FAN5355

FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator May 2010 FAN5355 1A / 0.8A, 3MHz Digitally Programmable Regulator Features 93% Efficiency at 3MHz 800mA or 1A Output Current I C™-Compatible Interface up to 3.4Mbps 6-bit VOUT Programmable from 0.75V to 1.975V 2.7V to 5.5V Input Voltage Range 3MHz Fixed-Frequency Operation Excellent Load and Line Transient Response Small Size, 1μH Inductor Solution ±2% PWM DC Voltage Accuracy 35ns Minimum On-Time High-Efficiency, Low-Ripple, Light-Load PFM Smooth Transition between PWM and PFM 37μA Operating PFM Quiescent Current Pin-Selectable or I C™ Programmable Output Voltage On-the-Fly External Clock Synchronization 10-lead MLP (3 x 3mm) or 12-bump CSP Packages 2 2 Description The FAN5355 device is a high-frequency, ultra-fast transient response, synchronous step-down DC-DC converter optimized for low-power applications using small, low-cost inductors and capacitors. The FAN5355 supports up to 800mA or 1A load current. The device is ideal for mobile phones and similar portable applications powered by a single-cell Lithium-Ion battery. With 2 an output-voltage range adjustable via I C™ interface from 0.75V to 1.975V, the device supports low-voltage DSPs and processors, core power supplies, and memory modules in smart phones, PDAs, and handheld computers. The FAN5355 operates at 3MHz (nominal) fixed switching frequency using either its internal oscillator or external SYNC frequency. During light-load conditions, the regulator includes a PFM mode to enhance light-load efficiency. The regulator transitions smoothly between PWM and PFM modes with no In hardware shutdown, the current glitches on VOUT. consumption is reduced to less than 200nA. The serial interface is compatible with Fast/Standard and 2 High-Speed mode I C specifications, allowing transfers up to 3.4Mbps. This interface is used for dynamic voltage scaling with 12.5mV voltage steps for reprogramming the mode of operation (PFM or Forced PWM), or to disable/enable the output voltage. The chip's advanced protection features include short-circuit protection and current and temperature limits. During a sustained over-current event, the IC shuts down and restarts after a delay to reduce average power dissipation into a fault. During startup, the IC controls the output slew rate to minimize input current and output overshoot at the end of soft start. The IC maintains a consistent soft-start ramp, regardless of output load during startup. The FAN5355 is available in 10-lead MLP (3x3mm) and 12-bump CSP packages. Applications Cell Phones, Smart Phones 3G, WiFi , WiMAX™, and WiBro Data Cards Netbooks , Ultra-Mobile PCs SmartReflex™-Compliant Power Supply Split Supply DSPs and μP Solutions OMAP™, XSCALE™ Mobile Graphic Processors (NVIDIA , ATI) LPDDR2 and Memory Modules ® ® ® ® I2C is a trademark of Philips Corporation. Wi-Fi® is a registered trademark of Wi-Fi Alliance Corporation. WiMax™ is a trademark of WIMAX Forum Corporation. WiBro® is a registered trademark of Telecommunications Technology Association. Netbooks® is a registered trademark of Netbooks, Inc. SmartReflex and OMAP are trademarks of Texas Instruments. XSCALE is a trademark of Intel Corporation. NVIDIA is a registered trademark of NVIDIA Corporation. © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Ordering Information Slave Address LSB Order Number (1) Output Current mA 800 800 800 1000 1000 VOUT Programming Min. 0.7500 0.7500 0.7500 0.7500 1.1875 Max. 1.5375 1.5375 1.4375 1.5375 1.9750 (2) Power-up Defaults VSEL0 VSEL1 Package 1.05 1.05 1.05 1.00 1.80 1.35 1.35 1.20 1.20 1.80 WLCSP-12, 2.23x1.46mm MLP-10, 3x3mm WLCSP-12, 2.23x1.46mm WLCSP-12, 2.23x1.46mm WLCSP-12, 2.23x1.46mm Option 00 00 02 03 06 A1 0 0 1 0 0 A0 0 0 0 0 0 FAN5355UC00X FAN5355MP00X FAN5355UC02X FAN5355UC03X FAN5355UC06X Notes: 1. The “X” designator specifies tape and reel packaging. 2. VOUT is limited to the maximum voltage for all VSEL codes greater than the maximum VOUT listed. Typical Application AVIN Q1 PVIN CIN VIN EN VSEL SYNC VCCIO SW VOUT L OUT COUT PGND VOUT MODULATOR SDA SCL AGND Q2 Figure 1. Typical Application Component L1 (LOUT) COUT CIN Description 1μH nominal 0603 (1.6x0.8x0.8) 10μF X5R or better 0603 (1.6x0.8x0.8) 4.7μF X5R or better Vendor Murata LQM31P or FDK MIPSA2520 Murata or equivalent GRM188R60G106ME47D Murata or equivalent GRM188R60J475KE19D Parameter L (3) Min. 0.7 Typ. 1.0 100 Max. 1.2 Units μH mΩ DCR (series R) C (4) 5.6 3.0 10.0 4.7 12.0 5.6 μF μF C(4) Table 1. Recommended External Components Notes: 3. Minimum L incorporates tolerance, temperature, and partial saturation effects (L decreases with increasing current). 