RT5070 Single Output LNB Supply and Control Voltage Regulator Features General Description The RT5070 is a highly integrated voltage regulator and interface IC, specifically design for supplying power and control signals from advanced satellite set-top box (STB) modules to the LNB down-converter in the antenna dish or to the multi-switch box. The device is consists of the independent current-mode boost controller and low dropout linear regulator for the LNB power. The RT5070 has fault protection (over-current, over-temperature and under-voltage lockout). Wide Input Supply Voltage Range : 8V to 16V Output Current Limit of 550mA with 45ms Timer Low Noise LNB Output Voltage (13.3V and 18.3V by SEL Pin) +/-3% High Accuracy for 0mA to 500mA Current Output Push-Pull Output Stage Minimizes 13.3V to 18.3V and 18.3V to 13.3V Output Transition Time Output Short Circuit Protection Over-Temperature Protection Applications The RT5070 are available in a SOP-8 (Exposed Pad) package to achieve optimized solution for thermal dissipation. Ordering Information LNB Power Supply and Control for Satellite Set-Top Box Analog and Digital Satellite Receivers/ Satellite TV, Satellite PC cards RT5070 Pin Configurations Package Type SP : SOP-8 (Exposed Pad-Option 2) (TOP VIEW) Lead Plating System G : Green (Halogen Free and Pb Free) Note : BOOST 2 LX 3 VIN 4 Richtek products are : GND GND 7 FAULT 6 SEL 5 EN 9 RoHS compliant and compatible with the current SOP-8 (Exposed Pad) requirements of IPC/JEDEC J-STD-020. 8 LNB Suitable for use in SnPb or Pb-free soldering processes. Simplified Application Circuit L1 D1 VIN CBST CIN1 LX BOOST VIN CIN2 D3 EN SEL 3.3V RT5070 Max. 550mA LNB D2 CLNB D4 R1 FAULT Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 March 2015 GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT5070 Marking Information RT5070GSP : Product Number YMDNN : Date Code RT5070 GSPYMDNN Functional Pin Description Pin No. Pin Name Pin Function 1 LNB Output Voltage for LNB. 2 BOOST Boost Output and Tracking Supply Voltage to LNB. 3 LX Switching Node of DC/DC Boost Converter. 4 VIN Power Supply Input. 5 EN LNB Output Enable. 6 SEL LNB Output Voltage Selection Pin (Low is for 13.3V, high is for 18.3V). 7 FAULT Fault Detection Pin. Pull to 3.3V by 4.7k resistor. Ground. The Exposed Pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 8, 9 (Exposed Pad) GND Function Block Diagram LX VIN BOOST OCP1 UVLO VR1 VFB1 RF1 EN Oscillator Error Amp PWM Controller RF2 OSC 2-steps Voltage Setting VD2 Dynamic Dropout Control Linear Regulator LNB VUD SEL DAC OCP2 Logic Bandgap Reference VD1 FAULT OTP VR1 Reference Voltage GND Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT5070 Operation The RT5070 integrates a current mode boost converter OTP and linear regulator. Use the SEL pin to control the LNB voltage and the boost converter track is at least greater 850mV than LNB voltage. The boost converter is the high efficiency PWM architecture with 700kHz operation frequency. The linear regulator has the capability to source current up to 550mA during When the junction temperature reaches the critical temperature (typically 150C), the boost converter and the linear regulator are immediately disabled. continuous operation. All the loop compensation, current sensing, and slope compensation functions are provided internally. OCP Both the boost converter and the linear regulator have independent current limit. In the boost converter (OCP1), this is achieved through cycle-by-cycle internal current limit (typ. 3A). In the linear regulator UVLO The UVLO circuit compares the VIN with the UVLO threshold (7.7V rising typically) to ensure that the input voltage is high enough for reliable operation. The 350mV (typ.) hysteresis prevents supply transients from causing a shutdown. PWM Controller The loop compensation, current sensing, and slope compensation functions are provided internally. (OCP2), when the linear regulator exceeds OCP more than 48ms, the LNB output will be disabled and re-start after 1.8s. