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| LTC1517-3.3 Micropower, Regulated 3.3V Charge Pump in a 5-Pin SOT-23 Package FEATURES s s s s s DESCRIPTION The LTC(R)1517-3.3 is a micropower charge pump DC/DC converter that produces a regulated 3.3V output. The input voltage range is 2V to 4.4V, allowing a single cell lithium battery to produce a regulated 3.3V output over the entire life of the battery. Extremely low operating current (typically 6A with no load) and low external parts count (one 0.1F flying capacitor and two small bypass capacitors at VIN and VOUT) make the part ideally suited for small, light load batterypowered applications. The total printed circuit board area of the application circuit shown below is only 0.045in2. The part operates as a Burst ModeTM switched-capacitor voltage doubler to produce a regulated output. The part has thermal shutdown capability and can survive a continuous short circuit from VOUT to GND. The device is available in a 5-pin SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. s s s s Ultralow Power: ICC = 6A Typ Short-Circuit/Thermal Protected 3.3V 4% Regulated Output VIN Range: 2V to 4.4V Output Current: 8mA (VIN 2V) 15mA (VIN 2.5V) No Inductors Ultrasmall Application Circuit (0.045in2) 700kHz Switching Frequency Available in 5-Pin SOT-23 APPLICATIONS s s s s s Cellular Telephones Battery-Operated Equipment Local Power Supplies Handheld Instruments PCMCIA Supplies TYPICAL APPLICATION Typical Output Voltage vs Output Current 0.1F 5 C1 - LTC1517-3.3 VIN VIN 2V TO 4.4V 3.3F 1 GND 2 VOUT 3 6.8F VOUT = 3.3V 4% IOUT = 8mA (VIN 2V) IOUT = 15mA (VIN 2.5V) 1517-3.3 TA01 3.40 TA = 25C C1 = 0.1F COUT = 6.8F OUTPUT VOLTAGE (V) 4 C1 + 3.35 3.30 VIN = 2V 3.25 VIN = 2.5V 3.20 0 20 30 10 OUTPUT CURRENT (mA) 40 1517 G05 U U U 1 LTC1517-3.3 ABSOLUTE MAXIMUM RATINGS (Note 1) PACKAGE/ORDER INFORMATION TOP VIEW VIN GND VOUT 1 2 3 4 C1 + 5 C1 - VIN to GND ...................................................- 0.3V to 6V VOUT to GND ................................................- 0.3V to 6V VOUT Short-Circuit Duration ............................. Indefinite Operating Temperature Range: Commercial (Note 2) .............................. 0C to 70C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C ORDER PART NUMBER LTC1517CS5-3.3 S5 PACKAGE 5-LEAD PLASTIC SOT-23 S5 PART MARKING LTEF TJMAX = 125C, JA = 256C/ W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS VIN = 2V to 4.4V, C1 = 0.1F, CIN = 3.3F, COUT = 6.8F, TMIN to TMAX, unless otherwise noted. SYMBOL VIN VOUT ICC fOSC tON ISC PARAMETER Operating Input Voltage Output Voltage Input Supply Current VOUT Ripple Oscillator Frequency VOUT Turn-On Time Output Short-Circuit Current VIN = 2.5V VIN = 3V 2V VIN 4.4V, IOUT 8mA 2.5V VIN 4.4V, IOUT 15mA 2V VIN 4.4V, IOUT = 0 VIN = 2.5V, IOUT = 15mA, COUT = 6.8F CONDITIONS q q q q MIN 2.0 3.17 3.17 TYP 3.3 3.3 6 50 700 1 60 MAX 4.4 3.43 3.43 15 UNITS V V V A mVP-P kHz ms mA The q denotes specifications that apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: Commercial grade parts are designed to operate over the temperature range of - 40C to 85C but are neither tested nor guaranteed beyond 0C to 70C. 2 U W U U WW W LTC1517-3.3 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Input Voltage 3.40 IOUT = 8mA COUT = 6.8F 100 IOUT = 8mA TA = 25C 80 TA = 70C 3.30 TA = 0C 3.25 TA = 25C 150 OUTPUT VOLTAGE (V) 3.35 60 VRIPPLE P-P (mV) EFFICIENCY (%) 3.20 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) No Load Input Current vs Input Voltage 10 IOUT = 0mA 8 TA = 70C 6 TA = 0C 4 TA = 25C INPUT CURRENT (A) EFFICIENCY (%) 2 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) Typical Output Current vs Temperature 50 VOUT SHORT-CIRCUIT CURRENT (mA) VOUT = 3.3V