LT1304 UTC | Alldatasheet

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UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 1 QW-R103-018,A MICROPOWER DC/DC CONVERTERS WITH LOW-BATTERY DETECTOR ACTIVE IN SHUTDOWN

DESCRIPTION

The UTC LT1304 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 UTC LT1304-3.3 and LT1304-5.0 generate regulated outputs of 3.3V and 5V and the adjustable LT1304 can deliver output voltages up to 25V.Quiescent current,120 μ A in active mode, decreases to just 10 μ A 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 I LIM pin to ground. The high speed operation of the UTC LT1304 allows the use of small, surface-mountable inductors and capacitors.

FEATURES

*5V at 200mA from two cells. *10μA quiescent current in shutdown. *Operates with VIN as low as1.5V *Low battery detector active in shutdown *Low switch V CESAT:370mV at 1A typical. *120μA quiescent current in active mode. *Switching frequency up to 300kHz *Programmable peak current with one resistor. DIP-8 SOP-8

APPLICATIONS

*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. PIN CONFIGURATION LBI SW VIN LBO GND ILIM SHDN FB(SENSE)*

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 2 QW-R103-018,A ABSOLUTE MAXIMUM RATINGS PARAMETER SYMBOL RATING UNIT Input Voltage V IN 8 V SW Voltage -0.4 ~ +25 V FB Voltage(LT1304) V IN+0.3 V ILIM Voltage(LT1304-3.3/LT1304-5.0) 5 V SHDN Voltage 6 V LBI Voltage V IN V LBO Voltage 8 V Maximum Power Dissipation P D 500 mW Junction Temperature Tj 125 °C Operating Temperature Range Topr 0 ~ 70 °C Storage Temperature Range Tstg -65 ~ +150 °C Lead Temperature (soldering,10sec) 300 °C ELECTRICAL CHARACTERISTICS (VIN=2V,VSHDN=2V Unless otherwise noted.) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Minimum Operating Voltage * 1.5 1.65 V Operating Voltage Range * 8 V Quiescent Current * VSHDN=2V,Not switching 120 200 µA * VSHDN=0V,VIN=2V 7 15 µA Quiescent Current In Shutdown * VSHDN=0V,VIN=5V 27 50 µA Comparator Trip Point * 1.22 1.24 1.26 V FB Pin Bias Current * 10 25 nA Sense Pin Leakage in Shutdown * VSHDN=0V,Fixed Output Versions 0.002 1 µA Line Regulation * 1.8V ≤VIN≤8V 0.04 0.15 %/V LBI Input Threshold * Falling Edge 1.10 1.17 1.25 V LBI Bias Current * 6 20 nA LBI Input Hysteresis * 35 65 mV LBO Output Voltage Low * I SINK=500µA 0.2 0.4 V LBO Output Leakage Current * LBI=1.5V,LBO=5V 0.01 0.1 µA SHDN Input Voltage High * 1.4 V SHDN Input Voltage Low * 0.4 V * V SHDN=5V 5 8 µA SHDN Pin Bias Current * V SHDN=0V -5 -2 µA Switching Off Time * 1 1.5 2 µs Switch On Time * Current Limit Not Asserted 4 6 8 µs Maximum Duty Cycle * Current Limit Not Asserted 76 80 88 % I LIM Pin Open,VIN=5V 0.8 1 1.2 A Peak Switch Current 20K from I LIM to GND 500 mA Isw=1A 0.37 V Switch Saturation Voltage * Isw=700mA 0.26 0.35 V

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 3 QW-R103-018,A PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Switch Leakage Switch off, Vsw=5V 0.01 7 µA The * denotes specifications which apply over the 0°C to 70°C operating temperature range. PIN FUNCTIONS PIN No. SYMBOL DESCRIPTION 1 LBI Low Battery Detector Input. When voltage on this pin is less than 1.17V,detector output is low 2 LBO Low Battery Detector Output. Open collector can sink up to 500µA.Low battery detector remains active when device is shut down. 3 VIN Input Supply. Must be bypassed close (<0.2”) to the pin. See required layout in the Typical Applications 4 SW Collector of Power NPN. Keep copper traces on this pin short and direct to minimize RFI 5 GND Device Ground. Must be low impedance; solder directly to ground plane 6 ILIM Current Limit Set Pin. Float for 1A peak switch current; a resistor to ground will lower peak current SHDN 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 V IN

