www.fairchildsemi.com FAN5307 High-Efficiency Step-Down DC-DC Converter Features Description • • • • • • • • • • • • • • The FAN5307, a high efficiency low noise synchronous PWM current mode and Pulse Skip (Power Save) mode DC-DC converter is designed for battery-powered applications. It provides up to 300mA of output current over a wide input range from 2.5V to 5.5V. The output voltage can be either internally fixed or externally adjustable over a wide range of 0.7V to 5.5V by an external voltage divider. Custom output voltages are also available. 95% Efficiency, Synchronous Operation Adjustable Output Voltage Option from 0.7V to VIN 2.5V to 5.5V Input Voltage Range Customized Fixed Output Voltage Options Up to 300mA Output Current Fixed Frequency 1MHz PWM Operation High Efficiency Power Save Mode 100% Duty Cycle Low Dropout Operation Soft Start Dynamic Output Voltage Positioning 15µA Quiescent Current Excellent Load Transient Response 5-Lead SOT-23 Package 6-Lead MLP 3x3mm Package Applications • • • • • Pocket PCs, PDAs Cell Phones Battery-Powered Portable Devices Digital Cameras Low Power DSP Supplies At moderate and light loads pulse skipping modulation is used. Dynamic voltage positioning is applied, and the output voltage is shifted 0.8% above nominal value for increased headroom during load transients. At higher loads the system automatically switches to current mode PWM control, operating at 1 MHz. A current mode control loop with fast transient response ensures excellent line and load regulation. In Power Save mode, the quiescent current is reduced to 15µA in order to achieve high efficiency and to ensure long battery life. In shut-down mode, the supply current drops below 1µA. The device is available in 5-lead SOT-23 and 6-lead MLP 3x3mm packages. Typical Application EFFICIENCY vs. LOAD CURRENT VOUT = 1.8V 100 95 VIN=2.5V Efficiency [%] 90 VIN=3.6V 85 VIN=5.5V 80 75 70 65 0.01 0.1 1 10 100 1000 Load Current [mA] REV. 1.0.2 6/22/04 PRODUCT SPECIFICATION FAN5307 Pin Assignment Pin Description 5SOT-23 Pin No. Pin Name Pin Description 1 VIN Supply voltage input. 2 GND 3 EN Enable Input. Logic high enables the chip and logic low disables the chip and reduces supply current to <1µA. Do not float this pin. 4 FB Feedback Input. In case of fixed voltage options, connect this pin directly to the output. For an adjustable voltage option, connect this pin to the resistor divider. 5 LX Inductor pin. This pin is connected to the internal MOSFET switches. Ground. Pin Description 6-Lead 3x3mm MLP Pin No. 2 Pin Name Pin Description 1 EN Enable Input. Logic high enables the chip and logic low disables the chip and reduces supply current to <1µA. Do not float this pin. 2 GND 3 VIN Supply voltage input. 4 LX Inductor pin. This pin is connected to the internal MOSFET switches. 5 PGND 6 FB Reference ground. Power ground. Internal N-channel MOSFET is connected to this pin. Feedback Input. In case of fixed voltage options, connect this pin directly to the output. For an adjustable voltage option, connect this pin to the resistor divider. REV. 1.0.2 6/22/04 FAN5307 PRODUCT SPECIFICATION Absolute Maximum Ratings Parameter Min VIN Unit -0.3 6.5 V GND-0.3 VIN + 0.3 V Junction to case, SOT-23 130 °C/W Junction to tab, MLP 3x3 8 Voltage on any other pin Thermal Resistance (Note 1) Max Lead Soldering Temperature (10 seconds) 260 Storage Temperature Electrostatic Discharge (ESD) Protection Level (Note 2) -65 HBM 4 CDM 1 150 °C °C kV Recommended Operating Conditions Parameter Min Supply Voltage Range Output Voltage Range, Adjustable Version Typ Max Unit 2.5 5.5 V 0.7 VIN V 300 mA Output Current Inductor (Note 3) 10 µH Input Capacitor (Note 3) 4.7 µF Output Capacitor (Note 3) 10 µF Operating Ambient Temperature Range -40 +85 °C Operating Junction Temperature Range -40 +125 °C Notes: 1. Junction to ambient thermal resistance, θJA, is a strong function of PCB material, board thickness, thickness and number of copper planes, number of vias used, diameter of via used, available copper surface, and attached heat sink characteristics. 