LTC1514-3.3/LTC1514-5 Step-Up/Step-Down Switched Capacitor DC/DC Converters with Low-Battery Comparator FEATURES DESCRIPTION n 3.3V or 5V Output Voltages The LTC 1514-3.3/LTC1514-5 are micropower switched n capacitor DC/DC converters that produce a regulated 2V to 10V Input Voltage Range n output voltage by either stepping up or stepping down Up to 50mA Output Current n the input voltage. Output voltage is fixed at either 3.3V Only Three External Capacitors Required n (LTC1514-3.3) or 5V (LTC1514-5) by an internal resistor Soft Start Limits Inrush Current at Turn-On divider. n Low Operating Current: 60A n Low Shutdown Current: 10A A unique architecture allows the parts to accommodate n Shutdown Disconnects Load from V a wide input voltage range (2V to 10V) while maintaining IN n Short-Circuit and Overtemperature Protected 4% regulation. Additional circuitry prevents excessive n 650kHz Switching Frequency inrush current and output voltage ripple when large V IN n Low-Battery Comparator Active in Shutdown to V differentials are present. OUT n Available in SO-8 Package An internal uncommitted comparator is kept active in U shutdown. The comparator has an open-drain output for APPLICATIONS flexible interfacing. n Battery-Operated Equipment The parts are short-circuit and overtemperature pro- n Smart Card Readers tected. Battery life is maximized by very low operating n Local Power Supplies currents (I = 60A typ, 10A in shutdown). Both parts CC n are available in an SO-8 package. Handheld Instruments n Battery Backup Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION LTC1514-5 Output Voltage 5V Step-Up/Step-Down Power Supply with Low-Battery Detect vs Input Voltage 5.2 100k I = 10mA OUT 1.33M 1% LTC1514-5 5.1 1 8 V = 5V OUT ON OFF SHDN V OUT I = 50mA OUT 2 7 LOW BAT LBO V IN + 3 6 + 5.0 V 10F LBI C1 IN 0.22F 4-CELL 4 5 + 499k GND C1 NiCd 10F 1% 4.9 1514 TA01 4.8 2 3 4 5 6 7 8 9 10 INPUT VOLTAGE (V) LT1514 TA02 1 OUTPUT VOLTAGE (V) U ULTC1514-3.3/LTC1514-5 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) V to GND................................................ 0.3V to 12V IN ORDER PART V to GND ............................................. 0.3V to 12V NUMBER OUT TOP VIEW SHDN, LBI, LBO to GND ........................... 0.3V to 12V SHDN 1 8 V LTC1514CS8-3.3 OUT V Short-Circuit Duration............................. Indefinite OUT LTC1514CS8-5 LBO 2 7 V IN Operating Temperature Range + LTC1514IS8-3.3 LBI 3 6 C1 Commercial ............................................. 0C to 70C LTC1514IS8-5 GND 4 5 C1 Industrial ........................................... 40C to 85C Storage Temperature Range ................. 65C to 150C S8 PACKAGE S8 PART MARKING 8-LEAD PLASTIC SO Lead Temperature (Soldering, 10 sec).................. 300C T = 125C, = 110C/ W JMAX JA 15143 1514I3 15145 1514I5 Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS V = 2V to 10V, SHDN = 3V, C1 = 0.22F, C = C = 10F, unless otherwise noted (Note 2). IN IN OUT PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage LTC1514-3.3 l 2.0 8 V IN LTC1514-5 l 2.7 10 V V (LTC1514-3.3) 2V V 8V, I 15mA l 3.17 3.3 3.43 V OUT IN OUT 3V V 8V, I 50mA l 3.17 3.3 3.43 V IN OUT V (LTC1514-5) 2.7V V 10V, I 15mA l 4.8 5 5.2 V OUT IN OUT 3.3V V 10V, I 50mA l 4.8 5 5.2 V IN OUT V Operating Current V 5V, I = 0, SHDN = 3V l 60 100 A IN IN OUT V > 5V, I = 0, SHDN = 3V l 75 120 A IN OUT V Shutdown Current SHDN = 0V, V 5V l 10 20 A IN IN SHDN = 0V, V > 5V 35 A IN Output Ripple Full Load (Note 2) 100 mV P-P Switching Frequency l 500 650 800 kHz LBI Trip Point LBI Ramping Negative l 1.110 1.145 1.180 V LBI Trip Point Hysteresis 1% LBI Input Current LBI = 1.145V l 50 50 nA LBO V I = 100A, V = 3V l 0.025 0.4 V OL SINK IN LBO Leakage Current V = 5V, LBI = V l 1 1 A LBO IN SHDN Input Threshold V l 0.4 1 V IL V l 1 1.6 V IH SHDN Input Current SHDN = V l 1 1 A IN SHDN = 0V l 1 1 A I Short-Circuit Current V = 0V l 12 40 mA OUT OUT t Soft Start Turn-On Time 4 ms ON The l denotes specifications which apply over the full operating Note 2: For V 8V, C = 22F. IN OUT temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. 2 U W U W U WW