EVALUATION KIT AVAILABLE MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator General Description Benefits and Features The MAX15053 utilizes a current-mode control architecture with a high gain transconductance error amplifier. The current-mode control architecture facilitates easy compensation design and ensures cycle-by-cycle current limit with fast response to line and load transients. High Performance Suits Wide Range of Point-ofLoad Applications * 1% Output-Voltage Accuracy Over Load, Line, and Temperature * Continuous 2A Output Current Over Temperature * Operates from 2.7V to 5.5V Supply * Adjustable Output from 0.6V to Up to 0.94 x VIN The MAX15053 high-efficiency, current-mode, synchronous step-down switching regulator with integrated power switches delivers up to 2A of output current. The device operates from 2.7V to 5.5V and provides an output voltage from 0.6V up to 94% of the input voltage, making the device ideal for distributed power systems, portable devices, and preregulation applications. The MAX15053 offers selectable skip-mode functionality to reduce current consumption and achieve a higher efficiency at light output load. The low RDS(ON) integrated switches ensure high efficiency at heavy loads while minimizing critical inductances, making the layout design a much simpler task with respect to discrete solutions. Utilizing a simple layout and footprint assures first-pass success in new designs. The MAX15053 features a 1MHz, factory-trimmed, fixedfrequency PWM mode operation. The high switching frequency, along with the PWM current-mode architecture, allows for a compact, all-ceramic capacitor design. The MAX15053 offers a capacitor-programmable softstart reducing inrush current, startup into PREBIAS operations, and a PGOOD open-drain output that can be used as an interrupt and for power sequencing. The MAX15053 is available in a 9-bump (3 x 3 array), 1.5mm x 1.5mm WLP package and is specified over the -40NC to +85NC temperature range. Applications Distributed Power Systems Preregulators for Linear Regulators Portable Devices Notebook Power Server Power IP Phones Simpler, Smaller Design than Discrete Solutions * Integrated 30m (typ) RDS(ON) High-Side and 18m (typ) Low-Side MOSFETs at 5V * Factory-Trimmed, 1MHz Switching Frequency * Stable with Low-ESR Ceramic Output Capacitors * Supported by Free EE-Sim(R) Design and Simulation Tool High Efficiency Across Light and Heavy Loads Reduces Power Consumption and Heat * 96% Efficiency with 3.3V Output at 2A * Internal 30m (typ) RDS(ON) High-Side and 18mI (typ) Low-Side MOSFETs at 5V * Skip-Mode Functionality for Light Loads Control Power Startup and Sequencing for GlitchFree Processor Operation * Enable Input/Power-Good Output Enables Sequencing * Safe-Startup Into Prebiased Output * Programmable Soft-Start * External Reference Input Can be Used to Drive Soft-Start Directly Integrated Protection Features for Improved PowerSupply Reliability * Fully Protected Against Overcurrent and Overtemperature * Input Undervoltage Lockout * Cycle-by-Cycle Overcurrent Protection Ordering Information PART TEMP RANGE PIN-PACKAGE MAX15053EWL+ -40C to +85C 9 WLP +Denotes a lead(Pb)-free/RoHS-compliant package. Typical Operating Circuit appears at end of data sheet. EE-Sim is a registered trademark of Maxim Integrated Products, Inc. 19-5240; Rev 3; 4/15 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Absolute Maximum Ratings IN, PGOOD to GND.................................................-0.3V to +6V LX to GND...................................................-0.3V to (VIN + 0.3V) LX to GND........................................-1V to (VIN + 0.3V) for 50ns EN, COMP, FB, SS/REFIN, SKIP to GND....