2. Using Mil Std. 883E, method 3015.7(Human Body Model) and EIA/JESD22C101-A (Charge Device Model). 3. Refer to the applications section for further details. REV. 1.0.2 6/22/04 3 PRODUCT SPECIFICATION FAN5307 General Electrical Characteristics VIN = 2.5V to 5.5V, IOUT = 200mA, EN = VIN, CIN = 4.7µF, COUT = 22µF, LX = 10µH, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Parameter Conditions Input Voltage Quiescent Current IOUT = 0mA, Device is not switching Shutdown Supply Current EN = GND Enable High Input Voltage Min. Typ. 2.5 Max. Units 5.5 V 15 30 µA 0.1 1 µA 1.3 V Enable Low Input Voltage 0.4 V En Input Bias Current EN = VIN or GND 0.01 0.1 µA PMOS On Resistance VIN = VGS = 3.6V 530 690 mΩ VIN = VGS = 2.5V 670 850 VIN = VGS = 3.6V 430 540 VIN = VGS = 2.5V 530 660 520 700 mA 0.1 1 µA NMOS On Resistance P-channel Current Limit 2.5V < VIN < 5.5V N-channel Leakage Current VDS = 5.5V P-channel Leakage Current VDS = 5.5V Switching Frequency 800 Line Regulation VIN = 2.5 to 5.5V, IOUT = 10mA Load Regulation 6-Lead 3x3mm MLP Load Regulation 5-Lead SOT-23 Output Voltage Accuracy (5SOT23) 400 mΩ 0.1 1 µA 1000 1200 kHz 0.16 %/V 100 m A ≤ I O U T ≤ 300 m A 0.0014 %/mA 100 m A ≤ I O U T ≤ 300 m A 0.0022 %/mA VIN = 2.5 to 4.5V, 0 m A ≤ I O U T ≤ 300 m A -3 3 % VIN = 2.5 to 5.5V, 0 m A ≤ I O U T ≤ 300 m A -4 3 % Leakage Current into SW Pin VIN > VOUT, 0 V ≤ Vs w ≤ VI N 0.1 1 µA Reverse Leakage Current into pin SW VIN = Open, EN = GND, Vsw = 5.5V 0.1 1 µA Output Voltage Accuracy (6-Lead 3x3mm MLP) VIN = 2.5 to 5.5V, 0 m A ≤ I O U T ≤ 300 m A 3 % Max. Units -3 Electrical Characteristics For Adjustable Version VIN = 2.5V to 5.5V, IOUT = 200mA, EN = VIN, CIN = 4.7µF, COUT = 22µF, LX = 10µH, TA = 25°C. Parameter Feedback (FB) Voltage 4 Conditions Min. Typ. 0.5 V REV. 1.0.2 6/22/04 FAN5307 PRODUCT SPECIFICATION Electrical Characteristics for Fixed VOUT = 1.8V Version VIN = 2.5V to 5.5V, IOUT = 200mA, EN = VIN, CIN = 4.7µF, COUT = 22µF, LX = 10µH, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Parameter Conditions Min. Typ. Max. Units PFM to PWM Transition Voltage (Note 4) VIN = 3.7V, TA = 25°C, 0.1 m A ≤ I O U T ≤ 300 m A 72 mV PFM to PWM Transition Voltage (Note 4) VIN = 4.2V, TA = 25°C, 0.1 m A ≤ I O U T ≤ 300 m A 72 mV 1.93 V 1.93 V Output Voltage during Mode Transition (Note 5, 6) 1.7 Over Voltage Clamp Threshold Incl. line, load, load transients, and temperature 1.878 Note: 4. Transition voltage is defined as the difference between the output voltage measured at 0.1m A (PFM mode) and 300mA (PWM mode), respectively. ILOAD (mA) 5. 200 tf = 2µS tr = 10µS 2 0 0.01 ss 0.587 0.589 4.6 Time (mSec) Load Transient Response Test Waveform 6. These limits also apply to any mode transition caused by any kind of load transition within specified output current range. REV. 1.0.2 6/22/04 5 PRODUCT SPECIFICATION FAN5307 Typical Performance Characteristics (TA = 25°C, Cin = Cout = 10µF, L = 10µH, VOUT = 1.8V, unless otherwise noted.) LINE TRANSIENT RESPONSE START-UP LOAD TRANSIENT RESPONSE NO LOAD QUIESCENT CURRENT vs. INPUT VOLTAGE EFFICIENCY vs. LOAD CURRENT VOUT = 1.8V 26 95 No Load Quiescent Current [µA] 100 VIN=2.5V Efficiency [%] 90 VIN=3.6V 85 VIN=5.5V 80 75 70 65 0.01 0.1 1 10 100 1000 Load Current [mA] FREQUENCY vs. TEMPERATURE 24 TA=+85ºC 22 20 TA=+25ºC 18 16 14 2.5 TA=-40ºC 3.0 3.5 4.0 4.5 Input Voltage [V] 5.0 5.5 POWER SAVE (PFM) MODE OPERATION 1060 1040 VIN=5.5V Frequency [kHz] 1020 1000 980 VIN=3.6V 960 940 920 VIN=2.5V 900 880 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 Temperature [ºC] 6 REV. 1.0.2 6/22/04 PRODUCT SPECIFICATION FAN5307 Block Diagram VIN EN DIGITAL SOFT START IS UNDER VOLTAGE LOCKOUT IS CURRENT SENSE PFM COMPARATOR REF FB ERROR AMPLIFIER LOGIC CONTROL COMPARATOR MOSFET DRIVER LX 0.5V GND IS OVER VOLTAGE COMPARATOR