4. Minimum C is a function of initial tolerance, maximum temperature, and the effective capacitance being reduced due to frequency, dielectric, and voltage bias effects. © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 2 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Pin Configuration Top View Bottom View Top View Figure 3. MLP10, 3x3mm Figure 2. WLCSP-12, 2.23x1.46mm Pin Definitions Pin # WLCSP A1, B1 A2 A3 MLP 9 10 1 Name (5) Description Power GND. Power return for gate drive and power transistors. Connect to AGND on PCB. The connection from this pin to the bottom of CIN should be as short as possible. Switching Node. Connect to output inductor. Power Input Voltage. Connect to input power source. The connection from this pin to CIN should be as short as possible. Sync. When toggling and SYNC_EN bit is HIGH, the regulator synchronizes to the frequency on this pin. In PWM mode, when this pin is statically LOW or statically HIGH, or when its frequency is outside of the specified capture range, the regulator’s frequency is controlled by its internal 3MHz clock. Analog Input Voltage. Connect to input power source as close as possible to the input bypass capacitor. Analog GND. This is the signal ground reference for the IC. All voltage levels are measured with respect to this pin. Enable. When this pin is HIGH, the circuit is enabled. When LOW, quiescent current is minimized. This pin should not be left floating. SDA. I2C interface serial data. Output Voltage Monitor. Tie this pin to the output voltage. This is a signal input pin to the control circuit and does not carry DC current. Voltage Select. When HIGH, VOUT is set by VSEL1. When LOW, VOUT is set by VSEL0. This behavior can be overridden through I2C register settings. This pin should not be left floating. SCL. I2C interface serial clock. PGND SW PVIN B2 N/A SYNC B3 C1 C2 C3 D1 D2 D3 2 8, PAD 7 3 6 5 4 AVIN AGND EN SDA VOUT VSEL SCL Note: 5. All logic inputs (SDA, SCL, SYNC, EN, and VSEL) are high impedance and should not be left floating. For minimum 2 quiescent power consumption, tie unused logic inputs to AVIN or AGND. If I C control is unused, tie SDA and SCL to AVIN. © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 3 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable 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 VCC ESD TJ TSTG TL Parameter AVIN, SW, PVIN Pins Other Pins 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 Min. -0.3 -0.3 3.5 1.5 –40 –65 Max. 6.5 AVIN + 0.3 (6) Units V V KV KV +150 +150 +260 °C °C °C Note: 6. Lesser of 6.5V or AVIN+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 VIN f VCCIO TA TJ Parameter Supply Voltage Frequency Range SDA and SCL Voltage Swing(7) Ambient Temperature Junction Temperature Min. 2.7 2.7 –40 –40 Max. 5.5 3.3 2.5 +85 +125 Units V MHz V °C °C Note: 2 7. The I C interface operates with tHD;DAT = 0 as long as the pull-up voltage for SDA and SCL is less than 2.5V. If voltage 2 swings greater than 2.5V are required (for example if the I C bus is pulled up to VIN), the minimum tHD;DAT must be 2 increased to 80ns. Most I C masters change SDA near the midpoint between the falling and rising edges of SCL, which provides ample tHD;DAT . Dissipation Ratings(8) Package Molded Leadless Package (MLP) Wafer-Level Chip-Scale Package (WLCSP) RθJA (9) Power Rating at TA ≤ 25°C 2050mW 900mW Derating Factor > TA = 25ºC 21mW/ºC 9mW/ºC 49ºC/W 110ºC/W Notes: 8. 9. Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = [TJ(max) - TA ] / θJA. This thermal data is measured with high-K board (four-layer board according to JESD51-7 JEDEC standard). © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 4 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Electrical Specifications VIN = 3.6V, EN = VIN, VSEL = VIN, SYNC = GND, VSEL0(6) bit = 1, CONTROL2[4:3] = 00. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Circuit and components according to Figure 1. Symbol VIN IQ Parameter Input Voltage Range Quiescent Current Conditions Min. 2.7 Typ. Max. 5.5 Units V μA mA Power Supplies IO = 0mA, PFM Mode IO = 0mA, 3MHz PWM Mode EN = GND ISD Shutdown Supply Current EN = VIN, EN_DCDC bit = 0, SDA = SCL = VIN VIN Rising VIN Falling 2.00 200 1.2 0.4 Input tied to GND or VIN VIN = 3.6V, CSP Package RDS(ON)P ILKGP RDS(ON)N ILKGN RDIS P-Channel MOSFET On Resistance P-Channel Leakage Current N-Channel MOSFET On Resistance N-Channel Leakage Current Discharge Resistor for Power-Down Sequence VIN = 3.6V, MLP Package VIN = 2.7V, MLP Package VDS = 6V VIN = 3.6V, CSP Package VIN = 3.6V, MLP Package VIN = 2.7V, MLP Package VDS = 6V Options 03 and 06 2.7V ≤ VIN ≤ 4.2V, Options 00 and 02 ILIMPK P-MOS Current Limit 2.7V ≤ VIN ≤ 5.5V, Options 00 and 02 2.7V ≤ VIN ≤ 4.2V, Options 03 and 06 2.7V ≤ VIN ≤ 5.5V, Options 03 and 06 TLIMIT THYST fSW fSYNC DSYNC Thermal Shutdown Thermal Shutdown Hysteresis Oscillator Frequency Synchronization Range Synchronization Duty Cycle 2.65 2.7 20 1150 1050 1350 1250 60 1350 1350 1550 1550 150 20 3.00 3.0 3.35 3.3 80 75 95 101 1 120 1600 1600 1800 1800 °C °C MHz MHz % mA μA Ω mΩ 0.01 145 165 200 1 μA mΩ 1.00 37 4.8 0.1 0.1 2.40 2.15 250 2.0 2.0 2.60 2.30 300 μA V V mV V V μA 50 VUVLO VUVHYST VIH VIL IIN Under-Voltage Lockout Threshold Under-Voltage Lockout Hysteresis HIGH-Level Input Voltage LOW-Level Input Voltage Input Bias Current ENABLE, VSEL, SDA, SCL, SYNC Power Switch and Protection Frequency Control Continued on the following page… © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 5 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Electrical Specifications (Continued) VIN = 3.6V, EN = VIN, VSEL = VIN, SYNC = GND, VSEL0(6) bit = 1, CONTROL2[4:3] = 00. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Circuit and components according to Figure 1. Symbol Parameter Conditions IOUT(DC) = 0, Forced PWM, VOUT = 1.35V Option 00 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.5375, IOUT(DC) = 0 to 800mA, Forced PWM 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.5375, IOUT(DC) = 0 to 800mA, PFM Mode IOUT(DC) = 0, Forced PWM, VOUT = 1.20V Option 02 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.4375, IOUT(DC) = 0 to 800mA, Forced PWM 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.4375, IOUT(DC) = 0 to 800mA, PFM Mode VOUT VOUT Accuracy Option 03 IOUT(DC) = 0, Forced PWM, VOUT = 1.20V 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.5375, IOUT(DC) = 0 to 1A, Forced PWM 2.7V ≤ VIN ≤ 5.5V, VOUT from 0.75 to 1.5375, IOUT(DC) = 0 to 1A, PFM Mode IOUT(DC) = 0, Forced PWM, VOUT = 1.800V Option 06 2.7V ≤ VIN ≤ 5.5V, VOUT from 1.185 to 1.975, IOUT(DC) = 0 to 1A, Forced PWM 2.7V ≤ VIN ≤ 5.5V, VOUT from 1.185 to 1.975, IOUT(DC) = 0 to 1A, PFM Mode ΔVOUT ΔILOAD ΔVOUT ΔVIN Min. –1.5 –2 –1.5 –1.5 –2 –1.5 –1.5 –2 –1.5 –1.5 –2 –1.5 Typ. Max. 1.5 2 3.5 1.5 2 3.5 1.5 2 3.5 1.5 2 3.5 Units % % % % % % % % % % % % Output Regulation Load Regulation IOUT(DC) = 0 to 800mA, Forced PWM –0.5 %/A Line Regulation 2.7V ≤ VIN ≤ 5.5V, IOUT(DC) = 300mA PWM Mode, VOUT = 1.35V PFM Mode, IOUT(DC) = 10mA 0 2.2 20 %/V mVPP mVPP VRIPPLE Output Ripple Voltage Continued on the following page… © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 6 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Electrical Specifications (Continued) VIN = 3.6V, EN = VIN, VSEL = VIN, SYNC = GND, VSEL0(6) bit = 1, CONTROL2[4:3] = 00. TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Circuit and components according to Figure 1. Symbol 6-Bit DAC Differential Nonlinearity Timing I2CEN tV(L-H) Soft Start tSS VSLEW Regulator Enable to Regulated VOUT Option 06 All Other Options (10) Parameter Conditions Monotonicity Assured by Design Min. Typ. Max. 0.8 Units LSB EN HIGH to I2C Start VOUT LOW to HIGH Settling RLOAD = 75Ω, Transition from 1.0 to 1.5375V VOUT Settled to within 2% of Set Point RLOAD > 5Ω, to VOUT = 1.8000V RLOAD > 5Ω, to VOUT = Power-up Default 250 7 μs μs 170 140 18.75 210 180 μs μs V/ms Soft-start VOUT Slew Rate Note: 10. Option 03 and 06 slew rates are 35.5V/ms during the first 16μs of soft start. AVIN Q1 PVIN CIN VIN EN VSEL SYNC SDA SCL 7-bit DAC I2C INTERFACE AND LOGIC REF SW Q2 VOUT L OUT COUT SOFT START FPWM EN_REG CLK MODULATOR PGND VOUT 3 MHz Osc Figure 4. Block Diagram AGND © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 7 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator I2C Timing Specifications Guaranteed by design. Symbol fSCL Parameter SCL Clock Frequency Conditions Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode Standard Mode Fast Mode High-Speed Mode Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode Standard Mode Fast Mode High-Speed Mode Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode, CB < 100pF High-Speed Mode, CB < 400pF Standard Mode Fast Mode High-Speed Mode Min. Typ. Max. 100 400 3400 1700 Units kHz kHz kHz kHz μs μs μs ns ns μs ns ns ns μs ns ns ns μs ns ns ns ns ns tBUF Bus-Free Time between STOP and START Conditions START or Repeated-START Hold Time 4.7 1.3 4 600 160 4.7 1.3 160 320 4 600 60 120 4.7 600 160 250 100 10 0 0 0 0 20+0.1CB 20+0.1CB 10 20 20+0.1CB 20+0.1CB 10 20 20+0.1CB 20+0.1CB 10 20 20+0.1CB 20+0.1CB 10 20 4 600 160 3.45 900 70 150 1000 300 80 160 300 300 40 80 1000 300 80 160 300 300 80 160 tHD;STA tLOW SCL LOW Period tHIGH SCL HIGH Period tSU;STA Repeated-START Setup Time tSU;DAT Data Setup Time tHD;DAT Data Hold Time (7) tRCL SCL Rise Time tFCL SCL Fall Time tRDA tRCL1 SDA Rise Time Rise Time of SCL After a Repeated START Condition and After ACK Bit tFDA SDA Fall Time μs ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns μs ns ns pF tSU;STO CB Stop Condition Setup Time Capacitive Load for SDA and SCL 400 © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 8 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Timing Diagrams tF tSU;STA tBUF SDA tR TSU;DAT tHIGH tHD;DAT tHD;STA REPEATED START STOP START tHD;STO SCL tHD;STA tLOW START 2 Figure 5. I C Interface Timing for Fast and Slow Modes tFDA tRDA tSU;DAT REPEATED START STOP SDAH tSU;STA tRCL1 tLOW tHD;STA REPEATED START tFCL tHIGH tHD;DAT note A tRCL tSU;STO SCLH = MCS Current Source Pull-up = RP Resistor Pull-up Note A: First rising edge of SCLH after Repeated Start and after each ACK bit. Figure 6. I C Interface Timing for High-Speed Mode 2 © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 9 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics Unless otherwise specified, Auto-PWM/PFM, VIN = 3.6V, TA = 25°C, and recommended components as specified in Table 1. Efficiency 100 % 90% 80% 70% 100 % 90% 80% 70% Auto PWM/PFM Forced PWM Efficiency 60% 50% 40% 30% 20% 10% 0% 1 Auto PWM/PFM Forced PWM Eff iciency 60% 50% 40% 30% VIN = 3.6V VOUT = 1.05V 20% 10% 0% VIN = 3.6V VOUT = 1.35V 10 I LOAD 100 Ou tput Curre nt (mA) 100 0 1 I 10 LOAD 100 Ou tput Curre nt (mA) 100 0 Figure 7. Efficiency vs. Load at VOUT = 1.05V 100 % 90% 80% 70% Auto PWM/PFM Forced PWM Figure 8. Efficiency vs. Load at VOUT = 1.35V 100% 90% 80% 70% Auto PWM/PFM Forced PWM Efficiency Efficiency VIN = 3.6V VOUT = 1.5V 60% 50% 40% 30% 20% 10% 0% 1 60% 50% 40% 30% 20% 10% 0% VIN = 3.6V VOUT = 1.8V 10 I LOAD 10 0 Ou tpu t Curre nt (mA) 100 0 1 I 10 LOAD 100 Output Current (mA) 1000 Figure 9. Efficiency vs. Load at VOUT = 1.50V Figure 10. Efficiency vs. Load at VOUT = 1.80V © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 10 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics Unless otherwise specified, Auto-PWM/PFM, VIN = 3.6V, TA = 25°C, and recommended components as specified in Table 1. 