LT1304

LT1304/LT1304-3.3/LT1304-5 Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown FEATURES s s s s s s s s s DESCRIPTION The LT®1304 is a micropower step-up DC/DC converter ideal for use in small, low voltage, battery-operated systems. The devices operate from a wide input supply range of 1.5V to 8V. The LT1304-3.3 and LT1304-5 generate regulated outputs of 3.3V and 5V and the adjustable LT1304 can deliver output voltages up to 25V. Quiescent current, 120µA in active mode, decreases to just 10µA in shutdown with the low-battery detector still active. Peak switch current, internally set at 1A, can be reduced by adding a single resistor from the ILIM pin to ground. The high speed operation of the LT1304 allows the use of small, surface-mountable inductors and capacitors. The LT1304 is available in an 8-lead SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. 5V at 200mA from Two Cells 10µA Quiescent Current in Shutdown Operates with VIN as Low as 1.5V Low-Battery Detector Active in Shutdown Low Switch VCESAT: 370mV at 1A Typical 120µA Quiescent Current in Active Mode Switching Frequency Up to 300kHz Programmable Peak Current with One Resistor 8-Lead SO Package APPLICATIONS s s s s s s 2-, 3-, or 4-Cell to 5V or 3.3V Step-Up Portable Instruments Bar Code Scanners Palmtop Computers Diagnostic Medical Instrumentation Personal Data Communicators/Computers TYPICAL APPLICATION 2-Cell to 5V Step-Up Converter with Low-Battery Detect 22µH* 3 1 VIN LBI 4 SW SENSE LT1304-5 6 ILIM SHDN 7 SHUTDOWN *SUMIDA CD54-220 **1N5817 1304 TA01 D1** 90 499k 8 100k 2 CELLS 100µF 604k NC 100µF LBO LOW WHEN VBAT < 2.2V EFFICIENCY (%) + + 5V 200mA 80 70 LBO GND 5 2 60 VIN = 3.3V VIN = 2.5V VIN = 1.8V 1 10 100 LOAD CURRENT (mA) 500 1304 TA02 50 40 0.1 U U U Efficiency 1 LT1304/LT1304-3.3/LT1304-5 ABSOLUTE MAXIMUM RATINGS VIN Voltage ................................................................ 8V SW Voltage ............................................... – 0.4V to 25V FB Voltage (LT1304) ...................................... VIN + 0.3V Sense Voltage (LT1304-3.3/LT1304-5) ..................... 8V ILIM Voltage .............................................................. 5V SHDN Voltage ............................................................ 6V LBI Voltage ............................................................... VIN LBO Voltage ............................................................... 8V Maximum Power Dissipation ............................. 500mW Junction Temperature.......................................... 125°C Operating Temperature Range ..................... 0°C to 70°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW LBI 1 LBO 2 VIN 3 SW 4 8 7 6 5 FB (SENSE)* SHDN ILIM GND LT1304CS8 LT1304CS8-3.3 LT1304CS8-5 S8 PART MARKING 1304 13043 13045 S8 PACKAGE 8-LEAD PLASTIC SO *FIXED OUTPUT VERSION TJMAX = 125°C, θJA = 150°C/W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS PARAMETER Minimum Operating Voltage Operating Voltage Range Quiescent Current Quiescent Current in Shutdown Comparator Trip Point FB Pin Bias Current Sense Pin Leakage in Shutdown Output Sense Voltage Line Regulation LBI Input Threshold LBI Bias Current LBI