RT9986A RICHTEK | Alldatasheet
Document overview
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Technical content
Features
zzzzz CH2 Step-Up/Step-Down Auto-Selected by External Topology zzzzz Preset On/Off Sequence of CH1, CH2, CH3, CH4 (1 → 3 → 4 → 2) zzzzz Preset On/Off Sequence of CH5, CH6 (5→ 6) zzzzz All Channels with Internal Compensation zzzzz All Power Switches Integrated zzzzz All Step-Up Converter with Load Disconnect zzzzz Step-Down DC/DC Converter \\\\\ Up to 95% Efficiency \\\\\ 100% (max) Duty Cycle zzzzz Low Voltage Step-Up DC/DC Converter \\\\\ Adjustable Output Voltage \\\\\ Up to 95% Efficiency zzzzz WLED Driver \\\\\ Auto-Selected by External Topology \\\\\ Current Source Mode with 30mA DC Current \\\\\ Step-Up Mode with LED Open Protection (OVP7) \\\\\ Direct PWM Dimming Control zzzzz Fixed 2MHz Switching Frequency for CH1/2/3/4, Fixed 1MHz Switching Frequency for CH5/6/7 zzzzz Small 32-Lead WQFN Package zzzzz RoHS Compliant and Halogen Free
Applications
EZ= : Product Code YMDNN : Date CodeEZ=YM DNN
DS9986A-00 May 2011www.richtek.com RT9986A Pin Configurations (TOP VIEW) WQFN-32L 4x4 FB1 VOUT6 FB6 VREF FB2 VDDM RTCPWR SYSR PVDD4 FB4 VCHK VNEG LX1 PVDD1 BAT LX6 PVDD7 FB7 PVDD5 LX5 LX4 EN56 FB3 PVDD2 LX7 FB5 PVDD3 LX2 LX3 EN1234 EN7 10 11 12 13 31 30 29 28 187 178 GND RST
Ordering Information
Note : Richtek products are : \ RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. \ Suitable for use in SnPb or Pb-free soldering processes. RT9986A Package Type QW : WQFN-32L 4x4 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free)
DS9986A-00 May 2011 www.richtek.com RT9986A For 2AA Typical Application Circuit RT9986A GND 33 (Exposed Pad) EN56OFF ON
25 EN1234
3.3VPVDD2 27 LX2 26 FB2 2.2µH 10µF x 2R3 470k 150k VBATC5 4.7µF
5 FB75V
2.2µH 10µF x 2 470k 88.7k VBATC3 4.7µF R10 26.1k PVDD5 LX5 20VBAT FB5 C13 R9 287k 15V 10µH 4.7µF C14 10µF x 2 C12 27pF
21 VDDM
1µF LX6 FB63 28-7V C18 66.5k R11 10.5k R12 VREF2 10µH
4 VOUT6
10µF x 2 C15 1nF C16 0.1µF LX4 9 2.2µH 10µF 1.8V FB4 11 C10R7 470k 374k
6 PVDD7
10µF 10PVDD4 5V or VBAT LX77 VCHK12 R14 10k RTCPWR RST
23 SYSR
3.3V BAT29VBAT 4.7µF 360k PVDD3 15 LX3 16 FB3 2.2µH 4.7µF 768k 2.5V 10µF VNEG13 C17 0.1µF C21 4.7pF C22 4.7pF
DS9986A-00 May 2011www.richtek.com RT9986A For Li-ion RT9986A GND 33 (Exposed Pad) EN56OFF ON 3.3VLX2 26 PVDD2 27 FB2 2.2µH 10µFR3 470k 150k VBATC6 4.7µF EN78 PVDD1 30 LX1 31 FB1 2.2µH 10µF x 2 470k 88.7k VBATC4 4.7µF R10 26.1k PVDD5 LX5 20V BAT FB5 C13 R9 287k 15V 10µH 4.7µF C14 10µF x 2 C12 27pF 1µF LX6 FB63 28-7V C18 66.5k R11 10.5k R12 VREF2 10µH 10µF x 2 C15 1nF C16 0.1µF LX4 9 2.2µH 10µF FB4 11 C10R7 23.2k 93.1k 4.7µF 10PVDD4 5V or VBAT VCHK12 R14 10k RTCPWR RST 3.3V BAT29VBAT 4.7µF 374k PVDD3 15 LX3 16 FB3 2.2µH 4.7µF 470k 1.8V VBAT 10µF VNEG13 C17 0.1µF
