LTC1754-3.3/LTC1754-5 Micropower, Regulated 3.3V/5V Charge Pump with Shutdown in SOT-23 U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Ultralow Power: IIN = 13µA Regulated Output Voltage: 3.3V ±4%, 5V ±4% 5V Output Current: 50mA (VIN ≥ 3.0V) 3.3V Output Current: 40mA (VIN ≥ 2.5V) No Inductors Needed Very Low Shutdown Current: <1µA Shutdown Disconnects Load from VIN Internal Oscillator: 600kHz Short-Circuit and Overtemperature Protected Ultrasmall Application Circuit: (0.052 Inch2) 6-Pin SOT-23 Package The LTC®1754 is a micropower charge pump DC/DC converter that produces a regulated output. The input voltage range is 2V to 4.4V for 3.3V output and 2.7V to 5.5V for 5V output. Extremely low operating current and a low external parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) make the LTC1754 ideally suited for small, battery-powered applications. The total component area of the application circuit shown below is only 0.052 inch2. The LTC1754 operates as a Burst ModeTM switched capacitor voltage doubler to produce a regulated output. It has thermal shutdown capability and can survive a continuous short circuit from VOUT to GND. U APPLICATIO S ■ ■ ■ ■ ■ ■ The LTC1754 is available in a 6-pin SOT-23 package. SIM Interface Supplies for GSM Cellular Telephones White LED Power Supplies Li-Ion Battery Backup Supplies Handheld Computers Smart Card Readers PCMCIA Local 5V Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. U TYPICAL APPLICATIO 10µF 2 ON/OFF 3 VOUT LTC1754-X GND VIN SHDN C – LTC1754-3.3 Output Voltage vs Supply Voltage 6 5 3.40 1µF 4 VIN 10µF 1754 TA01 Regulated 3.3V Output from 2V to 4.4V Input VOUT = 3.3V ± 4% IOUT = 0mA TO 20mA, VIN > 2.0V IOUT = 0mA TO 40mA, VIN > 2.5V 5.15 IOUT = 20mA COUT = 10µf CFLY = 1µF 5.10 3.35 TA = 85°C 3.30 TA = 25°C TA = –40°C 3.25 Regulated 5V Output from 2.7V to 5.5V Input VOUT = 5V ± 4% IOUT = 0mA TO 25mA, VIN > 2.7V IOUT = 0mA TO 50mA, VIN > 3.0V LTC1754-5 Output Voltage vs Supply Voltage OUTPUT VOLTAGE (V) VOUT C+ OUTPUT VOLTAGE (V) 1 IOUT = 25mA COUT = 10µF CFLY = 1µF 5.05 TA = 25°C TA = 85°C 5.00 TA = –40°C 4.95 4.90 3.20 2.0 2.5 3.5 4.0 3.0 SUPPLY VOLTAGE (V) 4.5 1754 TA02 4.85 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 1574 TA03 1 LTC1754-3.3/LTC1754-5 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) VIN to GND .................................................. – 0.3V to 6V VOUT to GND ............................................... – 0.3V to 6V SHDN to GND .............................................. – 0.3V to 6V IOUT (Note 4) ......................................................... 75mA VOUT Short-Circuit Duration ............................ Indefinite Operating Temperature Range (Note 3) ... – 40°C to 85°C Storage Temperature Range .................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C ORDER PART NUMBER TOP VIEW VOUT 1 6 C+ GND 2 5 VIN SHDN 3 4 C– LTC1754ES6-3.3 LTC1754ES6-5 S6 PART MARKING S6 PACKAGE 6-LEAD PLASTIC SOT-23 TJMAX = 150°C, θJA = 230°C/ W LTGK LTLW Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. CFLY = 1µF (Note 2), CIN = 10µF, COUT = 10µF. SYMBOL PARAMETER LTC1754-3.3 VIN Input Supply Voltage VOUT Output Voltage ICC VR η fOSC tON ISC LTC1754-5 VIN VOUT Operating Supply Current Output Ripple Efficiency Switching Frequency VOUT Turn-On Time Output Short-Circuit Current Input Supply Voltage Output Voltage ICC Operating Supply Current VR Output Ripple η Efficiency fOSC Switching Frequency tON VOUT Turn-On Time ISC Output Short-Circuit Current LTC1754-3.3/LTC1754-5 ISHDN Shutdown Supply Current VIH VIL IIH IIL SHDN Input Threshold (High) SHDN Input Threshold (Low) SHDN Input Current (High) SHDN Input Current (Low) CONDITIONS ● 2.0V ≤ VIN ≤ 4.4V, IOUT ≤ 20mA 2.5V ≤ VIN ≤ 4.4V, IOUT ≤ 40mA 2.0V ≤ VIN ≤ 4.4V, IOUT = 0mA, SHDN = VIN VIN = 2.5V, IOUT = 40mA VIN = 2.0V, IOUT = 20mA Oscillator Free Running VIN = 2.0V, IOUT = 0mA VIN = 2.5V, VOUT = 0V, SHDN = 2.5V ● ● 2.0 3.17 3.17 ● ● 2.7V ≤ VIN ≤ 5.5V, IOUT ≤ 25mA 3.0V ≤ VIN ≤ 5.5V, IOUT ≤ 50mA 2.7V ≤ VIN ≤ 5.5V, IOUT = 0mA, SHDN = VIN VIN = 3V, IOUT = 50mA VIN = 3V, IOUT = 50mA Oscillator Free Running VIN = 3V, IOUT = 0mA VIN = 3V, VOUT = 0V, SHDN = 3V ● ● VIN ≤ 3.6V, IOUT = 0mA, VSHDN = 0V 3.6V < VIN, IOUT = 0mA, VSHDN = 0V ● ● 2.7 4.8 4.8 ● ● SHDN = VIN SHDN = 0V ● ● TYP 3.30 3.30 11 23 82 600 0.8 118 5.0 5.0 13 65 82.7 700 0.4 150 0.01 MAX UNITS 4.4 3.43 3.43 30 V V V µA mVP-P % kHz ms mA 5.5 5.2 5.2 30 V V V µA mVP-P % kHz ms mA 1 2.5 1.4 ● Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: 0.6µF is the minimum required CFLY capacitance for rated output current capability. Depending on the choice of capacitor material, a somewhat higher value of capacitor may be required to attain 0.6µF over temperature. 2 MIN –1 –1 0.3 1 1 Note 3: The LTC1754ES6-X is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 4: Based on long term current density limitations. µA µA V V µA µA LTC1754-3.3/LTC1754-5 U W TYPICAL PERFOR A CE CHARACTERISTICS No Load Supply Current vs Supply Voltage 20 3.35 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) TA = 25°C COUT = 10µF CFLY = 1µF VIN = 2.5V 3.30 VIN = 2V 3.25 Supply Current vs VSHDN 20 IOUT = 0µA CFLY = 1µF VSHDN = VIN 15 SUPPLY CURRENT (µA) Output Voltage vs Output Current 3.40 LTC1754-3.3, TA = 25°C unless otherwise noted. TA = 85°C TA = 25°C 10 TA = 25°C IOUT = 0µA 15 VIN = 4.5V VIN = 2.5V 10 VIN = 2V 5 TA = – 40°C 3.20 5 0 20 60 80 40 OUTPUT CURRENT (mA) 2.0 100 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) VOUT Short-Circuit Current vs Supply Voltage 3 4 2 VSHDN CONTROL VOLTAGE (V) 5 1754 G03 Efficiency vs Load Current 100 TA = 25°C CFLY = 1µF 90 160 80 140 EFFICIENCY (%) VOUT SHORT-CIRCUIT CURRENT (mA) 1 1754 G02 1754 G01 180 0 4.5 120 100 TA = 25°C VIN = 2V CFLY = 1µF 70 60 50 40 30 20 80 10 0 0.001 60 2.0 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) 4.5 0.01 0.1 1 10 LOAD CURRENT (mA) 1754 G05 1735 G04 Output Ripple Load Transient Response 100 Start-Up Time IOUT 0mA to 20mA 10mA/DIV SHDN 1V/DIV VOUT AC COUPLED 20mV/DIV VOUT 1V/DIV VOUT AC COUPLED 20mV/DIV VIN = 2V COUT = 10µF 50µs/DIV 1754 G07 VIN = 2V COUT = 10µF IOUT = 20mA 5µs/DIV 1754 G08 VIN = 2V COUT = 10µF 200µs/DIV 1754 G9 3 LTC1754-3.3/LTC1754-5 U W TYPICAL PERFOR A CE CHARACTERISTICS No Load Supply Current vs Supply Voltage Output Voltage vs Output Current 25 IOUT = 0µA CFLY = 1µF VSHDN = VIN 5.05 SUPPLY CURRENT (µA) OUTPUT VOLTAGE (V) 20 TA = 25°C COUT = 10µF CFLY = 1µF 5.10 Supply Current vs VSHDN VIN = 3V 5.00 VIN = 2.7V 4.95 15 TA = 25°C 10 TA = –40°C VIN = 5.5V VIN = 3.3V 15 VIN = 2.7V 10 5 4.90 4.85 0 20 5 2.5 100 40 60 80 OUTPUT CURRENT (mA) 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 1574-5 G02 2 4 5 3 VSHDN CONTROL VOLTAGE (V) 6 1574 G12 Efficiency vs Load Current VIN = 3V 90 TA = 25°C CFLY = 1µF 80 TA = 25°C CFLY = 1µF 180 EFFICIENCY (%) VOUT SHORT-CIRCUIT CURRENT (mA) 1 100 220 200 0 5.5 1754 G11 VOUT Short-Circuit Current vs Supply Voltage 160 140 70 60 50 40 30 20 120 10 100 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 0 0.001 5.5 0.01 0.1 1 10 LOAD CURRENT (mA) Load Transient Response 100 1754-5 G05 1754 G13 Output Ripple Start-Up Time IOUT 0mA to 50mA 25mA/DIV SHDN 5V/DIV VOUT AC COUPLED 20mV/DIV VOUT AC COUPLED 50mV/DIV VIN = 3V COUT = 10µF 4 TA = 25°C IOUT = 0µA 20 TA = 85°C SUPPLY CURRENT (µA) 5.15 LTC1754-5, TA = 25°C unless otherwise noted. 