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 Absolute Maximum Ratings (Note 1) Supply Input Voltage, VIN ------------------------------------------------------------------------------------------- 0.3V to 30V Output Voltage LNB, LX and BOOST Pins --------------------------------------------------------------------- 0.3V to 30V Others Pin to GND ---------------------------------------------------------------------------------------------------- 0.3V to 6V Power Dissipation, PD @ TA = 25C SOP-8 (Exposed pad) ------------------------------------------------------------------------------------------------ 3.44W Package Thermal Resistance (Note 2) SOP-8 (Exposed pad), JA ------------------------------------------------------------------------------------------ 29C/W SOP-8 (Exposed pad), JC------------------------------------------------------------------------------------------ 2C/W Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 260C Junction Temperature ------------------------------------------------------------------------------------------------ 150C Storage Temperature Range --------------------------------------------------------------------------------------- 65C to 150C ESD Susceptibility HBM (Human Body Model) ----------------------------------------------------------------------------------------- 2kV MM (Machine Model) ------------------------------------------------------------------------------------------------- 200V (Note 3) Recommended Operating Conditions (Note 4) Supply Input Voltage ------------------------------------------------------------------------------------------------- 8V to 16V Ambient Temperature Range--------------------------------------------------------------------------------------- 40C to 85C Junction Temperature Range -------------------------------------------------------------------------------------- 40C to 125C Electrical Characteristics (VIN (typ.) = 12V, VIN = 8V to 16V, TA = 25C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit ERR Relative to selected VLNB target level, ILOAD = 0 to 450mA -3 -- 3 % IIN_OFF EN = 0, LNB output disabled -- 0.3 0.5 IIN_ON EN = 1, VLNB = 18.3V, Tone = 0V -- 10 18 Boost Switch On Resistance RDS(ON) ILOAD = 450mA -- 150 300 m Switching Frequency f SW 600 700 800 kHz Switch Current Limit ILIMSW VIN = 10V, VOUT = 20.5V -- 3 -- A Linear Regulator Voltage Drop VDROP VBOOST-VLNB, ILOAD = 450mA -- 0.85 -- V Output Voltage Rise Time TR_LNB For VLNB = 13.3V18.3V, CTCA P= 100nF, ILOAD = 450mA -- 3 10 ms Output Voltage Pull-Down Time TF_LNB For VLNB = 18.3V13.3V, CLOAD = 100nF, ILOAD = 0mA -- 3 10 ms 20MHz Bandwidth Limit (GBD) -- 20 -- mVPP General LNB Output Accuracy, Load and Line Regulation Supply Current mA Ripple and Noise on LNB VRIP_PP Output Copyright © 2015 Richtek Technology Corporation. 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DS5070-00 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT5070 Parameter Load Regulation Line Regulation Symbol Test Conditions Min Typ Max VOUT = 13.3V, IOUT = 50mA to 450mA -- 38 76 VOUT = 18.3V, IOUT = 50mA to 450mA -- 45 90 VIN = 9 to 14V, VOUT = 13.3V, IOUT = 50mA -10 -- 10 VIN = 9 to 14V, VOUT = 18.3V, IOUT = 50mA -10 -- 10 VOUT_LOAD VOUT_LINE Unit mV mV Protection Output Over-Current Limit ILIM_LNB1 VLNB = 13.3V/18.3V 500 550 650 mA Output Over-Current Disable Time TDIS_ON VLNB Short to GND -- 45 -- ms Output Over-Current Disable Time TDIS_OFF VLNB Short to GND (GBD) -- 1800 -- ms VIN Under-Voltage Lockout VUVLO Threshold VIN Falling -- 7.35 -- V VIN Turn On Threshold VIN Rising -- 7.7 8 V VIN Under-Voltage Lockout VUVLOHYS Hysteresis -- 350 -- mV OTP Threshold TOTP -- 140 -- o OTP Hysteresis TOTPHYS -- 15 -- o VEN_H 1.2 -- -- VEN_L -- -- 0.4 IENLKG -- 5 10 VSEL_H 1.2 -- -- VSEL_L -- -- 0.4 ISELLKG -- 5 10 VIN_TH C C ENABLE, SEL Pins EN Logic Input EN Input Leakage V SEL Logic Input SEL Input Leakage A V A Note 1. 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. JA is measured at TA = 25C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. JC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Operation at VIN = 16V may be limited by power loss in the linear regulator. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 Typical Application Circuit L1 10uH D1 SS14 VIN CBST 20uF /30uF CIN1 2x10uF LX BOOST VIN CIN2 1uF D3 SS14 EN RT5070 Max. 550mA LNB SEL 3.3V D2 SS14 CLNB 0.1uF D4 SMDJ20A R1 4.7kΩ FAULT GND Note : (1) D2, D3, D4, are used for surge protection. The clamping voltage of D4 is 30V, the break down voltage must be higher than 24V as recommended. (2) The capacitor C3 should not be less than 1F for the power stability. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT5070 Typical Operating Characteristics Boost Efficiency vs. Output Current System Efficiency vs. Output Current 95 95 90 90 Efficiency (%) 100 Efficiency (%) 100 85 80 75 85 80 75 70 70 65 65 VIN = 12V, V BOOST = 14.3V, V LNB = 13.3V VIN = 12V, VBOOST = 14.3V 60 60 0 0.1 0.2 0.3 0.4 0.5 0 0.6 0.1 0.2 0.4 Output Voltage v.s Temperature 0.6 Output Voltage vs. Output Current 19 19 18 18 VLNB_ 18.3V Output Voltage (V) VLNB_18.3 17 16 15 14 VLNB_13.3 17 16 15 14 VLNB_13.3V 13 13 VIN = 12V VIN = 12V 12 12 -50 -25 0 25 50 75 100 0.00 125 0.10 0.20 0.30 0.40 0.50 0.60 Output Current (A) Temperature (°C) Under Voltage Lockout vs. Temperature Over Current Protect vs. Temperature 0.70 Under Voltage Lockout (V)1 8.00 0.65 Current (A) 0.5 Output Current (A) Output Current (A) Output Voltage (V) 0.3 0.60 0.55 7.80 7.60 7.40 7.20 VIN = 12V, VLNB = 13.3V 0.50 7.00 -25 0 25 50 75 100 Temperature (°C) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 125 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 Output Voltage Transition Rising Output Voltage Transition Falling VLNB (5V/Div) VLNB (5V/Div) VIN = 12V VSEL from 0V to 3.3V, CLNB = 0.1F, VLNB from 13V to 18V VIN = 12V, VSEL from 3.3V to 0V, CLNB = 1F, VLNB from 18V to 13V VSEL (2V/Div) VSEL (2V/Div) Time (500s/Div) Time (500s/Div) Power On Sequence Over Current Protection VBOOST (5V/Div) VLNB (5V/Div) VIN (10V/Div) VBOOST (10V/Div) ILNB (500mA/Div) VLNB (10V/Div) Time (5ms/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 VIN = 12V VIN = 12V March 2015 Time (500ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT5070 Application Information Boost Converter/Linear Regulator The 5070 integrates a current-mode boost converter and linear regulator. Use the SEL pin to control the LNB voltage and the boost converter track is at least greater 800mV than the LNB voltage. The boost converter is high efficiency PWM architecture with 700kHz operation frequency. The linear regulator has the capability to source current up to 550mA during continuous operation. All the loop compensation, current sensing, and slope compensation functions are provided internally. The RT5070 has current limiting on the boost converter and the LNB output to protect the IC against short circuits. The internal MOSFET will turn off when the LX current is higher than 3A cycle-by-cycle. The LNB output will turn off when the output current higher than the 550mA and 45ms and turn-on after 1800ms automatically. Input Capacitor Selection The input capacitor reduces voltage spikes from the input supply and minimizes noise injection to the converter. A 30F capacitance is sufficient for most applications. Nevertheless, a higher or lower value may be used depending on the noise level from the input supply and the input current to the converter. Note that the voltage rating of the input capacitor must be greater than the maximum input voltage. Inductor Selection The inductance depends on the maximum input current. As a general rule, the inductor ripple current range is 20% to 40% of the maximum input current. If 40% is selected as an example, the inductor ripple current can be calculated according to the following equations : VOUT IOUT(MAX) VIN = 0.4 IIN(MAX) IIN(MAX) = IRIPPLE where η is the efficiency of the converter, IIN(MAX) is with half of the inductor ripple current as shown in the following equation : IPEAK = 1.2 x IIN(MAX) note that the saturated current of the inductor must be greater than IPEAK. The inductance can eventually be determined according to the following equation : η VIN VOUT VIN 2 L 0.4 VOUT I OUT(MAX)fOSC where f OSC is the switching frequency. For better system performance, a shielded inductor is preferred to avoid EMI problems. Boost Output Capacitor Selection The RT5070 boost regulator is internally compensated and relies on the inductor and output capacitor value for overall loop stability. The output capacitor is in the 30F to 50F range with a low ESR, as strongly recommended. The voltage rating on this