1.064 1.062 1.060 VOUT (V) Auto PWM/PFM Forced PWM 1.364 1.362 1.360 VOUT (V) 1.358 1.356 1.354 1.352 1.350 1.348 Auto PWM/PFM Forced PWM 1.058 1.056 1.054 1.052 1.050 1.048 1 10 100 1000 1 10 100 1000 I LOAD Output Current (mA) I LOAD Output Current (mA) Figure 11. Load Regulation at VOUT = 1.05V 1.816 1.814 1.812 1.810 Output Voltage (V) Figure 12. Load Regulation at VOUT = 1.35V 0.10% 0.05% 0.00% -0.05% -0.10% -0.15% -0.20% -0.25% -0.30% VIN = 2.7V VIN = 3.6V VIN = 5.5V VOUT (V) 1.808 1.806 1.804 1.802 1.800 1.798 1 Auto PWM/PFM Forced PWM 10 100 1000 -40 -20 0 20 40 60 80 I LOAD Output Current (m A) Temperature (C) Figure 13. Load Regulation at VOUT = 1.80V 70 65 Quiescent Current (μA) 60 55 50 45 40 35 30 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 VIN Input Voltage (V) VSEL = 1.8V VSEL = 0V Figure 14. % VOUT Shift vs. Temperature (Normalized) 6.0 Shutdown Current (µA) 5.0 VSEL = 1.8V 4.0 3.0 2.0 1.0 VSEL = 0V 2.5 3.0 3.5 4.0 4.5 5.0 5.5 V IN Input Voltage (V) Figure 15. Quiescent Current, ILOAD = 0, EN = 1.8V Figure 16. Shutdown Current, ILOAD = 0, EN = 0 © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 11 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics (Continued) Unless otherwise specified, VIN = 3.6V, VOUT = 1.35V, and load step tR = tF < 100ns. Load Transient Response Figure 17. 50mA to 400mA to 50mA, Forced PWM Figure 18. 50mA to 400mA to 50mA, Auto PWM/PFM Figure 19. 400mA to 750mA to 400mA, Auto PWM/PFM Figure 20. 0mA to 125mA to 0mA, Auto PWM/PFM © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 12 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics (Continued) Unless otherwise specified, VIN = 3.6V. VSEL Transitions Figure 21. Single-Step, RLOAD = 6.2Ω Figure 22. Single-Step, RLOAD = 6.2Ω Figure 23. Single-Step, RLOAD = 50Ω Figure 24. Single-Step, RLOAD = 50Ω © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 13 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics (Continued) Unless otherwise specified, VIN = 3.6V. VSEL Transitions Figure 25. Single-Step from Forced PWM (MODE1=0), RLOAD = 50Ω Figure 26. Single-Step, RLOAD = 6.2Ω IL VOUT VSEL Figure 27. Single–Step from Auto PWM/PFM (MODE1=1), RLOAD = 50Ω Figure 28. Multi-Step, Controlled DAC Step (9.6mV/µs) DEF_Slew 6 (110), 800mA Load © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 14 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics (Continued) RLOAD is switched with N-channel MOSFET from VOUT to GND. VIN = 3.6V, initial VOUT = 1.35V, initial ILOAD = 0mA. Short Circuit and Over-Current Fault Response Figure 29. Metallic Short Applied at VOUT Figure 30. Metallic Short Applied at VOUT Figure 31. RLOAD = 660mΩ Figure 32. RLOAD = 660mΩ © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 15 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Typical Performance Characteristics (Continued) Unless otherwise specified, VIN = 3.6V. Figure 33. SW-Node Jitter (Infinite Persistence), ILOAD = 200mA Figure 34. SW-Node Jitter, External Synchronization (Infinite Persistence), ILOAD = 200mA 70 Attenuation (dB) 60 50 40 30 20 10 (10) 0.1 1.0 10.0 Frequency (KHz) 100.0 1,000.0 IOUT=500mA IOUT=150mA IOUT=20mA Figure 35. Soft Start, RLOAD = 50Ω PSRR Figure 36. VIN Ripple Rejection (PSRR) © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 16 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Circuit Description Overview The FAN5355 is a synchronous buck regulator that typically operates at 3MHz with moderate to heavy load currents. At light load currents, the converter operates in power-saving PFM mode. The regulator automatically transitions between fixed-frequency PWM and variable-frequency PFM mode to maintain the highest possible efficiency over the full range of load current. The FAN5355 uses a very fast non-linear control architecture to achieve excellent transient response with minimum-sized external components. The FAN5355 integrates an I C-compatible interface, allowing transfers up to 3.4Mbps. This communication interface can be used to: 1. 2. 3. 4. 5. Dynamically re-program the output voltage in 12.5mV increments. Reprogram the mode of operation to enable or disable PFM mode. Control voltage transition slew rate. Control the frequency of operation by synchronizing to an external clock. Enable / disable the regulator. 2 2 Power-Up, EN, and Soft-Start All internal circuits remain de-biased and the IC is in a very low quiescent-current state until the following are true: 1. 