RT9971

RT9971 RICHTEK | Alldatasheet

Document overview

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Technical content

Features

l One Synchronous Step-Up or Step-Down Selectable Convertor l Support 2AA or Li-ion Battery Applications l Preset On/Off Sequence l 5 CHs with Internal Compensation l All Power Switches Integrated l Up to 95% Efficiency l 100% (max) Duty Cycle for Step-Down Converter l Adjustable Output Voltage l LED PWM Dimming Control l LED Open Protection l Transformerless Inverting Converter for CCD l Fixed 1MHz Switching Frequency at CH1 to CH7 l RTC_LDO/SW1 Selectable by CN Pin l 40-Lead WQFN Package l RoHS Compliant and Halogen Free General Description The RT9971 is a complete power supply solution for digital still cameras and other hand held devices. The RT9971 is a multi-channel power management IC including two step- up DC/DC converters, two step-down DC/DC converters, one selectable step-up/step-down DC/DC converter, one inverting DC/DC converter and one WLED driver. The RT9971 is designed to fulfill the applications for DSC just as follows : CH1 is a synchronous step-up output for motor or DSC system I/O power CH2 is a selectable synchronous step-up/step-down output for motor or DSC system I/O power CH3 and CH4 are synchronous step-down outputs for DSP core and memory power supply CH5 is a high voltage step-up output for CCD bias power supply CH6 is an inverting output for negative CCD bias power supply CH7 is a high voltage step-up output for driving WLED For the CH2, the step-up or step-down converter, operation mode can be selected by the SEL pin. Among all CHs, there are 5 CHs with the built-in internal compensation. The RT9971 also provides a transformerless inverting converter for supplying the CCD power. For the synchronous step-up and step down converters, the efficiency can be up to 95%. The IC provides load disconnection for CH 1 and CH 5. The IC has selectable RTC_LDO/SW1 that can be determined by the CN pin. The RT9971 is able to support Li-ion and 2AA battery applications. The RT9971 provides WLED open protection, current limit, thermal shutdown protection, over voltage and under voltage protection to achieve complete protection. The RT9971 is available in WQFN-40L 5x5 package.

Applications

QW : WQFN-40L 5x5 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free)

DS9971-01 April 2011www.richtek.com RT9971 Pin Configurations (TOP VIEW) WQFN-40L 5x5 31323334353637383940 20191817161514131211 PVDD2 VDDM CFB7 GND LX7 LX5 VOUT7 FB3 EN7 LX3 PVDD1 PVDD6 CP CN PNEG FB6 FB4 EN6 LX4 PVDD4 SW5O SW5I FB5 VREF SEL RTC_R RTC_PWR PVDD3 EN2 COMP1 FB1 OK VOUT1 FB2 COMP2 EN134 LX2 GND LX6 EN5 LX1

DS9971-01 April 2011 www.richtek.com RT9971 Note : (1) SEL = High, CH2 is Step -Up, CN Connect to CAP (2) VBAT = 1.8V to 3.2V For 2AA Typical Application Circuit PVDD1 FB2 OK FB1 LX2 PVDD2 SW5O SW5I LX5 RT9971 10µF/25V VBAT FB5 PVDD3 C14 10µH VOUT1 COMP1 COMP2 3V3 LX321 4.7µH 10µF C10 2.5V FB323

11 PVDD4

4.7µH 10µF C13 1.8V FB48 1nF C15 10µH 63.4k 11.3k 10µF/16V x 2 0.1µF 2LX6 7FB6 16VREF 18RTC_R 10k 4CP 5CN C12 C18 C19 R10 R11 R12 R13 R14 R16 10µF/25V C16 1000k 90.9k 39k R6560pF 10uF 768k 360k 22pF 3V3 10uF C11 470k 374k 33pF VBAT LX7 VOUT7 CFB7 1µF/16V C20 R15 10µH PVDD6 3 VBAT LX1