5 FB7
10µH C19 1µF VBAT C20 1µFD2 R13 C21 4.7pF C22 10pF
DS9986A-00 May 2011 www.richtek.com RT9986A Timing Diagram Timing Diagram for CH1 to CH4 CH5 and CH6 Power Sequence The power on sequence is : When EN56 goes high, CH5 will turn on first. After 10ms, CH6 will turn on. The power off sequence is : When EN56 goes low, CH6 will turn off first and VOUT6 will be internally pulled to GND. When VOUT6 > −0.12V, CH6 discharging completes and then CH5 turns off. Finally, the whole IC shuts down. Power On Sequence : CH5 HV Step-Up 15V→ CH6 INV −7V Power Off Sequence : CH6 INV −7V → CH5 HV Step-Up 15V EN1234 CH1 VOUT CH3 VOUT CH4 VOUT CH2 VOUT User define VDDM = Max (BAT, PVDD1) 3.5ms 3.5ms 3.5ms Wait until FB4 < 0.1V Wait until FB3 < 0.1V 3.5ms Wait until FB2 < 0.1V EN56 CH5 VOUT 10msCH6 VOUT Discharge by internal N-MOSFET Wait until VOUT6 close to 0V Constant Current Pre-Charge. 10ms
DS9986A-00 May 2011www.richtek.com RT9986A Functional Pin Description Pin No. Pin Name Pin Function 1 FB1 Feedback Input Pin of CH1. 2 VREF 1.8V Reference Output Pin. 3 FB6 Feedback Input Pin of CH6. 4 VOUT6 Sense Input Pin of CH6 Inverting Output Node.
5 FB7 Feedback input pin of CH7 in step-up mode or current sink pin of CH7 in current
source mode. 6 PVDD7 Power Output Pin of CH7. 7 LX7 Switch Node of CH7 in Step-Up Mode. LX7 initial voltage determines CH7 operation mode. 8 EN7 Enable Pin of CH7 and PWM Dimming Signal Input Pin. 9 LX4 Switch Node of CH4. 10 PVDD4 Power Input Pin of CH4. 11 FB4 Feedback Input Pin of CH4. 12 VCHK Sense Pin of Voltage Detector. 13 VNEG Output Pin of Negative Regulator. 14 FB3 Feedback Input Pin of CH3. 15 PVDD3 Power Input Pin of CH3. 16 LX3 Switch Node of CH3. 17 RST Voltage Detector Open Drain Output Pin. 18 FB5 Feedback Input Pin of CH5. 19 PVDD5 Power Output Pin of CH5. 20 LX5 Switch Node of CH5. 21 VDDM IC Analog Power Pin. 22 RTCPWR Internal Control Circuit Power Pin. That must connect to a bypass capacitor for better noise rejection. 23 SYSR System Reset Open-Drain Output Pin. 24 FB2 Feedback Input Pin of CH2. 25 EN1234 Enable Pin of CH1, CH2, CH3, CH4. 26 LX2 Switch Node of CH2. 27 PVDD2 Power Input Pin for Step-Down of CH2. Power Output Pin for Step-Up of CH2. 28 LX6 Switch Node of CH6. 29 BAT Battery Power Pin. 30 PVDD1 Power Output Pin of CH1. 31 LX1 Switch Node of CH1. 32 EN56 Enable Pin of CH5, CH6. 33 (Exposed pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum thermal dissipation.