-0.3V to (VIN + 0.3V) LX Current (Note 1).................................................... -5A to +5A Output Short-Circuit Duration.....................................Continuous Continuous Power Dissipation (TA = +70NC) 9-Bump WLP Multilayer Board (derate 14.1mW/NC above TA = +70NC).....................1127mW Operating Temperature Range........................... -40NC to +85NC Operating Junction Temperature (Note 2).......................+105NC Storage Temperature Range............................. -65NC to +150NC Soldering Temperature (reflow).......................................+260NC Note 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should not exceed the IC's package power dissipation limits. Note 2: Limit the junction temperature to +105NC for continuous operation at maximum output current. Package Thermal Characteristics (Note 3) WLP Junction-to-Case Thermal Resistance (BJC)....................26NC/W Junction-to-Ambient Thermal Resistance (BJA)...............71NC/W Note 3: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Electrical Characteristics (VIN = 5V, TA = -40NC to +85NC, unless otherwise noted, typical values are at TA = +25NC.) (Note 4) PARAMETER IN Voltage Range IN Shutdown Supply Current SYMBOL VIN CONDITIONS MIN 2.7 MAX 5.5 UNITS V 0.2 2 FA VEN = 5V, VFB = 0.65V, no switching 1.56 2.3 mA VIN Undervoltage Lockout Threshold LX starts switching, VIN rising 2.6 2.7 V VIN Undervoltage Lockout Hysteresis LX stops switching, VIN falling 200 mV 1.5 mS IN Supply Current ERROR AMPLIFIER Transconductance Voltage Gain FB Set-Point Accuracy FB Input Bias Current COMP to Current-Sense Transconductance IIN VEN = 0V TYP gMV AVEA VFB IFB 90 Over line, load, and temperature 594 VFB = 0.6V -500 gMC 600 dB 606 mV +500 nA 18 A/V 0.94 V LX On-Resistance, High-Side pMOS 30 mI LX On-Resistance, Low-Side nMOS 18 mI 4 A 4 A COMP Clamp Low VFB = 0.65V, VSS = 0.6V POWER SWITCHES High-Side Switch Current-Limit Threshold Low-Side Switch Sink CurrentLimit Threshold www.maximintegrated.com IHSCL Maxim Integrated 2 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Electrical Characteristics (continued) (VIN = 5V, TA = -40NC to +85NC, unless otherwise noted, typical values are at TA = +25NC.) (Note 4) PARAMETER SYMBOL CONDITIONS MIN Low-Side Switch Source CurrentLimit Threshold VEN = 0V RMS LX Output Current Maximum Duty Cycle Minimum Controllable On-Time fSW DMAX VSLOPE ENABLE EN Input High Threshold Voltage EN Input Low Threshold Voltage EN Input Leakage Current 10 SKIP Input Leakage Current SOFT-START, PREBIAS, REFIN Soft-Start Current SS/REFIN Discharge Resistance SS/REFIN Prebias Mode Stop Voltage ISS A 1000 94 95.8 % 70 ns 1.15 V 320 mV 1150 1.45 VSS/REFIN = 0.45V, sourcing kHz 0.025 V V FA 25 FA 0.4 VSKIP = VEN = 5V RSS FA 850 Extrapolated to 100% duty cycle VEN rising VEN falling VEN = 5V UNITS A 2 Slope Compensation Ramp Valley Slope Compensation Ramp Amplitude MAX 4 LX Leakage Current OSCILLATOR Switching Frequency TYP 10 FA ISS/REFIN = 10mA, sinking 8.3 I VSS/REFIN rising 0.58 V External Reference Input Range VIN 1.8 0 V HICCUP Number of Consecutive CurrentLimit Events to Hiccup Timeout POWER-GOOD OUTPUT PGOOD Threshold PGOOD Threshold Hysteresis PGOOD VOL PGOOD Leakage VFB rising VFB falling IPGOOD = 5mA, VFB = 0.5V VPGOOD = 5V, VFB = 0.65V THERMAL SHUTDOWN Thermal Shutdown Threshold Thermal Shutdown Hysteresis Temperature falling 0.535 8 Events 1024 Clock Cycles 0.555 0.575 28 20 V mV 60 mV 0.013 FA 150 NC 20 NC Note 4: Specifications are 100% production tested at TA = +25C. Limits over the operating temperature range are guaranteed by design and characterization. www.maximintegrated.com Maxim Integrated 3 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Typical Operating Characteristics (VIN = 5V, VOUT = 1.8V, ILOAD = 2A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.) EFFICIENCY vs. OUTPUT CURRENT (PWM MODE) 95 90 70 60 55 400 800 1200 1600 2000 2400 400 0 OUTPUT CURRENT (mA) 800 1200 1600 2000 OUTPUT CURRENT (mA) OUTPUT