2. VIN is above its rising UVLO threshold, and EN is HIGH. 2 At that point, the IC begins a soft-start cycle, its I C interface is enabled, and its registers are loaded with their default values. During the initial soft start, VOUT ramps linearly to the set point programmed in the VSEL register selected by the VSEL pin. The soft start features a fixed output-voltage slew rate of 18.75V/ms and achieves regulation approximately 90μs after EN rises. PFM mode is enabled during soft start until the output is in regulation, regardless of the MODE bit settings. This allows the regulator to start into a partially charged output without discharging it; in other words, the regulator does not allow current to flow from the load back to the battery. As soon as the output has reached its set point, the control forces PWM mode for about 85μs to allow all internal control circuits to calibrate. Symbol Description tSSDLY tREG Time from EN to start of soft-start ramp VOUT ramp start Opt 03, 06 to regulation Opt 00, 02 PWROK (CONTROL2[5]) rising from end of tREG and regulator stays in PWM mode during this time Value (μs) 75 16 +(VSEL–0.7) X 53 (VSEL–0.1) X 53 10 For more details, refer to the I C Interface and Register Description sections. Output Voltage Programming Option (11) tPOK (1) (2) VOUT Equation 00, 02, 03 06 VOUT = 0.75 + NVSEL • 12.5mV VOUT = 1.1875 + NVSEL • 12.5mV Table 2. Soft-Start Timing (see Figure 37) where NVSEL is the decimal value of the setting of the VSEL register that controls VOUT. Note: 11. Option 02 maximum voltage is 1.4375V (see Table 3). Figure 37. Soft-Start Timing © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 17 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Table 3. VSEL vs. VOUT VSEL Value Dec Binary Hex 0 000000 00 1 000001 01 2 000010 02 3 000011 03 4 000100 04 5 000101 05 6 000110 06 7 000111 07 8 001000 08 9 001001 09 10 001010 0A 11 001011 0B 12 001100 0C 13 001101 0D 14 001110 0E 15 001111 0F 16 010000 10 17 010001 11 18 010010 12 19 010011 13 20 010100 14 21 010101 15 22 010110 16 23 010111 17 24 011000 18 25 011001 19 26 011010 1A 27 011011 1B 28 011100 1C 29 011101 1D 30 011110 1E 31 011111 1F 32 100000 20 33 100001 21 34 100010 22 35 100011 23 36 100100 24 37 100101 25 38 100110 26 39 100111 27 40 101000 28 41 101001 29 42 101010 2A 43 101011 2B 44 101100 2C 45 101101 2D 46 101110 2E 47 101111 2F 48 110000 30 49 110001 31 50 110010 32 51 110011 33 52 110100 34 53 110101 35 54 110110 36 55 110111 37 56 111000 38 57 111001 39 58 111010 3A 59 111011 3B 60 111100 3C 61 111101 3D 62 111110 3E 63 111111 3F 00, 03 0.7500 0.7625 0.7750 0.7875 0.8000 0.8125 0.8250 0.8375 0.8500 0.8625 0.8750 0.8875 0.9000 0.9125 0.9250 0.9375 0.9500 0.9625 0.9750 0.9875 1.0000 1.0125 1.0250 1.0375 1.0500 1.0625 1.0750 1.0875 1.1000 1.1125 1.1250 1.1375 1.1500 1.1625 1.1750 1.1875 1.2000 1.2125 1.2250 1.2375 1.2500 1.2625 1.2750 1.2875 1.3000 1.3125 1.3250 1.3375 1.3500 1.3625 1.3750 1.3875 1.4000 1.4125 1.4250 1.4375 1.4500 1.4625 1.4750 1.4875 1.5000 1.5125 1.5250 1.5375 VOUT 02 0.7500 0.7625 0.7750 0.7875 0.8000 0.8125 0.8250 0.8375 0.8500 0.8625 0.8750 0.8875 0.9000 0.9125 0.9250 0.9375 0.9500 0.9625 0.9750 0.9875 1.0000 1.0125 1.0250 1.0375 1.0500 1.0625 1.0750 1.0875 1.1000 1.1125 1.1250 1.1375 1.1500 1.1625 1.1750 1.1875 1.2000 1.2125 1.2250 1.2375 1.2500 1.2625 1.2750 1.2875 1.3000 1.3125 1.3250 1.3375 1.3500 1.3625 1.3750 1.3875 1.4000 1.4125 1.4250 1.4375 1.4375 1.4375 1.4375 1.4375 1.4375 1.4375 1.4375 1.4375 06 1.1875 1.2000 1.2125 1.2250 1.2375 1.2500 1.2625 1.2750 1.2875 1.3000 1.3125 1.3250 1.3375 1.3500 1.3625 1.3750 1.3875 1.4000 1.4125 1.4250 1.4375 1.4500 1.4625 1.4750 1.4875 1.5000 1.5125 1.5250 1.5375 1.5500 1.5625 1.5750 1.5875 1.6000 1.6125 1.6250 1.6375 1.6500 1.6625 1.6750 1.6875 1.7000 1.7125 1.7250 1.7375 1.7500 1.7625 1.7750 1.7875 1.8000 1.8125 1.8250 1.8375 1.8500 1.8625 1.8750 1.8875 1.9000 1.9125 1.9250 1.9375 1.9500 1.9625 1.9750 Software Enable The EN_DCDC bit, VSELx[7] can be used to enable the regulator in conjunction with the EN pin. Setting EN_DCDC with EN HIGH begins the soft-start sequence described above. EN_DCDC Bit 0 1 1 0 EN Pin 0 1 0 1 IC OFF ON OFF ON 2 REGULATOR OFF ON OFF OFF Table 4. EN_DCDC Behavior Light-Load (PFM) Operation The FAN5355 offers a low-ripple, single-pulse PFM mode to save power and improve efficiency when the load current is very low. PFM operation features: Smooth transitions between PFM and PWM modes Single-pulse operation for low ripple Predictable PFM entry and exit currents. PFM begins after the inductor current has become discontinuous, crossing zero during the PWM cycle in 32 consecutive cycles. PFM exit occurs when discontinuous current mode (DCM) operation cannot supply sufficient current to maintain regulation. During PFM mode, the inductor current ripple is about 40% higher than in PWM mode. The load current required to exit PFM mode is thereby about 20% higher than the load current required to enter PFM mode, providing sufficient hysteresis to prevent “mode chatter.” While PWM ripple voltage is typically less than 4mVPP, PFM ripple voltage can be up to 30mVPP during very light load. To prevent significant undershoot when a load transient occurs, the initial DC set point for the regulator in PFM mode is set 10mV higher than in PWM mode. This offset decays to about 5mV after the regulator has been in PFM mode for ~100μs. The maximum instantaneous voltage in PFM is 30mV above the set point. PFM mode can be disabled by writing to the mode control bits: CONTROL1[3:0] (see