DS9986A-00 May 2011 www.richtek.com RT9986A Function Block Diagram CH1 C-Mode Step-Up CH2 C-Mode Step-Up or Step-Down CH3 C-Mode Step-Down 0.8V REF CH5 C-Mode Step-Up PWM 1.25V REF FB5 LX5 VDDM GND LX1 LX2 FB3 PVDD3 PVDD1 PVDD2 LX3 CH6 Inverting PVDD5 LX6 FB6 CH7 C-Mode Step-Up or Current Source PWM Dimming Mode Selector 0.25V REFFB7 LX7 EN7 LX4 FB4 CH4 C-Mode Step-Down 0.8V REF PVDD4 EN1234 EN56 Power On/Off Sequence Control Logic Block VDDM BAT VDDM VDDM Body Diode Control VNEG VDDM VOUT6 30mA(max.) VDDM VDDM VDDM 0.8V REF FB2 0.8V REF FB1 Voltage Detector SYSR VCHK FB2 RTCPWR Soft-Start UVLOUVLO Body Diode Control RTC_LDO W/ Body Diode Control VDDI RTCPWR Body Diode Control 0.6V REF 1.8V REFVREF PVDD7 Body Diode Control RST SYS_Reset VDDM BAT BAT BAT BAT BAT VDDI
DS9986A-00 May 2011www.richtek.com RT9986A
Electrical Characteristics
(VDDM = VBAT = 3.3V, TA = 25°C, unless otherwise specified) Absolute Maximum Ratings (Note 1) z Power Dissipation, PD @ TA = 25°C z Package Thermal Resistance (Note 2) z ESD Susceptibility (Note 3) Recommended Operating Conditions (Note 4) Parameter Symbol Test Conditions Min Typ Max Unit Supply Input Voltage BAT Startup Voltage V ST 1.5 -- -- V BAT UVLO Threshold BAT Falling -- 1.3 -- V BAT UVLO Hysteresis -- 0.2 -- V VDDM OVP Threshold VDDM Rising 5.85 6 6.15 V VDDM OVP Hysteresis -- −0.25 -- V VDDM UVLO Threshold VDDM Rising 2.2 2.4 2.6 V VDDM UVLO Hysteresis -- 0.3 -- V Supply Current Shutdown Supply Current (IBAT + IVDDM) IOFF All EN pins = 0, V BAT = 3.3V -- 10 20 μA CH1 Synchronous Step-Up Supply Current into VDDM IQ1 Non switching, V EN1234 = 3.3V -- -- 800 μA CH2 Synchronous Step-Up or Step-Down Supply Current into VDDM IQ2 Non switching, V EN1234 = 3.3V -- -- 800 μA CH3 Synchronous Step-Down Supply Current into VDDM IQ3 V EN1234 = 3.3V -- -- 800 μA To be continued
DS9986A-00 May 2011 www.richtek.com RT9986A To be continued Parameter Symbol Test Conditions Min Typ Max Unit CH4 Synchronous Step-Down Supply Current into VDDM IQ4 Non switching, V EN1234 = 3.3V -- -- 800 μA CH5 Synchronous Step-Up Supply Current into VDDM IQ5 Non switching, V EN56 = 3.3V -- -- 800 μA CH6 (Inverting) Supply Current into VDDM IQ6 Non switching, V EN56 = 3.3V -- -- 800 μA CH7 (WLED) in Step-Up Mode Supply Current into VDDM IQ7b Non switching, V EN7 = 3.3V -- -- 800 μA CH7 (WLED) in Current Source Mode Supply Current into VDDM IQ7c V EN7 = 3.3V, VLX7 = 0V -- -- 800 μA Oscillator CH1, 2, 3, 4 Operation Frequency f OSC 1800 2000 2200 kHz CH5, 6, 7 Operation Frequency f OSC2 CH7 in Step-Up mode 900 1000 1100 kHz CH1 Maximum Duty Cycle (Step-Up) V FB1 = 0.75V 80 83 86 % CH2 Maximum Duty Cycle (Step-Up) V FB2 = 0.75V 80 83 86 % CH2 Maximum Duty Cycle (Step-Down) V FB2 = 0.75V -- -- 100 % CH3 Maximum Duty Cycle (Step-Down) V FB3 = 0.75V -- -- 100 % CH4 Maximum Duty Cycle (Step-Down) V FB4 = 0.75V -- -- 100 % CH5 Maximum Duty Cycle (Step-Up) V FB5 = 1.15V 91 93 97 % CH6 Maximum Duty Cycle (Inverting) V FB6 = 0.7V 91 93 97 % CH7 Maximum Duty Cycle (Step-Up) V FB7 = 0.15V 91 93 97 % Feedback, Regulation Voltage Feedback Regulation Voltage @ FB1, FB2, FB3, FB4 0.788 0.8 0.812 V Feedback Regulation Voltage @ FB5 V FB5 1.237 1.25 1.263 V Feedback Regulation Voltage @ FB6 (Inverting) VFB6 0.59 0.6 0.61 V Feedback Regulation Voltage @ FB7 V FB7 0.237 0.25 0.263 V Output Current (CS Mode) 28.5 30 31.5 mA Dropout Voltage @ FB7 (CS Mode) V LX7 = 0V -- -- 0.3 V VREF Output Voltage V REF 1.782 1.8 1.818 V VREF Load Regulation 0 μA < IREF < 200μA -- -- 10 mV Power Switch P-MOSFET V PVDD1 = 3.3V -- 200 300 CH1 On-Resistance N-MOSFET RDS(ON)1 VPVDD1 = 3.3V -- 150 250 mΩ CH1 Current Limitation (Step-Up) I LIM1 2.2 3 4 A P-MOSFET V PVDD2 = 3.3V -- 200 300 CH2 On Resistance N-MOSFET RDS(ON)2 VPVDD2 = 3.3V -- 150 250 mΩ CH2 Current Limitation (Step-Down) I LIM2_D 1.2 1.6 2 A CH2 Current Limitation (Step-Up) I LIM2_U 2.2 3 4 A
