LTC1503-1.8 LINER
Document overview
- Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 12
Technical content
LTC1503-1.8/LTC1503-2 High Efficiency Inductorless Step-Down DC/DC Converters n Input Voltage Range: 2.4V to 6V n Fixed Output Voltages: 1.8V –4%, 2V –4% n Output Current: Up to 100mA n No Inductors n Typical Efficiency 25% Higher than LDOs n Low Operating Current: 25mA n Low Shutdown Current: 5mA n 600kHz Switching Frequency n Shutdown Disconnects Load from VIN n Soft-Start Limits Inrush Current at Turn-On n Short-Circuit and Overtemperature Protected n Available in 8-Pin MSOP and SO Packages The LTC 1503-1.8/LTC1503-2 are switched capacitor step-down DC/DC converters that produce a regulated output from a 2.4V to 6V input. The parts use switched capacitor fractional conversion to achieve high efficiency over the entire input range. No inductors are required. Internal circuitry controls the step-down conversion ratio to optimize efficiency as the input voltage and load condi- tions vary. Typical efficiency is 25% higher than that of a low dropout (LDO) linear regulator. Regulation is achieved by sensing the output voltage and enabling the internal switching network as needed to maintain a fixed output voltage. This method of regulation enables the parts to achieve high efficiency at extremely light loads. Low operating current (25mA with no load, 5mA in shutdown) and low external parts count (two 1mF flying capacitors and two 10 mF bypass capacitors) make the LTC1503-1.8/LTC1503-2 ideally suited for space con- strained battery-powered applications. The parts are fully short-circuit and overtemperature protected. The LTC1503-1.8/LTC1503-2 are available in 8-pin MSOP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. n Cellular Phones n Handheld Computers n Smart Card Readers n Low Power DSP Supplies n Portable Electronic Equipment n Handheld Medical Instruments Efficiency vs Input Voltage Single Li-Ion to 2V DC/DC Converter FEATURES DESCRIPTIO U APPLICATIO SU TYPICAL APPLICATIO U VIN C1– C1+ SHDN/SS VOUT C2– C2+ GND LTC1503-2 1mF 1503-1.8/2 TA01 1mF 10mF1-CELL Li-Ion OR 3-CELL NiMH 10mF VOUT = 2V IOUT = 100mA INPUT VOLTAGE (V) EFFICIENCY (%) 1503-1.8/2 TA02 3 4 5 100 LTC1503-2 VOUT = 2V IOUT = 100mA IOUT = 1mA “IDEAL” LDO
LTC1503-1.8/LTC1503-2 Specified Temperature Range (Note 2) ... – 40°C to 85°C (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS VIN Operating Voltage l 2.4 6 V VOUT LTC1503-1.8, 0mA < IOUT < 100mA l 1.728 1.8 1.872 V LTC1503-2, 0mA < IOUT < 100mA l 1.920 2.0 2.080 V VIN Operating Current I OUT = 0mA l 25 50 mA VIN Shutdown Current SHDN/SS = 0V l 51 0 mA Output Ripple Voltage LTC1503-X, V IN = 3.6V, IOUT = 100mA 25 mV P-P Efficiency LTC1503-2, V IN = 3.6V, IOUT = 100mA 82.9 % Switching Frequency Oscillator Free Running 600 kHz SHDN/SS Input Threshold l 0.2 0.35 0.5 V SHDN/SS Input Current V SHDN/SS = 0V (Note 3) l –3.5 –2 –1 mA VSHDN/SS = VIN l –1 1 mA VOUT Short-Circuit Current V OUT = 0V (Note 4) l 82 2 5 0 m A VOUT Turn-On Time C SS = 0nF, VIN = 3.6V, COUT = 10mF 0.1 ms CSS = 10nF 8 ms Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC1503C is guaranteed to meet specified performance from 0°C to 70°C and is designed, characterized and expected to meet these extended temperature limits, but are not tested at – 40°C and 85°C. The LTC1503I is guaranteed to meet the extended temperature limits. Note 3: Currents flowing into the device are positive polarity. Currents flowing out of the device are negative polarity. Note 4: When VOUT is less than 150mV, IOUT is limited to much less than the maximum rated output current to prevent damage to the output devices. ORDER PART NUMBER LTC1503CMS8-1.8 LTC1503CMS8-2 MS8 PART MARKING LTFX LTHN ORDER PART NUMBER LTC1503CS8-1.8 LTC1503CS8-2 LTC1503IS8-1.8 LTC1503IS8-2 S8 PART MARKING 150318 15032 Consult factory for Military grade parts. TJMAX = 125°C, qJA = 200°C/W V OUT C1– C1+ VIN GND C2+ SHDN/SS TOP VIEW MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125°C, qJA = 150°C/W TOP VIEW S8 PACKAGE 8-LEAD PLASTIC SO VOUT C1– C1+ VIN C2– GND C2+ SHDN/SS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = VIN(MIN) to VIN(MAX), C1 = C2 = 1mF, CIN = COUT = 10mF unless otherwise noted. 