 50mA by setting the ISET resistor. z LED2 LED1 ISET1 ISET2 1 2 8 GND 6 3 4 7 9 5 LED3 GND VIN ISET3 WDFN-8L 3x3 DS9301-05 April 2011 www.richtek.com 1 RT9301 Typical Application Circuit VBAT ON OFF VIN LED1 RSET1 VSET1 ISET2 RSET3 VSET3 LED2 LED3 ISET1 R SET2 VSET2 GPIO 1uF RT9301 GND ISET3 Figure 1. Application circuit for RGB LED VBAT 1uF VIN RSET1 LED1 LED2 LED3 ISET1 RSET2 GPIO ISET2 RSET3 ISET3 RT9301 GND Figure 2. Application Circuit for Backlight VBAT 1uF RSET1 RSET2 GPIO RSET3 VIN LED1 LED2 LED3 ISET1 ISET2 ISET3 RT9301 GND Figure 3. Application Circuit for Keypad ILED1 ~ 3 = 800 x ISET1 ~ 3 = 800 x VSET 1 ~ 3 − 0.9V RSET1 ~ 3 GPIO (V) ILED (mA) 1.8 2.8 www.richtek.com 2 15 20 15 20 RSET (kΩ) Nearest Standard Values for RSET (kΩ) 48 36 101 76 47.5 36 100 75 DS9301-05 April 2011 RT9301 Function Block Diagram VIN ISET1 UVLO + VREF - ISET2 LED1 + VREF Current Source - LED2 LED3 ISET3 + VREF - GND Functional Pin Description Pin No. RT9301□J8 Pin Name Pin Function RT9301GQW RGB or White LED cathode connection pin. 2mA to 50mA C urrent 1 8 LED3 flows into LED. Floating or connection to ground is used to disable this pin. 2 7, Exposed Pad (9) GND Ground Pin. The exposed pad must be soldered to a large PCB and connected to GND for maximum pow er dissipation. 3 6 VIN Power Input Pin. 4 5 ISET3 Current setting for LED3. Connect to GND if not use. 5 4 ISET2 Current setting for LED2. Connect to GND if not use. 6 3 ISET1 Current setting for LED1. Connect to GND if not use. 7 2 LED1 RGB or White LED cathode connection pin. 2mA to 50mA C urrent flows into LED. Floating or connection to ground is used to disable this pin. 8 1 LED2 RGB or White LED cathode connection pin. 2mA to 50mA C urrent flows into LED. Floating or connection to ground is used to disable this pin. DS9301-05 April 2011 www.richtek.com 3 RT9301 Absolute Maximum Ratings l l l l l l l l l (Note 1) Supply Input Voltage ------------------------------------------------------------------------------------------------ −0.3V to 6V LED1,2,3 Pin Voltage ----------------------------------------------------------------------------------------------- −0.3V to VIN + 0.3V Other I/O Pin Voltages ---------------------------------------------------------------------------------------------- −0.3V to 6V Power Dissipation, PD @ TA = 25°C TSOT-23-8 ------------------------------------------------------------------------------------------------------------- 0.382W WDFN-8L 3x3 --------------------------------------------------------------------------------------------------------- 0.926W Package Thermal Resistance (Note 2) TSOT-23-8, θJA ------------------------------------------------------------------------------------------------------- 262°C/W WDFN-8L 3x3, θJA --------------------------------------------------------------------------------------------------- 108°C/W WDFN-8L 3x3, θJC --------------------------------------------------------------------------------------------------- 8.2°C/W Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 260°C Junction Temperature ----------------------------------------------------------------------------------------------- 150°C Storage Temperature Range --------------------------------------------------------------------------------------- −65°C to 150°C ESD Susceptibility (Note 3) HBM (Human Body Mode) ----------------------------------------------------------------------------------------- 2kV MM (Machine Mode) ------------------------------------------------------------------------------------------------ 200V Recommended Operating Conditions l l (Note 4) Junction Temperature Range -------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 3.6V, TA = 25°C, Unless Otherwise specification) Parameter Test Conditions Symbol Input Supply Voltage VIN UVLO Threshold VUVLO_L Falling UVLO Hysteresis Dropout Voltage Max Unit 2.8 -- 5.5 V 2 2.2 2.4 V -- 100 -- mV -- 40 120 mV 90% of ILED = 16mA 0.8 0.9 1 V IQ LED Open, ISET = 20 uA -- 0.5 1 mA ILED = 16mA −5 -- +5 % ILED = 16mA −5 -- +5 % All V SET1~3 < 0.25V -- 0.1 2 µA ILED Matching ILED Accuracy Typ VLED ISET Reference Voltage Quiescent Current Min ILED Shutdown current V SET Enable Threshold VSET VSET connect RSET = 47kΩ to ISET 1.3 -- -- V V SET Disable Threshold VIL VSET connect RSET = 47kΩ to ISET -- -- 0.25 V Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The case point of θJC is on