Input Hysteresis LBO Output Voltage Low LBO Output Leakage Current SHDN Input Voltage High SHDN Input Voltage Low SHDN Pin Bias Current Switch OFF Time Switch ON Time Maximum Duty Cycle Peak Switch Current VSHDN = 5V VSHDN = 0V ISINK = 500µA CONDITIONS VIN = 2V, VSHDN = 2V unless otherwise noted. MIN q q TYP 1.5 120 7 27 MAX 1.65 8 200 15 50 1.26 25 1 3.43 5.25 0.15 1.25 20 65 0.4 0.1 0.4 UNITS V V µA µA µA V nA µA V V %/V V nA mV V µA V V µA µA µs µs % A mA VSHDN = 2V, Not Switching VSHDN = 0V, VIN = 2V VSHDN = 0V, VIN = 5V LT1304 LT1304 VSHDN = 0V, Fixed Output Versions LT1304-3.3 LT1304-5 1.8V ≤ VIN ≤ 8V Falling Edge q q q q q q q q q q q q q q q q q q q 1.22 1.24 10 0.002 3.17 4.80 1.10 3.3 5.05 0.04 1.17 6 35 0.2 0.01 LBI = 1.5V, LBO = 5V 1.4 5 –2 1.5 6 80 1 500 8 2 8 88 1.2 –5 1 4 76 0.8 Current Limit Not Asserted Current Limit Not Asserted ILIM Pin Open, VIN = 5V 20k from ILIM to GND q q 2 U W U U WW W LT1304/LT1304-3.3/LT1304-5 ELECTRICAL CHARACTERISTICS PARAMETER Switch Saturation Voltage Switch Leakage CONDITIONS ISW = 1A ISW = 700mA VIN = 2V, VSHDN = 2V unless otherwise noted. MIN q q TYP 0.37 0.26 0.01 MAX 0.35 7 UNITS V V µA Switch Off, VSW = 5V The q denotes specifications which apply over the 0°C to 70°C operating temperature range. TYPICAL PERFORMANCE CHARACTERISTICS Switch Saturation Voltage 500 TA = 25°C 1.2 SATURATION VOLTAGE (mV) 400 PEAK CURRENT (A) 1.0 0.9 0.8 0.7 TIME (µs) 300 200 100 0 0 0.2 0.4 0.6 0.8 SWITCH CURRENT (A) 1.0 1.2 1304 G01 Feedback Voltage 1.250 1.245 1.240 FEEDBACK VOLTAGE (V) BIAS CURRENT (nA) 1.235 1.230 1.225 1.220 1.215 1.210 1.205 1.200 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 20 18 14 12 10 8 6 4 2 0 –50 –25 25 50 0 TEMPERATURE (°C) 75 100 1304 G05 SUPPLY CURRENT (µA) UW 1304 G04 Peak Switch Current Limit 1.3 8 7 6 5 4 3 2 1 –25 0 25 50 TEMPERATURE (°C) 75 100 1304 G02 On- and Off-Times MAXIMUM ON-TIME 1.1 OFF-TIME 0.6 –50 0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 1304 G03 Feedback Pin Bias Current 300 Supply Current TA = 25°C 250 200 150 100 50 0 VSHDN = VIN NOT SWITCHING 16 VSHDN = 0V 0 1 2 6 4 3 5 INPUT VOLTAGE (V) 7 8 1304 G06 3 LT1304/LT1304-3.3/LT1304-5 TYPICAL PERFORMANCE CHARACTERISTICS Load Transient Response VOUT 100mV/DIV AC COUPLED ILOAD 200mA 0 100µs/DIV 1304 G07 PIN FUNCTIONS LBI (Pin 1): Low-Battery Detector Input. When voltage on this pin is less than 1.17V, detector output is low. LBO (Pin 2): Low-Battery Detector Output. Open collector can sink up to 500µA. Low-battery detector remains active when device is shut down. VIN (Pin 3): Input Supply. Must be bypassed close (< 0.2") to the pin. See required layout in the Typical Applications. SW (Pin 4): Collector of Power NPN. Keep copper traces on this pin short and direct to minimize RFI. GND (Pin 5): Device Ground. Must be low impedance; solder directly to ground plane. ILIM (Pin 6): Current Limit Set Pin. Float for 1A peak switch current; a resistor to ground will lower peak current. SHDN (Pin 7): Shutdown Input. When low, switching regulator is turned off. The low-battery detector remains active. The SHDN input should not be left floating. If SHDN is not used, tie the pin to VIN. FB/SENSE (Pin 8): On the LT1304 (adjustable) this pin goes to the comparator input. On the fixed-output versions, the pin connects to the resistor divider which sets output voltage. The divider is disconnected from the pin during shutdown. 