50µs/DIV 1754 G16 VOUT 1V/DIV VIN = 3V COUT = 10µF IOUT = 50mA 5µs/DIV 1754 G17 VIN = 3V COUT = 10µF 100µs/DIV 1754 G18 LTC1754-3.3/LTC1754-5 U W TYPICAL PERFOR A CE CHARACTERISTICS LTC1754-3.3. LTC1754-5, TA = 25°C unless otherwise noted. Oscillator Frequency vs Supply Voltage Efficiency vs Supply Voltage EFFICIENCY (%) 80 OSCILLATOR FREQUENCY (kHz) 90 LTC1754-5 IOUT = 25mA 70 60 50 40 30 2.0 850 TA = 25°C CFLY = 1µF LTC1754-3.3 IOUT = 20mA 2.5 0.95 800 0.90 TA = 85°C 750 THRESHOLD VOLTAGE (V) 100 VSHDN Threshold Voltage vs Supply Voltage 700 TA = 25°C 650 600 550 TA = –40°C 5.0 5.5 TA = 25°C 0.80 TA = 85°C 0.75 0.70 500 4.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) TA = –40°C 0.85 450 2.0 2.5 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 3.0 0.65 2.0 5.5 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 1754 G20 1754 G19 5.0 5.5 1754 G21 U U U PI FU CTIO S VOUT (Pin 1): Regulated Output Voltage. For best performance, VOUT should be bypassed with a 6.8µF (min) low ESR capacitor as close as possible to the pin. GND (Pin 2): Ground. Should be tied to a ground plane for best performance. C – (Pin 4): Flying Capacitor Negative Terminal. VIN (Pin 5): Input Supply Voltage. VIN should be bypassed with a 6.8µF (min) low ESR capacitor. C + (Pin 6): Flying Capacitor Positive Terminal. SHDN (Pin 3): Active Low Shutdown Input. A low on SHDN disables the LTC1754. SHDN must not be allowed to float. W W SI PLIFIED BLOCK DIAGRA * VOUT C+ 2 COUT 10µF CFLY 1µF 1 VIN CIN 10µF + COMP1 CONTROL 2 – C– VREF 1 SHDN 1754 BD *CHARGE PUMP SHOWN IN PHASE 1, THE CHARGING PHASE. PHASE 1 IS ALSO THE SHUTDOWN PHASE 5 LTC1754-3.3/LTC1754-5 U W U U APPLICATIO S I FOR ATIO Operation (Refer To Block Diagram) The LTC1754 uses a switched-capacitor charge pump to boost VIN to a regulated output voltage. Regulation is achieved by sensing the output voltage through an internal resistor divider and enabling the charge pump when the divided output drops below the lower trip point of COMP1. When the charge pump is enabled, a two-phase nonoverlapping clock activates the charge pump switches. The flying capacitor is charged to VIN on phase one of the clock. On phase two of the clock it is stacked in series with VIN and connected to VOUT. This sequence of charging and discharging the flying capacitor continues at a free running frequency of 600kHz (typ). Once the attenuated output voltage reaches the upper trip point of COMP1, the charge pump is disabled. When the charge pump is disabled the LTC1754 draws only 13µA from VIN thus providing high efficiency under low load conditions. In shutdown mode all circuitry is turned off and the LTC1754 draws only leakage current from the VIN supply. Furthermore, VOUT is disconnected from VIN. The SHDN pin is a CMOS input with a threshold voltage of approximately 0.8V, but may be driven to a logic level that exceeds VIN. The LTC1754 is in shutdown when a logic low is applied to the SHDN pin. Since the SHDN pin is a high impedance CMOS input, it should never be allowed to float. To ensure that its state is defined, it must always be driven with a valid logic level. Power Efficiency The efficiency (η) of the LTC1754 is similar to that of a linear regulator with an effective input voltage of twice the actual input voltage. This results because the input current for a voltage doubling charge pump is approximately twice the output current. In an ideal voltage doubling