the expose pad for the WDFN package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. www.richtek.com 4 DS9301-05 April 2011 RT9301 Typical Operating Characteristics LED Current vs. Input Voltage LED Current vs. VSET 25 60 Vf1 = 3.02V, Vf2 = 3.06V, Vf3 = 3.17V RSET = 36k LED1 LED2 LED Current (mA) 20 LED Current (mA) RSET = 51k RSET = 75k 50 15 LED3 10 5 40 30 RSET = 160k 20 RSET = 360k 10 0 0 2 2.5 3 3.5 4 4.5 5 5.5 1 1.5 2 2.5 3 3.5 4 4.5 Input Voltage (V) VSET (V) LED Current vs. Temperature Dimming Operation 20.4 5 5.5 VBAT = 5.0V ILED = 20mA 20.3 LED Current (mA) (1V/Div) 20.2 VSET 20.1 20 (10mA/Div) 19.9 19.8 ILED 19.7 -40 -25 -10 5 20 35 50 65 80 95 Time (100μs/Div) Temperature (°C) Enable & Shutdown Response Line Transient Response VBAT = 5.0V VBAT = 3.7V to 4.2V, ILED = 20mA (1V/Div) (1V/Div) VSET (10mA/Div) VIN (10mA/Div) I LED ILED Time (50μs/Div) DS9301-05 April 2011 Time (50μs/Div) www.richtek.com 5 RT9301 Applications Information The RT9301 is a 3-Channel current source driver for RGB LED or white LEDs. The output current can be controlled from 2mA to 50mA by adjusting the setting current from external. It is easy to support a multi-color RGB LED. The LED current of each channel can be controlled from 2mA to 50mA. It is easy to obtain a multi-color output by changing the current of ISET1, ISET2, and ISET3 respectively. 60 Input UVLO VSET2 VSET3 RSET1 RSET2 RSET3 RSET = 75k 40 30 RSET = 160k 20 RSET = 360k 10 1 The LED current is setting by the current of ISET pin. The LED current of the three channels (LED1, LED2, LED3) could be set from the ISET (ISET1, ISET2, ISET3) pins individually. The typical application circuit shows as Figure 1. VSET1 RSET = 51k 0 Output Current Setting VBAT RSET = 36k 50 LED Current (mA) The input operating voltage range of the RT9301 is 2.8V to 5.5V. An input capacitor at the VIN pin could reduce ripple voltage. It is recommended to use a ceramic 1uF or larger capacitance as the input capacitor. This IC provides an under voltage lockout (UVLO) function to prevent it from unstable issue when startup. The UVLO threshold of input falling voltage is set at 2.1V typically with a hysteresis 0.1V. 1uF VIN LED1 LED2 LED3 ISET1 ISET2 ISET3 RT9301 GND 1.5 2 2.5 3 3.5 4 4.5 5 5.5 V SET (V) Figure 2. LED Current Setting Figure 2 shows the characteristics of ILED vs. VSET . If the RSET is selected, the LED current could be controlled from VSET . The voltage of VSET must be higher than 1.3V to enable the LED. For low LED current application, it is recommended to use a higher resistance on RSET (for example: RSET = 360kΩ). To disable the LED current, the ISET pin should be connected to ground or floating. For one LED or two LEDs application, the unused ISET pin should be connected to GND. In addition, don’ t short VSETx to ISETx pin. Figure 1. Typical Application Circuit VBAT The LED current can be controlled from an external voltage (VSET ) and a resistor (RSET ) between VSET and ISET pin. The voltage range of VSET is from 1.3V to 5.5V. The internal reference voltage at ISET pin is 0.9V typically. LED current is set as 800 times the current flowing into ISET pin. Therefore, the LED current can be calculated as the following equation. ILED1 ~ 3 = 800 x ISET1 ~ 3 = 800 x VSET1 VSET2 RSET1 RSET2 1uF VIN LED1 LED2 LED3 ISET1 ISET2 ISET3 RT9301 GND VSET1 ~ 3 - 0.9V RSET1 ~ 3 Figure 3. Application Circuit for Two LEDs For example, RSET1 = 45kΩ and VSET1 = 1.8V, the current of LED1 is equal to 16mA. www.richtek.com 6 DS9301-05 April 2011 RT9301 GPIO Control Figure 4 shows an application circuit for backlight with GPIO. The three setting resistors are connected to GPIO. The LED current can be controlled by GPIO directly. The RT9301 provides low dropout voltage and 5% maximum current matching. It also allows dimming control frequency up to 10kHz. Figure 5 shows another application circuit for keypad backlight with GPIO. There are 9 LEDs operation in parallel. A battery or a regulated power source drives the LEDs. Each channel supports three LEDs. The LED brightness adjustment can be set with proper setting resistor for each channel and be controlled from GPIO. Thermal Considerations VBAT 1uF RSET1 VIN LED1 LED2 LED3 ISET1 RSET2 GPIO RSET3 ISET2 ISET3 RT9301 GND For continuous operation, do not exceed absolute maximum operation junction temperature 125°C. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = ( TJ(MAX) − TA ) / θJA Figure 4. Application Circuit for Backlight with GPIO The LED current can be set at different value with proper setting resistor. For typical application of GPIO 1.8V/2.8V and LED current 15mA/20mA, the recommended current setting resistors are showed as below table. Table 1. RSET Value Selection GPIO (V) 1.8 2.8 ILED (mA) RSET Nearest Standard Values for (kΩ) RSET (kΩ) 15 48 47.5 20 36 36 15 101 100 20 76 75 For recommended operating conditions specification of RT9301, where T J(MAX) is the maximum junction temperature of the die (125°C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance θJA is layout dependent. The thermal resistance θJA for TSOT-23-8 is 262°C/W, and WDFN-8L 3x3 is 108°C/W on the standard JEDEC 51-3 single-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : PD(MAX) = (125°C − 25°C) / (262°C/W) = 0.382W for TSOT-23-8 packages PD(MAX)) = (125°C − 25°C) / (108°C/W) = 0.926W for WDFN-8L 3x3 packages VBAT 1uF RSET1 GPIO Where T J(MAX) is the maximum operation junction temperature 125°C, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. RSET2 RSET3 The maximum power dissipation depends on operating ambient temperature for fixed TJ(MAX) and thermal resistance θJA. For RT9301 packages, the Figure 1 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. VIN LED1 LED2 LED3 ISET1 ISET2 ISET3 RT9301 GND Figure 5. Application Circuit for Keypad Backlight DS9301-05 April 2011 www.richtek.com 7 RT9301 Maximum Power Dissipation (W) 1 All the traces of LED and V IN running from chip to LEDs should be wide and short to reduce the parasitic connection resistance. Single Layer PCB 0.9 0.8 0.7 Input capacitor (C IN) should be placed close to LEDs Pin and connected to ground plane. The Anodes of LEDs must connect to C IN , not battery directly. WDFN-8L 3x3 0.6 0.5 0.4 TSOT-23-8 0.3 0.2 Battery 0.1 0 0 25 50 75 100 LED3 1 8 LED2 GND 2 7 LED1 VIN 3 6 ISET1 ISET3 4 5 ISET2 125 Ambient Temperature (°C) Ground Plane Figure 6. Derating Curves for RT9301 Packages The GND should be connected to a strong ground plane for heat sinking and noise protection. Layout Consideration For best performance, careful PCB layout is necessary. Place all peripheral components as close to the IC as possible. A short connection is highly recommended. The following guidelines should be strictly followed when designing a PCB layout for the RT9301. Figure 7. ecommended PCB Layout of TSOT-23-8 Package All the traces of LED and VIN running from chip to LEDs should be wide and short to reduce the parasitic connection resistance. 1. All the traces of LED and VIN pin running from chip to LEDs should be wide and short to reduce the parasitic connection resistance. 2. Input capacitor (CIN) must be placed close to LEDs and connected to ground plane. The anodes of LEDs must be connected to CIN, not battery directly. LED2 1 8 LED3 LED1 2 7 GND ISET1 ISET2 3 6 4 5 VIN ISET3 Input capacitor (CIN) should be placed close to LEDs Pin and connected to ground plane. The Anodes of LEDs must connect to CIN, not battery directly. Battery 3. Current setting resistors RSET should be placed as close to the chip as possible. 4. The GND should be connected to a strong ground plane for heat sinking and noise protection. 5. The current setting resistors should be placed as close to the IC as possible. www.richtek.com 8 Grand Plane The GND should be connected to a strong ground plane for heat sinking and noise protection. Figure 8. Recommended PCB Layout of WDFN-8L 3x3 Package DS9301-05 April 2011 RT9301 Outline Dimension H D L C B b A A1 e Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 1.000 0.028 0.039 A1 0.000 0.100 0.000 0.004 B 1.397 1.803 0.055 0.071 b 0.220 0.380 0.009 0.015 C 2.591 3.000 0.102 0.118 D 2.692 3.099 0.106 0.122 e 0.585 0.715 0.023 0.028 H 0.080 0.254 0.003 0.010 L 0.300 0.610 0.012 0.024 TSOT-23-8 Surface Mount Package DS9301-05 April 2011 www.richtek.com 9 RT9301 D2 D L E2 E 1 e SEE DETAIL A b 2 1 2 1 A A1 A3 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.200 0.300 0.008 0.012 D 2.950 3.050 0.116 0.120 D2 2.100 2.350 0.083 0.093 E 2.950 3.050 0.116 0.120 E2 1.350 1.600 0.053 0.063 e L 0.650 0.425 0.026 0.525 0.017 0.021 W-Type 8L DFN 3x3 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: marketing@richtek.com Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. www.richtek.com 10 DS9301-05 April 2011