503I18 1503I2 ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W
ELECTRICAL CHARACTERISTICS
LTC1503-1.8/LTC1503-2 LTC1503-X Input Operating Current vs Input Voltage INPUT VOLTAGE (V) INPUT CURRENT (µA) TA = 25°C
1503 G01
IOUT = 0mA TA = –40°C TA = 85°C LTC1503-1.8 Output Voltage vs Input Voltage LTC1503-2 Output Voltage vs Input Voltage LTC1503-1.8 Efficiency vs Input Voltage INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 2.00 2.05
1503 G03
1.95 1.90 3 4 5 2.10 IOUT = 50mA TA = –40°C TA = 85°C TA = 25°C INPUT VOLTAGE (V) EFFICIENCY (%) 1503-1.8/2 G05 3 4 5 100 “IDEAL” LDO TA = 25°C IOUT = 100mA IOUT = 1mA LTC1503-1.8 Efficiency vs Output Current LTC1503-X Input Shutdown Current vs Input Voltage INPUT VOLTAGE (V) INPUT SHUTDOWN CURRENT (µA) 7.5 1503-1.8/2 TA02 2.5 3 4 5 VOUT = 0V VSHDN/SS = 0V TA = –40°C TA = 85°C TA = 25°C INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.80 1.85 1503-1.8/2 G03 1.75 1.70 3 4 5 1.90 IOUT = 50mA TA = –40°C TA = 85°C TA = 25°C OUTPUT CURRENT (mA) 0.01 EFFICIENCY (%) 100 100 1503-1.8/2 G06 0.1 1 10 1000 VIN = 5V VIN = 4.4V VIN = 3.6V VIN = 3V VIN = 2.4V TA = 25°C LTC1503-2 Efficiency vs Output Current OUTPUT CURRENT (mA) 0.01 EFFICIENCY (%) 100 100 1503-1.8/2 G07 0.1 1 10 1000 VIN = 5V VIN = 4.4V VIN = 3.6V VIN = 3V VIN = 2.4V TA = 25°C LTC1503-1.8 Output Voltage vs Output Current OUTPUT CURRENT (mA) 0.01 OUTPUT VOLTAGE (V) 1.80 1.82 1.84 100 1503-1.8/2 G08 1.78 1.76 1.74 0.1 1 10 1000 VIN = 3.3V TA = –40°C TA = 85°C TA = 25°C LTC1503-2 Output Voltage vs Output Current OUTPUT CURRENT (mA) 0.01 OUTPUT VOLTAGE (V) 2.00 2.02 2.04 100 1503-1.8/2 G09 1.98 1.96 1.94 0.1 1 10 1000 VIN = 3.3V TA = –40°C TA = 85°C TA = 25°C TYPICAL PERFOR A CE CHARACTERISTICS UW
LTC1503-1.8/LTC1503-2 TYPICAL PERFOR A CE CHARACTERISTICS UW LTC1503-X Output Short-Circuit Current vs Input Voltage LTC1503-X Start-Up Time vs Soft-Start Capacitor INPUT VOLTAGE (V) OUTPUT CURRENT (mA) 1503-1.8/2 G10 3 4 5 VOUT SHORTED TO GND TA = –40°C TA = 85°C TA = 25°C SOFT-START CAPACITOR (nF) 0.01 START-UP TIME (ms) 100 1503-1.8/2 G10 0.1 0.01 0.1 1 10 100 VIN = 3.6V TA = –40°C TA = 25°C TA = 85°C Output Load Transient Response (LTC1503-1.8,1mA to 100mA Step) IOUT 50mA/DIV VOUT 50mV/DIV AC COUPLED 100mA 1mA 1ms/DIV 1503-1.8/2 G12 Output Ripple, COUT = 10mF VOUT 10mV/DIV AC COUPLED 5ms/DIV 1503-1.8/2 G13 VIN = 3.6V VOUT = 2V IOUT = 100mA COUT = 10mF CERAMIC Output Ripple, COUT = 22mF VOUT 10mV/DIV AC COUPLED 5ms/DIV 1503-1.8/2 G14VIN = 3.6V VOUT = 2V IOUT = 100mA COUT = 22mF CERAMIC VOUT (Pin 1): Regulated Output Voltage. VOUT is discon- nected from VIN during shutdown. Bypass VOUT to ground with a ‡ 10mF low ESR capacitor. C1– (Pin 2): Flying Capacitor One Negative Terminal. C1+ (Pin 3): Flying Capacitor One Positive Terminal. VIN (Pin 4): Input Voltage. VIN may be between 2.4V and 6V. Bypass VIN to ground with a ‡10mF low ESR capacitor. SHDN/SS (Pin 5): Shutdown/Soft-Start Control. The pin is designed to be driven with an external open-drain output. Holding the SHDN/SS pin below 0.25V will force the part into shutdown mode. An internal pull-up current of 2mA will force the SHDN/SS voltage to climb to V IN once the device driving the pin is forced into a Hi-Z state. To limit inrush current on start-up, connect a capacitor between the SHDN/SS pin and ground. Capacitance on the SHDN/SS pin will limit the dV/dt of the pin during turn- on which, in turn, will limit the dV/dt of V OUT. By selecting an appropriate soft-start capacitor for a known output capacitor, the user can control the inrush current during UUUPI FU CTIO S