regulator the power efficiency would be given by: ( )( ) ( )( ) VOUT IOUT P V η = OUT = = OUT 2VIN PIN VIN 2IOUT At moderate-to-high output power, the switching losses and quiescent current of the LTC1754 are negligible and the expression above is valid. For example, an LTC1754-5 with 6 VIN = 3V, IOUT = 25mA and VOUT regulating to 5V, has a measured efficiency of 82.7%, which is in close agreement with the theoretical 83.3% calculation. The LTC1754 continues to maintain good efficiency even at fairly light loads because of its inherently low power design. Short-Circuit/Thermal Protection During short-circuit conditions, the LTC1754 will draw between 100mA and 400mA from VIN causing a rise in the junction temperature. On-chip thermal shutdown circuitry disables the charge pump once the junction temperature exceeds approximately 150°C and reenables the charge pump once the junction temperature drops back to approximately 140°C. The LTC1754 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the short circuit on VOUT is removed. Capacitor Selection The style and value of capacitors used with the LTC1754 determine several important parameters such as output ripple, charge pump strength and turn-on time. To reduce noise and ripple, it is recommended that low ESR (< 0.1Ω) capacitors be used for both CIN and COUT. These capacitors should be either ceramic or tantalum and be 6.8µF or greater. Aluminum capacitors are not recommended because of their high ESR. If the source impedance to VIN is very low up to several megahertz, CIN may not be needed. A ceramic capacitor is recommended for the flying capacitor with a value in the range of 1µF to 2.2µF. Note that a large value flying capacitor (> 2.2µF) will increase output ripple unless COUT is also increased. For very low load applications, CFLY may be reduced to 0.01µF to 0.047µF. This will reduce output ripple at the expense of maximum output current and efficiency. In order to achieve the rated output current it is necessary to have at least 0.6µF of capacitance for the flying capacitor. Capacitors of different material lose their capacitance over temperature at different rates. For example, a ceramic capacitor made of X7R material will retain most of its capacitance from – 40°C to 85°C, whereas a Z5U or Y5V style capacitor will lose considerable capacitance over that LTC1754-3.3/LTC1754-5 U W U U APPLICATIO S I FOR ATIO range. The capacitor manufacturer’s data sheet should be consulted to determine what style and value of capacitor is needed to ensure 0.6µF at all temperatures. Output Ripple Low frequency regulation mode ripple exists due to the hysteresis in the sense comparator and propagation delay in the charge pump control circuit. The amplitude and frequency of this ripple are heavily dependent on the load current, the input voltage and the output capacitor size. For large VIN the ripple voltage can become substantial because the increased strength of the charge pump causes fast edges that may outpace the regulation circuitry. Generally the regulation ripple has a sawtooth shape associated with it. A high frequency ripple component may also be present on the output capacitor due to the charge transfer action of the charge pump. In this case the output can display a voltage pulse during the charging phase. This pulse results from the product of the charging current and the ESR of the output capacitor. It is proportional to the input voltage, the value of the flying capacitor and the ESR of the output capacitor. Typical combined output ripple for the LTC1754-5 with VIN = 3V under maximum load is 