LTC1503-1.8/LTC1503-2 High Efficiency Inductorless Step-Down DC/DC Converters FEATURES DESCRIPTIO n Input Voltage Range: 2.4V to 6V The LTC 1503-1.8/LTC1503-2 are switched capacitor n Fixed Output Voltages: 1.8V 4%, 2V 4% step-down DC/DC converters that produce a regulated n Output Current: Up to 100mA output from a 2.4V to 6V input. The parts use switched n No Inductors capacitor fractional conversion to achieve high efficiency n Typical Efficiency 25% Higher than LDOs over the entire input range. No inductors are required. n Low Operating Current: 25m A Internal circuitry controls the step-down conversion ratio n Low Shutdown Current: 5m A to optimize efficiency as the input voltage and load condi- n 600kHz Switching Frequency tions vary. Typical efficiency is 25% higher than that of a n Shutdown Disconnects Load from V low dropout (LDO) linear regulator. IN n Soft-Start Limits Inrush Current at Turn-On Regulation is achieved by sensing the output voltage and n Short-Circuit and Overtemperature Protected enabling the internal switching network as needed to n Available in 8-Pin MSOP and SO Packages maintain a fixed output voltage. This method of regulation enables the parts to achieve high efficiency at extremely U light loads. Low operating current (25m A with no load, 5m A APPLICATIO S in shutdown) and low external parts count (two 1m F flying n Cellular Phones capacitors and two 10m F bypass capacitors) make the n Handheld Computers LTC1503-1.8/LTC1503-2 ideally suited for space con- n Smart Card Readers strained battery-powered applications. The parts are fully n Low Power DSP Supplies short-circuit and overtemperature protected. n Portable Electronic Equipment The LTC1503-1.8/LTC1503-2 are available in 8-pin MSOP n Handheld Medical Instruments and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO Efficiency vs Input Voltage 100 I = 100mA OUT Single Li-Ion to 2V DC/DC Converter 80 LTC1503-2 4 1 V = 2V OUT I = 1mA V V OUT IN OUT I = 100mA OUT 1-CELL Li-Ion OR 2 8 60 10m F 10m F 3-CELL NiMH C1 C2 1m F 1m F 3 6 + + IDEAL LDO C1 C2 5 7 SHDN/SS GND 40 1503-1.8/2 TA01 LTC1503-2 V = 2V OUT 20 2 3 4 5 6 INPUT VOLTAGE (V) 1503-1.8/2 TA02 1 EFFICIENCY (%) U ULTC1503-1.8/LTC1503-2 ABSOLUTE AXI U RATI GS (Note 1) + + V , C1 , C1 , C2 , C2 to GND ............... 0.3V to 6.5V Industrial Temperature Range ............... 40 C to 85 C IN SHDN/SS to GND......................... 0.3V to (V + 0.3V) Specified Temperature Range (Note 2) ... 40 C to 85 C IN V Short-Circuit Duration ............................. Indefinite Storage Temperature Range ................ 65 C to 150 C OUT Commercial Temperature Range ............ 40 C to 85 C Lead Temperature (Soldering, 10 sec)................. 300 C UUW PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART TOP VIEW NUMBER NUMBER TOP VIEW V 1 8 C2 OUT LTC1503CMS8-1.8 LTC1503CS8-1.8 V 1 8 C2 OUT C1 2 7 GND C1 2 7 GND LTC1503CMS8-2 LTC1503CS8-2 + + C1 3 6 C2 + + C1 3 6 C2 LTC1503IS8-1.8 V 4 5 SHDN/SS IN V 4 5 SHDN/SS IN LTC1503IS8-2 MS8 PACKAGE MS8 PART MARKING 8-LEAD PLASTIC MSOP S8 PACKAGE S8 PART MARKING T = 125 C, q = 200 C/W JMAX JA 8-LEAD PLASTIC SO LTFX T = 125 C, q = 150 C/W JMAX JA 150318 503I18 LTHN 15032 1503I2 Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. A V = V to V , C1 = C2 = 1m F, C = C = 10m F unless otherwise noted. IN IN(MIN) IN(MAX) IN OUT PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage l 2.4 6 V IN V LTC1503-1.8, 0mA < I < 100mA l 1.728 1.8 1.872 V OUT OUT LTC1503-2, 0mA < I < 100mA l 1.920 2.0 2.080 V OUT V Operating Current I = 0mA l 25 50 m A IN OUT V Shutdown Current SHDN/SS = 0V l 510 m A IN Output Ripple Voltage LTC1503-X, V = 3.6V, I = 100mA 25 mV IN OUT P-P Efficiency LTC1503-2, V = 3.6V, I = 100mA 82.9 % IN OUT Switching Frequency Oscillator Free Running 600 kHz SHDN/SS Input Threshold l 0.2 0.35 0.5 V SHDN/SS Input Current V = 0V (Note 3) l 3.5 2 1 m A SHDN/SS V = V l 1 1 m A SHDN/SS IN V Short-Circuit Current V = 0V (Note 4) l 822 50 mA OUT OUT V Turn-On Time C = 0nF, V = 3.6V, C = 10m F 0.1 ms OUT SS IN OUT C = 10nF 8 ms SS Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: Currents flowing into the device are positive polarity. Currents of a device may be impaired. flowing out of the device are negative polarity. Note 2: The LTC1503C is guaranteed to meet specified performance from Note 4: When V is less than 150mV, I is limited to much less than OUT OUT 0 C to 70 C and is designed, characterized and expected to meet these the maximum rated output current to prevent damage to the output extended temperature limits, but are not tested at 40 C and 85 C. The devices. LTC1503I is guaranteed to meet the extended temperature limits. 2 U WWW