High Efficiency Switched Capacitor Step-Down DC/DC Regulator

www.DataSheet4U.com LM2770 High Efficiency Switched Capacitor Step-Down DC/DC Regulator with Sleep Mode December 2004 LM2770 High Efficiency Switched Capacitor Step-Down DC/DC Regulator with Sleep Mode General Description The LM2770 is a switched capacitor step-down regulator that is ideal for powering low-voltage applications in portable systems. The LM2770 can supply load currents up to 250mA and operates over an input voltage range of 2.7V to 5.5V. This makes the LM2770 a great choice for systems powered by 1-cell Li-Ion batteries and chargers. The output voltage of the LM2770 can be dynamically switched between two output levels with a logic input pin. Output voltage pairs currently available include 1.2V/1.5V and 1.2V/1.575V. Other pairs of voltage options can be developed upon request. LM2770 efficiency is superior to both fixed-gain switched capacitor buck regulators and low-dropout linear regulators (LDO’s). Multiple fractional gains maximize power efficiency over the entire input voltage and output current ranges. The LM2770 can also be switched into a low-power sleep mode when load currents are light (≤ 20mA). In sleep mode, the charge pump is off, and the output is driven with a low-noise, low-power linear regulator. Soft-start, short-circuit protection, current-limit protection, and thermal-shutdown protection are also included. The LM2770 is available in National’s small 10-pin Leadless Leadframe Package (LLP-10). Features n High Efficiency Multi-Gain Architecture: Peak Power Efficiency > 85% n Output Voltage Pairs: 1.2V/1.5V and 1.2V/1.575V n Dynamic Output Voltage Selection n ± 3% Output Voltage Accuracy n Output Currents up to 250mA n 2.7V to 5.5V Input Range n Low-Supply-Current Sleep Mode n 55µA Quiescent Supply Current in Full-Power Mode n Soft-Start n Short-Circuit Protection in Full-Power Mode n Current-Limit Protection in Sleep Mode n LLP-10 Package (3mm x 3mm x 0.8mm) Applications n n n n DSP Power Supplies Baseband Power Supplies Mobile Phones and Pagers Portable Electronic Equipment Typical Application Circuit LM2770 Efficiency vs. Low-Dropout Linear Regulator (LDO) Efficiency 20126011 20126001 © 2004 National Semiconductor Corporation DS201260 www.national.com LM2770 Connection Diagram and Package Mark Information 10-Pin Non-Pullback Leadless Frame Package (LLP-10) National Semiconductor Package Number SDA10A 20126002 Pin Description Pin # 1 Name VSEL Description Output Voltage Select Logic Input. If VSEL is high, VOUT = high voltage. If VSEL is low, VOUT = low voltage. (See Order Information for available voltage options) Enable Pin Logic Input. If high, part is enabled. If low, part is in shutdown. Flying Capacitor 2: Positive Termial Ground Flying Capacitor 2: Negative terminal Sleep Mode Logic Input. If high, the part operates in sleep mode, and the output is driven by a low power linear regulator. If low, the part operates in full-power mode, and the output is driven