CURRENT (mA) SWITCHING FREQUENCY vs. INPUT VOLTAGE EFFICIENCY vs. OUTPUT CURRENT (SKIP MODE) VOUT = 2.5V 80 VOUT = 1.5V VOUT = 1.8V 75 VOUT = 1.2V 70 65 60 55 1020 1000 980 960 940 2000 1800 1600 1400 1200 800 1000 600 1.79 5.2 1.87 1.85 VOUT = 3.3V 1.83 1.81 VOUT = 5V 1.79 1.77 IOUT = 0.5A 3.7 4.2 4.7 SUPPLY VOLTAGE (V) www.maximintegrated.com 4.7 1.89 OUTPUT VOLTAGE (V) 1.81 3.2 4.2 OUTPUT VOLTAGE vs. OUTPUT CURRENT 1.83 2.7 3.7 OUTPUT VOLTAGE vs. SUPPLY VOLTAGE 1.85 1.77 3.2 OUTPUT CURRENT (mA) MAX15053 toc06 400 200 2.7 INPUT VOLTAGE (V) 1.87 OUTPUT VOLTAGE (V) 1040 900 1.89 1.75 1060 920 VIN = 3.3V 0 50 1080 MAX15053 toc07 EFFICIENCY (%) 90 MAX15053 toc05 95 1100 SWITCHING FREQUENCY (kHz) MAX15053 toc04 100 85 2400 VIN = 5V 2000 0 50 1800 50 1600 VIN = 3.3V 1400 50 VOUT = 1.2V 70 65 55 VIN = 5V VOUT = 1.5V VOUT = 1.8V 1200 60 VOUT = 2.5V 75 800 65 60 80 1000 65 55 VOUT = 1.5V 85 600 VOUT = 2.5V VOUT = 1.5V 70 75 VOUT = 1.2V 400 75 VOUT = 2.5V VOUT = 1.8V 80 0 VOUT = 1.2V 200 VOUT = 3.3V VOUT = 1.8V 80 90 85 EFFICIENCY (%) 85 VOUT = 3.3V 95 EFFICIENCY (%) 90 100 MAX15053 toc02 95 EFFICIENCY (%) 100 MAX15053 toc01 100 EFFICIENCY vs. OUTPUT CURRENT (SKIP MODE) MAX15053 toc03 EFFICIENCY vs. OUTPUT CURRENT (PWM MODE) 5.2 1.75 0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT CURRENT (A) Maxim Integrated 4 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Typical Operating Characteristics (continued) (VIN = 5V, VOUT = 1.8V, ILOAD = 2A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.) SWITCHING WAVEFORMS (IOUT = 2A) LOAD-TRANSIENT RESPONSE MAX15053 toc9a MAX15053 toc08 VOUT 50mV/div AC-COUPLED VOUT 100mV/div AC-COUPLED ILX 1A/div IOUT 1A/div 0A 0A VLX 5V/div PWM MODE VIN = 5V 40s/div 400ns/div SWITCHING WAVEFORMS SWITCHING WAVEFORM IN SKIP MODE (IOUT = 10mA) MAX15053 toc10 MAX15053 toc09b VOUT 50mV/div AC-COUPLED VOUT 50mV/div AC-COUPLED ILX 1A/div 0A ILX 1A/div VLX 5V/div VLX 5V/div VIN = 3.3V 400ns/div 10s/div INPUT AND OUTPUT RIPPLE VOLTAGE WAVEFORM (IOUT = 2A) SHUTDOWN WAVEFORM MAX15053 toc11 MAX15053 toc12 VENABLE 5V/div INPUT 20mV/div AC-COUPLED VOUT 1V/div ILX 1A/div OUTPUT 100mV/div AC-COUPLED VPGOOD 5V/div 400ns/div www.maximintegrated.com 10s/div Maxim Integrated 5 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Typical Operating Characteristics (continued) (VIN = 5V, VOUT = 1.8V, ILOAD = 2A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.) SOFT-START WAVEFORMS (PWM) (IOUT = 2A) SOFT-START WAVEFORMS (SKIP MODE) (IOUT = 2A) MAX15053 toc13a MAX15053 toc13b VENABLE 5V/div VENABLE 5V/div VOUT 1V/div VOUT 1V/div ILX 1A/div ILX 1A/div VPGOOD 5V/div 200s/div 200s/div QUIESCENT CURRENT vs. INPUT VOLTAGE SHORT-CIRCUIT HICCUP MODE MAX15053 toc15 MAX15053 toc14 100 VEN = 0V 90 QUIESCENT CURRENT (nA) VPGOOD 5V/div 80 IIN 500mA/div 70 60 VOUT 1V/div 50 40 30 20 IOUT 5A/div 10 0 2.7 3.2 3.7 4.2 4.7 5.2 200s/div INPUT VOLTAGE (V) RMS INPUT CURRENT vs. INPUT VOLTAGE FB VOLTAGE vs. TEMPERATURE 604 FEEDBACK VOLTAGE (V) 80 70 60 50 40 30 20 MAX15053 toc17 90 RMS INPUT CURRENT (mA) 606 MAX15053 toc16 100 602 600 598 596 10 NO LOAD SHORT CIRCUIT ON OUTPUT 0 2.7 3.2 3.7 4.2 594 4.7 INPUT VOLTAGE (V) www.maximintegrated.com 5.2 -40 -20 0 20 40 60 80 AMBIENT TEMPERATURE (C) Maxim Integrated 6 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Typical Operating Characteristics (continued) (VIN = 5V, VOUT = 1.8V, ILOAD = 2A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.) SOFT-START WAVEFORMS (EXTERNAL REFIN) (PWM MODE) SOFT-START WAVEFORMS (EXTERNAL REFIN) (SKIP MODE) MAX15053 toc18a NO LOAD MAX15053 toc18b VSS/REFIN 500mV/div VOUT 1V/div NO LOAD ILX 1A/div ILX 1A/div VPGOOD 5V/div VPGOOD 5V/div 200s/div 200s/div STARTING INTO A PREBIASED OUTPUT (IOUT = 2A) STARTING INTO A PREBIASED OUTPUT (NO LOAD) MAX15053 toc19 MAX15053 toc20a VENABLE 5V/div VOUT 1V/div VENABLE 5V/div VOUT 1V/div