4 UW Burst ModeTM Operation VOUT 100mV/DIV AC COUPLED VSW 5V/DIV IL 500mA/DIV VIN = 2.5V VOUT = 5V ILOAD = 185mA L = 22µH 20µs/DIV 1304 G08 Burst Mode is a trademark of Linear Technology Corporation. U U U LT1304/LT1304-3.3/LT1304-5 BLOCK DIAGRA S VIN 1 R3 8 R4 FB Figure 1. LT1304 Block Diagram. Independent Low-Battery Detector A3 Remains Alive When Device Is in Shutdown 8 SENSE R1 = 355k (LT1304-3.3), 195k (LT1304-5) W LBI + C1 3 L1 VIN SW D1 4 + VOUT C2 2 LB0 1.5V UNDERVOLTAGE LOCKOUT 36mV + A2 + A3 BIAS ~1V – 1.17V – Q3 R2 1k R1 7.2Ω OFF – A1 ENABLE + 1.24V VREF TIMERS 6µs ON 1.5µs OFF DRIVER 1k Q2 ×1 Q1 × 200 SHUTDOWN 7 SHDN 6 ILIM 5 GND 1304 F01 LBI 1 LB0 2 1.5V UNDERVOLTAGE LOCKOUT 36mV VIN 3 SW 4 + A2 + A3 BIAS ~1V – 1.17V 590k – Q3 R2 1k R1 7.2Ω OFF – R1 A1 ENABLE + 1.24V VREF TIMERS 6µs ON 1.5µs OFF DRIVER 1k Q2 ×1 Q1 × 200 SHUTDOWN SHDN 7 6 ILIM 5 GND 1304 F02 Figure 2. LT1304-3.3/LT1304-5 Block Diagram 5 LT1304/LT1304-3.3/LT1304-5 OPERATIO The LT1304’s operation can best be understood by examining the block diagram in Figure 1. Comparator A1 monitors the output voltage via resistor divider string R3/R4 at the FB pin. When VFB is higher than the 1.24V reference, A2 and the timers are turned off. Only the reference, A1 and A3 consume current, typically 120µA. As VFB drops below 1.24V plus A1’s hysteresis (about 6mV), A1 enables the rest of the circuit. Power switch Q1 is then cycled on for 6µs, or until current comparator A2 turns off the ON timer, whichever comes first. Off-time is fixed at approximately 1.5µs. Q1’s switching causes current to alternately build up in inductor L1 and discharge into output capacitor C2 via D1, increasing the output voltage. As VFB increases enough to overcome C1’s hysteresis, switching action ceases. C2 is left to supply current to the load until VOUT decreases enough to force A1’s output high, and the entire cycle repeats. If switch current reaches 1A, causing A2 to trip, switch ON time is reduced. This allows continuous mode operation during bursts. A2 monitors the voltage across 7.2Ω resistor R1, which is directly related to the switch current. Q2’s collector current is set by the emitter-area ratio to 0.5% of Q1’s collector current. R1’s voltage drop exceeds 36mV, corresponding to 1A switch current, A2’s output goes high, truncating the ON time part of the switch cycle. The 1A peak current can be reduced by tying a resistor between the ILIM pin and ground, causing a voltage drop to appear across R2. The drop offsets some of the 36mV reference voltage, lowering peak current. A 22k resistor limits current to approximately 550mA. A capacitor connected between ILIM and ground provides soft start. Shutdown is accomplished by grounding the SHDN pin. The low-battery detector A3 has its own 1.17V reference and is always on. The open collector output device can sink up to 500µA. Approximately 35mV of hysteresis is built into A3 to reduce “buzzing” as the battery voltage reaches the trip