capacitor should be in the 25V to 35V range since it is connected to the boost VOUT rail. The output ripple voltage is an important index for estimating chip performance. This portion consists of two parts. One is the product of the inductor current with the ESR of the output capacitor, while the other part is formed by the charging and discharging process of the output capacitor. As shown in Figure 1, VOUT1 can be evaluated based on the ideal energy equalization. According to the definition of Q, the Q value can be calculated as the following equation : Q = 1 IIN 1 IL IOUT IIN 1 IL IOUT 2 2 2 V IN 1 = COUT VOUT1 VOUT fOSC where f OSC is the switching frequency and IL is the inductor ripple current. Bring COUT to the left side to estimate the value of VOUT1 according to the following equation : the maximum input current, and IRIPPLE is the inductor ripple current. The input peak current can 2 VOUT1 = D IOUT COUT fOSC then be obtained by adding the maximum input current Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 where D is the duty cycle and η is the boost converter efficiency. Finally, take ESR into consideration, the overall output ripple voltage can be determined by the operation. The 350mV (typ.) hysteresis prevents supply transients from causing a shutdown. Once the input voltage exceeds the UVLO rising threshold, start-up following equation : begins. When the input voltage falls below the UVLO falling threshold, all IC internal functions will be turned off by the controller. VOUT = IIN ESR D IOUT COUT fOSC The output capacitor, COUT, should be selected accordingly. ΔIL Input Current Inductor Current Output Current Time (1-D)TS Output Ripple Voltage (ac) Time ΔVOUT1 Over-Current Protection The RT5070 features an over-current protection function to prevent chip damage from high peak currents. Both the boost converter and the linear regulator have independent current limit. In the boost converter, this is achieved through cycle-by-cycle internal current limit. During the ON-period, the chip senses the inductor current that is flowing into the LX pin. The internal NMOS will be turned off if the peak inductor current reaches the current-limit value of 3A (typ.).When the linear regulator exceeds 550mA (typ.) more than 45ms, the LNB output will be disabled. During this period of time, if the current limit condition disappears, the OCP will be cleared and the part restarts. If the part is still in current limit after this time period, the linear regulator and boost converter will automatically disable to prevent the part from overheating. Figure 1. The Output Ripple Voltage without the Short Circuit Protection Contribution of ESR Schottky Diode Selection Schottky diodes are chosen for their low forward-voltage drop and fast switching speed. However, when making a selection, important parameters such as power dissipation, reverse voltage rating, and pulsating peak current should all be taken into consideration. A suitable Schottky diode’s reverse voltage rating must be greater than the maximum output voltage and its average current rating must exceed the average output current. The chosen diode should also have a sufficiently low leakage current level, since it increases with temperature. Under-Voltage Lockout (UVLO) The UVLO circuit compares the input voltage at VIN with the UVLO threshold (7.7V rising typically) to ensure that the input voltage is high enough for reliable Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 March 2015 If the LNB output is shorted to ground, and more than 45ms, the RT5070 will be disabled 1.8s then enable automatically. Over-Temperature Protection When the junction temperature reaches the critical temperature (typically 140 oC), the boost converter and the linear regulator are immediately disabled. When the junction temperature cools down to a lower temperature threshold specified, the RT5070 will be allowed to restart by normal start operation. LNB Output Voltage The RT5070 has voltage control function on the LNB output. This function provides 4 levels for the common standards and compensation if the cable line has voltage drop. These voltage levels are defined in table 1. The rise time and fall time of the VLNB is 3mS (typ.). is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT5070 Table 1 Thermal Considerations SEL Pin Status LNB Output Voltage 0 13.3V 1 18.3V Pull-Down Rate Control The output linear stage provides approximately 40mA of pull-down capability. This ensures that the output volts are ramped from 18.3V to 13.3V in a reasonable amount of time. Over-Current Disable Time If the LNB output current exceeds 550mA, typical, for more than 45ms, then the LNB output will be disabled and device enters a TON = 45ms/TOFF = 1800ms routine. It will be returned to normal operation after a successful soft-start process. If loading is 1000mA OCP1=1000mA OCP1=1000mA 25ms 25ms OCP2=550mA OCP2=550mA 20ms 20ms 1800ms If LNB is shorted to GND 25ms 25ms OCP2=138mA OCP2=138mA 20ms 20ms 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) / JA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and JA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125C. The junction to ambient thermal resistance, JA, is layout dependent. For SOP-8 (Exposed Pad) package, the thermal resistance, JA, is 29C/W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at TA = 25C can be calculated by the following formula : PD(MAX) = (125C 25C) / (29C/W) = 3.44W for SOP-8 (Exposed Pad) package The maximum power dissipation depends on the operating ambient temperature for fixed TJ(MAX) and OCP1=250mA OCP1=250mA For continuous operation, do not exceed absolute maximum junction temperature. The maximum power 1800ms thermal resistance, JA. The derating curve in Figure 2 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. At start-up or during a LNB reconfiguration event, a transient surge current above the normal DC operating level can be provided by the IC. This current increase can be as high as 550mA, typical, for as long as required, up to a maximum of 45ms. DC Current The RT5070 can handle up to 500mA during continuous operation. Maximum Power Dissipation (W) 1 Inrush Current 5.0 Four-Layer PCB 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 2. Derating Curve of Maximum Power Dissipation Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015 RT5070 Layout Consideration For high frequency switching power supplies, the PCB layout is important to get good regulation, high efficiency and stability. The following descriptions are the guidelines for better PCB layout. For good regulation, place the power components as close as possible. The traces should be wide and short enough especially for the high-current loop. Minimize the size of the LX node and keep it wide and shorter. The exposed pad of the chip should be connected to a strong ground plane for maximum thermal consideration. The CIN, CBST and CLNB should be placed as closed as possible to R T 5 0 4 7 f o r good filter. D 3 and D 4 should be placed as closed as possible to VOUT for surge protection. VOUT D4 CLNB1 The exposed pad of the chip should be connected to analog ground plane for thermal consideration. D2 LNB GND D3 BOOST CBST1 CBST2 CBST3 FAULT GND D1 LX SEL The SEL and EN pin should be connected to MCU or GND. Do not floating these pins. L1 VIN VIN CIN1 EN CIN2 The inductor should be placed as close as possible to the L X pin to minimize the noise coupling into other circuits. LX node copper area should be minimized for reducing EMI Place the power components as close as possible. The traces should be wide and short especially for the high-current loop. Figure 3. PCB Layout Guide Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS5070-00 March 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT5070 Outline Dimension Dimensions In Millimeters Symbol Dimensions In Inches Min Max Min Max A 4.801 5.004 0.189 0.197 B 3.810 4.000 0.150 0.157 C 1.346 1.753 0.053 0.069 D 0.330 0.510 0.013 0.020 F 1.194 1.346 0.047 0.053 H 0.170 0.254 0.007 0.010 I 0.000 0.152 0.000 0.006 J 5.791 6.200 0.228 0.244 M 0.406 1.270 0.016 0.050 X 2.000 2.300 0.079 0.091 Y 2.000 2.300 0.079 0.091 X 2.100 2.500 0.083 0.098 Y 3.000 3.500 0.118 0.138 Option 1 Option 2 8-Lead SOP (Exposed Pad) Plastic Package Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 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. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS5070-00 March 2015