ILX 1A/div VPGOOD 5V/div PWM MODE VSS/REFIN 500mV/div VOUT 1V/div ILX 1A/div VPGOOD 5V/div PWM MODE 200s/div 200s/div STARTING INTO A PREBIASED OUTPUT STARTING INTO A PREBIASED OUTPUT HIGHER THAN SET OUTPUT MAX15053 toc20b MAX15053 toc21 1.8V VENABLE 5V/div VOUT 1V/div VOUT 500mV/div IL 1A/div ILX 1A/div VSS/REFIN 500mV/div VPGOOD 5V/div 10I LOAD AT OUT 200s/div www.maximintegrated.com 400s/div Maxim Integrated 7 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Typical Operating Characteristics (continued) (VIN = 5V, VOUT = 1.8V, ILOAD = 2A, Circuit of Figure 5, TA = +25NC, unless otherwise noted.) CASE TEMPERATURE vs. AMBIENT TEMPERATURE INPUT CURRENT IN SKIP MODE vs. OUTPUT VOLTAGE 40 20 0 NO LOAD 4.0 INPUT CURRENT (mA) 60 4.5 3.5 3.0 VCC = 5.0V 2.5 2.0 1.5 1.0 -20 MAX15053 toc23 80 CASE TEMPERATURE (C) 5.0 MAX15053 toc22 100 VCC = 3.3V 0.5 0 -40 -40 -20 0 20 40 60 AMBIENT TEMPERATURE (C) www.maximintegrated.com 80 1.2 1.7 2.2 2.7 3.2 OUTPUT VOLTAGE (V) Maxim Integrated 8 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Pin Configuration TOP VIEW (BUMPS ON BOTTOM) MAX15053 GND LX IN A1 A2 A3 COMP SKIP EN B1 B2 B3 FB SS/REFIN PGOOD C1 C2 C3 WLP Pin Description BUMP NAME FUNCTION A1 GND Analog Ground/Low-Side Switch Source Terminal. Connect to the PCB copper plane at one point near the input bypass capacitor return terminal. A2 LX Inductor Connection. Connect LX to the switched side of the inductor. LX is high impedance when the IC is in shutdown mode. A3 IN Input Power Supply. Input supply range is from 2.7V to 5.5V. Bypass with a minimum 10FF ceramic capacitor to GND. See Figures 5 and 6. B1 COMP Voltage Error-Amplifier Output. Connect the necessary compensation network from COMP to GND. See the Closing the Loop: Designing the Compensation Circuitry section. B2 SKIP B3 EN Enable Input. EN is a digital input that turns the regulator on and off. Drive EN high to turn on the regulator. Connect to IN for always-on operation. C1 FB Feedback Input. Connect FB to the center tap of an external resistor-divider from the output to GND to set the output voltage from 0.6V up to 94% of VIN. C2 SS/REFIN Soft-Start/External Voltage Reference Input. Connect a capacitor from SS/REFIN to GND to set the startup time. See the Setting the Soft-Start Time section for details on setting the soft-start time. Apply a voltage reference from 0V to VIN - 1.5V to drive soft-start externally. C3 PGOOD Open-Drain Power-Good Output. PGOOD goes high when FB is above 555mV and pulls low if FB is below 527mV. www.maximintegrated.com Skip-Mode Input. Connect to EN to select skip mode or leave unconnected for normal operation. Maxim Integrated 9 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Block Diagram SKIP EN IN BIAS GENERATOR SHDN EN LOGIC, IN UVLO THERMAL SHDN SKIP-MODE LOGIC HIGH-SIDE CURRENT LIMIT SKPM LX VOLTAGE REFERENCE CURRENT-SENSE AMPLIFIER LX IN STRONG PREBIASED FORCED START IN SKPM 0.58V LX CONTROL LOGIC SS/REFIN IN CK SS/REFIN BUFFER 0.6V GND 10A PWM COMPARATOR ERROR AMPLIFIER LOW-SIDE SOURCE-SINK CURRENT LIMIT AND ZEROCROSSING COMPARATOR SINK SOURCE FB ZX C COMP RAMP OSCILLATOR RAMP GEN CK SKPM MAX15053 PGOOD POWER-GOOD COMPARATOR 0.555V RISING, 0.527V FALLING www.maximintegrated.com Maxim Integrated 10 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Detailed Description The MAX15053 high-efficiency, current-mode switching regulator can deliver up to 2A of output current. The MAX15053 provides output voltages from 0.6V to 0.94 x VIN from 2.7V to 5.5V input supplies, making the device ideal for on-board point-of-load applications. The MAX15053 delivers current-mode control architecture using a high gain transconductance error amplifier. The current-mode control architecture facilitates easy compensation design and ensures cycle-by-cycle current limit with fast response to line and load transients. The