LTC1517-5 Micropower, Regulated 5V Charge Pump in a 5-Pin SOT-23 Package U DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ Ultralow Power: ICC = 6µA Typ Short-Circuit/Thermal Protected 5V ±4% Regulated Output VIN Range: 2.7V to 5V Output Current: 10mA (VIN ≥ 2.7V) 20mA (VIN ≥ 3V) No Inductors Ultrasmall Application Circuit (0.045in2) 800kHz Switching Frequency Available in 5-Pin SOT-23 The LTC®1517-5 is a micropower charge pump DC/DC converter that produces a regulated 5V output. The input voltage range is 2.7V to 5V. Extremely low operating current (typically 6µA with no load) and low external parts count (one 0.1µF flying capacitor and two small bypass capacitors at VIN and VOUT) make the part ideally suited for small, light load battery-powered 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. U APPLICATIONS ■ ■ ■ ■ Cellular Telephones Battery-Operated Equipment Local Power Supplies Handheld Instruments PCMCIA Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. U ■ TYPICAL APPLICATION Typical Output Voltage vs Output Current 5.2 5 4 C1 – C1 + LTC1517-5 VIN 2.7V TO 5V 3.3µF VIN GND VOUT 1 2 3 6.8µF VOUT = 5V ± 4% IOUT = 10mA (VIN ≥ 2.7V) IOUT = 20mA (VIN ≥ 3V) OUTPUT VOLTAGE (V) 0.1µF TA = 25°C C1 = 0.1µF COUT = 6.8µF 5.1 5.0 4.9 VIN = 2.7V VIN = 3V VIN = 3.3V 1517 TA01 4.8 0 40 60 20 OUTPUT CURRENT (mA) 80 1517 TA02 1 LTC1517-5 U W U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) 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) .............................. 0°C to 70°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER TOP VIEW VIN 1 GND 2 VOUT 3 C1 – 5 LTC1517CS5-5 C1 + 4 S5 PART MARKING S5 PACKAGE 5-LEAD PLASTIC SOT-23 TJMAX = 125°C, θJA = 256°C/ W LTCJ Consult factory for Industrial and Military grade parts and for -3 and -3.3 version availability. ELECTRICAL CHARACTERISTICS VIN = 2.7V to 5V, C1 = 0.1µF, CIN = 3.3µF, COUT = 6.8µF, TMIN to TMAX, unless otherwise noted. SYMBOL PARAMETER VIN Operating Input Voltage VOUT Output Voltage ICC CONDITIONS ● 2.7 2.7V ≤ VIN ≤ 5V, IOUT ≤ 10mA 3V ≤ VIN ≤ 5V, IOUT ≤ 20mA ● ● 4.8 4.8 Input Supply Current 2.7V ≤ VIN ≤ 5V, IOUT = 0 ● VOUT Ripple VIN = 3V, IOUT = 20mA, COUT = 6.8µF fOSC Oscillator Frequency tON VOUT Turn-On Time VIN = 3V The ● 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. 2 MIN TYP MAX UNITS 5 V 5.0 5.0 5.2 5.2 V V 6 15 µA 75 mVP-P 800 kHz 1 ms Note 2: Commercial grade parts are designed to operate over the temperature range of – 40°C to 85°C but are neither tested nor guaranteed beyond 0°C to 70°C. LTC1517-5 U W TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage vs Input Voltage Efficiency vs Input Voltage 5.15 IOUT = 10mA COUT = 10µF 5.05 TA = 70°C 5.00 TA = 0°C TA = 25°C 4.95 VRIPPLE P-P (mV) EFFICIENCY (%) OUTPUT VOLTAGE (V) 200 80 70 60 3.0 4.0 4.5 3.5 INPUT VOLTAGE (V) 40 2.5 5.0 COUT = 3.3µF 150 COUT = 6.8µF 100 COUT = 10µF COUT = 22µF 50 50 4.90 2.5 IOUT = 10mA C1 = 0.1µF TA = 25°C IOUT = 10mA TA = 25°C 5.10 3.0 4.0 4.5 3.5 INPUT VOLTAGE (V) 1517-5 G01 5.0 0 2.5 3.0 4.0 4.5 3.5 INPUT VOLTAGE (V) 5.0 1517-5 G03 1517-5 G02 No Load Input Current vs Input Voltage Load Transient Response Efficiency vs Output Current 90 9 VIN = 3V SHDN = 0V TA = 25°C IOUT = 0mA 8 IOUT 0mA to 10mA 10mA/DIV 80 TA = 70°C 7 EFFICIENCY (%) INPUT CURRENT (µA) Output Ripple vs Input Voltage 250 90 TA = 25°C TA = 0°C 6 VOUT AC COUPLED 50mV/DIV 70 60 5 VIN = 3V COUT = 6.8µF 4 2.5 3.0 4.0 4.5 3.5 INPUT VOLTAGE (V) 5.0 1517-5 G04 50 0.01 0.1 1 10 OUTPUT CURRENT (mA) 500µs/DIV 1517-5 G06 100 1517-5 G05 3 LTC1517-5 U U U PIN FUNCTIONS VIN (Pin 1): Charge Pump Input Voltage. May be between 2.7V and 5V. VIN should be bypassed with a ≥ 3.3µF 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 ≥3.3µF 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. W W SI PLIFIED BLOCK DIAGRA C1 0.1µF C1 – VIN C1 + VOUT CHARGE PUMP CIN 3.75M COUT + 800kHz OSC – THERMAL SHDN 1.25M 1.25V REF LTC1517-5 1517 BD 4 LTC1517-5 U W U U APPLICATIONS INFORMATION Operation Output Ripple The LTC1517-5 uses a switched-capacitor charge