DS9986A-00 May 2011www.richtek.com RT9986A To be continued Parameter Symbol Test Conditions Min Typ Max Unit P-MOSFET V PVDD3 = 3.3V -- 300 400 CH3 On Resistance N-MOSFET RDS(ON)3 VPVDD3 = 3.3V -- 300 400 mΩ CH3 Current Limitation (Step-Down) I LIM3 1.2 1.6 2 A P-MOSFET V PVDD4 = 3.3V -- 300 400 CH4 On Resistance N-MOSFET RDS(ON)4 VPVDD4 = 3.3V -- 300 400 mΩ CH4 Current Limitation (Step-Down) I LIM4 1.2 1.6 2 A P-MOSFET V PVDD5 = 16V -- 0.8 1 CH5 On Resistance N-MOSFET RDS(ON)5 VPVDD5 = 3.3V -- 0.6 0.8 Ω CH5 Current Limitation of N-MOSFET ILIM5 0.9 1.2 1.6 A CH6 On Resistance of P-MOSFET R DS(ON)6 -- 0.5 0.7 Ω CH6 Current Limitation of P-MOSFET ILIM6 1 1.5 2 A P-MOSFET V PVDD7 = 10V -- 3 -- CH7 On Resistance N-MOSFET RDS(ON)7 VPVDD7 = 3.3V -- 0.9 1.1 Ω CH7 Current Limitation of N-MOSFET ILIM7 0.6 0.8 1 A Protection Over Voltage Protection of PVDD1 and PVDD2 5.85 6 6.15 V Over Voltage Protection of PVDD5 20 21 22 V Over Voltage Protection of VOUT6 -- −13 -- V Over Voltage Protection of PVDD7 (Step-Up Mode) 14.3 15 16 V CH1, CH2 Step-Up Under Voltage Protection of PVDD1 and PVDD2 -- VBAT −0.8V -- V CH1/2/3/4 Under Voltage Protection At VFBx < 0.4V after soft-start ends 0.35 0.4 0.45 V CH5 Under Voltage Protection At VFB5 < 0.6V after soft-start ends 0.5 0.6 0.7 V CH6 Under Voltage Protection At VFB6 > 1.2V after soft-start end 1.1 1.2 1.3 V CH1/2/3/4 Over Load Protection At VFBx < 0.7V after fault delay (100ms) 0.65 0.7 0.75 V CH5 Over Load Protection At VFB5 < 1.1V after fault delay (100ms) 1.05 1.1 1.15 V CH6 Over Load Protection At VFB6 > 0.74V after fault delay (100ms) 0.69 0.74 0.79 V Protection Fault Delay -- 100 -- ms Control Logic-High 1.3 -- -- EN1234, EN56, EN7 Input Threshold Voltage Logic-Low -- -- 0.4 V Logic-High High to Select Step-Up Mode 1 -- -- LX7 Input Threshold Voltage Logic-Low Low to Select CS Mode -- 0.25 -- V EN1234, EN56, EN7 Sink Current -- 2 6 μA EN7 Low Time for Shutdown t SHDN -- 32 -- ms
DS9986A-00 May 2011 www.richtek.com RT9986A 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. θ JA is measured in natural convection at TA = 25°C on a high-effective thermal conductivity four-layer test board of JEDEC 51-7 thermal measurement standard. The measurement case position of θJC is on the exposed pad of the 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 Conditions Min Typ Max Unit Thermal Protection Thermal Shutdown T SD 125 160 -- °C Thermal Shutdown Hysteresis ΔTSD -- 20 -- °C System Reset SYSR, FB2 Regulation Threshold for SYSR to go low 0.709 0.72 0.731 V SYSR, FB2 Hysteresis -- 40 -- mV SYSR Rising Delay Time -- 10 -- ms SYSR Sink Capability V SYSR = 0.5V 4 -- -- mA Voltage Detector Voltage Detector Reset Threshold (VCHK < Threshold Æ RST = L) VCHK Falling 1.57 1.6 1.63 V Voltage Detector Reset Hysteresis -- 16 -- mV Standby Current V VCHK = 3V -- 2 4 μA RST Rising Delay Time 35 55 75 ms RST Sink Capability V RST = 0.5V, VVCHK = 1.5V 4 -- -- mA RTC LDO Standby Current V DDM = 4.2V -- 5 8 μA Regulated Output Voltage @ RTCPWR I OUT = 0mA 3.1 3.2 3.3 V Max Output Current (Current Limit) V DDM = 4.2V 60 130 200 mA IOUT = 50mA -- -- 1000 IOUT = 10mA -- -- 150 Dropout Voltage IOUT = 3mA -- -- 60 mV
DS9986A-00 May 2011www.richtek.com RT9986A Typical Operating Characteristics CH1 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 3V VBAT = 2.7V VBAT = 2.5V VBAT = 2.2V VBAT = 2V VBAT = 1.8V VOUT = 3.3V, L = 2.2μH, COUT = 10μF x 2 CH1 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 4.5V VBAT = 4.2V VBAT = 3.9V VBAT = 3.6V VBAT = 3.3V VBAT = 3V VOUT = 5V, L = 2.2μH, COUT = 10μF x 2 CH2 Step-Up Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 3.6V VBAT = 3.3V VBAT = 3V VBAT = 2.7V VBAT = 2.5V VBAT = 2.2V VBAT = 1.8V VOUT = 5V, L = 2.2μH, COUT = 10μF x 2 CH2 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 3.4V VBAT = 3.7V VBAT = 3.9V VBAT = 4.2V VBAT = 4.5V VBAT = 5V VOUT = 3.3V, L = 2.2μH, COUT = 10μF CH 3 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 2.7V VBAT = 3V VBAT = 3.3V VBAT = 3.6V VBAT = 3.9V VBAT = 4.2V VBAT = 4.5V VOUT = 1.8V, L = 2.2μH, COUT = 10μF CH4 Step-Down Efficiency vs. Output Current 100 10 100 1000 Output Current (mA) Efficiency (%) VBAT = 1.8V VBAT = 2.5V VBAT = 3V VBAT = 3.3V VBAT = 3.6V VBAT = 4.2V VBAT = 4.5V VOUT = 1V, L = 2.2μH, COUT = 10μF
