FAN5601

FAN5601 Regulated Step-Down Charge Pump DC/DC Converter July 2005 FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Features ■ > 85% Peak Efficiency ■ Low EMI ■ Low Ripple ■ ■ ■ ■ ■ Output Voltage 1.3V/1.8V Input Voltage Range: 2.2V to 5.5V Output Current: Up to 250mA ±2.5% Output Voltage Accuracy 30µA Operating Current Description The FAN5601 is an advanced third generation switched capacitor step down DC/DC converter utilizing Fairchild’s proprietary ScalarPump™ technology. This innovative architecture utilizes scalar switch re-configuration and fractional switching techniques to produce low output ripple, low ESR spikes and improve efficiency over a wide load range. The FAN5601 produces a fixed regulated output from 2.2V to 5V input voltage. Customized output voltages are available in 100mV increments from 1V to 1.8V. Contact marketing for customized outputs. In order to maximize efficiency, the FAN5601 achieves regulation by skipping pulses. Depending upon load current, the size of the switches is scaled dynamically, consequently, current spikes and EMI are minimized. An internal soft start circuitry prevents excessive current drawn from the supply. The device is internally protected against short circuit and over temperature conditions. The FAN5601 is available in 6-lead 3x3mm MLP. ScalarPump™ is a registered trademark of Fairchild Semiconductor Corporation. ■ ICC < 1µA in Shutdown Mode ■ 2MHz Operating Frequency ■ Shutdown Isolates Output from Input ■ Soft-Start Limits Inrush Current ■ Short Circuit and Over Temperature Protection ■ Minimum External Component Count ■ 6-Lead 3x3mm MLP Package Applications ■ Cell Phones ■ Handheld Computers ■ Portable Electronic Equipment ■ Core Supply to Next Generation Processors ■ Low Voltage DC Bus ■ Digital Cameras ■ DSP Supplies Typical Application CB = 1µF VIN CIN = 10µF FAN5601 INPUT 2.2V to 5.5V C+ CVOUT OUTPUT 1.0V t o 1.8V ENABLE GND COUT = 10µF ©2005 Fairchild Semiconductor Corporation 1 www.fairchildsemi.com FAN5601 Rev. 1.0.5 FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Pin Assignment FAN5601 Top-View C+ CENABLE 1 2 3 6 5 4 VIN VOUT GND 6-Lead 3x3mm MLP Pin Description Pin Name Pin No. 1 2 3 4 5 6 6-Lead 3x3mm MLP C+ CENABLE GND VOUT VIN Pin Function Description Bucket Capacitor Positive Connection Bucket Capacitor Negative Connection Enable Pin Ground Regulated Output Voltage. Bypass this pin with 10µF ceramic low ESR capacitor. Supply Voltage Input 2 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Absolute Maximum Ratings (Note1) Parameter VIN,VOUT, ENABLE to GND C+, C-, to GND VOUT Short Circuit Duration Lead Soldering Temperature (10 seconds) Operating Temperature Range Junction Temperature Storage Temperature Electrostatic Discharge (ESD) Protection (Note2) HBM CDM -55 4 1 -40 Min -0.3 -0.3 Max 6.0 VIN + 0.3 INDEFINITE 300 +85 150 150 Unit V V °C °C °C °C kV Recommended Operating Conditions Parameter Input Voltage Output Current Operating Ambient Temperature Thermal Resistance Junction to Tab Thermal Resistance Junction to Ambient 6-lead 3x3mm MLP 6-lead 3x3mm MLP (Note 3) -40 8 90 Package Min 2.2 Typ Max 5.5 250 85 Unit V mA °C °C/W °C/W Notes: 1. Operation beyond the absolute maximum rating may cause permanent damage to device. 2. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model). 3. One square inch, 1oz bottom side GND plane connected to top side GND plane by field of via. 3 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Electrical Characteristics VIN = 2.2V to 5.5V, IOUT = 1mA, CB = 1µF, CIN = 10µF, COUT = 10µF, TA = -40°C to +85°C, typical values measured at TA = 25°C, unless otherwise noted. Parameter Input Undervoltage Lockout Output Voltage Output Voltage Accuracy TA = 25°C, VIN = 3.3V VIN = 3.3V Output Voltage Temperature Coefficient Load Regulation Line Regulation No load Supply Current (Note 4) Shutdown Supply Current Output Short-circuit Current (Note 5) Efficiency VIN at