40 VDDM

2.2µH 15V 1nF WLED 3V3 RTC Reset 19RTC_PWR RTC 3.25V 0.1µF C28 PNEG 6 1µF C29 3.3V 50k C1 R19 10µF 4.7pF 470k 150k R2 39k R3560pF VOUT_SW1 10µFx2 C5 470k 88.7k VBAT L22.2 µH 15V -7V 10µF C22 10µF x 2 C27 10µF 1µF C23 1µF C24 C17 1µF C26 1µF C25 VOUT_CH2 VOUT_CH3 VOUT_CH4 VOUT_CH5 VOUT_CH6 3V3 4.7pF 27, Exposed Pad (41)GND

17 SEL

32 EN134

39 EN2

VOUT_CH1 VBAT VDDM EN2, EN134 VOUT_CH1 3.3V VOUT_CH3 2.5V VOUT_CH4 1.8V VOUT_SW1 3.3V Wait until FB4 < 0.1V Wait until VOUT1 < 0.4V Wait until FB3 < 0.1V IC shutdown VOUT_CH2 5V Depends on loading User define 3.5ms 3.5ms 3.5ms 3.5ms 3.5ms Timing Diagram → → → → → → Power On Sequence : CH1 Step -Up 3.3V CH3 Step -Down 2.5V CH4 Step -Down 1.8V (CH2 Step -Up 5V and SW1 3.3V) Power Off Sequence : (CH2 Step -Up 5V and SW1 3.3V) CH4 Step -Down 1.8V CH3 Step -Down 2.5V CH1 Step -Up 3.3V

DS9971-01 April 2011www.richtek.com RT9971 Timing Diagram For Li-ion Note : (1) SEL = Low, CH2 is Step -Down, CN Pull High (2) VBAT = 2.7V to 4.2V VDDM EN2, EN134 VOUT_CH1 5V VOUT_CH3 2.5V VOUT_CH4 1.8V VOUT_CH2 3.3V Wait until FB3 < 0.1V IC shutdown 3.5ms User define Wait until FB4 < 0.1V Wait until FB2 < 0.1V 3.5ms 3.5ms 3.5ms → → → → → → Power On Sequence : CH1 Step -Up 5V CH3 Step -Down 2.5V CH4 Step -Down 1.8V CH2 Step -Down 3.3V Power Off Sequence : CH2 Step -Down 3.3V CH4 Step -Down 1.8V CH3 Step -Down 2.5V CH1 Step -Up 5V 5V PVDD1 FB2 OK FB1 LX2 PVDD2 PNEG SW5O SW5I LX5 RT9971 10µF/25V VBAT FB5 3.3V 10µF PVDD3 C14 4.7µH 10µH 10µF x 2 COMP1 COMP2 VBAT LX321 4.7µH 10µF C10 2.5V FB323 4.7µH 10µF C13 1.8V FB48 1nF C15 15V 10µH 63.4k 11.3k 10µF/16V x 2 0.1µF 2LX6 7FB6 16VREF 18RTC_R 10k 90.9k 4.7pF 470k 88.7k R2 39k R3560pF 10µF 470k 150k R5 15k R62200pF 10pF 10µF 768k 360k 22pF VBAT 10µF C11 470k 374k 33pF VBAT LX7 VOUT7 CFB7 1µF/16V C20 R15 10µH PVDD6 3 VBAT LX1 2.2µH 15V 1nF WLED VBAT or 5V RTC Reset 19RTC_PWR RTC 3.25V EN134 EN722 10k R18 VBAT VBAT -7V VOUT135RTC 3.25V 0.22F C21 10µF C22 1µF C23 1µF C24 C17 1µF C26 1µF C25 VOUT_CH1 VOUT_CH2 VOUT_CH3 VOUT_CH4 VOUT_CH5 VOUT_CH6 27, Exposed Pad (41)GND

