RT9953 4+1 CH Power Management IC General Description Features The RT9953 is a complete power supply solution for digital still cameras and other handheld devices. The RT9953 is a multi-CH power management IC including one synchronous step-up DC/DC converter, one selectable synchronous step-up/step-down DC/DC converter, two synchronous step-down DC/DC converters, and one low dropout linear regulator. z One Synchronous Step-Up/Step-Down Selectable Converter z Support 2AA or Li-ion Battery Applications Internal Soft-Start Control 4 CHs with Internal Compensation Power Switches Integrated Up to 95% Efficiency 100% (max) Duty Cycle for Step-Down Converter Adjustable Output Voltage Fixed 1MHz Switching Frequency LDO Works with Low-ESR Ceramic Capacitors Fast Line/Load Transient Response High PSRR Linear Regulator RoHS Compliant and Halogen Free z z z z z z z z Applications z Package Type QW : WQFN-24L 4x4 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) Note : FB2 EN4 SEL 24 23 22 21 20 19 LX1 1 18 LX2 PVDD1 2 17 PVDD2 EN3 3 16 VDDM FB4 4 15 FB3 SS 5 14 EN2 PVDD4 6 13 PVDD3 GND 25 7 8 9 10 11 12 LX3 RT9953 (TOP VIEW) FB5 Ordering Information Pin Configurations PVDD5 The RT9953 provides over current protection, thermal shutdown protection, over voltage and under voltage protection to achieve complete protection. The RT9953 is available in the WQFN-24L 4x4 package. z CMOS Digital Still Camera CMOS DV Portable Devices FB1 The RT9953 is designed to support Li+ and 2AA battery applications. The selectable step-up/step-down converter can be set by SEL pin. For the synchronous step-up and step down converters, the efficiency can be up to 95%. z LX4 CH5 is a 500mA, low dropout, low noise linear regulator with soft-start function. GND CH3 and CH4 are synchronous step-down outputs for DSP core and memory power supply z EN5 CH2 is a selectable synchronous step-up/step-down output for motor or DSC system I/O power z VOUT5 CH1 is a synchronous step-up output for motor or DSC system I/O power EN1 The RT9953 is designed to fulfill the applications for DSC as follows : z WQFN-24L 4x4 Richtek products are : ` RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. DS9953-02 April 2011 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. www.richtek.com 1 RT9953 Typical Application Circuit For 2AA RT9953 L2 2.2µH V BAT 18 LX2 LX1 1 L1 2.2µH V BAT C4 10µF V OUT_CH2 5V C1 10µF 17 PVDD2 C5 10µF x 2 PVDD1 2 R3 470k C3 4.7pF 21 FB2 FB1 VOUT_CH4 1.8V C11 10µF R2 133k 6 PVDD4 C10 10µF R7 470k L4 4.7µH 7 LX4 V BAT LX3 12 C16 1µF Chip Enable 3.6V C7 10µF L3 4.7µH C9 22pF 19 16 3.6V FB4 R5 768k C8 10µF V OUT_CH3 2.5V FB3 15 R6 360k SEL VDDM 24 EN1 14 EN2 3 EN3 20 EN4 8 EN5 23, 25 (Exposed Pad) GND www.richtek.com 2 PVDD3 13 C12 33pF 4 R8 374k R1 470k V OUT_CH1 3.6V 22 R4 88.7k 3.6V C2 10µF x 2 PVDD5 11 3.6V C13 1µF VOUT5 9 C15 10pF FB5 R9 47k C14 1µF V OUT_CH5 2.5V 10 SS 5 C17 0.47nF R10 22.1k DS9953-02 April 2011 RT9953 For Li-ion RT9953 17 PVDD2 VBAT or 5V C4 10µF V OUT_CH2 3.3V C5 10µF R3 470k L2 2.2µH LX1 1 L1 2.2µH V BAT C1 10µF 18 LX2 PVDD1 2 C3 4.7pF C6 10pF 21 FB2 FB1 R2 88.7k 6 