level. Inductor Selection Inductors used with the LT1304 must be capable of handling the worst-case peak switch current of 1.2A without saturating. Open flux rod or drum core units may be biased into saturation by 20% with only a small reduc- 6 U tion in efficiency. For the majority of 2-cell or 3-cell input LT1304 applications, a 22µH or 20µH inductor such as the Sumida CD54-220 (drum) or Coiltronics CTX20-1 (toroid) will suffice. If switch current is reduced using the ILIM pin, smaller inductors such as the Sumida CD43 series or Coilcraft DO1608 series can be used. Minimizing DCR is important for best efficiency. Ideally, the inductor DCR should be less than 0.05Ω, although the physical size of such an inductor makes its use prohibitive in many space conscious applications. If EMI is a concern, such as when sensitive analog circuitry is present, a toroidal inductor such as the Coiltronics CTX20-1 is suggested. A special case exists where the VOUT/VIN differential is high, such as a 2V to 12V boost converter. If the required duty cycle for continuous mode operation is higher than the LT1304 can provide, the converter must be designed for discontinuous operation. This means that the inductor current decreases to zero during the switch OFF time. For a simple step-up (boost) converter, duty cycle can be calculated by the following formula: DC = 1 – [(VIN – VSAT)/(VOUT + VD)] where, VIN = Minimum input voltage VSAT = Switch saturation voltage (0.3V) VOUT = Output voltage VD = Diode forward voltage (0.4V) If the calculated duty cycle exceeds the minimum LT1304 duty cycle of 76%, the converter should be designed for discontinuous mode operation. The inductance must be low enough so that current in the inductor reaches the peak current in a single cycle. Inductor value can be calculated by: L = (VIN – VSAT)(tON /1A) where, tON = Minimum on-time of LT1304 (4µs) One advantage of discontinuous mode operation is that inductor values are usually quite low so very small units can be used. Ripple current is higher than with continuous mode designs and efficiency will be somewhat less. LT1304/LT1304-3.3/LT1304-5 OPERATIO Table 1 lists inductor suppliers along with appropriate part numbers. Table 1. Recommended Inductors VENDOR Sumida Coiltronics Dale Coilcraft SERIES CD54, CD43 CTX20-1 LPT4545 DO3316, DO1608, DO3308 PHONE NUMBER (708) 956-0666 (407) 241-7876 (605) 665-9301 (708) 639-6400 Capacitor Selection Low ESR (Equivalent Series Resistance) capacitors should be used at the output of the LT1304 to minimize output ripple voltage. High quality input bypassing is also required. For surface mount applications AVX TPS series tantalum capacitors are recommended. These have been specifically designed for switch mode power supplies and have low ESR along with high surge current ratings. A 100µF, 10V AVX TPS surface mount capacitor typically limits output ripple voltage to 70mV when stepping up from 2V to 5V at a 200mA load. For through hole applications Sanyo OS-CON capacitors offer extremely low ESR in a small package size. Again, if peak switch current is reduced using the ILIM pin, capacitor requirements can be eased and smaller, higher ESR units can be used. Suggested