LTC1503-1.8/LTC1503-2 C1+ VIN C1– C2+ C2– 150mV 800k 680k 330k 990k 1.2M 1.2V VREF COUT CIN VOUT GND 1503-1.8/2 BD SHDN/SS 350mV + 10mVCOMP2 MODE SKIP REG ENABLE SOFT-START LTC1503-2 SHORT CIRCUIT VOUT COMP1 350mV VIN SHDN 2mA VREF RAMP STEP-DOWN CHARGE PUMP MODE CONTROL 600kHz OSCILLATOR turn-on (see Applications Information). If neither of the two functions are desired, the pin may be floated or tied to V IN. C2+ (Pin 6): Flying Capacitor Two Positive Terminal. GND (Pin 7): Ground. Connect to a ground plane for best performance. C2– (Pin 8): Flying Capacitor Two Negative Terminal. UUUPI FU CTIO S BLOCK DIAGRA W
flying caps C1 and C2 with values of 0.47 mF to 2.2 mF. the same capacitance value for both C1 and C2. with a low ESR 10mF output capacitor. results in higher ripple due to higher output voltage dV/dt. COUT charge current of only 5mA (see Figure 2c). Figure 2. Shutdown/Soft-Start Operation
LTC1503-1.8/LTC1503-2 Dimensions in inches (millimeters) unless otherwise noted. 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) MSOP (MS8) 1098 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 0.021 – 0.006 (0.53 – 0.015) 0° – 6° TYP SEATING PLANE 0.007 (0.18) 0.040 – 0.006 (1.02 – 0.15) 0.012 (0.30) REF 0.006 – 0.004 (0.15 – 0.102) 0.034 – 0.004 (0.86 – 0.102) 0.0256 (0.65) BSC 12 3 4 0.193 – 0.006 (4.90 – 0.15) 8 7 6 5 0.118 – 0.004* (3.00 – 0.102) 0.118 – 0.004** (3.00 – 0.102) UPACKAGE DESCRIPTIO
LTC1503-1.8/LTC1503-2 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) Dimensions in inches (millimeters) unless otherwise noted. 0.016 – 0.050 (0.406 – 1.270) 0.010 – 0.020 0°– 8° TYP 0.008 – 0.010 (0.203 – 0.254) SO8 1298 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) TYP 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) BSC 1 2 3 4 0.150 – 0.157** (3.810 – 3.988) 8 7 6 5 0.189 – 0.197* (4.801 – 5.004) 0.228 – 0.244 (5.791 – 6.197) 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 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. UPACKAGE DESCRIPTIO
LTC1503-1.8/LTC1503-2 ª LINEAR TECHNOLOGY CORPORATION 1 999 150312f LT/TP 0200 4K • PRINTED IN USA Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear-tech.com PART NUMBER DESCRIPTION COMMENTS LTC1474/LTC1475 Low Quiescent Current Step-Down DC/DC Converter I OUT to 250mA, IQ = 10mA; 8-Lead MSOP LTC1502-3.3 Single Cell to 3.3V Quadrupler Charge Pump V IN = 0.9V to 1.8V, IOUT = 10mA; IQ = 40mA LTC1514/LTC1515 Micropower, Regulated 5V Step-Up/Step-Down 2V to 10V Input Range; Up to 50mA Output Current: Short-Circuit Charge Pump DC/DC Converters and Overtemperature Protected LTC1555/LTC1556 SIM Power Supply and Level Translator Step-Up/Step-Down Charge Pump Generates 5V or 3V LTC1627 Monolithic Synchronous Buck Step-Down 2.65V to 8.5V Input Range; V OUT from 0.8V, IOUT to 500mA; Switching Regulator Low Dropout Operation; 100% Duty Cycle LTC1754-3.3 3.3V Charge Pump with Shutdown in SOT-23 50mA Output Current, I CC = 13mA LTC1754-5 5V Charge Pump with Shutdown in SOT-23 50mA Output Current, I CC = 13mA RELATED PARTS DC/DC Converter with Shutdown and Soft-Start LTC1503-1.8 1mF 10nF2N7002ON OFF 1503-1.8/2 TA03 1mF 10mF1-CELL Li-Ion OR 3-CELL NiMH 10mF VOUT = 1.8V IOUT = 100mAVOUT C2– C2+ GND VIN C1– C1+ SHDN/SS TYPICAL APPLICATIO U