PVDD4 V BAT VOUT_CH4 1.8V C11 10µF R7 470k L4 4.7µH 7 LX4 PVDD3 13 R8 374k C9 22pF 19 16 5V C16 1µF Chip Enable V BAT C7 10µF L3 4.7µH LX3 12 C12 33pF 4 FB4 VDDM 24 EN1 14 EN2 R5 768k C8 10µF V OUT_CH3 2.5V FB3 15 R6 360k SEL 3 EN3 20 EN4 8 EN5 23, 25 (Exposed Pad) GND PVDD5 11 V BAT C13 1µF VOUT5 9 C15 10pF FB5 R9 47k C14 1µF V OUT_CH5 2.5V 10 SS 5 C17 0.47nF DS9953-02 April 2011 R1 470k V OUT_CH1 5V 22 R4 150k C10 10µF C2 10µF x 2 R10 22.1k www.richtek.com 3 RT9953 Table 1. Recommended Components for the Typical Application Circuit Channel CH3 Formula V OUT_CH3 = (1+R5/R6) x 0.8 VOUT_CH3 (V) 3.3 2.5 1.8 1.5 1.3 1.2 1.0 L3 (µH) 4.7 4.7 4.7 4.7 4.7 4.7 4.7 R5 (kΩ) 86.6 768 470 330 237 187 23.2 R6 (kΩ) 27.4 360 374 374 374 374 93.1 C9 (pF) 22 22 33 47 68 82 47 C8 (µF) 10 10 10 10 10 10 10 Channel CH4 Application V OUT_CH4 = (1+R7/R8) x 0.8 VOUT_CH4 (V) 3.3 2.5 1.8 1.5 1.3 1.2 1.0 L4 (µH) 4.7 4.7 4.7 4.7 4.7 4.7 4.7 R7 (kΩ) 86.6 768 470 330 237 187 23.2 R8 (kΩ) 27.4 360 374 374 374 374 93.1 C12 (pF) 22 22 33 47 68 82 47 C11 (µF) 10 10 10 10 10 10 10 Channel CH5 Formula V OUT_CH5 = (1+R9/R10) x 0.8 VOUT_CH5 (V) 2.5 R9 (kΩ) 47 R10 (kΩ) 22.1 C15 (pF) 10 C14 (µF) 1 www.richtek.com 4 DS9953-02 April 2011 RT9953 Functional Pin Description Pin No. Pin Name Pin Function 1 LX1 Switch Node of CH1. High impedance in shutdown mode. 2 PVDD1 Power Input of CH1. 3 EN3 Enable Control Input of CH3. 4 FB4 Feedback Input of CH4. High impedance in shutdown mode. 5 SS Soft-Start Control Input. 6 PVDD4 Power Input of CH4. 7 LX4 Switch Node of CH7. High impedance in shutdown mode. 8 EN5 Enable Control Input of CH5. 9 VOUT5 Output Voltage of CH5. 10 FB5 Feedback Input of CH5. High impedance in shutdown mode. 11 PVDD5 Power Input of CH5. 12 LX3 Switch Node of CH3. High impedance in shutdown mode. 13 PVDD3 Power Input of CH3. 14 EN2 Enable Control Input of CH2. 15 FB3 Feedback Input of CH3. High impedance in shutdown mode. 16 VDDM Analog Power Input. 17 PVDD2 Power Input of CH2. 18 LX2 19 SEL 20 EN4 Switch Node of CH2. High impedance in shutdown mode. Selection Input for CH2 step-up or step-down operation mode. Logic state can not be changed during operation. Enable Control Input of CH4. 21 FB2 Feedback Input of CH2. High impedance in shutdown mode. 22 FB1 23, GND 25 (Exposed Pad) 24 EN1 DS9953-02 April 2011 Feedback Input of CH1. High impedance in shutdown mode. Ground Pin. The exposed pad must be soldered to a large PCB and connected to GND for maximum thermal dissipation. Enable Control Input of CH1. www.richtek.com 5 RT9953 Function Block Diagram VDDM PVDD2 PVDD1 CH2 C-Mode Step-Up or Step-Down LX2 CH1 C-Mode Step-Up + FB2 LX1 + 0.8V REF FB1 0.8V REF PVDD4 PVDD3 CH4 C-Mode Step-Down LX4 CH3 C-Mode Step-Down + FB4 0.8V REF LX3 + FB3 0.8V REF VDDM Enable Mode Sequence PVDD5 SS CH5 LDO VOUT5 EN1 EN2 EN3 EN4 EN5 SEL www.richtek.com 6 + FB5 0.8V REF GND DS9953-02 April 2011 RT9953 Absolute Maximum Ratings (Note 1) Supply Voltage, VDDM, PVDD5 -------------------------------------------------------------------------------------- 0.3V to 7V Power Switch : LX1, LX2, LX3, LX4------------------------------------------------------------------------------------------------------- −0.3V to 6.5V l The Other Pins ----------------------------------------------------------------------------------------------------------- −0.3V to 6.5V l Power Dissipation, PD @ TA = 25°C WQFN 24L 4x4 ----------------------------------------------------------------------------------------------------------- 1.852W l Package Thermal Resistance (Note 2) WQFN 24L 4x4, θJA ----------------------------------------------------------------------------------------------------- 54°C/W WQFN 24L 4x4, θJC ----------------------------------------------------------------------------------------------------- 7°C/W l Junction Temperature --------------------------------------------------------------------------------------------------- 150°C l Lead Temperature (Soldering, 10 sec.)------------------------------------------------------------------------------ 260°C l Storage Temperature Range ------------------------------------------------------------------------------------------- −65°C to 150°C l ESD Susceptibility (Note 3) HBM (Human Body Mode) --------------------------------------------------------------------------------------------- 2kV MM (Machine Mode) ---------------------------------------------------------------------------------------------------- 200V l l 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 (VDDM = 3.3V, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ M ax Unit Supply Voltage VDDM Operating Voltage V DDM 2.7 -- 5.5 V VDDM Startup Voltage V ST 1.5 -- -- V 5.7 6 6.25 V 2.5 -- 5.5 V VDDM Over Voltage Protection PVDD5 Operating Voltage V PVDD5 Supply Current Shutdown Supply Current into VDDM CH1 (Syn Step-Up) : Supply Current into VDDM IOFF All EN = 0 -- -- 0.1 µA IQ1 Non Switching, EN1 = 3.3V -- -- 800 µA IQ2 Non Switching, EN2 = 3.3V -- -- 800 µA IQ3 Non Switching, EN3 = 3.3V -- -- 800 µA IQ4 Non Switching, EN4 = 3.3V -- -- 800 µA IQ5 EN5 = 3.3V, IOUT = 0mA -- 90 130 µA CH2 (Syn Step-Up or Syn Step-Down) : Supply Current into VDDM CH3 (Syn Step-Down) : Supply Current into VDDM CH4 (Syn Step-Down) : Supply Current into VDDM CH5 (LDO) : Supply Current into PVDD5 To be continued DS9953-02 April 2011 www.richtek.com 7 RT9953 Parameter Min Typ Max Unit VFB1 = 0.7V 900 80 1000 83 1100 86 kHz % CH2 Maximum Duty Cycle (Step-Up) VFB2 = 0.7V 80 83 86 % CH2 Maximum Duty Cycle (Step-Down) VFB2 = 0.7V -- -- 100 % VFB3 = 0.7V -- -- 100 % VFB4 = 0.7V -- -- 100 % 0.788 0.8 0.812 V −3 -- 3 % P-MOSFET, PVDD1 = 3.3V -- 200 250 N-MOSFET, PVDD1 = 3.3V -- 150 200 Oscillator CH1,2,3,4 Operating Frequency CH1 Maximum Duty Cycle (Step-Up) Symbol Test Conditions fOSC CH3 Maximum Duty Cycle (Step-Down) CH4 Maximum Duty Cycle (Step-Down) Feedback Regulation Voltage Feedback Regulation Voltage @ FB1, FB2, FB3, FB4, FB5 Total Accuracy (Including load regulation and line regulation) Power Switch CH1 On Resistance of MOSFET RDS(ON) CH1 Current Limitation (Step-Up) mΩ -- 3 -- P-MOSFET, PVDD2 = 3.3V -- 200 250 N-MOSFET, PVDD2 = 3.3V -- 150 200 CH2 Current Limitation (Step-Down) -- 1.8 -- A CH2 