Table 1. Recommended Components for the Typical Application Circuit

DS9971-01 April 2011www.richtek.com RT9971 Functional Pin Description Pin No. Pin Name Pin Function 1 PVDD1 Power Output of CH1. 2 LX6 Switch Node of CH6. High impedance in shutdown mode. 3 PVDD6 Power Input of CH6. 4 CP Charge Pump External Driver. 5 CN Charge Pump External Driver. 6 PNEG Negative Output of Charge Pump. 7 FB6 Feedback Input of CH6. High impedance in shutdown mode. 8 FB4 Feedback Input of CH4. High impedance in shutdown mode. 9 EN6 Enable Control Input of CH6. 10 LX4 Switch Node of CH4. High impedance in shutdown mode. 11 PVDD4 Power Input of CH4. 12 EN5 Enable Control Input of CH5. 13 SW5O Output of CH5 Load Disconnect. 14 SW5I Input of CH5 Load Disconnect. 15 FB5 Feedback Input of CH5. High impedance in shutdown mode. 16 VREF 1.25V Reference Output. 17 SEL Li-ion or 2AA Select. Logic state can not be changed during operation. 18 RTC_R RTC_Reset Output. 19 RTC_PWR Power Input of RTC_Reset. 20 PVDD3 Power Input of CH3. 21 LX3 Switch Node of CH3. High impedance in shutdown mode. 22 EN7 Enable Control Input of CH7. 23 FB3 Feedback Input of CH3. High impedance in shutdown mode. 24 VOUT7 Sense Input for CH7 Output Voltage. 25 LX5 Switch Node of CH5. High impedance in shutdown mode. 26 LX7 Switch Node of CH7. High impedance in shutdown mode. 27, 41 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum thermal dissipation. 28 CFB7 Feedback Input of CH7. 29 VDDM IC Analog Power Input.

30 PVDD2 Power Input of CH2 step-down converter, or power output of CH2 step-up

converter. 31 LX2 Switch Node of CH2. High impedance in shutdown mode. 32 EN134 Enable Control Input of CH1, CH3 and CH4. 33 COMP2 Compensation of CH2. Pull to GND in shutdown mode. 34 FB2 Feedback input of CH2. High impedance in shutdown mode. 35 VOUT1 CN is set to low or floating : Sense Pin for CH1 Output Voltage. High impedance in shutdown. CN is set to High: Output pin of RTC_LDO. 36 OK CN is set to low or floating : External Switch Control . High impedance in shutdown. CN is set to High : Power input pin of RTC_LDO. 37 FB1 Feedback Input of CH1. High impedance in shutdown mode. 38 COMP1 Compensation of CH1. Pull to GND in shutdown mode. 39 EN2 Enable Control Input of CH2. 40 LX1 Switch Node of CH1. High impedance in shutdown mode.

DS9971-01 April 2011 www.richtek.com RT9971 Function Block Diagram Timing Diagram CH5 and CH6 Timing Diagram SW5O (to CCD +) EN5 10ms SW5I EN6 Depends on loading Depends on loading Depends on loading 10ms VOUT_CH6 (to CCD -) CH1 C-Mode Step-Up 0.8V REF CH2 C-Mode Step-Up or Step-Down 0.8V REF CH5 C-Mode Step-Up PWM 1.25V REF OK VOUT7 FB5 LX5 SW5I VDDM GND FB1 COMP1 LX1 LX2 PVDD1 COMP2 PVDD2 FB2 SW5O CH6 C-Mode Inverting PVDD6 LX6 FB6 CH7 C-Mode Step-Up PWM 0.25V REF CFB7 LX7 EN7 Enable Mode Sequence EN134 EN5 EN6 Negative Charge Pump CP CN PNEG RTC LDOSW1VOUT1 1.25V REFVREF SW5 SEL VDDM RTC Reset RTC_R RTC_PWR CH4 C-Mode Step-Down PVDD4 LX4 FB4 0.8V REF CH3 C-Mode Step-Down PVDD3 LX3 FB3 0.8V REF EN2