REF FB OSC SLOPE COMPENSATION NEG. LIMIT COMPARATOR NEG. LIMIT SENSE GND Detailed Operation Description is turned off and the next clock cycle starts. The FAN5307 is a step-down converter operating in a current-mode PFM/PWM architecture with a typical switching frequency of 1MHz. At moderate to heavy loads, the converter operates in pulse-width-modulation (PWM) mode. At light loads the converter enters a power-save mode (PFM pulse skipping) to keep the efficiency high. PFM (Power Save) Mode PWM Mode In PWM mode, the device operates at a fixed frequency of 1MHz. At the beginning of each clock cycle, the P-channel transistor is turned on. The inductor current ramps up and is monitored via an internal circuit. The P-channel switch is turned off when the sensed current causes the PWM comparator to trip when the output voltage is in regulation or when the inductor current reaches the current limit (set internally to typically 520mA). After a minimum dead time the Nchannel transistor is turned on and the inductor current ramps down. As the clock cycle is completed, the N-channel switch 7 As the load current decreases and the peak inductor current no longer reaches the typical threshold of 80mA, the converter enters pulse-frequency-modulation (PFM) mode. In PFM mode the device operates with a variable frequency and constant peak current thus reducing the quiescent current to minimum. Consequently, the high efficiency is maintained at light loads. As soon as the output voltage falls below a threshold, set at 0.8% above the nominal value, the P-channel transistor is turned on and the inductor current ramps up. The P-channel switch turns off and the N-channel turns on as the peak inductor current is reached (typical 140mA). The N-channel transistor is turned off before the inductor current becomes negative. At this time the P-channel is switched on again starting the next pulse. The converter continues these pulses until the high threshold (typical 1.6% above nominal value) is reached. A higher output voltage in REV. 1.0.2 6/22/04 PRODUCT SPECIFICATION FAN5307 PFM mode gives additional headroom for the voltage drop during a load transient from light to full load. The voltage overshoot during this load transient is also minimized due to active regulation during turning on the N-channel rectifier switch. The device stays in sleep mode until the output voltage falls below the low threshold. The FAN5307 enters the PWM mode as soon as the output voltage can no longer be regulated in PFM with constant peak current. Soft Start 100% Duty Cycle Operation Short-Circuit Protection As the input voltage approaches the output voltage and the duty cycle exceeds the typical 95%, the converter turns the P-channel transistor continuously on. In this mode the output voltage is equal to the input voltage minus the voltage drop across the P-channel transistor: The switch peak current is limited cycle by cycle to a typical value of 520mA. In the event of a output voltage short circuit the device operates at minimum duty cycle, therefore the average input current is typically 100mA. The FAN5307 has an internal soft-start circuit that limits the inrush current during start-up. This prevents possible voltage drops of the input voltage and eliminates the output voltage overshoot. The soft-start is implemented as a digital circuit increasing the switch current in four steps to the P-channel current limit (520mA). Typical start-up time for a 10µF output capacitor and a load current of 200mA is 500µs. VOUT = VIN – ILOAD × (RdsON + RL), where RdsON = P-channel switch ON resistance ILOAD = Output current RL = Inductor DC resistance 8 REV. 1.0.2 6/22/04 FAN5307 PRODUCT SPECIFICATION Application Information Adjustable Output Voltage Version Input Capacitor Selection The output voltage for the adjustable version is set by the external resistor divider, as shown below: For best performances, a low ESR input capacitor