capacitor sources are listed in Table 2. Table 2. Recommended Capacitors VENDOR AVX Sanyo Sprague SERIES TPS OS-CON 595D TYPE Surface Mount Through Hole Surface Mount PHONE NUMBER (803) 448-9411 (619) 661-6835 (603) 225-1961 Diode Selection Best performance is obtained with a Schottky rectifier such as the 1N5818. Motorola makes the MBRS130L Schottky which is slightly better than the 1N5818 and comes in a surface mount package. For lower switch currents, the MBR0530 is recommended. It comes in a very small SOD-123 package. Multiple 1N4148s in parallel can be used in a pinch, although efficiency will suffer. U ILIM Function The LT1304’s current limit (ILIM) pin can be used for soft start. Upon start-up, the LT1304 will draw maximum current (about 1A) from the supply to charge the output capacitor. Figure 3 shows VOUT and VIN waveforms as the device is turned on. The high current flow can create IR drops along supply and ground lines or cause the input supply to drop out momentarily. By adding R1 and C1 as shown in Figure 4, the switch current is initially limited to well under 1A as detailed in Figure 5. Current flowing into C1 from R1 and the ILIM pin will eventually charge C1 and R1 effectively takes C1 out of the circuit. R1 also provides a discharge path for C1 when SHUTDOWN is brought low for turn-off. VOUT 2V/DIV IIN 500mA/DIV VSHDN 10V/DIV 1ms/DIV 1304 F03 Figure 3. Start-Up Response. Input Current Rises Quickly to 1A. VOUT Reaches 5V in Approximately 1ms. Output Drives 20mA Load 22µH* MBRS130L VIN LBI SW SENSE LT1304-5 5V 200mA + 2 CELLS 100µF LB0 GND SHDN ILIM R1 1M + 100µF + C1 1µF SHUTDOWN 1304 F04 *SUMIDA CD54-220 Figure 4. 2-Cell to 5V/200mA Boost Converter Takes Four External Parts. Components with Dashed Lines Are for Soft Start (Optional) 7 LT1304/LT1304-3.3/LT1304-5 OPERATIO If the full power capability of the LT1304 is not required, peak switch current can be limited by connecting a resistor RLIM from the ILIM pin to ground. With RLIM = 22k, peak switch current is reduced to approximately 500mA. Smaller power components can then be used. The graph in Figure 6 shows switch current vs RLIM resistor value. VOUT 2V/DIV I IN 500mA/DIV VSHDN 10V/DIV SHUTDOWN 1ms/DIV 1304 F05 Figure 5. Start-Up Response with 1µF/1MΩ Components in Figure 2 Added. Input Current Is More Controlled. VOUT Reaches 5V in 6ms. Output Drives 20mA Load 1000 900 PEAK CURRENT (mA) 800 700 600 500 400 VOUT COUT GND (BATTERY AND LOAD RETURN) 1304 F07 10 100 RLIM (kΩ) 1000 1304 F06 Figure 6. Peak Switch Current vs RLIM Value Figure 7. Suggested Layout for Best Performance. Input Capacitor Placement as Shown Is Highly Recommended. Switch Trace (Pin 4) Copper Area Is Minimized Layout/Input Bypassing The LT1304’s high speed switching mandates careful attention to PC board layout. Suggested component placement is shown in Figure 7. The input supply must have low impedance at AC and the input capacitor should be placed as indicated in the figure. The value of this capacitor depends on how close the input supply is to the IC. In situations where the input supply is more than a few inches away from the IC, a 47µF to 100µF solid tantalum Low-Battery Detector The LT1304 contains an independent low-battery detector that remains active when the device is shut down. This detector, actually a hysteretic comparator, has an open collector output that can sink up to 500µA. The comparator also operates below the switcher’s undervoltage lockout threshold, operating until VIN reaches approximately 1.4V. Figure 8 illustrates the input/output characteristic of the detector. Hysteresis is clearly evident in the figure. 