DS9971-01 April 2011www.richtek.com RT9971

Electrical Characteristics

(VDDM = 3.3V, TA = 25°C, unless otherwise specified) Absolute Maximum Ratings (Note 1) l Power Switch : l Power Dissipation, PD @ TA = 25°C l Package Thermal Resistance (Note 2) l ESD Susceptibility (Note 3) Recommended Operating Conditions (Note 4) Parameter Symbol Test Condition Min Typ Max Unit Supply Voltage VDDM Operating Voltage VDDM 2.7 -- 5.5 V VDDM Startup Voltage VST 1.5 -- -- V VDDM Over Voltage Protection 6 6.25 6.5 V Supply Current Shutdown Supply Current into VDDM I OFF All EN = 0, CN = 3.3V -- 5 10 µA CH1 (Syn-Step-Up) : Supply Current into VDDM IQ1 Non Switching, EN134 = 3.3V -- -- 800 µA CH2 (Syn-Step-Up or Syn-Step-Down) : Supply Current into VDDM IQ2 Non Switching, EN2 = 3.3V -- -- 800 µA CH3 (Syn-Step-Down) : Supply Current into VDDM IQ3 Non Switching, EN134 = 3.3V -- -- 800 µA CH4 (Syn-Step-Down) : Supply Current into VDDM IQ4 Non Switching, EN134 = 3.3V -- -- 800 µA CH5 (Asyn-Step-Up) : Supply Current into VDDM IQ5 Non Switching, EN5 = 3.3V -- -- 800 µA CH6 (Inverting) + Charge pump : Supply Current into VDDM IQ6 Non Switching, EN6 = 3.3V PVDD6 = 3.3V -- -- 800 µA CH7 (WLED): Supply Current into VDDM IQ7 Non Switching, EN7 = 3.3V -- -- 800 µA To be continued

DS9971-01 April 2011 www.richtek.com RT9971 Parameter Symbol Test Condition Min Typ Max Unit Oscillator CH1,2,3,4, 5, 6, 7 Operating Frequency fOSC 900 1000 1100 kHz CH1 Maximum Duty Cycle (Step-Up) VFB1 = 0.7V 80 83 86 % CH2 Maximum Duty Cycle (Step-Up) VFB2 = 0.7V 80 83 86 % CH2 Maximum Duty Cycle (Step-Down) VFB2 = 0.7V -- -- 100 % CH3 Maximum Duty Cycle (Step-Down) VFB3 = 0.7V -- -- 100 % CH4 Maximum Duty Cycle (Step-Down) VFB4 = 0.7V -- -- 100 % CH5 Maximum Duty Cycle (Step-Up) VFB5 = 1.15V 91 94 97 % CH6 Maximum Duty Cycle (Inverting) VFB6 = 0.1V 91 94 97 % CH7 Maximum Duty Cycle (WLED) VFB7 = 0.15V 91 94 97 % Feedback Regulation Voltage Feedback Regulation Voltage @ FB1, FB2, FB3, FB4 0.788 0.8 0.812 V Feedback Regulation Voltage @ FB5 1.237 1.25 1.263 V Feedback Regulation Voltage @ FB6 (Inverting) -15 0 15 mV Feedback Regulation Voltage @ CFB7 0.237 0.25 0.263 V OK Sink Current OK = 1V 50 -- -- µA Reference VREF Output Voltage VREF 1.237 1.25 1.263 V VREF Load Regulation 0µA < IREF < 200µA -- -- 10 mV Negative Charge Pump PVDD6 Low Threshold to Start Pump 3.4 3.6 3.8 V PVDD6 Hysteresis Gap to Stop Pump 0.1 0.3 0.5 V (PVDD6 − PNEG) Clamped Voltage PVDD6 = 3.3V 4.1 4.5 4.9 V Power Switch P-MOSFET, PVDD1 = 3.3V -- 150 -- CH1 On Resistance of MOSFET RDS(ON) N-MOSFET, PVDD1 = 3.3V -- 150 -- mΩ CH1 Current Limitation (Step-Up) -- 3 -- A P-MOSFET, PVDD2 = 3.3V -- 150 -- CH2 On Resistance of MOSFET RDS(ON) N-MOSFET, PVDD2 = 3.3V -- 150 -- mΩ CH2 Current Limitation (Step-Down) -- 1.5 -- A CH2 Current Limitation (Step-Up) -- 3 -- A P-MOSFET, PVDD3 = 3.3V -- 200 -- CH3 On Resistance of MOSFET R DS(ON) N-MOSFET, PVDD3 = 3.3V -- 200 -- mΩ CH3 Current Limitation (Step-Down) -- 1.5 -- A P-MOSFET, PVDD4 = 3.3V -- 200 -- CH4 On Resistance of MOSFET R DS(ON) N-MOSFET, PVDD4 = 3.3V -- 200 -- mΩ CH4 Current Limitation (Step-Down) -- 1.5 -- A CH5 Load Disconnect MOSFET P-MOSFET, SW5I = 3.3V -- 0.5 -- Ω CH5 On Resistance of MOSFET N-MOSFET -- 0.5 -- Ω CH5 Current Limitation N-MOSFET -- 1.2 -- A To be continued

