FAN5361UMP18X

FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator September 2008 FAN5361 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Features 6MHz Fixed-Frequency Operation 35µA Typical Quiescent Current Best-in-Class Load Transient 600mA Output Current Capability 2.3V to 5.5V Input Voltage Range 1.0 to 1.82V Fixed Output Voltage Low Ripple Light-Load PFM Mode Forced PWM and External Clock Synchronization Internal Soft-Start Input Under-Voltage Lockout (UVLO) Thermal Shutdown and Overload Protection 6-bump WLCSP, 0.4mm Pitch 6-pin 2 x 2mm UMLP Description The FAN5361 is a 600mA, step-down, switching voltage regulator that delivers a fixed output from an input voltage supply of 2.3V to 5.5V. Using a proprietary architecture with synchronous rectification, the FAN5361 is capable of delivering a peak efficiency of 92%, while maintaining efficiency over 80% at load currents as low as 1mA. The regulator operates at a nominal fixed frequency of 6MHz, which reduces the value of the external components to 470nH for the output inductor and 4.7µF for the output capacitor. The PWM modulator can be synchronized to an external frequency source. At moderate and light loads, pulse frequency modulation is used to operate the device in power-save mode with a typical quiescent current of 35µA. Even with such a low quiescent current, the part exhibits excellent transient response during large load swings. At higher loads, the system automatically switches to fixed-frequency control, operating at 6MHz. In shutdown mode, the supply current drops below 1µA, reducing power consumption. For applications that require minimum ripple or fixed frequency, PFM mode can be disabled using the MODE pin. The FAN5361 is available in 6-bump, 0.4mm pitch, WaferLevel Chip-Scale Package (WLCSP) and a 6-lead 2 x 2mm ultra-thin MLP package. Applications Cell Phones Portable Media Players WLAN, 3G, and 4G Data Cards Typical Applications MODE L1 470nH FB 4.7 F COUT Figure 1. Typical Applications SW A1 B1 C1 A2 B2 C2 VIN EN GND CIN 2.2 F © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Ordering Information Part Number FAN5361UC10X FAN5361UC12X FAN5361UC13X FAN5361UC15X FAN5361UC18X (2) (2) (2) (2) Output (1) Voltage 1.0V 1.2V 1.3V 1.5V 1.8V 1.82V (2) (2) (2) (2) (2) Package Eco Status Temperature Range Packing WLCSP-6 0.4mm Pitch Green –40 to +85°C Tape and Reel FAN5361UC182X FAN5361UMP10X FAN5361UMP12X FAN5361UMP13X FAN5361UMP15X FAN5361UMP18X 1.0V 1.2V 1.3V 1.5V 1.8V 6 Lead UMLP 2 x 2mm RoHS –40 to +85°C Tape and Reel For Fairchild’s definition of “green” Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. Notes: 1. Other voltage options available on request. Contact a Fairchild representative. 2. Preliminary release. Pin Configuration MODE SW FB A1 B1 C1 A2 B2 C2 VIN EN GND VIN EN GND A2 B2 C2 A1 B1 C1 MODE SW FB Figure 2. WLCSP, Bumps Facing Down Figure 3. WLCSP, Bumps Facing Up Figure 4. UMLP, Leads Facing Down Pin Definitions Pin # WLCSP MLP A1 B1 C1 C2 B2 A2 3 2 1 6 5 4 Name Description MODE. Logic 1 on this pin forces the IC to stay in PWM mode. A logic 0 allows the IC to automatically MODE switch to PFM during light loads. The regulator also synchronizes its switching frequency to four times the frequency provided on this pin. Do not leave this pin floating. SW FB GND EN VIN Switching Node. Connect to output inductor. Feedback / VOUT. Connect to output voltage. Ground. Power and IC ground. All signals are referenced to this pin. Enable. The device is in shutdown mode when voltage to this pin is 1.2V. Do not leave this pin floating. Input Voltage. Connect to input power source. © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 2 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Absolute Maximum Ratings Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol VIN VSW VCTRL Parameter Input Voltage Voltage on SW Pin EN and MODE Pin Voltage Other Pins ESD TJ TSTG TL Electrostatic Discharge Protection Level Junction Temperature Storage Temperature Lead Soldering Temperature, 10 Seconds Human Body Model per JESD22-A114 Charged Device Model per JESD22-C101 –40 –65 Min. –0.3 –0.3 –0.3 –0.3 4 1.5 +150 +150 +260 Max. 7.0 VIN + 0.3 VIN + 0.3 VIN + 0.3 (3) (3) (3) Units V V V V kV kV °C °C °C Note: 3. Lesser of 7V or VIN+0.3V. Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol VCC IOUT L CIN COUT TA TJ Supply Voltage Range Output Current Inductor Input Capacitor Output Capacitor Parameter Min. 2.3 0 Typ. Max. 5.5 600 Units V mA µH µF µF 0.47 2.2 4.7 –40 –40 +85 +125 Operating Ambient Temperature Operating Junction Temperature °C °C Thermal Properties Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 1s2p boards in accordance to JEDEC standard JESD51. Special attention must be paid not to exceed junction temperature TJ(max) at a given ambient temperate TA. Symbol Parameter θJA Junction-to-Ambient Thermal Resistance WLCSP MLP Typical 150 49 Units °C/W °C/W © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 3 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Electrical Characteristics Minimum and maximum values are at VIN = VEN = 2.3V to 5.5V, AUTO Mode, TA = -40°C to +85°C; circuit of Figure 1, unless otherwise noted. Typical values are at TA = 25°C, VIN = VEN = 3.6V. Symbol Parameter Conditions No load, Not Switching PWM Mode VIN = 3.6V, EN = GND Rising VIN Min. Typ. 35 6 0.05 2.15 150 Max. 55 1.00 2.25 Units µA mA µA V mV V Power Supplies IQ I(SD) VUVLO VUVHYST V(ENH) V(ENL) I(EN) V(MH) V(ML) I(M) fSW fSYNC Regulation 1.82V 1.80V 1.50V 1.30V 1.20V 1.00V tSS Soft-Start PMOS On Resistance NMOS On Resistance PMOS Peak Current Limit Thermal Shutdown Thermal Shutdown Hysteresis ILOAD = 0 to 600mA PWM Mode ILOAD = 0 to 600mA PWM Mode ILOAD = 0 to 600mA PWM Mode ILOAD = 0 to 600mA PWM Mode ILOAD = 0 to 600mA PWM Mode ILOAD = 0 to 600mA PWM Mode From EN Rising Edge VIN = VGS = 3.6V VIN = VGS = 3.6V Open-Loop CCM Only 900 1.784 1.784 1.764 1.764 1.470 1.470 1.274 1.274 1.174 1.174 0.974 0.974 1.820 1.820 1.800 1.800 1.500 1.500 1.300 1.300 1.200 1.200 1.000 1.000 150 350 225 1000 150 15 1250 1.875 1.856 1.854 1.836 1.545 1.530 1.339 1.326 1.239 1.226 1.039 1.026 300 V V V V V V V V V V V V µs mΩ mΩ mA °C °C Quiescent Current Shutdown Supply Current Under-Voltage Lockout Threshold Under-Voltage Lockout hysteresis Enable HIGH-Level Input Voltage Enable LOW-Level Input Voltage Enable Input Leakage Current MODE HIGH-Level Input Voltage MODE LOW-Level Input Voltage MODE Input Leakage Current Switching Frequency MODE Synchronization Range (4) 1.2 0.4 EN to VIN or GND 1.2 0.4 MODE to VIN or GND VIN = 3.6V, TA = 25°C Squarewave at MODE Input 5.4 1.3 0.01 6.0 1.5 1.00 6.6 1.7 0.01 1.00 V µA V V µA MHz MHz Switching and Synchronization VO Output Voltage Accuracy Output Driver RDS(on) ILIM TTSD THYS Notes: 4. Limited by the effect of tOFF minimum (see Figure 13 in Typical Performance Characteristics). © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 4 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C. 100% 95% 90% 85% 100% 95% 90% 85% Efficiency 75% 70% 65% 60% 55% 50% 1 10 100 Auto 2.3VIN Auto 2.7VIN Auto 3.6VIN Auto 4.2VIN Efficiency 80% 80% 75% 70% 65% 60% 55% 50% -30C 85C 25C 1000 1 10 100 1000 I LOAD Output Current (mA) I LOAD Output Current (mA) Figure 5. Efficiency vs. Load Current vs. Input Supply Figure 6. Efficiency vs. Load Current vs. Temperature 100% 95% 90% 85% 100% 95% 90% 85% Efficiency 80% 75% 70% 65% 60% 55% 50% 1 10 100 1000 VIN=2.3V VIN=2.7V VIN=3.6V VIN=4.2V VOUT = 1.2 V Efficiency 80% 75% 70% 65% 60% 55% 50% 1 10 100 1000 Auto PFM/PWM Forced PWM I LOAD Output Current (mA) I LOAD Output Current (mA) Figure 7. Efficiency vs. Load Current vs. Input Supply 1.82 Figure 8. Efficiency, Auto PWM/PFM vs. Forced PWM 1.215 VIN=2.3V 1.210 1.81 VIN=2.7V VIN=3.6V Output Voltage (V) 1.80 V OUT (V) 1.205 VIN=4.2V VIN=2.3V VIN=2.7V 1.79 1.200 VIN=3.6V VIN=4.2V 1.78 0 100 200 300 400 500 600 1.195 1.190 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Load Current (mA) I LOAD Output Current (A) Figure 9. Load Regulation vs. Input Supply Figure 10. 