C1 = 0.1F 40 OUTPUT CURRENT (mA) 30 VIN = 2.5V 20 VIN = 2V 10 0 -50 -25 0 25 50 TEMPERATURE (C) UW 1517 G01 1517 G04 Efficiency vs Input Voltage 200 Output Ripple vs Input Voltage IOUT = 8mA C1 = 0.1F CIN = 3.3F TA = 25C COUT = 3.3F 100 COUT = 6.8F 50 COUT = 10F 40 4.5 20 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) 4.5 1517 G02 0 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) 4.5 1517 G03 Typical Efficiency vs Output Current 100 TA = 25C C1 = 0.1F COUT = 6.8F VIN = 2V VIN = 2.5V 60 VOUT AC COUPLED 50mV/DIV IOUT 0mA to 10mA 5mA/DIV Load Transient Response 80 40 20 VIN = 2.5V COUT = 6.8F 500s/DIV 1517 G06 4.5 0 0.001 0.01 1 10 0.1 OUTPUT CURRENT (mA) 100 1517 TA02 VOUT Short-Circuit Current vs Input Voltage 200 TA = 25C C1 = 0.1F 160 VIN = 2.7V 120 80 40 75 100 1517 G09 0 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) 4.5 1517 G10 3 LTC1517-3.3 TYPICAL PERFORMANCE CHARACTERISTICS Oscillator Frequency vs Input Voltage 900 TA = 25C OSCILLATOR FREQUENCY (kHz) OSCILLATOR FREQUENCY (kHz) 800 700 600 500 2.0 2.5 3.5 4.0 3.0 INPUT VOLTAGE (V) PIN FUNCTIONS VIN (Pin 1): Charge Pump Input Voltage. May be between 2V and 4.4V. VIN should be bypassed with a 3.3F low ESR capacitor as close as possible to the pin for best performance. GND (Pin 2): Ground. Should be tied to a ground plane for best performance. VOUT (Pin 3): Regulated Output Voltage. VOUT should be bypassed with a 3.3F low ESR capacitor as close as possible to the pin for best performance. C1 + (Pin 4): Charge Pump Flying Capacitor Positive Terminal. C1 - (Pin 5): Charge Pump Flying Capacitor Negative Terminal. SI PLIFIED BLOCK DIAGRA VIN CIN 700kHz OSC 4 W UW Oscillator Frequency vs Temperature 900 VIN = 2.5V 800 700 600 500 4.5 1517 G07 400 -50 -25 0 25 50 TEMPERATURE (C) 75 100 1517 G08 U U W U C1 0.1F C1 - C1 + VOUT 2.05M COUT CHARGE PUMP + - THERMAL SHDN 1.25V REF 1.25M 1517-3.3 BD LTC1517-3.3 APPLICATIONS INFORMATION Operation The LTC1517-3.3 uses a switched-capacitor charge pump to boost VIN to a 3.3V 4% regulated output. The part achieves regulation by sensing the output voltage through an internal resistor divider and enabling the charge pump when the divided output droops below the comparator's lower trip point (set by VREF). When the charge pump is enabled, a 2-phase nonoverlapping clock controls the internal charge pump switches. Flying capacitor C1 is charged to VIN on phase one of the clock. On phase two of the clock, C1 is stacked in series with VIN and connected to VOUT through an internal switch. This sequence of charging and discharging the flying capacitor occurs at a free running frequency of 700kHz (typ) and continues until the divided output voltage reaches the upper trip point of the comparator. Once the output is back in regulation, the charge pump is disabled. This method of bursting the charge pump on and off enables the LTC1517-3.3 to achieve high efficiency at extremely low output loads. Capacitor Selection For best performance, it is recommended that low ESR capacitors be used for both CIN and COUT to reduce noise and ripple. The CIN and COUT capacitors should be either ceramic or tantalum and should be 3.3F or greater. Ceramic capacitors will provide the smallest size for a given capacitance. If the input source impedance is very low (< 0.5), CIN may not be needed. Ceramic capacitors are recommended for the flying capacitor C1 with values of 0.1F or 0.22F. Smaller value flying capacitors may be used in low IOUT applications. Output Ripple Normal LTC1517-3.3 operation produces voltage ripple on the VOUT pin. Output voltage ripple is required for the parts to regulate. Low frequency ripple exists due to the hysteresis in the sense comparator and propagation delays in the charge pump