DS9971-01 April 2011www.richtek.com RT9971 Parameter Symbol Test Condition Min Typ Max Unit CH6 On Resistance of MOSFET P-MOSFET, PVDD6 = 3.3V -- 0.5 -- Ω CH6 Current Limitation P-MOSFET -- 1.5 -- A CH7 On Resistance of MOSFET N-MOSFET -- 1 -- Ω CH7 Current Limitation N-MOSFET -- 0.8 -- A Protection Over Voltage Protection of PVDD1 and PVDD2 6 6.25 6.5 V Under Voltage Protection of VOUT1 -- 1.75 -- V Over Voltage Protection of SW5I 18 -- 21 V Over Voltage Protection of VOUT7 12 -- 16 V CH5 Load Disconnect UVP of SW5O 0.35 0.4 0.45 V Under Voltage Protection of FB2 (Step-Down) -- 0.4 -- V Under Voltage Protection of FB3 -- 0.4 -- V Under Voltage Protection of FB4 -- 0.4 -- V Under Voltage Protection of FB5 -- 0.8 -- V Under Voltage Protection of FB6 -- 0.4 -- V Protection Fault Delay -- 100 -- ms Control EN134, EN2, EN5, EN6, EN7 Input High Level Threshold 1.3 -- -- V EN134, EN2, EN5, EN6, EN7 Input Low Level Threshold -- -- 0.4 V EN134, EN2, EN5, EN6, EN7 Sink Current -- 2 6 µA SEL Input High Level Threshold 1.3 -- -- V SEL Input Low Level Threshold -- -- 0.4 V SEL Sink Current SEL = 3.3V -- 2 6 µA Thermal Protection Thermal Shutdown TSD 125 160 -- °C Thermal Shutdown Hysteresis ΔTSD -- 20 -- °C RTC Reset RTC_PWR Reset Threshold 1.57 1.6 1.63 V Hysteresis -- 16 -- mV Standby Current RTC_PWR = 3V -- 2 4 µA RTC_R Rising Delay Time 35 55 75 ms RTC_R Sink Capability RTC_R = 0.5V, RTC_PWR = 1.5V 4 -- -- mA To be continued

DS9971-01 April 2011 www.richtek.com RT9971 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 exposed 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. Parameter Symbol Test Condition Min Typ Max Unit RTC LDO, CN = High Input Voltage Range VIN -- -- 5.5 V Standby Current VIN = 4.2V -- 5 8 µA Output Voltage VOUT IOUT = 0mA -- 3.25 3.3 V Maximum Output Current VIN = 4.2V 60 -- -- mA Dropout Voltage VDROP I OUT = 20mA -- -- 200 mV

DS9971-01 April 2011www.richtek.com RT9971 CH1 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) CH1 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) CH2 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) CH2 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) CH3 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) CH4 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) Typical Operating Characteristics VDDM = 3V, V OUT_CH1 = 3.3V, L1 = 2.2µH, C1 = 10µFx2 VBAT = 3V VBAT = 2.7V VBAT = 2.5V VBAT = 2.2V VBAT = 2V VBAT = 1.8V VDDM = 5V, V OUT_CH1 = 5V, L1 = 2.2µH, C1 = 10µFx2 VBAT = 4.5V VBAT = 4.2V VBAT = 3.9V VBAT = 3.6V VBAT = 3.3V VBAT = 3V VDDM = 3V, V OUT_CH2 = 5V, L2 = 2.2µH, C5 = 10µFx2 VBAT = 3.4V VBAT = 3V VBAT = 2.7V VBAT = 2.5V VBAT = 2.2V VBAT = 1.8V VDDM = 5V, V OUT_CH2 = 3.3V, L2 = 4.7µH, C5 = 10µF VBAT = 3.4V VBAT = 3.6V VBAT = 3.9V VBAT = 4.2V VBAT = 4.5V VBAT = 5V VDDM = 5V, V OUT_CH3 = 2.5V, L3 = 4.7µH, C9 = 10µF VBAT = 2.7V VBAT = 3V VBAT = 3.3V VBAT = 3.6V VBAT = 3.9V VBAT = 4.2V VBAT = 4.5V VDDM = 3V, V OUT_CH4 = 1V, L4 = 4.7µH, C12 = 10µF VBAT = 1.8V VBAT = 2.5V VBAT = 3V VBAT = 3.3V VBAT = 3.6V VBAT = 4.5V