1.2VOUT Load Regulation vs. Input Supply © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 5 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C. 45 VIN=2.5V VIN=3.6V 50 45 40 40 35 2.5VIN 3.6VIN V OUT R ipple (mVpp) VIN=5.5V V OUT R ipple (m Vpp) 35 30 25 20 15 10 5 0 0.1 0.2 0.3 0.4 0.5 0.6 30 5.5VIN 25 20 15 10 5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 VOUT=1.2V COUT=4.7µF nom. COUT=4.7μF nom. ILOAD Output Current (A) ILOAD Output Current (A) Figure 11. Peak-to-Peak Output Voltage Ripple Figure 12. 1.2VOUT Peak-to-Peak Output Voltage Ripple 7 6 5 4 3 2 VIN>2.4V 1 VOUT=1.2V 0 0 0.1 0.2 0.3 0.4 0.5 0.6 VIN=2.3V Switching Frequency (MHz) Load Current (A) Figure 13. Effect of tOFF(MIN) on Switching Frequency Figure 14. 1.2VOUT Effect of tOFF(MIN) on Switching Frequency 350 350 300 Always PWM 250 200 150 100 Always PFM 50 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 PFM Border 300 Always PWM Load Current (mA) Load Current (mA) 250 The switching mode changes at these borders 200 The switching mode changes at these borders 150 100 Always PFM 50 PFM border PWM border 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 PWM Borde Input Voltage (V) Input Voltage (V) Figure 15. PFM / PWM Boundaries Figure 16. 1.2VOUT PFM / PWM Boundaries © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 6 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C. 42 1.810 40 Quiescent Current ( μ A) 1.805 38 36 V OUT (V) VEN=VIN VEN=1.8V 1.800 34 1.795 32 1.790 Auto PWM/PFM Forced PWM 3.0 3.5 4.0 4.5 5.0 5.5 30 2.0 2.5 1.785 1 10 100 1,000 VIN Input Voltage (V) I LOAD Output Current (mA) Figure 17. Quiescent Curent vs. Input Voltage Figure 18. Load Regulation, Auto PFM / PWM and Forced PWM 0.20 0.18 0.16 VIN=5.5V VEN=0V Supply Current (µA) 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0.00 -40 -20 0 20 40 60 80 Ambient Temperature (°C) Figure 19. Shutdown Current vs. Temperature © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 7 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C, 5µs/div. horizontal sweep. Figure 20. Line Transient 3.3VIN to 3.9VIN, 50mA Load, 10µs/div. Figure 21. Line Transient 3.3VIN to 3.9VIN, 250mA Load, 10µs/div. Figure 22. Combined Line/Load Transient 3.3 to Figure 23. Combined Line/Load Transient 3.9 to 3.3VIN Combined with 400mA to 40mA Load Transient 3.9VIN Combined with 400mA to 40mA Load Transient Figure 24. Load Transient 0 to 150mA, 2.5VIN Figure 25. Load Transient 50 to 250mA, 2.5VIN © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 8 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C, 5µs/div. horizontal sweep. Figure 26. Load Transient 150 to 400mA, 2.5VIN Figure 27. Load Transient 0 to 150mA, 3.6VIN Figure 28. Load Transient 50 to 250mA, 3.6VIN Figure 29. Load Transient 150 to 400mA, 3.6VIN Figure 30. Load Transient 0 to 150mA, 4.5VIN Figure 31. Load Transient 50 to 250mA, 4.5VIN Figure 32. Load Transient 150 to 400mA, 4.5VIN © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 9 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C, 5µs/div. horizontal sweep. Figure 33. Metallic Short Applied at VOUT, 20μs/div. Figure 34. Metallic Short Applied at VOUT Figure 35. Over-Current Fault Response, RLOAD = 1Ω, 20μs/div. Figure 36. Over-Current Fault Response, RLOAD = 1Ω Figure 37. 