Table 10 for details). Some vendors provide both “Light PFM” (LPFM) and “Fast PFM” (FPFM) modes, while the FAN5355 provides only one PFM mode. The FAN5355’s single PFM mode features the fast transient recovery of FPFM, but does this with the low quiescent current consumption similar to LPFM mode. © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 18 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Switching-Frequency Control and Synchronization The nominal internal oscillator frequency is 3MHz. The regulator runs at its internal clock frequency until these conditions are met: 1. EN_SYNC bit, CONTROL1[5], is set; and 2. A valid frequency appears on the SYNC pin. CONTROL2 PLL_MULT 00 01 10 11 Multi-Step Mode: Applies to Options 03 and 06 only. The internal DAC is stepped at a rate defined by DEFSLEW, CONTROL2[2:0], ranging from 000 to 110. This mode minimizes the current required to charge COUT and thereby minimizes the current drain from the battery when transitioning. The PWROK bit, CONTROL2[5], remains LOW until about 1.5μs after the DAC completes its ramp. VHIGH fSYNC Valid Min. 1.80 0.90 0.60 0.45 fSYNC Divider 1 2 3 4 Typ. 3.00 1.50 1.00 0.75 Max. 4.00 2.00 1.33 1.00 VSEL PWROK VOUT VLOW Table 5. SYNC Frequency Validation for fOSC(INTERNAL)=3.0MHz If the EN_SYNC is set and SYNC fails validation, the regulator continues to run at its internal oscillator frequency. The regulator is functional if fSYNC is valid, as defined in Table 5, but its performance is compromised if fSYNC is outside the fSYNC window in the Electrical Specifications. When CONTROL1[3:2] = 00 and the VSEL line is LOW, the converter operates according to the MODE0 bit, CONTROL1[0], with synchronization disabled regardless of the state of the EN_SYNC and HW_nSW bits. tPOK(L-H) Figure 38. Multi-Step VOUT Transition Single-Step Mode: Used if DEFSLEW, CONTROL2[2:0] = 111. The internal DAC is immediately set to the higher voltage and the regulator performs the transition as quickly as its current-limit circuit allows, while avoiding excessive overshoot. Figure 39 shows single-step transition timing. tV(L-H) is the time it takes the regulator to settle to within 2% of the new set point and is typically 7μs for a full-range transition (from 000000 to 111111). The PWROK bit, CONTROL2[5], goes LOW until the transition is complete and VOUT settled. This typically occurs ~2μs after tV(L-H). It is good practice to reduce the load current before making positive VSEL transitions. This reduces the time required to make positive load transitions and avoids current-limit-induced overshoot. VHIGH Output Voltage Transitions The IC regulates VOUT to one of two set point voltages, as determined by the VSEL pin and the HW_nSW bit. VSEL Pin 0 1 x HW_nSW Bit 1 1 0 VOUT Set Point VSEL0 VSEL1 VSEL1 PFM Allowed Per MODE1 Per MODE1 Table 6. VOUT Set Point and Mode Control MODE_CTRL, CONTROL1[3:2] = 00 If HW_nSW = 0, VOUT transitions are initiated through the following sequence: 1. Write the new setpoint in VSEL1. 2. Write desired transition rate in DEFSLEW, CONTROL2[2:0], and set the GO bit in CONTROL2[7]. If HW_nSW = 1, VOUT transitions are initiated either by changing the state of the VSEL pin or by writing to the VSEL register selected by the VSEL pin. tV(L-H) 98% VHIGH VOUT VLOW VSEL PWROK tPOK(L-H) Positive Transitions When transitioning to a higher VOUT, the regulator can perform the transition using multi-step or single-step mode. Figure 39. Single-Step VOUT Transition All positive VOUT transitions inhibit PFM until the transition is complete, which occurs at the end of tPOK(L-H). © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 19 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Negative Transitions When moving from VSEL=1 to VSEL=0, the regulator enters PFM mode, regardless of the condition of the SYNC pin or MODE bits, and remains in PFM until the transition is completed. Reverse current through the inductor is blocked, and the PFM minimum frequency control inhibited, until the new set point is reached, at which time the regulator resumes control using the mode established by MODE_CTRL. The transition time from VHIGH to VLOW is controlled by the load current and output capacitance as: I2C Interface The FAN5355’s serial interface is compatible with standard, 2 fast, and HS mode I C bus specifications. The FAN5355’s SCL line is an input and its SDA line is a bi-directional opendrain output; it can only pull down the bus when active. The SDA line only pulls LOW during data reads and when signaling ACK. All data is shifted in MSB (bit 7) first. SDA and SCL are normally pulled up to a system I/O power 2 supply (VCCIO), as shown in Figure 1. If the I C interface is not used, SDA and SCL should be tied to AVIN to minimize quiescent current consumption. t V (H−L ) = COUT • VHIGH − VLOW ILOAD VHIGH (3) Addressing FAN5355 has four user-accessible registers: Address VOUT VSEL PWROK tV(L-H) VLOW 7 VSEL0 VSEL1 CONTROL1 CONTROL2 2 6 0 0 0 0 5 0 0 0 0 4 0 0 0 0 3 0 0 0 0 2 0 0 0 0 1 0 0 1 1 0 0 1 0 1 tPOK(L-H) 0 0 0 0 Table 7. I C Register Addresses Figure 40. Negative VOUT Transition Slave Address Protection Features Current Limit / Auto-Restart The regulator includes cycle-by-cycle current limiting, which prevents the instantaneous inductor current from exceeding the current-limit threshold. The IC enters “fault” mode after sustained over-current. If current limit is asserted for more than 32 consecutive cycles (about 20μs), the IC returns to shut-down state and remains in that condition for ~80μs. After that time, the regulator attempts to restart with a normal soft-start cycle. If the fault has not cleared, it shuts down ~10μs later. If the fault is a short circuit, the initial current limit is ~30% of the normal current limit, which produces a very small drain on the system power source. In Table 8, A1 and A0 are according to the Ordering Information table on page 2. 