DS9971-01 April 2011 www.richtek.com RT9971 CH5 Step-Up Efficiency vs. Output Current 100 1 10 100 Output Current (mA) Efficiency (%) CH6 Inverting Efficiency vs. Output Current 100 1 10 100 Output Current (mA) Inverting Efficiency (%) CH1 Step-Up Output Voltage vs. Output Current 5.050 5.055 5.060 5.065 5.070 5.075 5.080 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) CH1 Step-Up Output Voltage vs. Output Current 3.25 3.27 3.29 3.31 3.33 3.35 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) CH2 Step-Down Output Voltage vs. Output Current 3.300 3.305 3.310 3.315 3.320 3.325 3.330 3.335 3.340 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VDDM = 5V VBAT = 4.5V VBAT = 5V VDDM = 3V VBAT = 1.8V VBAT = 4.5V VDDM = 5V VBAT = 3V VBAT = 4.5V CH7 Efficiency vs. Input Voltage 100 Input Voltage (V) Efficiency (%) VDDM = 5V, L7 = 10µH, C20 = 1µF, IOUT = 25mA VDDM = 5V, V OUT_CH5 = 16V, L5 = 10µH, C16 = 10µF VBAT = 4.5V VBAT = 4.2V VBAT = 3.9V VBAT = 3.6V VBAT = 3.4V VDDM = 5V, V OUT_CH6 = -8V, L6 = 10µH, C18 = 10µFx2 VBAT = 3.4V VBAT = 3.6V VBAT = 3.9V VBAT = 4.2V VBAT = 4.5V

DS9971-01 April 2011www.richtek.com RT9971 CH2 Step-Up Output Voltage vs. Output Current 5.02 5.03 5.04 5.05 5.06 5.07 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) CH3 Step-Down Output Voltage vs. Output Current 2.490 2.495 2.500 2.505 2.510 2.515 2.520 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) CH4 Step-Down Output Voltage vs. Output Current 0.995 0.997 0.999 1.001 1.003 1.005 1.007 1.009 1.011 1.013 1.015 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) CH5 Step-Up Output Voltage vs. Output Current 15.7 15.8 15.9 16.0 16.1 16.2 16.3 02 0 4 0 6 0 8 0 1 0 0 Output Current (mA) Output Voltage (V) CH6 Inverting Output Voltage vs. Output Current -8.3 -8.25 -8.2 -8.15 -8.1 -8.05 02 0 4 0 6 0 8 0 1 0 0 Output Current (mA) Inverting Output Voltage (V) VDDM = 3V VBAT = 3.4V VDDM = 5V VBAT = 4.5V VBAT = 3V VBAT = 3V VBAT = 1.8V VBAT = 4.5V VDDM = 3V VBAT = 4.5V VBAT = 3.4V VBAT = 2.7V VDDM = 5V VBAT = 4.5V VBAT = 3.4V VBAT = 2.7V VDDM = 5V Power On Time (5ms/Div) VOUT_CH1 (5V/Div) VOUT_CH2 (5V/Div) VOUT_CH3 (2V/Div) VOUT_CH4 (1V/Div) VDDM = 5V, VBAT = 3.7V, SEL = Low

DS9971-01 April 2011 www.richtek.com RT9971 CH6 Output Voltage Ripple Time (1 μs/Div) LX6 (10V/Div) VOUT_CH6_ac (10mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH6 = -8V, IOUT = 50mA, L6 = 10μH, C18 = 10μFx2 CH5 Output Voltage Ripple Time (1 μs/Div) LX5 (10V/Div) VOUT_CH5_ac (10mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH5 = 16V, IOUT = 30mA, L5 = 10μH, C16 = 10μF CH3 Output Voltage Ripple Time (1 μs/Div) LX3 (2V/Div) VOUT_CH3_ac (10mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH3 = 2.5V, IOUT = 300mA, L3 = 4.7μH, C9 = 10μF CH2 Output Voltage Ripple Time (1 μs/Div) LX2 (2V/Div) VOUT_CH2_ac (10mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH2 = 3.3V, IOUT = 400mA, L2 = 4.7μH, C5 = 10μF Power Off Time (1ms/Div) VOUT_CH1 (5V/Div) VOUT_CH2 (5V/Div) VOUT_CH3 (2V/Div) VOUT_CH4 (1V/Div) VDDM = 5V, VBAT = 3.7V, SEL = Low CH1 Output Voltage Ripple Time (1 μs/Div) LX1 (2V/Div) VOUT_CH1_ac (20mV/Div) VDDM = 5V, V BAT = 3.7V, VOUT_CH1 = 5V, IOUT = 400mA, L1 = 2.2μH, C1 = 10μFx2