1.2VOUT Overload Recovery to Light Load © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 10 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Typical Performance Characteristics (Continued) Unless otherwise noted, VIN = VEN = 3.6V, VMODE = 0V, VOUT = 1.82V, TA = 25°C. Figure 38. Soft-Start, RLOAD = 50Ω, 20μs/div. Figure 39. SW-Node Jitter (Infinite Persistence), ILOAD = 200mA, 50ns/div. Figure 40. Power Supply Rejection Ratio at 300mA Load © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 11 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Operation Description The FAN5361 is a 600mA, step-down, switching voltage regulator that delivers a fixed output from an input voltage supply of 2.3V to 5.5V. Using a proprietary architecture with synchronous rectification, the FAN5361 is capable of delivering a peak efficiency of 92%, while maintaining efficiency over 80% at load currents as low as 1mA. The regulator operates at a nominal frequency of 6MHz at full load, which reduces the value of the external components to 470nH for the inductor and 4.7µF for the output capacitor. cycle-by-cycle. After 21µs of current limit, the regulator triggers an over-current fault, causing the regulator to shut down for about 86μs before attempting a restart. If the fault was caused by short circuit, the soft-start circuit attempts to restart at 33% of normal current limit and produces an over-current fault after about 21μs, which results in a duty cycle of less than 25% providing current into a short. Under-Voltage Lockout (UVLO) When EN is high, the under-voltage lock-out keeps the part from operating until the input supply voltage rises high enough to properly operate. This ensures no misbehavior of the regulator during start-up or shutdown. Control Scheme The FAN5361 uses a proprietary, non-linear, fixed-frequency PWM modulator to deliver a fast load transient response, while maintaining a constant switching frequency over a wide range of operating conditions. The regulator performance is independent of the output capacitor ESR, allowing for the use of ceramic output capacitors. Although this type of operation normally results in a switching frequency that varies with input voltage and load current, an internal frequency loop holds the switching frequency constant over a large range of input voltages and load currents. For very light loads, the FAN5361 operates in discontinuous current (DCM) single-pulse PFM mode, which produces low output ripple compared with other PFM architectures. Transition between PWM and PFM is seamless, with a glitch of less than 18mV at VOUT during the transition between DCM and CCM modes. Combined with exceptional transient response characteristics, the very low quiescent current of the controller (35µA) maintains high efficiency; even at very light loads, while preserving fast transient response for applications requiring tight output regulation. Thermal Shutdown (TSD) When the die temperature increases, due to a high load condition and/or a high ambient temperature, the output switching is disabled until the temperature on the die has fallen sufficiently. The junction temperature at which the thermal shutdown activates is nominally 150°C with a 15°C hysteresis. Minimum Off-Time Effect on Switching Frequency tOFF(MIN) is 50ns. This imposes constraints on the maximum VOUT that the FAN5361 can provide, while maintaining a VIN fixed switching frequency in PWM mode. VOUT ≤ 1 − tOFF ( MIN ) • fSW ≈ 0.7 VIN fSW ≈ VIN − VOUT 50ns • VIN Enable and Soft-Start Maintaining the EN pin LOW keeps the FAN5361 in nonswitching mode, in which all circuits are off and the part draws ~50nA of current. Increasing EN above its threshold voltage activates the part and starts the soft-start cycle. The output ramp during soft-start is a fixed slew rate of 50mV/μs from 0 to 1VOUT, then 25mV/μs for 1.82VOUT