7 1 6 0 2 5 0 4 1 3 0 2 A1 1 A0 0 R/ W Table 8. I C Slave Address Bus Timing As shown in Figure 41, data is normally transferred when SCL is LOW. Data is clocked in on the rising edge of SCL. Typically, data transitions shortly at or after the falling edge of SCL to allow ample time for the data to set up before the next SCL rising edge. Data change allowed Thermal Protection When the junction temperature of the IC exceeds 150°C, the device turns off all output MOSFETs and remains in a low quiescent-current state until the die cools to 130°C before commencing a normal soft-start cycle. SDA TH SCL TSU Under-Voltage Lockout (UVLO) The IC turns off all MOSFETs and remains in a very low quiescent-current state until VIN rises above the UVLO threshold. Figure 41. Data Transfer Timing Each bus transaction begins and ends with SDA and SCL HIGH. A transaction begins with a “START” condition, which is defined as SDA transitioning from 1 to 0 with SCL HIGH, as shown in Figure 42. 20 www.fairchildsemi.com © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator SDA THD;STA Slave Address MS Bit The master then generates a repeated-start condition (Figure 44) that causes all slaves on the bus to switch to HS mode. 2 The master then sends I C packets, as described above, using the HS-mode clock rate and timing. The bus remains in HS mode until a stop bit (Figure 43) is sent by the master. While in HS mode, packets are separated by repeated-start conditions (Figure 44). Slave Releases tSU;STA tHD;STA SLADDR MS Bit ACK(0) or NACK(1) SCL Figure 42. Start Bit A transaction ends with a “STOP” condition, which is defined as SDA transitioning from 0 to 1 with SCL HIGH, as shown in Figure 43. Slave Releases Master Drives tHD;STO SDA SCL SDA ACK(0) or NACK(1) Figure 44. Repeated-Start Timing SCL Read and Write Transactions Figure 43. Stop Bit The following figures outline the sequences for data read and write. Bus control is signified by the shading of the packet, defined as Master Drives Bus During a read from the FAN5355 (Figure 46), the master issues a “Repeated Start” after sending the register address and before resending the slave address. The “Repeated Start” is a 1 to 0 transition on SDA while SCL is HIGH, as shown in Figure 44. and Slave Drives Bus . All addresses and data are MSB first. Symbol Definition S A A High-Speed (HS) Mode The protocols for High-Speed (HS), Low-Speed (LS), and Fast-Speed (FS) modes are identical, except the bus speed for HS mode is 3.4MHz. HS mode is entered when the bus master sends the HS master code 00001XXX after a start condition. The master code is sent in FS mode (less than 400KHz clock) and slaves do not ACK this transmission. R P START, see Figure 42. ACK. The slave drives SDA to 0 to acknowledge the preceding packet. NACK. The slave sends a 1 to NACK the preceding packet. Repeated START, see Figure 44. STOP, see Figure 43. Table 9. I C Bit Definitions for Figure 45 - Figure 46 2 7 bits S Slave Address 0 0 A 8 bits Reg Addr 0 A 8 bits Data 0 A P Figure 45. Write Transaction 7 bits S Slave Address 0 0 A 8 bits Reg Addr 0 A R 7 bits Slave Address 1 0 A 8 bits Data 1 A P Figure 46. Read Transaction © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 21 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Register Descriptions Default Values Each option of the FAN5355 (see Ordering Information on page 2) has different default values for the some of the register bits. Table 10 defines both the default values and the bit’s type (as defined in Table 11) for each available option. VSEL0 Option 00 02 03 06 VSEL1 3 1 1 0 0 7 1 1 1 1 6 1 1 1 1 5 0 0 0 1 4 1 1 1 1 2 0 0 1 0 1 0 0 0 0 0 0 0 0 1 VOUT 1.05 1.05 1.00 1.80 Option 00 02 03 06 7 1 1 1 1 6 1 1 1 1 5 1 1 1 1 4 1 0 0 1 3 0 0 0 0 2 0 1 1 0 1 0 0 0 0 0 0 0 0 1 VOUT 1.35 1.20 1.20 1.80 CONTROL1 Option 00, 02 03, 06 CONTROL2 3 0 0 7 1 1 6 0 0 5 0 0 4 1 1 2 0 0 1 0 0 0 0 0 Option 00, 02 03, 06 7 0 0 6 0 0 5 1 1 4 0 0 3 0 0 2 1 1 1 1 1 0 1 1 Table 10. Default Values and Bit Types for VSEL and CONTROL Registers # # # Active bit. Disabled. Read-only. Changing this bit changes the behavior of the converter, as described below. Converter logic ignores changes made to this bit. Bit can be written to and read-back. Writing to this bit through I2C does not change the read-back value, nor does it change converter behavior. Table 11. Bit-Type Definitions for Table 10 © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 22 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Bit Definitions The following table defines the operation of each register bit. Superscript characters define the default state for each option. 