pump to boost VIN to a 5V ±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 800kHz (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 LTC1517-5 to achieve high efficiency at extremely low output loads. Normal LTC1517-5 operation produces voltage ripple on the VOUT pin. Output voltage ripple is required for the part 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 = 3V under maximum load is 100mV peak-to-peak with a low ESR (< 0.5Ω) 3.3µF output capacitor (minimum recommended COUT). For applications requiring VIN to exceed 3.3V or for applications requiring < 100mV of peak-to-peak ripple, a 6.8µF to 10µF COUT capacitor is recommended. Slight further decreases in output ripple can be achieved by using COUT capacitors larger than 10µF. 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 3.3µF or greater. Ceramic capacitors will provide the smallest size and lowest ESR for a given capacitance. If the input source impedance is very low (< 0.5Ω), CIN may not be needed. Ceramic capacitors are recommended for the flying capacitor C1 with values of 0.1µF or 0.22µF. Smaller value flying capacitors may be used in low IOUT applications. Short-Circuit/Thermal Protection During short-circuit conditions, the LTC1517-5 will draw between 50mA and 200mA from VIN, causing a rise in junction temperature. On-chip thermal shutdown circuitry disables the charge pump once the junction temperature exceeds approximately 160°C. The charge pump is reenabled once the junction temperature drops to approximately 145°C. The LTC1517-5 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the VOUT short is removed. 5 LTC1517-5 U TYPICAL APPLICATIONS Low Noise Boosted 5V Supply 0.1µF 5 4 C1 – C1 + LTC1517-5 VIN 3.3V TO 5V VIN GND VOUT 1 2 3 50mV/DIV AC COUPLED B VOUT 2mV/DIV AC COUPLED A 1µF 470Ω Q1 3.3µF 470Ω A Q2 1µF 1µF Q1, Q2: 2N3904 VOUT = 5V IOUT = 1mA (VIN ≥ 3.3V) IOUT = 10mA (VIN ≥ 3.6V) B 1µF VRIPPLE < 2mVP-P 1517 TA04a VIN = 3.3V IOUT = 1mA 50µs/DIV Generating 5V and a Negative Supply 0.1µF 5 4 C1 – C1 + LTC1517-5 VIN 2.7V TO 5V VIN GND VOUT 1 2 3 3.3µF VOUT = 5V ± 4% IOUT = 10mA (2.7V ≤ VIN ≤ 5V) IOUT = 20mA (3V ≤ VIN ≤ 5V) 3.3µF 470Ω Q1 8.2k Q2 3.3k 0.1µF ** 1517 TA05 3.3µF * *CENTRAL SEMICONDUCTOR CMPSH-35 DUAL SCHOTTKY **OPTIONAL CIRCUITRY FOR MAINTAINING – VOUT WITH LOW VOUT LOADS Q1, Q2: 2N3904 6 – VOUT = – 1.4V TO – 3.5V – IOUT = 0mA to 5mA 1517-5 TA04b LTC1517-5 U PACKAGE DESCRIPTION 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) 0.10 – 0.60 (0.004 – 0.024) REF 0.09 – 0.20 (0.004 – 0.008) (NOTE 2) 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) 0.35 – 0.50 0.90 – 1.30 (0.014 – 0.020) (0.035 – 0.051) FIVE PLACES (NOTE 2) S5 SOT-23 0797 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. 7 LTC1517-5 U TYPICAL APPLICATION 3.3V to 1.9V, 6A Power Supply VIN 3.3V C1 Y5V CERAMIC 3.3µF 2 + 5 1 LTC1517-5 3 4 C3 0.22µF C6 TO C9* 330µF 6.3V C10 ×4 0.1µF R2 24k C2 Y5V CERAMIC 10µF L1 2.4µH, 8A SUMIDA CDRH127-2R4 Q1 Si4410 5V D1 BAT54 C5 1µF OFF 1 2 3 4 5 6 7 8 LTC1430CS 16 G1 G2 15 PVCC1 PVCC2 14 PGND VCC 13 IFB GND 12 – IMAX SENSE 11 FB FREQSET 10 + SENSE COMP 9 SHDN SS C12 0.1µF R1 100Ω D2 MBRS120 Q2 Si4410 R3 1k C4 0.1µF ON C11 1µF C16 0.018µF R5 4.99K 1% VOUT 1.9V 6A + R6 10K 1% C17 TO C21 * 330µF 6.3V ×5 R4 5.2k C13 390pF C14 0.012µF + C15 10µF 10V 1517 TA03 *AVX TPS TANTALUM RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1514-X Step-Up/Step-Down Switched-Capacitor DC/DC Converter with Low Battery Comparator 3.3V or 5V Output Up to 50mA LTC1515 Series Step-Up/Step-Down Switched-Capacitor DC/DC Converter with Reset Fixed or Adjustable Output Up to 50mA LTC1516 Micropower Regulated 5V Charge Pump DC/DC Converter 20mA for VIN ≥ 2V, 50mA for VIN ≥ 3V LTC1522 Micropower Regulated 5V Charge Pump DC/DC Converter Same as LTC1517-5 with Shutdown, Available in MSOP 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● (408) 432-1900 FAX: (408) 434-0507 ● TELEX: 499-3977 ● www.linear-tech.com 15175f LT/TP 0298 4K • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1997