ILC6370

ILC6370 IMPALA | Alldatasheet

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SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation Impala Linear Corporation 1(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 50mA boost converter in 5-lead SOT-89 package. Only 3 external components are needed to complete the switcher design, and frequency options of 50, 100, and 180kHz gives the designer the ability to trade off system needs with switcher design size. 87% max duty cycle gives conversion efficiencies of 85%. Standard voltage options of 2.5V, 3.3V, and 5.0V at ±2.5% accuracy feature on-chip phase compensation and soft- start design. ILC6371 drives an external transistor for higher current switcher design, with all of the features and benefits of the ILC6370. ! 85% efficiency at 50mA ! Start-up voltages as low as 900mV ! ±2.5% accurate outputs ! Complete switcher design with only 3 external components ! 50, 100 and 180kHz switching frequency versions available ! Shutdown to 0.5µA ! External transistor option allows several hundred milliamp switcher design ! Cellular Phones, Pagers ! Portable Cameras and Video Recorders ! Palmtops and PDAs Ordering Information* ILC6370CP-25 2.5V±2.5%@50kHz ILC6370CP-25 3.3V±2.5%@50kHz ILC6370CP-50 5.0V±2.5%@50kHz ILC6370BP-25 2.5V±2.5%@100kHz ILC6370BP-33 3.3V±2.5%@100kHz ILC6370BP-50 5.0V±2.5%@100kHz ILC6370AP-25 2.5V±2.5%@180kHz ILC6370AP-33 3.3V±2.5%@180kHz ILC6370AP-50 5.0V±2.5%@180kHz ILC6371CP-25 2.5V±2.5%@50kHz, external xtor ILC6371CP-33 3.3V±2.5%@50kHz, external xtor ILC6371CP-50 5.0V±2.5%@50kHz, external xtor ILC6371BP-25 2.5V±2.5%@100kHz, external xtor ILC6371BP-33 3.3V±2.5%@100kHz, external xtor ILC6371BP-50 5.0V±2.5%@100kHz, external xtor ILC6371AP-25 2.5V±2.5%@180kHz, external xtor ILC6371AP-33 3.3V±2.5%@180kHz, external xtor ILC6371AP-50 5.0V±2.5%@180kHz, external xtor Standard Product offering comes in tape and reel, quantity 1000 per reel, orientation right for SOT-89 VLX LIMI TER PW M C on t ro ll ed BUFFER LX VSS EX T CH IP EN A BLE OSC 5 0/1 00/180K Hz VDD VOUT CE Phas e c omp Vre f Slow St art VDD is i nternall y connec ted to the VOU T pi n. SOT -89-5 (TOP VI EW) 13 2 VOU T CE LX VSS N/C SOT -89-5 (TOP VI EW) 13 2 VOU T CE EXT VSS N/C ILC6370 ILC6371 General Description Features

Applications

Pin-Package Configurations

SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation 2(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 Parameter Symbol Ratings Units VOUT Input Voltage Pin VOUT 12 V CE Input Voltage VCE 12 V Voltage on pin LX VLX 12 V Current on pin LX ILX 400 mA Voltage on pin EXT VEXT 0.3 ~VOUT +0.3 V Current pin EXT IEXT +50 mA Continuous Total Power Dissipation (SOT-89-5) PD 500 mW Operating Ambient Temperature TOPR -30~+80 οC Storage Temperature TSTG -40~+125 οC Parameter Symbol Conditions Min Typ Max Units Output Voltage VOUT 3.218 3.300 3.383 V Input Voltage VIN 10 V Oscillation Startup Voltage VST2 LX :10kΩ Pull-up to.5V, VOUT = VST 500 600 mA Operation Startup Voltage VST1 IOUT +1mA 55 86 µA Supply Current 1 IDD1 LX :10kΩ Pull-up to.5V, VOUT = 4.5V 1.5 2.5 µA Supply Current 1 IDD2 Open Loop Measurement, VS/D = VIN, VLX =VIN- 0.4V, VOUT = 3V 0.64 0.85 Ω LX Switch-On Resistance RSWON Open Loop Measurement, VOUT = VIN, VLX = 0V 2.0 µA LX Leakage Current ILXL Measure Waveform at EXT pin VIN = 3.6V IOUT = 20mA 255 300 345 KHz Oscillator Frequency FOSC 100 % Maximum Duty Ratio MAXDTY No Load 10 17 25 % Satndb-by Current ISTB 95 % CE "High " Voltage VCEH Minimum VIN When Vref does not start up 1 1.8 V CE "Low " Voltage VCEL Vref rises to 0V from 0.9V 6.0 10.0 16.0 msec Note: Unless otherwise spcified, V IN = VOUT x 0.6, IOUT = 50mA. See Schematic, figure 1. Absolute Maximum Ratings (TA = 25°C) VOUT = 5.0V, FOSC = 100kHz, TA = 25°C, Test Circuit of figure 1 Elcetrical Characteristics ILC6370BP-50

SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation 3(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 Parameter Symbol Conditions Min Typ Max Units CE “High” Current ICEH LX: 10kΩ pull-up to 5V, VCE = VOUT = 4.5V 0.25 µA CE “Low” Current ICEL LX: 10kΩ pull-up to 5V, VOUT = 4.5V, VCE = 0V -0.25 µ LX Limit Voltage VLXLMT LX: 10kΩ pull-up to 5V, VOUT = 4.5V, FOSC > FOSC x 2(1) 0.7 1.1 V Efficiency EFFI 85 % Parameter Symbol Conditions Min Typ Max Units Output Voltage VOUT 4.87 5.000 5.125 V Input Voltage VIN 10 V Oscillation Startup Voltage VST EXT: 10kΩ pull-up to 5V, VOUT = VST 0.8 V Supply Current 1 IDD 1 EXT: 10kΩ pull-up to 5V, VOUT = 4.5V 38.4 64.1 µA Supply Current 2 IDD 2 EXT: 10kΩ pull-up to 5V, VOUT = 5.5V 6.9 13.8 µA EXT “High” On-Resistance REXTH EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, VEXT = 4.1V 30 50 Ω EXT “Low” On-Resistance REXTL VEXT = 0.4V, VOUT = 5.5V 30 50 Ω Oscillator Frequency FOSC EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, Measuring of EXT pin 85 100 115 kHz Maximum Duty Ratio MAXDTY EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, Measuring of EXT pin 80 87 92 % Stand-by Current ISTB EXT: 10kΩ pull-up to 5V, VOUT = 4.5V 0.5 µA CE “High” Voltage VCEH EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, Existance of LX Oscillation 0.75 V CE “Low” Voltage VCEL EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, Stopped LX Oscillation 0.20 V CE “High” Current ICEH EXT: 10kΩ pull-up to 5V, VOUT = VCE = 4.5V 0.25 µA CE “Low” Current ICEL EXT: 10kΩ pull-up to 5V, VOUT = 4.5V, VCE = 0V -0.25 µA Efficiency EFFI 85 % Slow Start Time TSS 10 msec VOUT = 5.0V, FOSC = 100kHz, TA = 25°C; Test Circuit of figure 1 1. Switching frequency determined by delay time of internal comparator to turn L X “OFF,” and minimum “ON” time as determined by MAXDTY spec. VOUT = 5.0V, FOSC = 100kHz, TA = 25°C; Test Curcuit of figure 2.

SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation 5(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 The ILC6370 performs boost DC-DC conversion by controlling the switch element shown in the circuit below. When the switch is closed, current is built up through the inductor. When the switch opens, this current has to go somewhere and is forced through the diode to the output. As this on and off switch- ing continues, the output capacitor voltage builds up due to the charge it is storing from the inductor current. In this way, the out- put voltage gets boosted relative to the input. The ILC6370 mon- itors the voltage on the output capacitor to determine how much and how often to drive the switch. In general, the switching characteristic is determined by the output voltage desired and the current required by the load. Specifically the energy transfer is determined by the power stored in the coil during each switching cycle. PL = ƒ(t ON, VIN) The ILC6370 and ILC6371 use a PWM or Pulse Width Modulation technique. The parts come in one of three fixed internal frequen- cies: 50, 100, or 180kHz. The switches are constantly driven at these frequencies. The control circuitry varies the power being delivered to the load by varying the on-time, or duty cycle, of the switch. Since more on-time translates to higher current build up in the inductor, the maxmim duty cycle of the switch determines the maximum load current that the device can support. The ILC6370 and ILC6371 both support up to 87% duty cycles, for maximum usable range of load currents. There are two key advantages of PWM type controllers. First, because the controller automatically varies the duty cycle of the switche’s on-time in response to changing load conditions, the PWM controller will always have an optimized waveform for a steady-state load. This translates to very good efficiency at high currents and minimal ripple on the output. [ Ripple is due to the output cap constanty accepting and storing the charge recieved from the inductor, and delivering charge as required by the load. The “pumping” action of the switch produces a sawtooth-shaped voltage as seen by the output. ] The other key advatage of the PWM type controllers is that the radiated noise due to the swtiching transients will always occur at the (fixed) switching frequency. Many applications do not care much about switching noise, but certain types of applications, especially communication equipment, need to minimze the high frequency interference within their system as much as is possible. Using a boost converter requires a certain amount of higher fre- quency noise to be generated; using a PWM converter makes that noise highly predictable; thus easier to filter out. There are downsides of PWM approaches, especially at very low currents. Because the PWM technique relies on constant switch- ing and varying duty cycle to match the load conditions, there is some point where the load current gets to small to be handled effi- ciently. If the ILC6370 had an ideal switch, this would not be such a problem. But an actual switch consumes some finite amount of current to switch on and off; at very low current this can be of the same magnitude as the load current itself, driving switching effi- ciencies down to 50% and below. The other limitation of PWM techniques is that, while the funda- mental switching frequency is easier to filter out since it’s constant, the higher order harmonics of PWM will be present and may have to be filtered out as well. Any filtering rquirements will vary by appli- cation and by actual system design and layout, so generalizations in this area are difficult, at best. [ For other boost converter tech- niques, please see the ILC6380/81 and ILC6390/91 data sheets.] However, PWM control for boost DC-DC conversion is widely used, especially in audio-noise sensitive applications or applica- tions requiring strict filtering of the high frequency components. Impala’s products give very good efficiencies of 85% at 50mA out- put (5V operation), 87% maximum duty cycles for high load con- ditions, while maintaining very low shutdown current levels of 0.5µA. The only difference between the ILC6370 and ILC6371 parts is that the 6371 is configured to drive an external transistor as the switch element. Since larger transistors can be selected for this element, higher effective loads can be regulated. Start-up Mode The ILC6370 has an internal soft-start mode which suppresses ringing or overshoot on the output during start-up. The following diagram illustrates this start-up condition’s typical performance External Components and Layout Consideration The ILC6370 is designed to provide a complete DC-DC convertor solution with a minmum of external components. Ideally, only three externals are required: the inductor, a pass diode, and an output capacitor. The inductor needs to be of low DC Resistance type, typically 1 Ω value. Toroidal wound inductors have better field containment (less high frequency noise radiated out) but tend to be more expensive. Some manufacturers like Coilcraft have new bobbin-wound induc- tors with shielding included, which may be an ideal fit for these applications. Contact the manufacturer for more information. The inductor size needs to be in the range of 47µH to 1mH. In general, larger inductor sizes deliver less current, so the load cur- rent wil determine the inductor size used. VIN - Vf VOUT MIN T SOFT-START (~10msec) t = 0 Functions and Operation

SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation 6(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 For load currents higher than 10mA, use an inductor from 47µH to 100µH. [The 100µH inductor shown in the data sheet is the most typical used for this application.] For load currents of around 5mA, such as pagers, use an indcutor in the range of 100µH to 330µH. 220µH is the most typical value used here. For lighter loads, an inductor of up to 1mH can be used. The use of a larger inductor will increase overall conversion efficiency, due to the reduction in switching currents through the device. For the ILC6371, using an external transistor, the use of a 47µH inductor is recommended based on our experience with the part. Note that these values are recommended for both 50kHz and 100kHz operation. If using the ILC6370 or ILC6371 at 180kHz, the inductor size can be reduced to approximately half of these stated values. The capacitor should, in general, always be tantalum type, as tan- talum has much better ESR and temperature stability than other capacitor types. NEVER use electrolytics or chemical caps, as the C-value changes below 0°C so much as to make the overall design unstable. Different C-values will directly impact the ripple seen on the output at a given load current, due to the direct charge-to-voltage rela- tionship of this element. Different C-Values will also indirectly affect system reliability, as the lifetime of the capacitor can be degraded by constant high current influx and outflux. Running a capacitor near its maximum rated voltage can deteriorate lifetime as well; this is especially true for tantalum caps which are particu- larly sensitive to overvoltage conditions. In general, this capacitor should always be 47µF, Tantalum, 16V rating. The diode must be of shottkey type for fast recovery and minimal loss. A diode rated at greater than 200mA and maximum voltage greater than 30V is recommended for the fastest switching time and best reliability over time. Different diodes may introduce dif- ferent level of high frequency switching noise into the output waveform, so trying out several sources may make the most sense for your system. For the ILC6371, much of the component selection is as described above, with the addition of the external NPN transistor and the base drive network. The transistor needs to be of NPN type, and shoud be rated for currents of 2A or more. [ This translates to lower effective on resistance and, therefore, higher overall effi- ciencies.] The base components should remain at 1k Ω and 3300kΩ ; any changes need to be verified prior to implementation. As for actual physical component layout, in general, the more compact the layout is, the better the overall performance will be. It is important to remember that everything in the circuit depends on a common and solid ground reference. Ground bounce can direct- ly affect the output regulation and presents difficult behavior to predict. Keeping all ground traces wide will elliminate ground bounce problems. It is also critical that the ground pin of C L and V SS pin of the device be the same pin on the board, as this capacitor serves two functions: that of the output load capacitor, and that of the input supply bypass capacitor. Layouts for DC-DC converter designs are critical for overall performance, but following these simple guidlines can simplify the task by avoiding some of the more common mistakes made in these cases. Once actual performance is completed, be sure to double check the design on an actual manufacturing prototype prodcut to verfy that nothing has changed which can affect the performance.