Configuration Change Oscillator Frequency Thermal Shutdown Threshold Thermal Shutdown Threshold Hysteresis ENABLE Logic Input High Voltage, VIH ENABLE Logic Input Low Voltage, VIL ENABLE Logic Input Current VOUT Turn On Time VIN = 2.2V to 5.5V VIN = 2.2V to 5.5V ENABLE = VIN or GND VIN = 3.6V, IOUT = 0mA, 10% to 90% -1 1 1.3 0.4 1 TA = 25°C IOUT = 0mA, VIN = 2.2V ENABLE =GND. VOUT = 0 VOUT = GND. VIN = 2.35 × VOUT IOUT =150mA From 2:1 to 1:1 mode VIN = 3.3V -2 -2.5 25 0.133 1.35 30 0.1 25 85 2.22 x Vnom 2.0 150 15 2 60 1 Conditions Min. 1.9 Typ. 2.0 Vnom Max. 2.17 Units V V +2 +2.5 % % ppm mV/mA mV/V µA µA mA % V MHz °C °C V V µA mS Notes: 4. No load supply current is measured when the oscillator is off. 5. The short circuit protection is designed to protect against pre-existing short circuit conditions, i.e. assembly shorts that exist prior to device power-up. The short circuit current limit is 25mAAverage. Short circuit currents in normal operation are inherently limited by the ON-resistance of internal device. Since this resistance is in the range of 1Ω, in some cases thermal shutdown may occur. However, immediately following the first thermal shutdown event, the short circuit condition will be treated as pre-existing, and the load current will reduce to 25mAAverage. 4 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Typical Performance Characteristics TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted. Line Transient Response Output Voltage Output Voltage Load Transient Response (50mV/div) (20mV/div) VIN = 3.3V V IN = 4.4V IOUT = 100mA Load Current (100mA/div) Input Voltage IOUT = 1mA (1V/div) V IN = 2V V IN = 2 V to 4.4V IOUT = 10mA Time (10µs/div) Time (1ms/div) Input Current vs Input Voltage 46 44 Shutdown Current vs Input Voltage 70 VOUT = 0V Shutdown Current (nA) IOUT = 0mA 60 50 40 30 20 10 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Input Current (µA) 42 40 38 36 34 32 30 28 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) Input Voltage (V) Output Voltage vs Ambient Temperature Threshold and Hysteresis (V) 1.31 1.30 Mode Change Threshold and Hysteresis vs Load Current 3.5 3.0 2.5 Low Threshold High Threshold Output Voltage (V) 1.29 1.28 1.27 1.26 -60 -40 -20 0 20 40 60 VIN = 4V IOUT = 10mA 2.0 1.5 1.0 0.5 0.0 0 20 40 60 80 100 120 140 160 Hysteresis 80 100 120 140 Ambient Temperature (°C) Load Current (mA) 5 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Typical Performance Characteristics (cont.) TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted. Enable Threshold vs Input Voltage IOUT = 10mA Enable Delay Output Voltage (500m V/div) 1.3 1.2 1.1 1.0 TA = 25°C IOUT = 10mA VIN = 2.2V V En able (V) 0.8 0.7 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 V IN (V) Time (400 s/div) Output Ripple Enable Voltage (5V/div) 0.9 Output Ripple IOUT = 1.3µA VIN = 2.2V VOUT = 1.3V IOUT = 1.3µA VIN = 2.7V VOUT = 1.3V Output Ripple (10mV/div) Time (40ms/div) Output Ripple (10mV/div) Time (40ms/div) Output Ripple Output Ripple IOUT = 1.3µA VIN = 3.6V IOUT = 1.3µA VIN = 4.2V VOUT = 1.3V Output Ripple (2mV/div) Time (20ms/div) Output Ripple (10mV/div) VOUT = 1.3V Time (20ms/div) 6 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Typical Performance Characteristics (cont.) TA = 25°C, CIN = COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted. Output Ripple Output Ripple IOUT = 1.3µA VIN = 5.5V VOUT = 1.3V IOUT = 10mA VIN = 2.2V VOUT = 1.3V Output Ripple Output Ripple (10mV/div) (10mV/div) Time (20ms/div) Time (100µs/div) Output Ripple Output Ripple IOUT = 10mA VIN = 2.7V IOUT = 10mA VIN = 3.6V Output Ripple Output Ripple (10mV/div) VOUT = 1.3V Time (100µ s/div) (10mV/div) VOUT = 1.3V Time (100µs/div) Output Ripple Output Ripple IOUT = 10mA VIN = 4.2V IOUT = 10mA VIN = 5.5V Output Ripple Output Ripple (10mV/div) VOUT = 1.3V Time (100µs/div) (10mV/div) VOUT = 1.3V Time (100µs/div) 7 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Typical