Current Limitation (Step-Up) -- 3 -- A CH2 On Resistance of MOSFET CH3 On Resistance of MOSFET RDS(ON) R P-MOSFET, PVDD3 = 3.3V -- 350 400 DS(ON) N-MOSFET, PVDD3 = 3.3V -- 300 400 -- 1.5 -- CH3 Current Limitation (Step-Down) CH4 On Resistance of MOSFET mΩ mΩ A R P-MOSFET, PVDD4 = 3.3V -- 350 400 DS(ON) N-MOSFET, PVDD4 = 3.3V -- 300 400 -- 1.5 -- -- 160 320 V Dro p 2.2V ≦ PVDD5 ≦ 2.7V, IOUT = 400mA 2.7V ≦ PVDD5 ≦ 5.5V, IOUT = 500mA -- 250 400 5.7 6 6.25 V -- 0.5 -- V FB Threshold 0.36 0.4 0.44 V 2.2V ≦ PVDD5 ≦ 2.7V 0.4 0.7 1.05 2.7V ≦ PVDD5 ≦ 5.5V 0.5 0.8 1.05 -- 100 -- CH4 Current Limitation (Step-Down) CH5 Dropout Voltage (LDO) A mΩ A mV Protection Over Voltage Protection of CH1, CH2 Step-Up, PVDD1 and PVDD2 Over Voltage Protection Hysteresis of CH1, CH2 Step-Up, PVDD1 and PVDD2 Under Voltage Protection (CH1 to CH5) CH5 Current Limit Protection Fault Delay ILIM A ms To be continued www.richtek.com 8 DS9953-02 April 2011 RT9953 Parameter Symbol Test Conditions Min Typ Max Unit Control EN1 to EN5, SEL Logic High 1.3 -- 5.5 V Input Threshold Logic Low -- -- 0.4 V EN1 to EN5, SEL Sink Current -- 2 6 µA -- -- 0.3 % -- -- 0.6 % CH5 LDO Regulation V PVDD5 = (VOUT5 + 1V) to 5.5V Line Regulation ΔVLINE Load Regulation ΔVLOAD 1mA < IOUT < 300mA PSRR COUT = 1uF, IOUT = 100mA Power Supply f = 100Hz Rejection Rate f = 10kHz IOUT = 1mA -- −60 -- -- −30 -- 125 160 -- °C -- 20 -- °C dB Thermal Protection Thermal Shutdown T SD Thermal Shutdown Hysteresis ΔT SD 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 high effective four layers thermal conductivity test board of JEDEC 51-7 thermal measurement standard. The case point of θJC is on the expose pad for the WQFN package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS9953-02 April 2011 www.richtek.com 9 RT9953 Typical Operating Characteristics CH1 Step-Up Efficiency vs. Output Current CH1 Step-Up Efficiency vs. Output Current 100 100 VBAT VBAT VBAT VBAT VBAT VBAT Efficiency (%) 80 70 60 50 = = = = = = 90 4.5V 4.2V 3.9V 3.6V 3.3V 3V 80 Efficiency (%) 90 40 30 20 VBAT VBAT VBAT VBAT VBAT VBAT 70 60 50 40 30 VDDM = 3V, VOUT_CH1 = 5V, L1 = 2.2µH, C2 = 10µFx2 10 0 0 10 100 1000 10 100 Output Current (mA) CH2 Step-Up Efficiency vs. Output Current 100 90 90 80 80 70 70 VBAT VBAT VBAT VBAT VBAT VBAT 50 40 30 = = = = = = Efficiency (%) 100 60 1000 Output Current (mA) CH2 Step-Down Efficiency vs. Output Current Efficiency (%) 3.4V 3V 2.7V 2.5V 2.2V 1.8V 20 VDDM = 5V, VOUT_CH1 = 5V, L1 = 2.2µH, C2 = 10µFx2 10 1.8V 3V 3.3V 3.6V 4.2V 4.5V 20 VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 = = = = = = 3V 2.7V 2.5V 2.2V 2V 1.8V 30 20 VDDM = 5V, VOUT_CH2 = 1.2V, L2 = 4.7µH, C5 = 10µF 10 VDDM = 3V, VOUT_CH2 = 3.3V, L2 = 2.2µH, C5 = 10µFx2 10 0 0 10 100 10 1000 100 CH3 Step-Down Efficiency vs. Output Current CH3 Step-Down Efficiency vs. Output Current 100 100 90 90 80 80 VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 = = = = = = 2.7V 3.3V 3.6V 3.9V 4.2V 4.5V Efficiency (%) 70 1000 Output Current (mA) Output Current (mA) Efficiency (%) = = = = = = 30 20 70 VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 30 = = = = = = 