DS9986A-00 May 2011 www.richtek.com RT9986A CH2 Step-Up Output Voltage vs. Output Current 5.00 5.02 5.04 5.06 5.08 5.10 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VBAT = 3V VBAT = 4.2V VOUT = 5V 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) VBAT = 1.8V VBAT = 3.2V VOUT = 3.3V CH1 Step-Up Output Voltage vs. Output Current 4.80 4.85 4.90 4.95 5.00 5.05 5.10 5.15 5.20 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VBAT = 3V VBAT = 4.5V VOUT = 5V CH7 Efficiency vs. Input Voltage 100 Input Voltage (V) Efficiency (%) IOUT = 25mA, L = 10μH, COUT = 1μF CH6 Inverting Efficiency vs. Output Current 100 1 10 100 Output Current (mA) Inverting Efficiency (%) VBAT = 4.2V VBAT = 3.9V VBAT = 3.6V VBAT = 3.3V VBAT = 3V VBAT = 2.7V VBAT = 4.5V VBAT = 2.5V VBAT = 2.2V VBAT = 2V VOUT = −8V, L = 10μH, COUT = 10μF x 2 CH5 Step-Up Efficiency vs. Output Current 100 0.001 0.01 0.1 Output Current (A) Efficiency (%) VBAT = 4.5V VBAT = 4.2V VBAT = 3.9V VBAT = 3.6V VBAT = 3.3V VBAT = 3V VBAT = 2.7V VBAT = 2.5V VBAT = 2.2V VBAT = 2V VOUT = 16V, L = 10μH, COUT = 10μF x 2
DS9986A-00 May 2011www.richtek.com RT9986A VBAT = 3.7V Time (2.5ms/Div) Power On Sequence VOUT_CH1 (5V/Div) VOUT_CH2 (2V/Div) VOUT_CH4 (2V/Div) VOUT_CH3 (2V/Div) CH2 Step-Down Output Voltage vs. Output Current 3.26 3.28 3.30 3.32 3.34 3.36 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VBAT = 4.5V VBAT = 5V VOUT = 3.3V CH3 Step-Down Output Voltage vs. Output Current 1.800 1.805 1.810 1.815 1.820 1.825 1.830 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VOUT = 1.8V VBAT = 3V VBAT = 4.5V CH4 Step-Down Output Voltage vs. Output Current 0.992 0.994 0.996 0.998 1.000 1.002 1.004 1.006 0 100 200 300 400 500 600 Output Current (mA) Output Voltage (V) VBAT = 4.5V VBAT = 2.7V VBAT = 3V VOUT = 1V CH5 Step-Up Output Voltage vs. Output Current 15.8 15.9 16.0 16.1 16.2 16.3 0 2 04 06 08 0 1 0 0 Output Current (mA) Output Voltage (V) VBAT = 3.4V VBAT = 4.5V VOUT = 16V CH6 Inverting Efficiency vs. Output Current -8.210 -8.205 -8.200 -8.195 -8.190 0 2 04 06 08 0 1 0 0 Output Current (mA) Output Voltage (V) VBAT = 2.7V VBAT = 3.4V VBAT = 4.5V VOUT = −8V
DS9986A-00 May 2011 www.richtek.com RT9986A Time (500ns/Div) CH3 Output Voltage Ripple VOUT_CH3_ac (5mV/Div) LX3 (2V/Div) VBAT = 3.7V, VOUT = 1.8V, IOUT = 400mA, L = 2.2μH, COUT = 10μF Time (500ns/Div) CH1 Output Voltage Ripple VOUT_CH1_ac (10mV/Div) LX1 (2V/Div) VBAT = 3.7V, VOUT = 5V, IOUT = 400mA, L = 2.2μH, COUT = 10μF x 2 Time (5ms/Div) Power On Sequence VOUT_CH6 (5V/Div) VOUT_CH5 (10V/Div) VBAT = 3.7V Time (1ms/Div) Power Off Sequence VBAT = 3.7V VOUT_CH1 (5V/Div) VOUT_CH2 (2V/Div) VOUT_CH4 (2V/Div) VOUT_CH3 (2V/Div) Time (2.5ms/Div) Power Off Sequence VOUT_CH6 (5V/Div) VOUT_CH5 (10V/Div) VBAT = 3.7V Time (500ns/Div) CH2 Output Voltage Ripple VOUT_CH2_ac (2mV/Div) LX2 (2V/Div) VBAT = 3.7V, VOUT = 3.3V, IOUT = 400mA, L = 2.2μH, COUT = 10μF
DS9986A-00 May 2011www.richtek.com RT9986A Time (1 μs/Div) CH5 Output Voltage Ripple VOUT_CH5_ac (10mV/Div) LX5 (10V/Div) VBAT = 3.7V, VOUT = 16V, IOUT = 30mA, L = 10μH, COUT = 10μF Time (1 μs/Div) CH6 Output Voltage Ripple VOUT_CH6_ac (10mV/Div) LX6 (10V/Div) VBAT = 3.7V, VOUT = −8V, IOUT = 50mA, L = 10μH, COUT = 10μF x 2 Time (1ms/Div) CH1 Load Transient Response VOUT_CH1_ac (100mV/Div) IOUT (100mA/Div) VBAT = 3.7V, VOUT = 5V, IOUT = 0 to 300mA, L = 2.2μH, COUT = 10μF x 2 Time (1ms/Div) CH3 Load Transient Response VOUT_CH3_ac (50mV/Div) IOUT (100mA/Div) VBAT = 3.7V, VOUT = 1.8V, IOUT = 0 to 300mA, L = 2.2μH, COUT = 10μF Time (1ms/Div) CH2 Load Transient Response VOUT_CH2_ac (50mV/Div) IOUT (100mA/Div) VBAT = 3.7V, VOUT = 3.3V, IOUT = 0 to 300mA, L = 2.2μH, COUT = 10μF Time (500ns/Div) CH4 Output Voltage Ripple VOUT_CH4_ac (5mV/Div) LX4 (2V/Div) VBAT = 3.7V, VOUT = 1V, IOUT = 400mA, L = 2.2μH, COUT = 10μF