0,2,3,6 A Superscripts signify the default values for options 00, 02, 03, and 06, respectively. signifies the default for all options. Bit Name Value Description VSEL0 7 6 5:0 EN_DCDC Reserved DAC[5:0] 0 1A 1 Table 10 0 1A 1 Table 10 10 A Register Address: 00 Device in shutdown regardless of the state of the EN pin. This bit is mirrored in VSEL1. A write to bit 7 in either register establishes the EN_DCDC value. Device enabled when EN pin is HIGH, disabled when EN is LOW. 6-bit DAC value to set VOUT. Register Address: 01 Device in shutdown regardless of the state of the EN pin. This bit is mirrored in VSEL0. A write to bit 7 in either register establishes the EN_DCDC value. Device enabled when EN pin is HIGH, disabled when EN is LOW. VSEL1 7 6 5:0 7:6 5 4 EN_DCDC Reserved DAC[5:0] 6-bit DAC value to set VOUT. Register Address: 02 Vendor ID bits. Writing to these bits has no effect on regulator operation. These bits can be used to distinguish between vendors via I2C. Disables external signal on SYNC from affecting the regulator. When a valid frequency is detected on SYNC, the regulator synchronizes to it and PFM is disabled, except when MODE = 00, VSEL pin = LOW, and HW_nSW = 1. VOUT is controlled by VSEL1. Voltage transitions occur by writing to the VSEL1, then setting the GO bit. VOUT is programmed by the VSEL pin. VOUT = VSEL1 when VSEL is HIGH, and VSEL0 when VSEL is LOW. Operation follows MODE0, MODE1. PFM with automatic transitions to PWM, regardless of VSEL. PFM disabled (forced PWM), regardless of VSEL. Unused. PFM disabled (forced PWM) when regulator output is controlled by VSEL1. PFM with automatic transitions to PWM when regulator output is controlled by VSEL1. PFM with automatic transitions to PWM when VSEL is LOW. Changing this bit has no effect on the operation of the regulator. Register Address: 03 This bit has no effect when HW_nSW = 1. Starts a VOUT transition if HW_nSW = 0. This bit must be written by the external master to 1 for the next VOUT transition to start, even if its value might have already been 1 from the last VOUT transition. When the regulator is disabled, VOUT is not discharged. When the regulator is disabled, VOUT discharges through an internal pull down. VOUT is not in regulation or is in current limit. VOUT is in regulation. fSW = fSYNC when synchronization is enabled. fSW = 2 X fSYNC when synchronization is enabled. fSW = 3 X fSYNC when synchronization is enabled. fSW = 4 X fSYNC when synchronization is enabled. VOUT slews at 0.15mV/μs during positive VOUT transitions. VOUT slews at 0.30mV/μs during positive VOUT transitions. VOUT slews at 0.60mV/μs during positive VOUT transitions. VOUT slews at 1.20mV/μs during positive VOUT transitions. VOUT slews at 2.40mV/μs during positive VOUT transitions. VOUT slews at 4.80mV/μs during positive VOUT transitions. VOUT slews at 9.60mV/μs during positive VOUT transitions. Positive VOUT transitions use single-step mode (see Figure 39). CONTROL1 Reserved EN_SYNC HW_nSW 0A 1 0 1A 00A 01 10 11 0A 1 0A 1 0A 1 0A 1 0 1 00A 01 10 11 000 001 010 011 100 101 110 111A 3:2 MODE_CTRL 1 0 MODE1 MODE0 CONTROL2 7 6 5 GO OUTPUT_ DISCHARGE PWROK (read only) PLL_MULT 4:3 2:0 DEFSLEW © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 23 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Physical Dimensions BALL A1 INDEX AREA 0.03 C E A B (Ø0.25) Cu PAD 0.50 2X D A1 0.50 1.00 (Ø0.35) SOLDER MASK OPENING TOP VIEW 0.03 C 2X RECOMMENDED LAND PATTERN (NSMD) 0.06 C 0.05 C 0.625 0.539 0.332±0.018 0.250±0.025 D C SEATING PLANE SIDE VIEWS (X)+/-.018 0.50 0.005 CAB 12 X Ø0.315 +/- .025 D 0.50 C B A 12 3 A. NO JEDEC REGISTRATION APPLIES B. DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 D DATUM C, THE SEATING PLANE, IS DEFINED BY THE SPHERICAL CROWNS OF THE BALLS. F FOR DIMENSIONS D, E, X, AND Y SEE (Y)+/-.018 BOTTOM VIEW PRODUCT DATASHEET. F. BALL COMPOSITION: Sn95.5Ag3.9Cu0.6 SAC405 ALLOY G. DRAWING FILENAME: MKT-UC012AArev2 Figure 47. 12-Bump WLCSP, 0.5mm Pitch Product-Specific Dimensions Product FAN5355UC D 2.210 +/-0.040 E 1.440 +/-0.040 X 0.220 Y 0.355 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 FAN5355 • Rev. 1.0.6 24 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator Physical Dimensions 0.10 C 3.0 A B 0.78 0.55 10 2X 2.25 2.40 2.00 6 2.33 3.0 0.10 C 0.23 0.02 D 1 0.50 5 0.25 0.8 MAX 0.10 C TOP VIEW 2X (0.20) 0.08 C 0.05 0.00 S E A TING P LA NE RECOMMENDED LAND PATTERN C SIDE VIEW (3.00±0.10) PIN #1 IDENT 1 2.40 (0.38) 5 1.40 (3.00±0.10) E 0.55±0.10 10 0.5 2.0 0.30 0.20 6 0.10 0.05 CAB C BOTTOM VIEW A. CONFORMS TO JEDEC REGISTRATION MO-229, VARIATION WEED-5 EXCEPT WHERE NOTED B . DIMENSIONS ARE IN MILLIMETERS. C. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994 D. LAND PATTERN DIMENSIONS ARE NOMINAL REFERENCE VALUES ONLY E. NOT COMPLIANT MLP10ArevB Figure 48. 10-pin, 3x3mm Molded Leadless Package (MLP) 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 FAN5355 • Rev. 1.0.6 25 1.55 2.00 3.10 www.fairchildsemi.com FAN5355 — 1A / 0.8A, 3MHz Digitally Programmable Regulator © 2008 Fairchild Semiconductor Corporation FAN5355 • Rev. 1.0.6 26 www.fairchildsemi.com