1.8V 2.5V 3V 3.3V 3.6V 4.5V 20 VDDM = 5V, VOUT_CH3 = 1.8V, L3 = 4.7µH, C8 = 10µF 10 0 VDDM = 5V, VOUT_CH3 = 1.2V, L3 = 4.7µH, C8 = 10µF 10 0 10 100 Output Current (mA) www.richtek.com 10 1000 10 100 1000 Output Current (mA) DS9953-02 April 2011 RT9953 CH4 Step-Down Efficiency vs. Output Current CH4 Step-Down Efficiency vs. Output Current 100 100 90 90 Efficiency (%) 80 70 60 = = = = = 3.4V 3.6V 3.9V 4.2V 4.5V 80 Efficiency (%) VBAT VBAT VBAT VBAT VBAT 50 40 30 20 70 VBAT VBAT VBAT VBAT VBAT VBAT 60 50 40 30 = = = = = = 1.8V 2.5V 3V 3.3V 3.6V 4.5V 20 VDDM = 5V, VOUT_CH4 = 3.3V, L4 = 4.7µH, C11 = 10µF 10 VDDM = 3V, VOUT_CH4 = 1.2V, L4 = 4.7µH, C11 = 10µF 10 0 0 10 100 1000 10 100 Output Current (mA) 1000 Output Current (mA) CH1 Step-Up Output Voltage vs. Output Current CH2 Step-Down Output Voltage vs. Output Current 5.000 1.210 4.995 1.208 4.985 VBAT = 3V 4.980 VBAT = 4.5V 4.975 4.970 4.965 Output Voltage (V) Output Voltage (V) 4.990 1.205 1.203 1.200 VBAT = 3V VBAT = 4.5V 1.198 1.195 4.960 1.193 4.955 VDDM = 5V VDDM = 5V 4.950 1.190 0 100 200 300 400 500 600 0 200 Output Current (mA) 600 800 1000 CH3 Step-Down Output Voltage vs. Output Current 3.45 1.85 3.40 1.84 3.35 3.30 VBAT = 1.8V VBAT = 3V 3.20 Output Voltage (V) Output Voltage (V) CH2 Step-Up Output Voltage vs. Output Current 3.25 400 Output Current (mA) 1.83 1.82 VBAT = 4.5V VBAT = 3V VBAT = 2.7V 1.81 1.80 1.79 VDDM = 3V VDDM = 5V 1.78 3.15 0 100 200 300 400 Output Current (mA) DS9953-02 April 2011 500 600 0 100 200 300 400 500 600 Output Current (mA) www.richtek.com 11 RT9953 CH4 Step-Down Output Voltage vs. Output Current CH1 Output Voltage Ripple 3.50 Output Voltage (V) 3.45 3.40 LX1 (2V/Div) 3.35 VBAT = 4.5V VBAT = 5V 3.30 VOUT_CH1_ac (10mV/Div) 3.25 3.20 VDDM = 5V, VBAT = 3.7V, VOUT_CH1 = 5V, IOUT = 300mA, L1 = 2.2μH, C2 = 10μFx2 VDDM = 5V 3.15 0 100 200 300 400 500 Time (500ns/Div) 600 Output Current (mA) CH2 Step-Down Output Voltage Ripple CH2 Step-Up Output Voltage Ripple LX2 (2V/Div) LX2 (2V/Div) VOUT_CH2_ac (5mV/Div) VOUT_CH2_ac (10mV/Div) VDDM = 5V, VBAT = 3.7V, VOUT_CH2 = 1.2V, IOUT = 300mA, L2 = 2.2μH, C5 = 10μF VDDM = 3V, VBAT = 1.8V, VOUT_CH2 = 3.3V, IOUT = 300mA, L2 = 2.2μH, C5 = 10μFx2 Time (500ns/Div) Time (500ns/Div) CH3 Output Voltage Ripple CH4 Output Voltage Ripple LX3 (2V/Div) LX4 (2V/Div) VOUT_CH3_ac (5mV/Div) VOUT_CH4_ac (5mV/Div) VDDM = 5V, VBAT = 3.7V, VOUT_CH3 = 1.8V, IOUT = 300mA, L3 = 4.7μH, C8 = 10μF Time (500ns/Div) www.richtek.com 12 VDDM = 5V, VBAT = 4.2V, VOUT_CH4 = 3.3V, IOUT = 300mA, L4 = 4.7μH, C11 = 10μF Time (500ns/Div) DS9953-02 April 2011 RT9953 CH2 Step-Down Load Transient Response CH1 Load Transient Response I LOAD (200mA/Div) I LOAD (200mA/Div) V OUT_CH1_ac (100mV/Div) V OUT_CH2_ac (50mV/Div) VDDM = 5V, VBAT = 3.7V, VOUT_CH2 = 1.2V, IOUT = 100mA to 400mA, L2 = 2.2μH, C5 = 10μF VDDM = 5V, VBAT = 3V, VOUT_CH1 = 5V, IOUT = 100mA to 400mA, L1 = 2.2μH, C2 = 10μFx2 Time (1ms/Div) Time (1ms/Div) CH3 Load Transient Response CH2 Step-Up Load Transient Response I LOAD (200mA/Div) I LOAD (200mA/Div) V OUT_CH2_ac (100mV/Div) V OUT_CH3_ac (50mV/Div) VDDM = 3V, VBAT = 