SOT-89 Step up Switching Regulator with Shutdown OUTPUT VOLTAGE vs. OUTPUT CURRENT OUTPUT VOLTAGE vs. OUTPUT CURRENT ILC6370CP-50 ILC6370CP-50 ILC6370CP-50 ILC6370CP-50, No Load Current ILC6370CP-30, No Load Current ILC6370CP-30 ILC6370CP-30 ILC6370CP-30 5.4 5.2 5.0 4.8 4.6 4.4 4.4 4.0 5.4 5.2 5.0 4.8 4.6 4.4 4.4 4.0 0 100 200 300 400 500 0 40 80 120 160 200 OUTPUT CURRENT IOUT (mA) OUTPUT VOLTAGE VOUT (v) OUTPUT VOLTAGE VOUT (v) VIN = 2.0V VIN = 2.0V VIN = 2.0V VIN = 3.0V VIN = 3.0V VIN = 3.0V VIN = 4.0V VIN = 4.0V VIN = 4.0V VIN = 1.0V VIN = 1.0V VIN = 1.0V VIN = 1.5V VIN = 1.5V VIN = 1.5V VIN = 2.0V VIN = 2.0V VIN = 2.0V VIN = 1.0V VIN = 1.0V VIN = .9V L = 100µH C = 47µF (Tantalum) L = 100µH C = 47µF (Tantalum) L = 100µH C = 47µF (Tantalum) L = 100µH C = 47µF (Tantalum) L = 100µH C = 47µF (Tantalum) L = 100µH C = 47µF (Tantalum) OUTPUT CURRENT IOUT (mA) 0 100 200 300 400 500 OUTPUT CURRENT IOUT (mA) 100 EFFICIENCY vs. OUTPUT CURRENT EFFICIENCY vs. OUTPUT CURRENT EFFICIENCY: EFFI (%) EFFICIENCY: EFFI (%) 100 OUTPUT CURRENT IOUT (mA) 0 40 80 120 160 200 OUTPUT CURRENT IOUT (mA) 100 0 50 100 150 200 RIPPLE VOLTAGE vs. OUTPUT CURRENTRIPPLE VOLTAGE vs. OUTPUT CURRENT RIPPLE Vr (mV p-p) 100 0 100 200 300 400 500 OUTPUT CURRENT IOUT (mA) RIPPLE Vr (mV p-p) INPUT VOLTAGE vs. OUTPUT CURRENT INPUT VOLTAGE vs. OUTPUT CURRENT 100 500 400 300 200 100 1 2 3 4 INPUT VOLTAGE VIN (V) INPUT CURRENT (µA)L = 100µH RL = 0 C = 47µF (Tantalum) L = 100µH RL = 0 C = 47µF (Tantalum) INPUT VOLTAGE VIN (V) 250 200 150 100 INPUT CURRENT (µA) Typical Performance Characteristics General conditions for all curves ILC6370/1 1.3 Impala Linear Corporation 7(408) 574-3939 www.impalalinear.com July 1999

SOT-89 Step up Switching Regulator with Shutdown Impala Linear Corporation 8(408) 574-3939 www.impalalinear.com July 1999 ILC6370/1 1.3 START VOLTAGE/HOLD VOLTAGE vs. IOUT ILC6370CP-50 ILC6370CP-50 VST , VHLD (ςς) 1.2 1.0 0.8 0.6 0.4 0.2 OUTPUT CURRENT IOUT (mA) 01 0 2 0 3 0 L = 100µH C = 47µF (Tantalum) VHLD VST TRANSIENT RESPONSE 7.0 6.0 5.0 4.0 3.0 -20 0 20 40 60 80 VIN = 3.0V IOUT = 1mA~30mA L = 100µH C = 47µF (Tantallum) TIME (µsec) OUTPUT VOLTAGE VOUT (V) Typical Performance Characteristics General conditions for all curves