RT9361A/B Tiny Package, High Performance, Regulated Charge Pump General Description Features Input Voltage Range : 2.8V to VOUT

Transcription

1 Tiny Package, High Performance, Regulated Charge Pump General Description The is a high performance charge pump DC/DC converter that produces a regulated 4.V and V output. No external inductor is required for operation. The operating voltage range is 2.8V to. Internal soft-start circuitry effectively reduces the in-rush current both while start-up and mode change. The features very low quiescent current, over current protection and short circuit protection. The is available in WDFN-6L 2x2, SOT-23-6 and TSOT-23-6 package. Ordering Information Package Type E : SOT-23-6 J6 : TSOT-23-6 QW : WDFN-6L 2x2 (W-Type) Lead Plating System P : Pb Free G : Green (Halogen Free and Pb Free) Output Voltage A : V B : 4.V Note : 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. Features Input Voltage Range : 2.8V to Internal Soft Start Function V/4.V Fixed Output Voltage Over Current Protection Function Short Circuit Protection Function RoHS Compliant and 00% Lead (Pb)-Free Applications Mobile phone, Smart Phone LED Backlight Camera Flash White LED LCD Display Supply Pin Configurations (TOP VIEW) CP 2 3 CP 6 SOT-23-6/TSOT WDFN-6L 2x2

2 Marking Information RT936AGJ6 AK= : Product Code AK=DNN RT936APJ6 AK-DNN AK- : Product Code RT936AGE RT936APE D3=DNN D3= : Product Code D3-DNN D3- : Product Code RT936AGQW RT936BPJ6 F8W F8 : Product Code W : Date Code AL-DNN AL- : Product Code RT936BGE RT936BPE D4=DNN D4= : Product Code D4-DNN D4- : Product Code Typical Application Circuit C PUMP V + C IN IN 3 2.8V to CP C OUT R R R LED LED LED Part No. Application Configuration C IN (μf) C PUMP (μf) C OUT (μf) RT936A RT936B I OUT < > 3.2V, or or 2.2 I OUT < > 3.2V, 0 0 I OUT < > 3.2V, or or 2.2 I OUT < > 3.2V, 0 0 2

3 Functional Pin Description Pin Number Pin Name T/SOT-23-6 WDFN-6L 2x2 Pin Function 6 Output Voltage 2, Exposed Pad (7) 3 4 Chip Enable (Active High) Ground. The exposed pad must be soldered to a large PCB and connected to for maximum power dissipation. 4 3 Flying Capacitor Negative Terminal 2 Power Input Voltage 6 CP Flying Capacitor Positive Terminal Function Block Diagram CP + MHz OSC - V REF Load Disconnect Voltage Reference Current Bias Short Circuit Protection 3

4 Absolute Maximum Ratings (Note ) Supply Input Voltage V to 6V Other I/O Pin Voltages V to 6V Power Dissipation, P T A = 2 C T/SOT W WDFN-6L 2x W Package Thermal Resistance (Note 2) T/SOT-23-6, θ JA C/W WDFN-6L 2x2, θ JA C/W Junction Temperature C Lead Temperature (Soldering, 0 sec.) C Storage Temperature Range C to 0 C ESD Susceptibility (Note 3) HBM (Human Body Mode) kV MM (Machine Mode) V Recommended Operating Conditions (Note 4) Ambient Temperature Range C to 8 C Junction Temperature Range C to 2 C Electrical Characteristics ( = 3.7V, T A = 2 C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Operation Voltage Range = V V Output Voltage RT936A, = 3.7V to 3.43V, IOUT ma V RT936A, > 3.2V, IOUT < 0mA V RT936B, > 3.2V, IOUT < 0mA V Quiescent Current IQ IOUT = ma Maximum Output Current IOUT RT936A, > 3.2V, CPUMP = μf RT936B, > 3.2V, CPUMP = μf ma OCP IOCP ma Short Circuit Current ma Output Ripple IOUT = 60mA, COUT = 2.2μF mv Shut Down Current ISHDN = 4.V, V < 0.4V μa Operation Frequency FOSC MHz Digital Input High Level VIH V Digital Input Low Level VIL V 4

5 Note. Stresses beyond those listed Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and 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 may affect device reliability. Note 2. θ JA is measured at T A = 2 C on a low effective thermal conductivity single-layer test board per JEDEC -3. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions.

6 Typical Operating Characteristics (For RT936A, C IN = C OUT = 2.2μF, C PUMP = 0.22μF, T A = 2 C, unless otherwise specified ) Output Voltage vs. Output Current Quiescent Current vs. Input Voltage..7 Output Voltage (V) = 3.2V = 3.7V = 4.3V = V Quiescent Current (ma) TA = 8 C TA = 2 C TA = -20 C TA = -40 C Output Current (ma) Output Voltage (V) Output Voltage vs. Input Voltage TA = 8 C TA = 2 C TA = -40 C Output Voltage (V) Output Voltage vs. Input Voltage IOUT = 0mA IOUT = 20mA IOUT = 30mA IOUT = 40mA IOUT = 0mA IOUT = 60mA IOUT = 70mA IOUT = 80mA Output Voltage (V) 4.84 IOUT = 60mA Output Voltage vs. Temperature IOUT = 0mA IOUT = 60mA Temperature ( C) Operation Frequency (MHz) Operation Frequency vs. Temperature.4.3 IOUT = 60mA.2. IOUT = 0mA Temperature ( C) 6