MAX15053 features a 1MHz fixed switching frequency, allowing for all-ceramic capacitor designs and fast transient responses. The high operating frequency minimizes the size of external components. The MAX15053 is available in a 1.5mm x 1.5mm (3 x 3 array) x 0.5mm pitch WLP package. The MAX15053 offers a selectable skip-mode functionality to reduce current consumption and achieve a higher efficiency at light output loads. The low RDS(ON) integrated switches (30mI high-side and 18mI low-side, typ) ensure high efficiency at heavy loads while minimizing critical inductances, making the layout design a much simpler task with respect to discrete solutions. Utilizing a simple layout and footprint assures first-pass success in new designs. The MAX15053 features 1MHz Q15%, factory-trimmed, fixed-frequency PWM mode operation. The MAX15053 also offers capacitor-programmable, soft-start reducing inrush current, startup into PREBIAS operation, and a PGOOD open-drain output for sequencing with other devices. Controller Function-PWM Logic The controller logic block is the central processor that determines the duty cycle of the high-side MOSFET under different line, load, and temperature conditions. Under normal operation, where the current-limit and temperature protection are not triggered, the controller logic block takes the output from the PWM comparator and generates the driver signals for both high-side and low-side MOSFETs. The control logic block controls the break-before-make logic and all the necessary timing. The high-side MOSFET turns on at the beginning of the oscillator cycle and turns off when the COMP voltage crosses the internal current-mode ramp waveform, which is the sum of the slope compensation ramp and the current-mode ramp derived from inductor current (currentsense block). The high-side MOSFET also turns off if the maximum duty cycle is 94%, or when the current limit is www.maximintegrated.com reached. The low-side MOSFET turns on for the remainder of the oscillation cycle. Starting into a Prebiased Output The MAX15053 can soft-start into a prebiased output without discharging the output capacitor. In safe prebiased startup, both low-side and high-side MOSFETs remain off to avoid discharging the prebiased output. PWM operation starts when the voltage on SS/REFIN crosses the voltage on FB. The MAX15053 can start into a prebiased voltage higher than the nominal set point without abruptly discharging the output. Forced PWM operation starts when the SS/REFIN voltage reaches 0.58V (typ), forcing the converter to start. In case of prebiased output, below or above the output nominal set point, if low-side sink current-limit threshold (set to the reduced value of -0.4A (typ) for the first 32 clock cycles and then set to -4A typ) is reached, the low-side switch turns off before the end of the clock period, and the high-side switch turns on until one of the following conditions is satisfied: * High-side source current hits the reduced high-side current limit (0.4A, typ); in this case, the high-side switch is turned off for the remaining time of the clock period. * The clock period ends. Reduced high-side current limit is activated to recirculate the current into the high-side power switch rather than into the internal high-side body diode, which could be damaged. Low-side sink current limit is provided to protect the low-side switch from excessive reverse current during prebiased operation. In skip mode operation, the prebias output needs to be lower than the set point. Enable Input The MAX15053 features independent device enable control and power-good signal that allow for flexible power sequencing. Drive the enable input (EN) high to enable the regulator, or connect EN to IN for always-on operation. Power-good (PGOOD) is an open-drain output that asserts when VFB is above 555mV (typ), and deasserts