DS9971-01 April 2011www.richtek.com RT9971 CH6 Load Transient Response Time (1ms/Div) IOUT (20mA/Div) VOUT_CH6_ac (50mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH6 = -8V, IOUT = 15mA to 50mA, L6 = 10μH, C18 = 10μFx2 CH5 Load Transient Response Time (1ms/Div) IOUT (20mA/Div) VOUT_CH5_ac (50mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH5 = 16V, IOUT = 10mA to 30mA, L5 = 10μH, C16 = 10μF CH4 Load Transient Response Time (1ms/Div) IOUT (200mA/Div) VOUT_CH4_ac (50mV/Div) VDDM = 3V, V BAT = 1.8V, VOUT_CH4 = 1V, IOUT = 100mA to 300mA, L4 = 4.7μH, C12 = 10μF CH3 Load Transient Response Time (1ms/Div) IOUT (200mA/Div) VOUT_CH3_ac (50mV/Div) VDDM = 5V, V BAT = 3V, V OUT_CH3 = 2.5V, IOUT = 100mA to 300mA, L3 = 2.2μH, C9 = 10μF CH1 Load Transient Response Time (1ms/Div) IOUT (200mA/Div) VOUT_CH1_ac (100mV/Div) VDDM = 3V, V BAT = 1.8V, V OUT_CH1 = 3.3V, IOUT = 50mA to 250mA, L1 = 2.2μH, C1 = 10μFx2 CH2 Load Transient Response Time (1ms/Div) IOUT (200mA/Div) VOUT_CH2_ac (100mV/Div) VDDM = 5V, V BAT = 3.7V, V OUT_CH2 = 3.3V, IOUT = 0 to 300mA, L2 = 4.7μH, C5 = 10μF

DS9971-01 April 2011 www.richtek.com RT9971

Application information

The RT9971 includes the following seven DC/DC converter CHs to build a multiple-output power-supply system. CH1 : Step-up synchronous current mode DC/DC converter with internal power MOSFETs. The output voltage could be load disconnected by a switch controller and an external P-MOSFET. CH2 : Selectable step-up or step-down synchronous current mode DC/DC converter with internal power MOSFETs. CH3 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and internal compensation network. CH4 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and internal compensation network. CH5 : Step-up asynchronous current mode DC/DC converter with internal power MOSFET and internal compensation network. The output voltage could be load disconnected by an internal P-MOSFET. CH6 : Inverting current mode DC/DC converter with internal power P-MOSFET and internal compensation network. CH7 : Current mode WLED driver with internal power N-MOSFET and internal compensation network. This CH also provides open LED protection. SW1 : Load disconnect controller. SW5 : Load disconnect switch for CH5 CH1 to CH7 operate in PWM mode with 1MHz constant frequency under moderate to heavy loading. RTC_LDO : Low quiescent current, high output voltage accuracy LDO for Real Time Clock. RTC_Reset : Accurate voltage detector for RTC LDO. 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 integrates 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 Where VFB1 is 0.8V typically. SW1 SW1 is an open drain controller to drive an external P-MOSFET and then functions as a load disconnect switch for CH1. This switch features soft-start, Power On/ Off Sequence and under voltage protection functions. OK is an open drain control pin. Once CH1, CH3, and CH4's soft-start are finished, SW1 will be turned on. The OK pin is slowly pulled low and controlled with soft-start to suppress the inrush current. VOUT1 is used for SW1 soft- start and under voltage protection. CH2 : Synchronous Step-Up or Step-Down Selectable DC/DC Converter The CH2 is a synchronous step-up or step-down selectable converter for motor or DSC system I/O power. Mode setting The CH2 of the RT9971 features flexible Step-up or Step- down topology setting for either 1 x Li-ion or 2 x AA application by the 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 network and synchronous rectifier for up to 95% efficiency.