or 12mV/µs for 1.2VOUT until the output reaches its setpoint. The switching frequency drops when the regulator cannot provide sufficient duty cycle at 6Mhz to maintain regulation. This occurs when VOUT is 1.8V or 1.82V and VIN is below 3V at high load currents (see Figure 13). The calculation for switching frequency is given by: ⎛ ⎞ 1 1 ⎟ fSW = min ⎜ , ⎜ tSW ( MAX ) 166.6ns ⎟ ⎝ ⎠ where: ⎛ VOUT + IOUT • ROFF tSW (MAX ) = 50ns • ⎜1 + ⎜ V −I IN OUT • RON − VOUT ⎝ ⎞ ⎟ ⎟ ⎠ (2) MODE pin Logic 1 on this pin forces the IC to stay in PWM mode. A logic 0 allows the IC to automatically switch to PFM during light loads. If the MODE pin is toggled, the converter synchronizes its switching frequency to four times the frequency on the mode pin (fMODE). The mode pin must be held LOW for at least 10μs or HIGH for 10μs to ensure that the converter does not attempt to synchronize to this pin. (1) Current Limit, Fault Shutdown, and Restart A heavy load or short circuit on the output causes the current in the inductor to increase until a maximum current threshold is reached in the high-side switch. Upon reaching this point, the high-side switch turns off, preventing high currents from causing damage. The regulator continues to limit the current where: ROFF RON = RDSON _ N + DCRL = RDSON _ P + DCRL © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 12 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Applications Information Selecting the Inductor The output inductor must meet both the required inductance and the energy handling capability of the application. The inductor value affects average current limit, the PWM-to-PFM transition point, output voltage ripple, and efficiency. The ripple current (∆I) of the regulator is: ⎛ V − VOUT V ΔI ≈ OUT • ⎜ IN ⎜ L•f VIN SW ⎝ ⎞ ⎟ ⎟ ⎠ The increased RMS current produces higher losses through the RDS(ON) of the IC MOSFETs, as well as the inductor ESR. Increasing the inductor value produces lower RMS currents, but degrades transient response. For a given physical inductor size, increased inductance usually results in an inductor with lower saturation current. Table 1 shows the effects of inductance higher or lower than the recommended 470nH on regulator performance. (3) Output Capacitor Table 2 suggests 0402 capacitors. 0603 capacitors may further improve performance in that the effective capacitance is higher. This improves transient response and output ripple. Increasing COUT has no effect on loop stability and can therefore be increased to reduce output voltage ripple or to improve transient response. Output voltage ripple, ∆VOUT, is: ⎛ ⎞ 1 ΔVOUT = ΔI • ⎜ + ESR ⎟ ⎜ 8 •C ⎟ OUT • fSW ⎝ ⎠ The maximum average load current, IMAX(LOAD), is related to the peak current limit, ILIM(PK) by the ripple current, given by: IMAX(LOAD ) = ILIM(PK ) − ΔI 2 (4) The transition between PFM and PWM operation is determined by the point at which the inductor valley current crosses zero. The regulator DC current when the inductor current crosses zero, IDCM, is: (7) IDCM = ΔI 2 (5) Input Capacitor The 2.2μF ceramic input capacitor should be placed as close as possible between the VIN pin and GND to minimize the parasitic inductance. If a long wire is used to bring power to the IC, additional “bulk” capacitance (electrolytic or tantalum) should be placed between CIN and the power source lead to reduce ringing that can occur between the inductance of the power source leads and CIN. The effective capacitance value decreases as VIN increases due to DC Bias effects. This has no significant impact on regulator performance. The FAN5361 is optimized for operation with L = 470nH, but is stable with inductances up to 1.2μH (nominal). The inductor should be rated to maintain at least 80% of its value at ILIM(PK). Efficiency is affected by the inductor DCR