Performance Characteristics (cont.) TA = 25°C, CIN= COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted. Output Ripple Output Ripple IOUT = 150mA VIN = 2.2V IOUT = 150mA VIN = 2.7V VOUT = 1.3V Output Ripple (20mV/div) Time (10µ s/div) Output Ripple (20mV/div) VOUT = 1.3V Time (10µ s/div) Output Ripple Output Ripple IOUT = 150mA VIN = 3.6V IOUT = 150mA VIN = 4.2V Output Ripple (20mV/div) Output Ripple (20mV/div) VOUT = 1.3V VOUT = 1.3V Time (10µ s/div) Time (1µs/div) Output Ripple IOUT = 150mA VIN = 5.5V VOUT = 1.3V Output Ripple (20mV/div) Time (1µs/div) 8 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Typical Performance Characteristics (cont.) TA = 25°C, CIN= COUT =10µF, CB = 1µF, VOUT = 1.3V, unless otherwise noted. Output Voltage vs Input Voltage 1.35 1.30 Efficiency vs Input Voltage 100 90 80 VOUT = 1.3V TA = 25°C Ouput Voltage (V) Efficiency (%) 1.25 1.20 1.15 1.10 1.05 1.00 0.95 1 2 3 4 5 6 70 60 50 40 30 20 10 0 1 2 3 4 Load Current = 1mA Load Current = 10mA Load Current = 50mA Load Current = 100mA Load Current = 150mA Load Current = 250mA Load Load Load Load Load Load Current Current Current Current Current Current = = = = = = 1mA 10mA 50mA 100mA 150mA 250mA 5 6 Input Voltage (V) Input Voltage (V) Output Voltage vs Load Current 1.32 VIN = 4.5V Peak Efficiency vs Load Current 88 VIN = 2.95V TA = 25° C 1.30 1.28 1.26 1.24 1.22 1.20 TA TA TA TA = = = = -40 °C 0 °C 80 °C 125 °C Peak Efficiency (%) 200 250 300 86 Ouput Voltage (V) 84 82 80 78 0 50 100 150 0 50 100 150 200 250 300 Load Current (mA) Load Current (mA) 9 FAN5601 Rev. 1.0.5 www.fairchildsemi.com FAN5601 Regulated Step-Down Charge Pump DC/DC Converter Block Diagram V IN 0.25SW1 0.25SW1 0.5SW1 OSCILLATOR (2MHz) IN VOLTAGE REF. OUT - CONFIGURATION + 0.25SW2 0.25SW2 0.5SW2 C+ SOFT START Vref RAMP Vref RAMP FB + PULSE_SKIP CONTROL LOGIC OUTPUT 150mV + SHORT_CKT. D R I V E R S 0.25SW3 0.25SW3 0.5SW3 VOUT C0.25SW4 0.25SW4 0.5SW4 0.5* INPUT 1V + UVLO SHUTDOWN THERMAL SHUTDOWN FB ENABLE GND. Detailed Description The FAN5601 switched capacitor DC/DC converter automatically configures switches to achieve a high efficiency and provides a regulated output voltage by means of pulse skipping, pulse frequency modulation (PFM). An internal soft start circuit prevents excessive inrush current drawn from the supply. Each switch is split into three segments. Based on the values of VIN, VOUT and IOUT, an internal circuitry determines the number of segments to be used to reduce current spikes. Pulse-skipping PFM and Fractional Switch Operation When the regulated output voltage reaches its upper limit, the switches are turned off the output voltage reaches its lower limit. Considering a step-down 2:1 mode of operation, 1.6V output as an example, when the output reaches about 1.62V(upper limit), the control logic turns off all switches. Switching stops completely. This is pulse-skipping mode. Since the supply is isolated from the output, the output voltage will drop. Once the output is dropped to about 1.58V(lower limit), the device will return to regular switching mode with one quarter of each switch turning on first. Another quarter of each switch will be turned on if VOUT cannot reach regulation by the time of arrival of the third charge cycle. Full switch operation occurs only during startup or under heavy load condition, when half switch operation cannot achieve regulation within seven charge cycles. Step-Down Charge Pump Operation When VIN ≥ 2.22 × VOUT, a 2:1 configuration shown in Fig.1(A) is enabled. The factor 0.9 is used instead of 1 in order to account for the effect of resistive losses across the switches and to accommodate hysteresis in the voltage detector comparator. Two phase non-overlapping clock signals are generated to drive four switches. When switches 1 and 3 are ON, switches 2 and 4 are OFF and CB is charged. When switches 2 and 4 are ON, switches 1 and 3 are OFF, charge is transferred from CB to COUT. When VIN