by the switched capacitor regulator Input Voltage. Recommended VIN operating range: 2.7V to 5.5V Flying Capacitor 1: Positive Terminal Flying Capacitor 1: Negative Terminal Output Voltage 2 3 4 5 10 EN C2+ GND C2SLEEP 9 8 7 6 VIN C1+ C1VOUT Order Information Output Voltages 1.2V / 1.5V 1.2V / 1.5V 1.2V / 1.575V 1.2V / 1.575V Order Number LM2770SD-1215 LM2770SDX-1215 LM2770SD-12157 LM2770SDX-12157 Package Mark ID L162B L162B L166B L166B SDA10A Non-Pullback LLP Package Supplied as: 1000 Units, Tape and Reel 4500 Units, Tape and Reel 1000 Units, Tape and Reel 4500 Units, Tape and Reel www.national.com 2 LM2770 Absolute Maximum Ratings (Notes 1, 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. VIN Pin Voltage EN, SLEEP, and VSEL Pin Voltages Continuous Power Dissipation (Note 3) VOUT Short to GND Duration (Note 4) Junction Temperature (TJ-MAX) Storage Temperature Range Maximum Lead Temperature (Note 5) ESD Rating (Note 6) Human Body Model: Machine Model -0.3V to 6.0V -0.3V to (VIN+0.3V) w/ 6.0V max Internally Limited Infinite 150oC -65oC to +150o C 265oC Operating Ratings Input Voltage Range (Notes 1, 2) 2.7V to 5.5V 0mA to 250mA -30˚C to +105˚C -30˚C to +85˚C Recommended Load Current Range Junction Temperature (TJ) Range Ambient Temperature (TA) Range (Note 6) Thermal Properties Juntion-to-Ambient Thermal Resistance (θJA), LLP10 Package (Note 7) 55˚C/W 2.0kV 200V (Notes 2, 9) Electrical Characteristics Limits in standard typeface are for TJ = 25oC. Limits in boldface type apply over the full operating junction temperature range (-30˚C ≤ TJ ≤ +105˚C) . Unless otherwise noted, specifications apply to the LM2770 Typical Application Circuit (pg. 1) with: VIN = 3.6V; V(EN) = VSEL = 1.8V, V(SLEEP) = 0V, CIN = COUT = 10µF, C1 = C2 = 1.0µF. (Note 10) Symbol VOUT-1215 Parameter LM2770-1215: 1.5V Output Voltage Regulation Condition VIN = 3.5V, IOUT = 150mA, VSEL = 1.8V 3.0V ≤ VIN ≤ 4.5V IOUT = 150mA, VSEL = 1.8V 4.5V < VIN ≤ 5.5V, IOUT = 150mA, VSEL = 1.8V LM2770-1215: 1.2V Output Voltage Regulation VIN = 3.5V, IOUT = 150mA, VSEL = 0V 3.0V ≤ VIN ≤ 4.5V IOUT - 150mA, VSEL =0V 4.5V < VIN ≤ 5.5V, IOUT = 150mA, VSEL = 0V VOUT-12157 LM2770-12157: 1.575V Output Voltage Regulation VIN = 3.5V, IOUT = 150mA, VSEL = 1.8V 3.1V ≤ VIN ≤ 4.5V IOUT = 150mA, VSEL = 1.8V 4.5V < VIN ≤ 5.5V, IOUT = 150mA, VSEL = 1.8V LM2770-12157: 1.2V Output Voltage Regulation VIN = 3.5V, IOUT = 150mA, VSEL = 0V 3.0V ≤ VIN ≤ 4.5V IOUT - 150mA, VSEL =0V 4.5V < VIN ≤ 5.5V, IOUT = 150mA, VSEL = 0V VOUT/IOUT Load Regulation IOUT = 1mA to 250mA Min 1.443 1.420 1.428 1.157 1.140 1.135 1.528 1.500 1.504 1.162 1.145 1.145 Typ 1.495 1.495 1.495 1.205 1.205 1.205 1.575 1.575 1.575 1.210 1.210 1.210 0.18 Max 1.547 1.570 1.562 1.253 1.270 1.275 1.622 1.650 1.646 1.258 1.275 1.275 mV/mA V Units V Output Voltage Specifications: Specific to Individual LM2770 Options 3 www.national.com LM2770 Electrical Characteristics (Notes 2, 9) (Continued) Limits in standard typeface are for TJ = 25oC. Limits in boldface type