7 0.8 Efficiency vs. Output Curent 00 Efficiency vs. Input Voltage = 3V Efficiency (%) = 3.4V = 4.2V Efficiency (%) IOUT = 0mA IOUT = 20mA IOUT = 30mA IOUT = 40mA IOUT = 0mA IOUT = 60mA Output Curent (ma) V IH vs. Input Voltage V IL vs. Input Voltage TA = -40 C.2 VIH (V).2. TA = 2 C VIL (V). TA = -40 C TA = 8 C TA = 2 C TA = 8 C Inrush Current Inrush Current (00mA/Div) (00mA/Div) I IN = 2.8V, IOUT = 60mA IIN = V, IOUT = 60mA Time (40μs/Div) Time (40μs/Div) 7

8 Normal Operation Normal Operation (V/Div) IOUT (0mA/Div) I OUT (0mA/Div) = 2.8V, IOU T = 60mA = V, IOUT = 60mA Time (400ns/Div) Time (400ns/Div) PWM IIN Dimming Operation (0mA/Div) = 3.7V Time (40μs/Div) Refer to Application Informatiom Figure PWM I IN Dimming Operation (0mA/Div) = 3.7V Time (0ms/Div) Refer to Application Informatiom Figure Maximum Output Current (ma) Maximum Output Current vs. Input Voltage TA = -40 C TA = -20 C TA = 2 C TA = 8 C

9 Application Information Capacitor Selection Careful selection of the three external capacitors C IN, C OUT and C PUMP is very important because they will affect rampup time, output ripple and transient performance. Optimum performance will be obtained when low ESR (<00mΩ) ceramic capacitors are used for C IN and C OUT and C PUMP. In general, low ESR may be defined as less than 00mΩ. In all cases, X7R or XR dielectric are recommended. For particular application, low ESR Tantalum capacitors may be substituted; however optimum output ripple performance may not be realized. Aluminum electrolytic capacitors are not recommended for using with the due the their inherent high ESR characteristic. In general, lower values for C IN, C OUT and C PUMP may be utilized for light load current applications (<60mA). Drawing a load current of 60mA or less may use a C IN and C OUT capacitor value as low as 2.2μF and a C PUMP value of 0.22μF. C IN and C OUT may range from μf for light loads to 0μF for heavy output load conditions (<0mA). C PUMP may range from 0.22μF for light loads to μf for heavy output load conditions. If C PUMP is increased, C OUT should also be increased by the same ratio to minimize output ripple. As a basic rule, the ratio between C IN, C OUT and C PUMP should be approximately 0 to. Lowering the C IN, C OUT and C PUMP value can decrease the ramp-up time of, but it will increase the output ripple oppositely. + C IN 2.2µF CP C PUMP 0.22µF C OUT 2.2µF R R R LED LED LED 20mA 20mA 20mA + + C IN 2.2µF CP C PUMP 0.22µF C OUT 2.2µF Figure 2. Application Circuits for Flash LEDs C IN 0µF CP C PUMP µf Figure 3. Application Circuits for Constant Load + 3.3V C IN 0µF CP C PUMP 0.22µF C PUMP CP 0.22µF R 4.V/0mA R R LED LED LED L µh C OUT 0µF C OUT 0µF V/0mA µf V/80mA Figure. Application Circuits for Backlight Dimming Figure 4. Application Circuits for Doubling the Output Current 9

10 Efficiency The efficiency of the charge pump regulator varies with the output voltage version, the applied input voltage, the load current, and the internal operation mode of the device. The approximate efficiency is given by : P Efficiency (%) P V 2V OUT IN OUT IN V 00 V OUT I 2I OUT ( 2 Charge Pump Operating Mode) For a charge pump with an output of volts and a nominal input of 3 volts, the theoretical efficiency is 83.33%. Due to internal switching losses and IC quiescent current consumption, the actual efficiency can be measured as 82.72%. Thermal Considerations 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 : P D(MAX) = ( T J(MAX) - T A ) / θ JA Where T J(MAX) is the maximum operation junction temperature 2 C, T A is the ambient temperature and the θ JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT936, where T J(MAX) is the maximum junction temperature of the die (2 C) and T A is the operated ambient temperature. The junction to ambient thermal resistance θ JA for T/SOT-23-6 is 20 C/W and WDFN-6L 2x2 is 6 C/W on the standard JEDEC -3 single layer thermal test board. The maximum power dissipation at T A = 2 C can be calculated by following formula : IN OUT Power Dissipation (W) 0.8 Single Layer PCB 0.7 T/SOT WDFN-6L 2x Ambient Temperature ( C) Figure. Derating Curves for RT936 Packages PCB Board Layout The is a high-frequency switched-capacitor converter, and therefore large transient currents will flow in and. For best performance and to minimize ripple, place all of the components as close to IC as possible. Besides a solid ground plane is recommended on the bottom layer of the PCB. The ground of C IN and C OUT should be connected together and as close to the IC as possible. Figure 6 and Figure 7 shows the typical PCB layout of EVB board. Figure 6 P D(MAX) = (2 C 2 C) / 20 C/W = 0.4W for T/SOT-23-6 packages P D(MAX) = (2 C 2 C) / 6 C/W = 0.606W for WDFN-6L 2x2 packages The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θ JA. For RT936 packages, the Figure of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. 0 Figure 7

11 Outline Dimension D H L C B b A A e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A A B b C D e H L SOT-23-6 Surface Mount Package

12 D H L C B b A A e Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A A B b C D e H L TSOT-23-6 Surface Mount Package 2

13 D D2 L E E2 SEE DETAIL A A A A3 e b 2 2 DETAIL A Pin # ID and Tie Bar Mark Options Note : The configuration of the Pin # identifier is optional, but must be located within the zone indicated. Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A A A b D D E E e L W-Type 6L DFN 2x2 Package Richtek Technology Corporation 4F, No. 8, Tai Yuen st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)26789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. 3