8 FB/SENSE

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. TYPICAL APPLICATION VIN SW LBI SENSE ILIM IBO SHDN GND 100μF 200mA

2 CELLS

22μH LT1304-5.0 2-Cell to 5V Step-Up Converter with Low-Battery Detect 499K 604K SHUTDOWN NC 3 4 100K 100μF LBO LOW WHEN VBAT＜2.2V LOAD CURRENT(mA) Efficiency EFFICIENCY (% 1 10 100 5000.01 VIN =3.3V VIN =2.5V VIN =1.8V 1N5817

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 4 QW-R103-018,A TYPICAL PERFORMANCE CHARACTERISTICS Saturation Voltage (mV) 200 300 400 500 1.2 0.2 0.4 0.6 100 0.8 1.0 1.2 Switch Saturation Voltage Switch Current (A) Ta =25 ℃ Peak Current (A) -50 0.8 0.9 1.0 1.1 100 0.6 -25 0 25 0.7 50 75 Peak Switch Current Limit Temperature( ℃) 1.3 Time ( μs) -50 100 -25 0 25 50 75 Temperature( ℃) On-and Off-times Maximum On-Time Off-Time 1.240 Feedback Voltage (V) -50 1.220 1.225 1.230 1.235 100 1.210 -25 0 25 1.215 50 75 1.245 1.250 Temperature( ℃) Feedback Voltage 1.205 1.200 Bias Current (nA) -50 100 -25 0 25 50 75 Temperature( ℃) Feedback Pin Bias Current Supply Current µ s) 150 200 250 300 123 100 Input Voltage (V) Supply Current VSHDN=VN NOT SW ITCHING VSHDN= 0 V Ta =25 ℃

Figure 1. LT1304 Block Diagram. Independent Low-Battery Detector A3 Remains Alive When Device Is in Shutdown

or until current comparator A2 turns off the ON timer, Whichever comes first. Off-time is fixed at approximately 1.5µs. left to supply current to the load until VOUT decreases enough to force A1’s output high, and the entire cycle repeats. accomplished by grounding the SHDN pin. Figure 2. LT1304-3.3/LT1304-5.0 Block Diagram

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 7 QW-R103-018,A DCR is important for best efficiency. Ideally, the inductor DCR should be less than 0.05W, 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 – [(V IN – VSAT)/(VOUT + VD)] where, V IN = 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 = (V IN – 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. 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 100 µF, 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. 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. 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 I LIM 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.

Figure 3. Start-Up Response.Input Current Rises Quickly to power components can then be used. The graph in Figure 6 shows switch current vs RLIM resistor value.

Figure 5. Start-Up Response with 1μF/1MΩComponents Reaches 5V in6ms.Output Drives 20mA Load.

1304 F05

required to restore low impedance at the IC.

Figure 10. Battery Life vs Current.Dots Specify

Figure 12. Overall System Efficiency Including Battery Efficiency

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 14 QW-R103-018,A + V IN SW SENSE ILIM SHDN GND 100μ F 3.3V 300mA 2 CELLS 22μH LT130-3.3 100μF 10V MBRS130L SHUTDOWN NC 2-Cell to 3.3V Boost Converter Load Current (mA) 2-Cell to 3.3V ConverterEfficiency Efficiency (% 1 10 100 10000.1 VIN=3.3V VIN=2.5V VIN=1.8V + VIN SW SENSE IL I M SHDN GND 47μF 16V 3.3V 300mA L1A LT1304-3.3 100μF 10V MBRS130L SHUTDOWN N C 1μF L1B VIN 2.5V TO 8V Load Current (mA) 3.3V SEPIC Efficiency Efficiency (% 1 10 100 500 VIN=4.5V VIN=3.5V VIN=2.5V 3.3V SEPIC Efficiency(Step-Up/Step-Down Converter) + VIN SW SENSE I LIM SHDN GND 47μF 16V 200mA L1A LT1304-5.0 100 μF 10V MBRS130L SHUTDOWN NC 1μF L1B VIN 3V TO 8V Load Current (mA) 5V SEPIC Efficiency Efficiency (% 1 10 100 500 VIN=6V VIN=4V VIN=3V VIN=5V 5V SPEC (Step-Up/Step-Down Converter)