1.8V, VOUT_CH2 = 3.3V, IOUT = 100mA to 400mA, L2 = 2.2μH, C5 = 10μFx2 VDDM = 5V, VBAT = 3.7V, VOUT_CH3 = 1.8V, IOUT = 50mA to 300mA, L3 = 4.7μH, C8 = 10μF Time (1ms/Div) Time (1ms/Div) Frequency vs. Temperature CH4 Load Transient Response 1050 1030 Frequency (kHz) 1010 I LOAD (200mA/Div) V OUT_CH4_ac (50mV/Div) 990 970 950 930 910 890 VDDM = 5V, VBAT = 3.7V, VOUT_CH4 = 3.3V, IOUT = 50mA to 300mA, L4 = 4.7μH, C11 = 10μF 870 VDDM = 3V, VBAT = 3V 850 Time (1ms/Div) -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temperature (°C) DS9953-02 April 2011 www.richtek.com 13 RT9953 CH5 LDO Dropout Voltage vs. Output Current 0.45 2.54 0.40 2.53 0.35 2.52 2.51 2.50 VBAT = 3V VBAT = 4.5V 2.49 2.48 2.47 2.46 Dropout Voltage (V) Output Voltage (V) CH5 LDO Output Voltage vs. Output Current 2.55 0 100 200 300 400 500 25°C 0.30 0.25 −40°C 0.20 0.15 0.10 0.05 VDDM = 5V 2.45 90°C VDDM = 5V, C14 = 1μF 0.00 600 0 100 Output Current (mA) 200 300 400 500 Output Current (mA) CH5 LDO Load Transient Response CH5 LDO Output Voltage vs. Temperature 2.55 2.54 Output Voltage (V) 2.53 I LOAD (200mA/Div) V OUT_CH5_ac (10mV/Div) 2.52 2.51 2.50 VBAT = 4.5V 2.49 2.48 VBAT = 3V 2.47 VDDM = 5V, VBAT = 3.7V, VOUT_CH5 = 2.5V, IOUT = 1mA to 300mA, C14 = 1μF 2.46 2.45 Time (1ms/Div) VDDM = 5V, C14 = 1μF, IOUT = 300mA -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temperature (°C) CH5 LDO PSRR 0 CH5 LDO IPVDD5 Quiescent Current vs. Temperature 130 -10 Quiescent Current (μA) 120 PSRR (dB) -20 -30 -40 -50 VBAT = 5V VBAT = 3.7V -60 110 100 90 80 70 60 50 40 -70 VDDM = 5V, C14 = 1μF, IOUT = 100mA -80 10 100 1000 10000 Frequency (Hz) www.richtek.com 14 100000 1000000 30 VDDM = 3.3V, VBAT = 3.3V, C14 = 1μF, IOUT = 0mA -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temperature (°C) DS9953-02 April 2011 RT9953 Application information The RT9953 includes the following four DC/DC converters and one LDO to build a multiple-output power-supply system. CH1 : Synchronous Step-Up DC/DC Converter The CH1 is a synchronous step-up converter for motor or DSC system I/O power. The converter operates at fixed frequency and PWM Current Mode. The CH1 converter integrated internal MOSFETs, compensation network and synchronous rectifier for up to 95% efficiency. The output voltage can be set by the following equation : VOUT_CH1 = (1+R1/R2) x VFB1 Step-Down : The converter operates at fixed frequency PWM mode and continuous current mode (CCM) with internal MOSFETs, compensation network and synchronous rectifier for up to 95% efficiency. The CH2 Step-down converter can be operating at 100% maximum duty cycle to extend the input operating voltage range. While the input voltage is close to the output voltage, the converter enters low dropout mode. The output voltage can be set by the following equation : VOUT_CH2 = (1+R3/R4) x VFB2 Where VFB2 is 0.8V typically. Where VFB1 is 0.8V typically. CH2 : Synchronous Step-Up or Step-Down Selectable DC/DC Converter The CH2 is a synchronous step-up/step-down selectable converter for motor or DSC system I/O power. Mode setting The CH2 of RT9953 features flexible Step-up or Step-down