DS9986A-00 May 2011 www.richtek.com RT9986A Time (1ms/Div) CH6 Load Transient Response VOUT_CH6_ac (20mV/Div) IOUT (20mA/Div) VBAT = 3.7V, VOUT = −8V, IOUT = 15 to 50mA, COUT = 10μF x 2 Time (1ms/Div) CH5 Load Transient Response VOUT_CH5_ac (50mV/Div) IOUT (20mA/Div) VBAT = 3.7V, VOUT = 16V, IOUT = 10 to 30mA, COUT = 10μF Time (1ms/Div) CH4 Load Transient Response VOUT_CH4_ac (20mV/Div) IOUT (100mA/Div) VBAT = 3.7V, VOUT = 1V, IOUT = 0 to 300mA, L = 2.2μH, COUT = 10μF
DS9986A-00 May 2011www.richtek.com RT9986A
Application Information
The RT9986A is a multiple output power supply system for digital still cameras and other small handheld devices. It includes six DC/DC converters as well as one WLED driver, one RTC LDO, one voltage detector, and one system reset. The WLED works in either current source mode or step-up mode. CH1 : Step-up synchronous current mode DC/DC converter with internal power MOSFETs and compensation network. The P-MOSFET body can be controlled to disconnect the load. CH2 : Step-up or step-down synchronous current mode DC/DC converter with internal power MOSFETs and compensation network. External circuit topology automatically determines whether CH2 is in step-up or step-down mode. During step-up mode, the P-MOSFET body can be controlled to disconnect the load if input voltage is not higher than the VBAT. CH3 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and compensation network. CH4 : Step-down synchronous current mode DC/DC converter with internal power MOSFETs and compensation network. CH5 : Step-up synchronous current mode DC/DC converter with internal power MOSFET and compensation network. The P-MOSFET body can be controlled to disconnect the load. CH6 : Asynchronous inverting current mode DC/DC converter with internal power MOSFET and compensation network. CH7 : A WLED driver operating in either current source mode or synchronous step-up mode with internal power MOSFET and compensation network. Operation mode is determined by LX7 initial voltage The P-MOSFET body in step-up mode can be controlled to disconnect the load disconnected. CH1 to CH4 operate in PWM mode with 2MHz, while CH5 to CH7 operate in PWM mode with 1MHz switching frequency. RTC_LDO : A 3.1V output LDO with low quiescent current and high output voltage accuracy. System Reset : Accurate voltage detector for checking CH2 output voltage status. Voltage Detector : A general, low quiescent current voltage detector for monitoring status of a node voltage such as for RTC_LDO output or others. CH1 : Synchronous Step-Up DC/DC Converter CH1 is a synchronous step-up converter which can be used for motor power. The converter operates at fixed frequency and PWM current mode. The 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. CH2 : Synchronous Step-Up / Step-Down Selectable DC/DC Converter CH2 is a synchronous step-up / step-down auto-select converter, typically for system I/O power. In either step- up or step-down, the converter operates in fixed frequency PWM mode, Continuous Current Mode (CCM), and Discontinuous Current Mode (DCM) with internal MOSFETs, compensation network and synchronous rectifiers for up to 95% efficiency. Step-Up : In step-up mode, CH2 also disconnects the load from its input power node and discharges output node of CH2 when it is turned off. Step-Down : In step-down mode, the CH2 converter can be operated at 100% maximum duty cycle to extend the input operating voltage range. When 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.