8 + + U bypass capacitor is required. If the input supply is close to the IC, a 1µF ceramic capacitor can be used instead. The LT1304 switches current in 1A pulses, so a low impedance supply must be available. If the power source (for example, a 2 AA cell battery) is within 1 or 2 inches of the IC, the battery itself provides bulk capacitance and the 1µF ceramic capacitor acts to smooth voltage spikes at switch turn-on and turn-off. If the power source is far away from the IC, inductance in the power source leads results in high impedance at high frequency. A local high capacitance bypass is then required to restore low impedance at the IC. 1 2 VIN 3 4 LT1304 8 7 6 5 CIN LT1304/LT1304-3.3/LT1304-5 OPERATIO HOURS (H) 10 VLBO 2V/DIV Figure 8. Low-Battery Detector Transfer Function. Pull-Up R = 22k, VIN = 2V, Sweep Frequency = 10Hz Battery Life How may hours does it work? This is the bottom line question that must be asked of any efficiency study. AA alkaline cells are not perfect power sources. For efficient power transfer, energy must be taken from AA cells at a rate that does not induce excessive loss. AA cells internal impedance, about 0.2Ω fresh and 0.5Ω end-of-life, results in significant efficiency loss at high discharge rates. Figure 10 illustrates battery life vs load current of Figure 9’s LT1304, 2-cell to 5V DC/DC converter. Note the accelerated decrease in hours at higher power levels. Figure 11 plots total watt hours vs load current. Watt hours are determined by the following formula: WH = ILOAD(5V)(H) L1 22µH D1 WATT HOURS (WH) B1 2 CELLS + C1 100µF B1 = 2 × EVEREADY INDUSTRIAL ALKALINE AA CELLS #EN91 C1, C2 = AVX TPSD107M010R0100 D1 = MOTOROLA MBRS130L L1 = SUMIDA CD54-220 Figure 9. 2-Cell to 5V Converter Used in Battery Life Study U 1000 100 VLBI 200mV/DIV 1304 F08 1 1 10 LOAD CURRENT (mA) 100 200 1304 F10 Figure 10. Battery Life vs Load Current. Dots Specify Actual Measurements 6 5 4 3 2 1 0 1 10 LOAD CURRENT (mA) 100 200 1304 F11 Figure 11. Output Watt Hours vs Load Current. Note Rapid Fall-Off at Higher Discharge Rates VIN SHDN SW SENSE LT1304-5 VOUT 5V 200mA LB1 ILIM LB0 GND + C2 100µF 1304 F09 Figure 11’s graph varies significantly from electrical efficiency plot pictured on the first page of this data sheet. Why? As more current is drawn from the battery, voltage drop across the cells’ internal impedance increases. This causes internal power loss (heating), reducing cell terminal voltage. Since the regulator input acts as a negative resistance, more current is drawn from the battery as the terminal voltage decreases. This positive feedback action compounds the problem. 