and inductance value. Decreasing the inductor value for a given physical size typically decreases the DCR; but since ∆I increases, the RMS current increases, as do the core and skin effect losses. IRMS = IOUT(DC ) + 2 ΔI 2 12 (6) Table 1. Effects of Changes in Inductor Value (from 470nH Recommended Value) on Regulator Performance Inductor Value Increase Decrease IMAX(LOAD) Increase Decrease ∆VOUT EQ. 7 Decrease Increase Transient Response Degraded Improved Table 2. Recommended Passive Components and their Variation Due to DC Bias Component Description L1 CIN COUT 470nH, 2012, 90mΩ,1.1A 2.2μF, X5R, 0402 4.7μF, X5R, 0402 Vendor Murata LQM21PNR47MG0 Hitachi Metals JLSI-2012AG-R47(D2A) Murata or Equivalent GRM155R60J225ME15 Murata or Equivalent GRM155R60G475M Min. Typ. Max. Comment Minimum value occurs at maximum current Decrease primarily due to DC bias (VIN) and elevated temperature Decrease primarily due to DC bias (VOUT) 300nH 470nH 520nH 1.0μF 1.6μF 2.2μF 4.7μF 2.4μF 5.2μF © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 13 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator PCB Layout Guidelines There are only three external components: the inductor and the input and output capacitors. For any buck switcher IC, including the FAN5361, it is important to place a low-ESR input capacitor very close to the IC, as shown in Figure 41. The input capacitor ensures good input decoupling, which helps reduce noise appearing at the output terminals and ensures that the control sections of the IC do not behave erratically due to excessive noise. This reduces switching cycle jitter and ensures good overall performance. It is important to place the common GND of CIN and COUT as close as possible to the FAN5361 C2 terminal. There is some flexibility in moving the inductor further away from the IC; in that case, VOUT should be considered at the COUT terminal. VIN A1 B1 A2 B2 C2 CIN GND 470nH C1 COUT VOUT Figure 41. PCB Layout Guidance © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 14 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Physical Dimensions F BALL A1 INDEX AREA 0.03 C E A B SOLDER MASK OPENING 0.40 A1 0.80 (Ø0.180) CU PAD 2X D (1.080) F 0.03 C (R0.140) (0.680) 2X TOP VIEW RECOMMENDED LAND PATTERN (NSMD) 0.06 C 0.05 C 0.625 0.547 0.378±0.018 E 0.208±0.021 C SEATING PLANE D SIDE VIEWS NOTES: Ø0.260±0.010 0.40 A. NO JEDEC REGISTRATION APPLIES. B. DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASMEY14.5M, 1994. D. DATUM C, THE SEATING PLANE IS DEFINED BY THE SPHERICAL CROWNS OF THE BALLS. E. PACKAGE TYPICAL HEIGHT IS 586 MICRONS ±39 MICRONS (547-625 MICRONS). F. FOR DIMENSIONS D, E, X, AND Y SEE PRODUCT DATASHEET. G. BALL COMPOSITION: Sn95.5-Ag3.9-Cu0.6. H. DRAWING FILENAME: UC006ACrev1. 6X 0.005 C B A 12 (X) +/-0.018 CAB 0.40 0.80 (Y) +/-0.018 F BOTTOM VIEW Figure 42. 6-Bump WLCSP, 0.4mm Pitch Product Specific Dimensions Product FAN5361UCX D 1.390 +/-0.030 E 0.990 +/-0.030 X 0.295 Y 0.295 Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 15 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator Physical Dimensions 0.10 C 2X 2.0 A B 2.0 6 1.60 1.50 4 0.50 0.10 C PIN1 IDENT 2X TOP VIEW 1.10 1.40 2.40 1 3 0.55 MAX 0.10 C 0.08 C (0.15) 0.65 0.30 0.05 0.00 RECOMMENDED LAND PATTERN C SEATING PLANE SIDE VIEW NOTES: PIN1 IDENT 1 1.50 MAX 3 A. OUTLINE BASED ON JEDEC REGISTRATION MO-229, VARIATION VCCC. B. DIMENSIONS ARE IN MILLIMETERS. 1.10 MAX 6x 0.35 0.25 6 4 C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994. D. DRAWING FILENAME: MKT-UMLP06Crev1 0.65 1.30 0.35 6x 0.25 0.10 C A B 0.05 C BOTTOM VIEW Figure 43. 6-Pin UMLP Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 16 FAN5361 — 6MHz, 600mA TinyBuck™ Synchronous Buck Regulator © 2008 Fairchild Semiconductor Corporation FAN5361 • Rev. 1.0.0 www.fairchildsemi.com 17