Table 1. CH7 WLED setting integrated internal MOSFETs and compensation network. where VFB3 is 0.8V typically. integrated internal MOSFETs and compensation network. where VFB4 is 0.8V typically. network and load disconnect function. where VFB5 is 1.25V typically. diode to provide CCD negative power supply. voltage is enabled by pulling EN6 to logic-high. by LX7's initial voltage level. holding EN7 low for more than 32ms will turn off CH7.
DS9986A-00 May 2011www.richtek.com RT9986A R is the current sense resistor from FB7 to GND and Duty is the duty of the PWM dimming signal into EN7 pin. Dimming frequency range is from 1kHz to 100kHz but 2kHz to 20kHz should be avoided to prevent distraction from audio noise. VDDM Bootstrap To support bootstrap function, the RT9986A includes a power selection circuit which selects between BAT and PVDD1 to create the internal node voltage VDDI and VDDM. VDDM is the power of all the RT9986A control circuits and must be connected to an external decoupling capacitor by way of the VDDM pin. The VDDI is the power input of the RTC LDO. The output PVDD1 of CH1 can bootstrap VDDM and VDDI. The RT9986A includes UVLO circuits to monitor VDDM and BAT voltage status. RTC LDO The RT9986A provides a 3.1V output LDO for real time clock. The LDO features low quiescent current (5µA) and high output voltage accuracy. This LDO is always on, even when the system is shut down. For better stability, is it recommended to connect a 0.1µF to the RTCPWR pin. The RTC LDO includes pass transistor body diode control to avoid the RTCPWR node from back-charging into the input node VDDI. System Reset The RT9986A also provides a system voltage detector to monitor system power status via FB2. If FB2 level is lower than 90% setting, the open drain output pin SYSR will pull down. When FB2 level is higher than 95% setting, the SYSR pin will go high after 10ms. Voltage Detector The RT9986A provides a voltage detector to detect the voltage status at the VCHK pin. The input power of the voltage detector is RTCPWR and the detector is always on. 55ms after VCHK voltage > 1.616V, the open drain output /RST will be pulled high. If VCHK < 1.6V, the /RST pin will be pulled down to GND immediately. Power On/Off Sequence for CH1 to CH4 EN1234 will turn on/off CH1 to CH4 in preset sequence. CH1 to CH4 Power On Sequence is: When EN1234 goes high, CH1 will turn on first. 3.5ms after CH1 is turned on, CH3 will turn on. 3.5ms after CH3 is turned on, CH4 will turn on. 3.5ms after CH4 is turned on, CH2 will turn on. CH1 to CH4 Power-Off Sequence is : When EN1234 goes low, CH2 will turn off first and internally discharge output. When FB2 < 0.1V, CH4 will turn off and also internally discharge output via the LX4 pin. When FB4 < 0.1V, CH3 will turn off and internally discharge output via the LX3 pin. Likewise, when FB3 < 0.1V, CH1 will turn off and discharge output. After FB1 < 0.1V, CH1 to 4 shutdown sequence will be completed. Thermal Considerations For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : PD(MAX) = (TJ(MAX) − TA) / θJA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJAis the junction to ambient thermal resistance. For recommended operating condition specifications of the RT9986A, the maximum junction temperature is 125°C and TA is the ambient temperature. The junction to ambient thermal resistance, θJA, is layout dependent. For WQFN- 32L 4x4 packages, the thermal resistance, θJA, is 27.8°C/ W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at T A = 25°C can be calculated by the following formula : PD(MAX) = (125 °C − 25 °C) / (27.8 °C/W) = 3.59W for WQFN-32L 4x4 package The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance,θJA. For the RT9986A package, the derating curve in Figure 1 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation.