DS9971-01 April 2011www.richtek.com RT9971 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 operated 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+R4/R5) x VFB2 Where VFB2 is 0.8V typically. CH3 : Synchronous Step-Down DC/DC Converter The converter operates at fixed frequency PWM mode, CCM, integrated internal MOSFETs and compensation network. The CH3 step-down converter can be operated at 100% maximum duty cycle to extend the 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+R7/R8) x VFB3 Where VFB3 is 0.8V typically. CH4 : Synchronous Step-Down DC/DC Converter The converter operates at fixed frequency PWM mode, CCM, integrated internal MOSFETs and compensation network. The CH4 step-down converter can be operated 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_CH4 = (1+R9/R10) x VFB4 Where VFB4 is 0.8V typically. CH5 : Step-Up DC/DC Converter It integrates asynchronous step-up converter with an internal N-MOSFET, internal compensation and an external schottky diode to provide CCD positive power supply. The converter is inactive until the SW5 soft-start procedure is finished. This feature provides load disconnect function and effectively limits inrush current at start up. The output voltage can be set by the following equation : VOUT_CH5 = (1+R11/R12) x VFB5 Where VFB5 is 1.25V typically. SW5 SW5 is an internal switch enabled by EN5 and functions as a load disconnection for CH5. This switch features soft- start, Powe On Sequence, over voltage (for SW5I) and under voltage (for SW5O) protection functions. CH6 : INV DC/DC Converter This converter integrates an internal P-MOSFET and an external schottky diode to provide CCD negative power supply. The output voltage can be set by the following equation : VOUT_CH6 = (R13/R14) x (-VREF) Where R13 and R14 are the feedback resisters connected to FB6, VREF equals to 1.25V in typical. Charge Pumps The charge pump will be enabled while the PVDD6 voltage is lower than 3.6V. This CH provides pump voltage to enhance P-MOSFET gate driving capability. This function is not necessary while battery is Li-ion type. Reference Voltage The RT9971 provides a precise 1.25V reference voltage with souring capability of 100µA. Connect a 0.1µF ceramic capacitor from the VREF pin to GND. Reference voltage is enabled by connecting EN6 to logic high. Furthermore, this reference voltage is internally pulled to GND at shutdown. CH7 : WLED Driver It is an asynchronous step-up converter with an internal MOSFET, internal compensation and an external schottky diode to drive up to 3 WLED. This CH also features PWM dimming control from EN7 pin and open diode protection. In addition, CH7 will be turned on until the CH4 soft-start is finished.

R : Current sense resistor from CFB7 to GND. range is from 30kHz to 100kHz. Hold EN7 low for more than 64µs will turn off CH7. for about 55ms, then the RTC_R will go high. Table 3. RTC_LDO and SW1 Setting turned on to wait for the completion of CH3's soft-start. soft-start will be completed. internally pulled low to wait for CH3's shutdown completion. shutdown will not be checked. Table 4. Power On/Off Sequence and temperature difference between junction to ambient. the junction to ambient thermal resistance. RT9971, The maximum junction temperature is 125°C.

Table 5. Protection Items N-MOSFET off, P-MOSFET off .

Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 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. DS9971-01 April 2011www.richtek.com RT9971 Richtek Technology Corporation Taipei Office (Marketing) 5F, No. 95, Minchiuan Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)86672399 Fax: (8862)86672377 Email: marketing@richtek.com Outline Dimension Symbol 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 0.150 0.250 0.006 0.010 D 4.950 5.050 0.195 0.199 D2 3.250 3.500 0.128 0.138 E 4.950 5.050 0.195 0.199 E2 3.250 3.500 0.128 0.138 e 0.400 0.016 L 0.350 0.450 0.014 0.018 W-Type 40L QFN 5x5 Package Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. DETAIL A Pin #1 ID and Tie Bar Mark Options 2 2 D E L b A e SEE DETAIL A