65mVP-P using a low ESR 10µF output capacitor. A smaller output capacitor and/or larger output current load will result in higher ripple due to higher output voltage slew rates. There are several ways to reduce output voltage ripple. For applications requiring higher VIN or lower peak-to-peak ripple, a larger COUT capacitor (22µF or greater) is recommended. A larger capacitor will reduce both the low and high frequency ripple due to the lower charging and discharging slew rates, as well as the lower ESR typically found with higher value (larger case size) capacitors. A low ESR ceramic output capacitor will minimize the high frequency ripple, but will not reduce the low frequency ripple unless a high capacitance value is used. To reduce both the low and high frequency ripple, a reasonable compromise is to use a 10µF to 22µF tantalum capacitor in parallel with a 1µF to 3.3µF ceramic capacitor on VOUT. An R-C filter may also be used to reduce high frequency voltage spikes (see Figure 1). VOUT LTC1754-X + VOUT 15µF TANTALUM 1µF CERAMIC 2Ω VOUT LTC1754-X + 10µF TANTALUM + VOUT 10µF TANTALUM 1754 F01 Figure 1. Output Ripple Reduction Techniques In low load or high VIN applications, smaller values for the flying capacitor may be used to reduce output ripple. A smaller flying capacitor (0.01µF to 0.47µF) delivers less charge per clock cycle to the output capacitor resulting in lower output ripple. However, with a smaller flying capacitor, the maximum available output current will be reduced along with the efficiency. Note that when using a larger output capacitor the turn on time of the device will increase. Inrush Currents During normal operation VIN will experience current transients in the 50mA to 100mA range whenever the charge pump is enabled. However during start-up, inrush currents may approach 250mA. For this reason it is important to minimize the source impedance between the input supply and the VIN pin. Too much source impedance may result in regulation problems or prevent start-up. Ultralow Quiescent Current Regulated Supply The LTC1754 contains an internal resistor divider (refer to the Simplified Block Diagram) that typically draws 1.5µA from VOUT. During no-load conditions, this internal load causes a droop rate of only 150mV per second on VOUT with COUT = 10µF. Applying a 2Hz to 100Hz, 2% to 5% duty cycle signal to the SHDN pin ensures that the circuit of Figure 2 comes out of shutdown frequently enough to maintain regulation. Since the LTC1754 spends nearly the entire time in shutdown, the no-load quiescent current is approximately (VOUT)(1.5µA)/(ηVIN). The LTC1754 must be out of shutdown for a minimum duration of 200µs to allow enough time to sense the output voltage and keep it in regulation. A 2Hz, 2% duty cycle 7 LTC1754-3.3/LTC1754-5 U W U U APPLICATIO S I FOR ATIO signal will keep VOUT in regulation under no-load conditions. As the VOUT load current increases, the frequency with which the LTC1754 is taken out of shutdown must also be increased. 1 VOUT 10µF 2 SHDN PIN WAVEFORM 3 VOUT C+ LTC1754-X GND SHDN VIN C– 6 5 4 1µF Layout Considerations Due to high switching frequency and high transient currents produced by the LTC1754, careful board layout is necessary. A true ground plane and short connections to all capacitors will improve performance and ensure proper regulation under all conditions. Figure 4 shows the recommended layout configuration VIN VIN 10µF VOUT LOW IQ MODE (2Hz TO 100Hz, 2% TO 5% DUTY CYCLE) 1µF 1754 F02 Figure 2. Ultralow Quiescent Current Regulated Supply 10µF 10µF GND LTC1754-X SHDN 1754-5 F04 6 SUPPLY CURRENT (µA) TA = 25°C IOUT = 0µA 5 CFLY = 1µF Figure 4. Recommended Layout Thermal Management LTC1754-5 4 3 LTC1754-3.3 2 1 0 2.0 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 1754 F03 Figure 3. No-Load Supply Current vs Supply Voltage for the Circuit Shown in Figure 2 8 For higher input voltages and maximum output current, there can be substaintial power dissipation in the LTC1754. If the junction temperature increases above approximately 150°C, the thermal shutdown circuitry will automatically deactivate the output. To reduce the maximum junction temperature, a good thermal connection to the PC board is recommended. Connecting the GND pin (Pin 2) to a ground plane and maintaining a solid ground plane under the device on at least two layers of the PC board can reduce the thermal resistance of the package and PC board system to about 150°C/W. LTC1754-3.3/LTC1754-5 U TYPICAL APPLICATIO S Low Power Battery Backup with Autoswitchover and No Reverse Current 3 LTC1521-3.3 1 1µF 2 4 1N4148 VIN 5V 75k 5 + 10µF 10µF 2-CELL NiCd BATTERY 6 C– C+ VIN VOUT VOUT = 3.3V IOUT ≤ 300mA IOUT ≤ 20mA BACKUP 1 10µF LTC1754-3.3 SHDN 3 GND 2 7 1.2M 4 8 3 475k 6 HIGH = BACKUP MODE LTC1540 10k 5 175433 TA03 2 1M 1 USB Port to Regulated 5V Power Supply 1µF 4 6 5 3 1 LTC1754-5 10µF VOUT 10µF 5V ±4% 50mA 2 1754 TA06 9 LTC1754-3.3/LTC1754-5 U TYPICAL APPLICATIO S 5V, 100mA Step-Up Generator from 3V 1µF 4 6 C– 5 VIN 3V VIN 10µF 3 C+ VOUT LTC1754-5 SHDN GND VOUT 5V 100mA 1 2 1µF 4 6 C– 5 3 ON/OFF VIN C+ VOUT LTC1754-5 SHDN GND 1 10µF 2 1754 TA07 Lithium-Ion Battery to 5V White or Blue LED Driver 1µF 4 5 3V TO 4.4V Li-Ion BATTERY C– VIN 10µF SHDN 100Ω 10µF LTC1754-5 3 ON/OFF 6 C+ 1 VOUT GND 100Ω 100Ω 2 1754 TA08 3.3V and 5V Step-Up Generator from 2V VOUT1 3.3V 1µF 1µF 4 5 VIN 2V 10µF ON/OFF C– VIN 6 4 C+ 1 VOUT LTC1754-3.3 3 SHDN GND I3.3 + 2I5 ≤ 20mA 5 6 C+ 1 VOUT LTC1754-5 10µF 2 C– VIN η≅ 3 SHDN GND VOUT2 5V 10µF 2 1754 TA09 10 3.3I3.3 + 5I5 VIN(2I3.3 + 4I5) LTC1754-3.3/LTC1754-5 U PACKAGE DESCRIPTION Dimensions in inches (millimeters), unless otherwise noted. S6 Package 6-Lead Plastic SOT-23 (LTC DWG # 05-08-1634) 2.80 – 3.00 (0.110 – 0.118) (NOTE 3) 2.6 – 3.0 (0.110 – 0.118) 1.50 – 1.75 (0.059 – 0.069) 0.35 – 0.55 (0.014 – 0.022) 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) SIX PLACES (NOTE 2) S6 SOT-23 0898 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. 11 LTC1754-3.3/LTC1754-5 U TYPICAL APPLICATIO Low Power Battery Backup with Autoswitchover and No Reverse Current Si4435DY 1µF 4 1N4148 VIN 5V 75k 5 + 10µF 10µF 3-CELL NiCd BATTERY 6 C– C+ VOUT VIN 1 VOUT = 5V IOUT ≤ 50mA 10µF LTC1754-5 SHDN 3 GND 2 BAT54C 7 1.43M 4 8 3 475k 6 LTC1540 10k 5 1M 2 1 1754 TA05 RELATED PARTS PART NUMBER DESCRIPTION LT1054 High Power Doubler Charge Pump Up to 100mA Output, VIN = 3.5V to 15V, SO-8 Package LTC1144 Charge Pump Inverter with Shutdown VIN = 2V to 18V, 15V to –15V Supply LTC1262 12V, 30mA Flash Memory Prog. Supply Regulated 12V ±5% Output, IQ = 500µA LTC1514/LTC1515 Buck/Boost Charge Pumps with IQ = 60µA 50mA Output at 3V, 3.3V or 5V; 2V to 10V Input LTC1516 Micropower 5V Charge Pump IQ = 12µA, Up to 50mA Output, VIN = 2V to 5V LTC1517-5/LTC1517-3.3 Micropower 5V/3.3V Doubler Charge Pumps IQ = 6µA, Up to 20mA Output LTC1522 Micropower 5V Doubler Charge Pump IQ = 6µA, Up to 20mA Output LT1615 Step-Up Switching Regulator in SOT-23 IQ = 20µA, VIN = 1.2V to 15V, Up to 34V Output LTC1682 Low Noise Doubler Charge Pump Output Noise = 60µVRMS, 2.5V to 5.5V Output 12 Linear Technology Corporation COMMENTS 175435f LT/TP 0400 4K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1999