topology setting for either 1 x Li-ion or 2 x AA application by SEL pin. Please refer to “Electrical Characteristics” for level of Logic-High or Logic-Low. When the CH2 operates as a Step-up converter, the SEL must be set at Logic-High. If the CH2 operates at Step-down mode, the SEL must be set at Logic-Low. In addition, please note that the logic state can not be changed during operation. Table 2. CH2 Mode Setting SEL CH2 Operating Mode Logic-High Step-Up Logic-Low Step-Down Step-Up : The converter operates at fixed frequency PWM Mode, continuous current mode (CCM), and discontinuous current mode (DCM) with internal MOSFETs, compensation network and synchronous rectifier for up to 95% efficiency. CH3 and CH4 : Synchronous Step-Down DC/DC Converter The converter operates at fixed frequency PWM mode, CCM and integrated internal MOSFETs and compensation network. The CH3 and CH4 Step-down converter can be operating at 100% maximum duty cycle to extend battery operating voltage range. When the input voltage is close to the output voltage, the converter could enter low dropout mode with low output ripple. The output voltage can be set by the following equation : VOUT_CH3 = (1+R5/R6) x VFB3 VOUT_CH4 = (1+R7/R8) x VFB4 Where VFB3 and VFB4 is 0.8V typically. CH5 : 500mA Low Dropout, Low Noise Linear Regulator Like any low-dropout regulator, this CH requires input and output decoupling capacitors. The CH5 linear regulator can support 500mA output current when PVDD5 > 2.7V. The typical current limit is 0.8A. If the output is shorted to ground, the Under Voltage Protection function will be triggered to shutdown the IC to prevent the part from damaging. The output voltage can be set by the following equation : VOUT_CH5 = (1+R9/R10) x VFB5 Where VFB5 is 0.8V typically. DS9953-02 April 2011 www.richtek.com 15 RT9953 Thermal Considerations Layout Considerations For continuous operation, do not exceed absolute maximum operation junction temperature. 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 : For the best performance of the RT9953, the following PCB layout guidelines must be strictly followed : PD(MAX) = (TJ(MAX) − TA ) / θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9953, the maximum junction temperature is 125°C. The junction to ambient thermal resistance θJA is layout dependent. For WQFN-24L 4x4 package, the thermal resistance θJA is 54°C/W on the standard JEDEC 51-7 four layers thermal test board. The maximum power dissipation at TA = 25°C can be calculated by following formula : } Place the input and output capacitors as close as possible to the input and output pins respectively for good filtering. } Keep the main power traces as wide and short as possible. } The switching node area connected to LX and inductor should be minimized for lower EMI. } Place the feedback components as close as possible to the FB pin and keep these components away from the noisy devices. } Connect the GND and Exposed Pad to a strong ground plane for maximum thermal dissipation and noise protection. } CH5 PCB trace and component had put different PCB side to avoid LX3 and