enable/disable circuits. High frequency ripple is also present mainly from the ESR (equivalent series resistance) in the output capacitor. Typical output ripple with VIN = 2.5V under maximum load is 75mV peak-to-peak with a low ESR 3.3F output capacitor (minimum recommended COUT). For applications requiring VIN to exceed 3.3V or for applications requiring less than 75mV of peak-to-peak ripple, a 6.8F to 10F COUT capacitor is recommended. Slight further decreases in output ripple can be achieved by using COUT capacitors larger than 10F. Short-Circuit/Thermal Protection During short-circuit conditions, the LTC1517-3.3 will draw between 20mA and 150mA from VIN, causing a rise in junction temperature. On-chip thermal shutdown circuitry disables the charge pump once the junction temperature exceeds approximately 160C. The charge pump is reenabled once the junction temperature drops to approximately 145C. The LTC1517-3.3 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the VOUT short is removed. U W U U 5 LTC1517-3.3 TYPICAL APPLICATIONS Low Noise Boosted 3.3V Supply 0.1F 5 C1 - LTC1517-3.3 VIN VIN 2.7V TO 4.4V 1 3.3F 470 Q2 Q1, Q2: 2N3904 3.3F 3.3F 1F 1517 TA04a 4 C1 + GND 2 VOUT 3 470 Q1 B VOUT = 3.3V IOUT = 8mA VRIPPLE = 2mVP-P A VIN 2V TO 4.4V 3.3F 6 U A 50mV/DIV AC COUPLED B VOUT 2mV/DIV AC COUPLED VIN = 2.7V IOUT = 5mA 10s/DIV 1517 TA04b Generating 3.3V and a Negative Supply 0.1F 5 C1 - LTC1517-3.3 VIN 1 GND 2 VOUT 3 3.3F 470 21.5k VOUT = 3.3V 4% IOUT = 5mA (2V VIN 4.4V) IOUT = 10mA (2.5V VIN 4.4V) 4 C1 + Q1 0.1F Q2 10k ** 1517 TA05 3.3F * *CENTRAL SEMICONDUCTOR CMPSH-35 DUAL SCHOTTKY **OPTIONAL CIRCUITRY FOR MAINTAINING - VOUT WITH LOW VOUT LOADS Q1, Q2: 2N3904 - VOUT = -0.8V TO - 3V - IOUT = 0mA to 5mA LTC1517-3.3 PACKAGE DESCRIPTION 0.10 - 0.60 (0.004 - 0.024) REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DIMENSIONS ARE INCLUSIVE OF PLATING 3. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 4. MOLD FLASH SHALL NOT EXCEED 0.254mm 5. PACKAGE EIAJ REFERENCE IS SC-74A (EIAJ) 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 its circuits as described herein will not infringe on existing patent rights. U Dimensions in inches (millimeters) unless otherwise noted. S5 Package 5-Lead Plastic SOT-23 (LTC DWG # 05-08-1633) 2.80 - 3.00 (0.110 - 0.118) (NOTE 3) 2.60 - 3.00 (0.102 - 0.118) 1.50 - 1.75 (0.059 - 0.069) 1.90 (0.074) REF 0.00 - 0.15 (0.00 - 0.006) 0.95 (0.037) REF 0.90 - 1.45 (0.035 - 0.057) 0.09 - 0.20 (0.004 - 0.008) (NOTE 2) 0.35 - 0.50 0.90 - 1.30 (0.014 - 0.020) (0.035 - 0.051) FIVE PLACES (NOTE 2) S5 SOT-23 0797 7 LTC1517-3.3 TYPICAL APPLICATION Low Power Battery Backup Supply with Autoswitchover and No Reverse Current MAIN SUPPLY 5V 75k 1.1M + 3.9VTRIP 470k 3 4 5 6 LTC1540 RELATED PARTS PART NUMBER LTC1514-X LTC1515 LTC1516 LTC1517-5 LTC1522 DESCRIPTION Step-Up/Step-Down Switched-Capacitor DC/DC Converter with Low Battery Comparator Step-Up/Step-Down Switched-Capacitor DC/DC Converter with POR Micropower Regulated 5V Charge Pump DC/DC Converter Micropower Regulated 5V Charge Pump in a 5-Pin SOT-23 Package Micropower Regulated 5V Charge Pump DC/DC Converter COMMENTS 3.3V or 5V Output up to 50mA Fixed or Adjustable Output up to 50mA 20mA for VIN 2V, 50mA for VIN 3V IOUT up to 20mA Same as LTC1517-5 with Shutdown 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com - U 3 1F BAT54 LT1521-3.3 2 1 1.5F VOUT = 3.3V, IOUT = 300mA (IOUT = 8mA IN BACKUP MODE) 0.1F TRICKLE CHARGE AND LTC1517-3.3 IDD 1 2-CELL NiCd 3.3F 5 4 3 3.3F SILICONIX Si2301DS LTC1517-3.3 2 7 8 LOGIC LOW = BACKUP MODE 1517-3.3 TA03 2 1 15173f LT/TP 0998 4K * PRINTED IN USA (c) LINEAR TECHNOLOGY CORPORATION 1998 |
Price & Availability of LTC1517CS5-33
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