apply over the full operating junction temperature range (-30˚C ≤ TJ ≤ +105˚C) . Unless otherwise noted, specifications apply to the LM2770 Typical Application Circuit (pg. 1) with: VIN = 3.6V; V(EN) = VSEL = 1.8V, V(SLEEP) = 0V, CIN = COUT = 10µF, C1 = C2 = 1.0µF. (Note 10) Symbol VLDO-1215 Parameter LM2770-1215: 1.5V Output Voltage Regulation - SLEEP Mode LM2770-1215: 1.2V Output Voltage Regulation - SLEEP Mode VLDO-12157 LM2770-12157: 1.575V Output Voltage Regulation - SLEEP Mode LM2770-12157: 1.2V Output Voltage Regulation - SLEEP Mode E EAVG IQ Power Efficiency Average Eficiency over Li-Ion Input Voltage Range (Note 11) Quiescent Supply Current: Full-power Mode Quiescent Supply Current: Sleep Mode Shutdown Current Current Limit - Sleep Mode Turn-on Time Switching Frequency Logic-low Input Voltage Logic-high Input Voltage Logic-high Input Current: SLEEP and VSEL pins Condition 3.0V ≤ VIN ≤ 5.5V, 0mA ≤ IOUT ≤ 20mA, VSEL= 0V, V(SLEEP) = 1.8V 3.0V ≤ VIN ≤ 5.5V, 0mA ≤ IOUT ≤ 20mA, VSEL = 0V, V(SLEEP) = 1.8V 3.0V ≤ VIN ≤ 5.5V, 0mA ≤ IOUT ≤ 20mA, VSEL= 0V, V(SLEEP) = 1.8V 3.0V ≤ VIN ≤ 5.5V, 0mA ≤ IOUT ≤ 20mA, VSEL = 0V, V(SLEEP) = 1.8V VIN = 3.6V, IOUT = 150mA VOUT =1.5V 3.0V ≤ VIN ≤ 4.2V IOUT = 200mA, VOUT = 1.5V 2.7V ≤ VIN ≤ 5.5V IOUT = 0mA V(SLEEP) = 0V 2.7V ≤ VIN ≤ 5.5V IOUT = 0mA V(SLEEP) = 1.8V 2.7V ≤ VIN ≤ 5.5V V(EN) = 0V 0V ≤ VOUT ≤ 0.2V V(SLEEP) = 1.8V VIN = 3.6V, COUT = 10µF 2.7V ≤ VIN ≤ 5.5V 2.7V ≤ VIN ≤ 5.5V 2.7V ≤ VIN ≤ 5.5V Logic Input = 3.0V 475 0 1.0 0.1 6 0 Min 1.435 Typ 1.495 Max 1.555 Units V 1.145 1.205 1.265 1.520 1.575 1.630 V 1.150 1.210 1.270 Specifications Below Apply to All LM2770 Options 82 73 55 75 % % µA ISLEEP 50 65 µA ISD ICL tON FSW VIL VIH IIH IIH-EN IIL 0.1 60 200 700 0.5 µA mA µs 925 0.4 VIN kHz V V µA µA µA Logic Pin Specifications: EN, ENA, ENB Logic-high Input Current: EN pin V(EN) = 1.8V (Note 12) Logic-low Input Current: All Logic Pins Logic Input = 0V Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables. Note 2: All voltages are with respect to the potential at the GND pin. Note 3: Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=150oC (typ.) and disengages at TJ=140oC (typ.). Note 4: Short circuit protection circuitry protects the part from immediate destructive failure when VOUT is shorted to GND. Applying a continuous GND short to the output may shorten the lifetime of the device. Note 5: For detailed information on soldering requirements and recommendations, please refer to National Semiconductor’s Application Note 1187 (AN-1187): Leadless Leadframe Package (LLP). Note 6: The Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. MIL-STD-883 3015.7 www.national.com 4 LM2770 Electrical Characteristics (Notes 2, 9) (Continued) Note 7: Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 105oC), the maximum power dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the following equation: TA-MAX = TJ-MAX-OP – (θJA x PD-MAX). Note 8: Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists, special care must be pa