9 LT1304/LT1304-3.3/LT1304-5 OPERATIO Figure 12 shows overall energy conversion efficiency, assuming availability of 6.5WH of battery energy. This efficiency approximates the electrical efficiency at load current levels from 1mA to 10mA, but drops severely at load currents above 10mA (load power above 50mW). The moral of the story is this: if your system needs 5V at more than 40mA to 50mA, consider using a NiCd battery (1/10 the internal impedance) instead of a AA cell alkaline battery. ELECTROCHEMICAL EFFICIENCY (%) TYPICAL APPLICATIONS Super BurstTM Low IQ DC/DC Converter IQ ≈ 10µA 200k 2N3906 47k 5V 100mA 33µH** MBR0530 + 2 CELLS LBO 100µF FB SHDN LT1304 LBI EFFICIENCY (%) VIN 47k *1% METAL FILM **SUMIDA CD54-330 10 U U 100 90 80 70 60 50 40 30 20 10 0 1 10 LOAD CURRENT (mA) 100 200 1304 F12 Figure 12. Overall System Efficiency Including Battery Efficiency vs Load Current. Internal Impedance of Alkaline AA Cells Accounts for Rapid Drop in Efficiency at Higher Load Current Super Burst Efficiency 90 0.01µF 80 SW 3.83M* VIN = 3V 70 VIN = 2V 60 ILIM GND 1.21M* + 220µF 50 22k 40 0.01 1304 TA03 0.1 1.0 10 LOAD CURRENT (mA) 100 1304 TA04 Super Burst is a trademark of Linear Technology Corporation. LT1304/LT1304-3.3/LT1304-5 TYPICAL APPLICATIONS 2-Cell to 3.3V Boost Converter L1* 22µH MBRS130L VIN + 2 CELLS C1** 100µF LT1304-3.3 SHDN ILIM EFFICIENCY (%) SHUTDOWN *SUMIDA CD54-220 **AVX TPSD107M010R0100 NC 3.3V SEPIC (Step-Up/Step-Down Converter) VIN 2.5V TO 8V C2† 47µF 16V L1A* 2 1 SW 4 L1B* LT1304-3.3 SHDN ILIM NC *COILTRONICS CTX20-1 **TOKIN 1E105ZY5U-C103-F † AVX TPSD476M016R0150 †† AVX TPSD107M010R0100 SENSE GND 3 3.3V 300mA MBRS130L C1** 1µF EFFICIENCY (%) + VIN SHUTDOWN 5V SEPIC (Step-Up/Step-Down Converter) VIN 3V TO 8V L1A* 2 1 SW 4 L1B* LT1304-5 SHUTDOWN SHDN ILIM NC *COILTRONICS CTX20-1 **TOKIN 1E105ZY5U-C103-F † AVX TPSD476M016R0150 †† AVX TPSD107M010R0100 SENSE GND 3 5V 200mA MBRS130L C1** 1µF EFFICIENCY (%) + 47µF† 16V VIN U 2-Cell to 3.3V Converter Efficiency 90 80 SW SENSE 3.3V 300mA 70 60 50 40 30 0.1 VIN = 3.3V VIN = 2.5V 1.8V VIN = 2.5V 1 10 100 LOAD CURRENT (mA) 1000 1304 TA06 GND + C2** 100µF 10V 1304 TA05 3.3V SEPIC Efficiency 80 75 70 65 60 55 50 1304 TA07 + C3†† 100µF 10V VIN = 4.5V VIN = 3.5V VIN = 2.5V 1 10 100 LOAD CURRENT (mA) 500 1304 TA08 5V SEPIC Efficiency 80 75 70 65 60 55 50 1304 TA09 + 100µF†† 10V VIN = 6V VIN = 5V VIN = 4V VIN = 3V 1 10 100 LOAD CURRENT (mA) 500 1304 TA10 11 LT1304/LT1304-3.3/LT1304-5 TYPICAL APPLICATIONS 5V to 12V DC/DC Converter L1* 22µH 5V D1† + VIN 47µF** LT1304 SW EFFICIENCY (%) SHUTDOWN SHDN FB GND 124k 1% *SUMIDA CD54-220 **AVX TPSD476M016R0150 † MOTOROLA MBRS130L Single Li-Ion Cell to 5V Converter with Load Disconnect at VIN < 2.7V MBRS130LT3 (5V) 5V (2.7V to 4.2V) + 100µF 16V 562k 1% 220k VIN NC ILIM LBI SW VOUT VOUT VIN2 LTC1477 VINS EN VIN3 GND NC NC SINGLE Li-Ion CELL* 432k 1% *PRIMARY Li-Ion BATTERY PROTECTION MUST BE PROVIDED BY AN INDEPENDENT CIRCUIT **SUMIDA CD54-220 † AVX TPSD107M010R0100 12 U 5V to 12V Converter Efficiency 90 85 80 1.07M 1% 12V 200mA 75 + 47µF** 16V 70 1304 TA11 65 1 10 100 LOAD CURRENT (mA) 300 1304 TA12 22µH** + 1µF SENSE LT1304CS8-5 + 100µF† 10V VIN1 SHDN GND LBO 1304 TA13 LT1304/LT1304-3.3/LT1304-5 TYPICAL APPLICATIONS Negative LCD Bias Generator L1* 10µH 1µF CERAMIC –VOUT –14V TO –22V 1mA TO 10mA + 2 CELLS 47µF ILIM + 22k 3.3µF * SUMIDA CD43-100 ** MOTOROLA MBR0530 VOLTAGE ADJUST 1kHz PWM INPUT 0V TO 5V Electroluminescent Panel Driver with 200Hz Oscillator MUR160 600V 4 EL PANEL CPANEL ≤ 20nF 1µF 200V VIN 2V TO 7V 1:12* + 3 47µF 1 6 MBR0530 5V = OPERATE 0V = SHUTDOWN 22k 22k 2N3906 75k 3.3k 1nF VIN SHDN LBO LT1304 SW FB D 51k G ! HI GER 10M AN 22k L H VO (3.3M × 3) FMMT458 LBI 0.01µF ILIM NC 200Hz GND 50k INTENSITY ADJUST 1/2 BAW56 * DALE LPE3325-A205 TRANSFORMER MEASURES 6.5mm × 8.2mm × 5.2mm (H) (605) 665-9301 + U ** VIN SW FB LT1304 90.9k 1% GND 1M 1% 110k 1% 1000pF 1.69M 1% ** ** 10µF 35V EFFICIENCY = 70% TO 75% AT ILOAD ≥ 2mA 1304 TA14 TAG E 22k 22k 1/2 BAW56 1304 TA15 13 LT1304/LT1304-3.3/LT1304-5 TYPICAL APPLICATIONS 2- to 4-Cell to 1kV Step-Up Converter 0.01µF 0.01µF 0.01µF 0.01µF 0.01µF VIN 2V TO 6V + 47µF 1 6 VIN 0.1µF LT1304 SHUTDOWN SHDN ILIM NC VIN 2V TO 6V VIN + *AVX TPS SERIES TANTALUM OR SANYO OS-CON **SUMIDA CD54-220 14 U T1* 3 4 0.01µF 0.01µF 0.01µF 0.01µF MBR0530 SW FB R1** 500M R2 620k D ER ANG ! HI G LT H VO AGE VOUT = 1.24V 1+ () R1 R2 VOUT 1kV 250µA GND * DALE LPE3325-A205 TRANSFORMER MEASURES 6.5mm × 8.2mm × 5.2mm (H) (605) 665-9301 ** IRC CGX-1/2 ALL 0.01µF CAPACITORS 250WVDC BAS21 OR MUR130 1304 TA16 2- to 4-Cell to 5V Converter with Output Disconnect 2k L1** 22µH MBRS130L ZTX788B SW SENSE 5V 100mA 47µF* SHDN ILIM SHUTDOWN NC LT1304-5 + GND 22µF* + 220µF* 1304 TA17 LT1304/LT1304-3.3/LT1304-5 TYPICAL APPLICATIONS 2-Cell to 5V Converter with Auxiliary 10V Output MBR0530 1µF CERAMIC 2 CELLS *SUMIDA CD54-220 1304 TA18 2 CELLS *SUMIDA CD54-220 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of circuits as described herein will not infringe on existing patent rights. + U + + + MBR0530 10V 20mA 10µF L1* 22µH MBRS130L VIN SW SENSE 5V 150mA 100µF SHDN ILIM SHUTDOWN NC LT1304-5 + GND 100µF 2-Cell to 5V Converter with Auxiliary – 5V Output L1* 22µH MBRS130L VIN SW SENSE 1µF CERAMIC MBR0530 GND MBR0530 10µF –5V 20mA 5V 150mA 100µF SHDN ILIM SHUTDOWN NC LT1304-5 + 100µF 1304 TA19 15 LT1304/LT1304-3.3/LT1304-5 PACKAGE DESCRIPTION 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE RELATED PARTS PART NUMBER LTC®1163 LT1239 LT1301 LT1302 LT1303 LTC1477 LT1521 DESCRIPTION Triple High Side Driver for 2-Cell Inputs Backup Battery Management System Fixed 5V/12V Step-Up Micropower DC/DC Converter High Output Current Micropower DC/DC Converter Micropower DC/DC Converter Protected Switch 300mA, 12µA IQ Low Dropout Regulator COMMENTS 1.8V Minimum Input, Drives N-Channel MOSFETs Easy-to-Use, Fail-Safe Backup Protection 12V/200mA from 5V, 120µA IQ, 88% Efficiency 5V/600mA from 2V, 2A Internal Switch, 200µA IQ Low-Battery Detector Inactive in Shutdown Ultralow RDS(ON) Switch: 0.07Ω 500mV Dropout at Full Load 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 U Dimension in inches (millimeter) unless otherwise noted. S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 8 7 6 5 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157** (3.810 – 3.988) 1 2 3 4 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) BSC SO8 0695 LT/GP 1195 10K • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1995