is required. A ceramic capacitor of at least 4.7µF, placed as close to the input pin of the device is recommended. VIN GND 2 3 EN FAN5307SX 4.7µF VOUT LX 1 5 10µH R1 4 FB Cf 4.7pF 10µF R2 Output Capacitor Selection The FAN5307’s switching frequency of 1MHz allows the use of a low ESR ceramic capacitor with a value of 10µF to 22µF. This provides low output voltage ripple. In power save mode the output voltage ripple is independent of the output capacitor value and the ripple is determined by the internal comparator thresholds. The typical output voltage ripple at light load is 1% of the nominal output voltage. and is calculated as: V O U T = 0.5 V × R 1 + ------1 R2 Capacitor Value 4.7µF To reduce noise sensitivity, R1 + R2 should not exceed 800kΩ. 10µF TDK The inductor parameters directly related to device performances are saturation current and dc resistance. The FAN5307 operates with a typical inductor value of 10µH. The lower the dc resistance, the higher the efficiency. For saturation current, the inductor should be rated higher than the maximum load current plus half of the inductor ripple current that is calculated as follows: 1 – ( VO U T ⁄ VI N ) ∆ I L = V O U T × -------------------------------------------------L × f where: f = Switching Frequency L = Inductor Value ∆IL = Inductor Ripple Current Inductor Vendor Part Number Value Sumida Taiyo Yuden CDRH5D28-100 CDRH5D18-100 Performance High Efficiency Part Number JMK212BY475MG JMK212BJ106MG JMK316BJ106KL Inductor Selection 10µH Vendor C12012X5ROJ106K C3216X5ROJ106M 22µF Murata GRM32DR60J226K Table 2: Recommended Capacitors PCB Layout Recommendations The inherently high peak currents and switching frequency of the power supplies require a careful PCB layout design. Therefore, use wide traces for the high current path and place the input capacitor, the inductor, and the output capacitor as close as possible to the integrated circuit terminals. For the adjustable version the resistor divider should be routed away from the inductor to avoid electromagnetic interference. The 6-lead MLP version of the FAN5307 separates the high current ground from the reference ground, therefore it is more tolerant to the PCB layout design and shows better performance. CDRH4D28-100 Murata LQH66SN100M 01L 6.8µH Sumida CDRH3D16-6R8 10µH CDRH4D18-100 Smallest Solution CR32-100 CR43-100 Murata LQH4C100K04 Table 1: Recommended Inductors REV. 1.0.2 6/22/04 9 PRODUCT SPECIFICATION FAN5307 Mechanical Dimensions 6-Lead 3x3mm MLP Package 3.0 0.15 C A 2X 2.45 B 0.10 C 2X 2.6 1.85 3.0 2.15 3.45 (0.65) 0.15 C 2.6 0.10 C 2X 0.95 TYP 2X TOP VIEW 0.65 TYP RECOMMENDED LAND PATTERN 1.0 MAX 0°~12° 0.10 C 1.00 0.65 0.08 C 0.05 (0.20) 0.00 SEATING PLANE C SIDE VIEW 1 2.25 0.95 3 0.45 0.20 1.65 0.2 MIN 4 6 1.90 0.30~0.45 Ø0.10 M C A B Ø0.05 M C BOTTOM VIEW NOTES: A. CONFORMS TO JEDEC REGISTRATION MO-229, VARIATION VEEA, DATED 11/2001 B. DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 10 REV. 1.0.2 6/22/04 FAN5307 PRODUCT SPECIFICATION Mechanical Dimensions 5-Lead SOT-23 Package B L c e H α E e1 D A A1 Symbol A Inches Millimeters Min Max Min Max .035 .057 .90 1.45 A1 .000 .006 .00 .15 B .008 .020 .20 .50 c .003 .010 .08 .25 D .106 .122 2.70 3.10 E .059 .071 1.50 1.80 e .037 BSC .95 BSC e1 .075 BSC 1.90 BSC H .087 .126 2.20 3.20 L .004 .024 .10 .60 α 0° 10° 0° 10° REV. 1.0.2 6/22/04 Notes Notes: 1. Package outline exclusive of mold flash & metal burr. 2. Package outline exclusive of solder plating. 3. EIAJ Ref Number SC_74A 11 PRODUCT SPECIFICATION FAN5307 Ordering Information Product Number FAN5307 VOUT (V) Package Type Order Code 1.8 5-Lead SOT-23 Tape and Reel FAN5307S18X 1.8 6-Lead 3x3mm MLP Tape and Reel FAN5307MP18X Adjustable 5-Lead SOT-23 Tape and Reel FAN5307SX Adjustable 6-Lead 3x3mm MLP Tape and Reel FAN5307MPX DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 6/22/04 0.0m 000 Stock#DS30005307 2004 Fairchild Semiconductor Corporation