Table 2. Protection Items
DS9986A-00 May 2011 www.richtek.com RT9986A Protection type Threshold (typical) Refer to Electrical spec Protection methods IC Shutdown Delay time Reset method Current Limit P-MOSFET Current > 1.6A N-MOSFET off, P-MOSFET off. Automatic reset at next clock cycle. 100ms VDDM power reset or all enable pins set to low FB3 UVP FB3 < 0.4V after soft-start end. N-MOSFET off, P-MOSFET off. No-delay VDDM power reset or all enable pins set to low CH3 Step-Down FB3 Over Load FB3 < 0.7V IC Shutdown when OL occur each cycle until 100ms. 100ms VDDM power reset or all enable pins set to low Current Limit P-MOSFET Current > 1.6A N-MOSFET off, P-MOSFET off. Automatic reset at next clock cycle. 100ms VDDM power reset or all enable pins set to low FB4 UVP FB4 < 0.4V after soft-start end. N-MOSFET off, P-MOSFET off. No-delay VDDM power reset or all enable pins set to low CH4 Step-Down FB4 Over Load FB4 < 0.7V IC Shutdown when OL occur each cycle until 100ms. 100ms VDDM power reset or all enable pins set to low Current Limit N-MOSFET Current > 1.2A N-MOSFET off, P-MOSFET off. Automatic reset at next clock cycle. 100ms VDDM power reset or all enable pins set to low PVDD5 OVP PVDD5 > 21V N-MOSFET off, P-MOSFET off. No-delay VDDM power reset or all enable pins set to low FB5 UVP FB5 < 0.6V after soft-start end. N-MOSFET off, P-MOSFET off. No-delay VDDM power reset or all enable pins set to low CH5 Step-Up FB5 Over Load FB5 < 1.1V IC Shutdown when OL occur each cycle until 100ms. 100ms VDDM power reset or all enable pins set to low Current Limit P-MOSFET Current > 1.5A P-MOSFET off. Automatic reset at next clock cycle. 100ms VDDM power reset or all enable pins set to low VOUT6 OVP VOUT6 < −13V P-MOSFET off. No-delay VDDM power reset or all enable pins set to low FB6 UVP FB6 >1.2V P-MOSFET off. No-delay VDDM power reset or all enable pins set to low CH6 Inverter FB6 Over Load FB6 > 0.74V IC Shutdown when OL occur each cycle until 100ms. 100ms VDDM power reset or all enable pins set to low Current Limit N-MOSFET Current > 0.8A N-MOSFET off, P-MOSFET off. Automatic reset at next clock cycle. 100ms VDDM power reset or all enable pins set to low CH7 WLED PVDD7 OVP PVDD7 > 15V Shutdown CH7 Not applicable VDDM power reset or all enable pins set to low Thermal Thermal Shutdown Temperature > 160°C All channels stop switching No-delay VDDM power reset or all enable pins set to low
DS9986A-00 May 2011www.richtek.com RT9986A 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. Richtek Technology Corporation Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 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 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 0.150 0.250 0.006 0.010 D 3.900 4.100 0.154 0.161 D2 2.650 2.750 0.104 0.108 E 3.900 4.100 0.154 0.161 E2 2.650 2.750 0.104 0.108 e 0.400 0.016 L 0.300 0.400 0.012 0.016 W-Type 32L QFN 4x4 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