LX4 switching noise. PD(MAX) = (125°C − 25°C) / (54°C/W) = 1.852W for WQFN-24L 4x4 The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9953 package, the Figure 1 of derating curve allows the designer to see the effect of rising ambient temperature on the maximum power dissipation allowed. Maximum Power Dissipation (W) 2.0 Four Layers PCB 1.8 1.6 1.4 WQFN-24L 4x4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 1. Derating Curves for RT9953 Package www.richtek.com 16 DS9953-02 April 2011 RT9953 Place the feedback components as LX should be connected to Inductor by close as possible to the FB pin and wide and short trace, keep sensitive keep away from noisy devices. compontents away from this trace V OUT2_CH2 GND C3 R1 C6 R3 V BAT GND C1 R2 C2 GND FB1 FB2 EN4 SEL 19 L2 1 18 LX2 2 17 PVDD2 EN3 3 FB4 4 SS 5 PVDD4 6 L4 7 8 9 10 11 12 FB5 PVDD5 LX3 25 C15 16 VDDM 15 FB3 14 EN2 13 PVDD3 R9 C4 V BAT C16 R5 C9 R6 V BAT C7 GND L3 C8 R10 VBAT C11 GND VOUT5 C17 C10 V OUT4_CH4 20 LX1 V BAT GND 21 LX4 Input/Output capacitors must be placed as close as possible to the Input/ Output pins. 22 PVDD1 R8 C12 23 EN5 R7 24 VOUT5_CH5 V OUT1_CH1 EN1 L1 GND C5 R4 C14 GND C13 V OUT3_CH3 Connect the Exposed Pad to a ground plane. Figure 2. PCB Layout Guide DS9953-02 April 2011 www.richtek.com 17 RT9953 Table 3. Protection Items Threshold (typical) Protection methods Refer to Electrical spec VDDM CH1 Step-Up CH2 Step-Up Protection type Over Voltage VDDM > 6V Protection Current Limit N-MOSFET current > 3A Delay time Disable all channels 100ms IC shutdown 100ms PVDD1 OVP PVDD1 > 6V IC shutdown No-delay VDDM power reset Current Limit N-MOSFET current > 3A IC shutdown 100ms PVDD2 OVP PVDD2 > 6V IC shutdown No-delay VDDM power reset Reset method Restart if VDDM < 5.5V (with hysteresis) VDDM power reset VDDM power reset OCP CH2 Step-Down UVP P-MOSFET current > 1.5A IC shutdown 100ms VDDM power reset FB2 < 0.4V IC shutdown 100ms VDDM power reset OCP CH3 Step-Down UVP P-MOSFET current > 1.5A IC shutdown 100ms VDDM power reset FB3 < 0.4V IC shutdown 100ms VDDM power reset OCP CH4 Step-Down UVP P-MOSFET current > 1.5A IC shutdown 100ms VDDM power reset 100ms VDDM power reset CH5 LDO Thermal FB4 < 0.4V IC shutdown IOUT (P-MOSFET current) > Current Limit Current Limiting 0.8A UVP FB5 < 0.4V IC shutdown Thermal All channels stop Temperature > 160°C shutdown switching www.richtek.com 18 No-delay No reset 100ms VDDM power reset 100ms Temperature < 140°C DS9953-02 April 2011 RT9953 Outline Dimension D2 D SEE DETAIL A L 1 E E2 e 1 2 DETAIL A b Pin #1 ID and Tie Bar Mark Options A A3 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. A1 Symbol 1 2 Dimensions In Millimeters Dimensions In Inches 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 0.180 0.300 0.007 0.012 D 3.950 4.050 0.156 0.159 D2 2.300 2.750 0.091 0.108 E 3.950 4.050 0.156 0.159 E2 2.300 2.750 0.091 0.108 e L 0.500 0.350 0.020 0.450 0.014 0.018 W-Type 24L QFN 4x4 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: [email protected] 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. DS9953-02 April 2011 www.richtek.com 19