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 15 QW-R103-018,A VIN SW FBSHDN GND 124K 47μF 47μF 16V 12V 200mA 1.07M 5V to 12V DC/DC Converter SHUTDONW 22μH D1 LT1304 MBRS130L 1 10 100 300 5V to 12V Converter Efficiency Efficiency (%) Load Current(mA) VIN SW LBI SENSEILIM IBO SHDN GND 100μF 22μH LT1304-5.0 Single Li-lon Cell to 5V Converter with Load Disconnect at Vin＜2.7V 220k NC MBRS130L 562k 432k SINGLE LI-ION CELL Vout VIN1 VINS EN Vout VIN2 VIN3 GND 1 μF NC NC

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 16 QW-R103-018,A VIN S W FB ILIM GND 110K 47μ F 10μF 35V VOLTAGE ADJUST 1kHz PWM INPUT 0V TO 5V Negative LCD Bias Generator L1* 10μH 90.9K 3.3μF 1000 pF 1μ F CERAMIC -VOUT -14V TO -22V 1mA TO 10mA EFFICIENCY =70% TO 75% AT ILOAD≧2mA 1.69M LT1304 MBR0530 MBR0530 MBR0530 VIN SW FB ILIM GND 47μF 1μF 200V 1/2 BAW56 Electroluminescent Panel Driver with 200Hz Oscillator VIN 2V TO 7V 5V=OPERATE 0V=SHUTDOWN SHDN 200Hz 22K 10M (3.3M*3) EL PANEL CPANEL≦ 20nF MUR160 600V NC LBO LBI 3 4 22K 22K51K 50K INTENSITY ADJUST 1/2 BAW56 0.01μF 1nF 22K22K 75K 3.3K LT1304 FMMT458 2N3906 MBR0530 1:12 DANGERI HIGH VOLTA GE

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 17 QW-R103-018,A VIN SW FB ILIM GND 47μF 2-to 4-Cell to 1kV Step-Up Converter VIN 2V TO 6V SHUTDOWN SHDN NC 3 4 620K 0.1μF VOUT 1kV 250μAR1 500M 0.01μF0 . 0 1 μF0 . 0 1 μF0 . 0 1 μF VOUT =1.24V(1+ )R2 LT1304 MBR0530 DANGERI HIGH VOLTAGE VIN SW SENSE ILIM SHDN GND 47μF 100mA 22μH LT1304-5.0 220μF MBRS130L SHUTDOWN NC 2- TO 4- Cell to 5V Converter with Output Disconnect VIN 2V TO 6V 22μF ZTX788B

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 18 QW-R103-018,A VIN SW SENSE ILIM SHDN GND 100μ F 150mA2CELLS 22μH LT1304-5.0 SHUTDOWN MBRS130L NC 10V 20mA 10μF 10μF MBR0530 MBR0530 1μF CERAMIC 2- Cell to 5V Converter with Auxiliary 10V Output VIN SW SENSE ILIM SHDN GND 100μF 150mA2 CELLS 22μH LT1304-5.0 SHUTDOWN 10μF+ MBRS130L NC -5V 20mA 2- Cell to 5V Converter with Auxiliary -5V Output MBR0530 MBR0530 1μF CERAMIC

UTC LT1304/LT1304-3.3V/LT1304-5.0V LINEAR INTEGRATED CIRCUIT UTC UNISONIC TECHNOLOGIES CO., LTD. 19 QW-R103-018,A UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.