low if VFB is below 527mV (typ). Programmable Soft-Start (SS/REFIN) The MAX15053 utilizes a soft-start feature to slowly ramp up the regulated output voltage to reduce input inrush current during startup. Connect a capacitor from SS/REFIN to GND to set the startup time (see the Setting the Soft-Start Time section for capacitor selection details). Maxim Integrated 11 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Error Amplifier A high-gain error amplifier provides accuracy for the voltage-feedback loop regulation. Connect the necessary compensation network between COMP and GND (see the Compensation Design Guidelines section). The erroramplifier transconductance is 1.5mS (typ). COMP clamp low is set to 0.94V (typ), just below the slope ramp compensation valley, helping COMP to rapidly return to the correct set point during load and line transients. PWM Comparator The PWM comparator compares COMP voltage to the current-derived ramp waveform (LX current to COMP voltage transconductance value is 18A/V typ). To avoid instability due to subharmonic oscillations when the duty cycle is around 50% or higher, a slope compensation ramp is added to the current-derived ramp waveform. The compensation ramp slope (0.3V x 1MHz = 0.3V/Fs) is equivalent to half the inductor current downslope in the worst case (load 2A, current ripple 30% and maximum duty-cycle operation of 94%). The slope compensation ramp valley is set to 1.15V (typ). Overcurrent Protection and Hiccup When the converter output is shorted or the device is overloaded, each high-side MOSFET current-limit event (4A typ) turns off the high-side MOSFET and turns on the low-side MOSFET. On each current-limit event a 3-bit counter is incremented. The counter is reset after three consecutive high-side MOSFETs turn on without reaching current limit. If the current-limit condition persists, the counter fills up reaching eight events. The control logic then discharges SS/REFIN, stops both high-side and lowside MOSFETs, and waits for a hiccup period (1024 clock cycles typ) before attempting a new soft-start sequence. The hiccup mode is also enabled during soft-start time. Thermal-Shutdown Protection The MAX15053 contains an internal thermal sensor that limits the total power dissipation to protect the device in the event of an extended thermal fault condition. When the die temperature exceeds +150NC (typ), the thermal sensor shuts down the device, turning off the DC-DC converter to allow the die to cool. After the die temperature falls by 20NC (typ), the device restarts, following the soft-start sequence. Skip Mode Operation The MAX15053 operates in skip mode when SKIP is connected to EN. When in skip mode, LX output becomes high impedance when the inductor current falls below www.maximintegrated.com 200mA (typ). The inductor current does not become negative. If during a clock cycle the inductor current falls below the 200mA threshold (during off-time), the low side turns off. At the next clock cycle, if the output voltage is above set point, the PWM logic keeps both high-side and lowside MOSFETs off. If instead the output voltage is below the set point, the PWM logic drives the high-side on for a minimum fixed on-time (300ns typ). In this way the system can skip cycles, reducing frequency of operations, and switches only as needed to service load at the cost of an increase in output voltage ripple (see the Skip Mode Frequency and Output Ripple section). In skip mode, power dissipation is reduced and efficiency is improved at light loads because power MOSFETs do not switch at every clock cycle. Applications Information Setting the Output Voltage The MAX15053 output voltage is adjustable from 0.6V up to 94% of VIN by connecting FB to the center tap of a resistor-divider between the output and GND (Figure 1). Choose R1 and R2 so that the DC errors due to the FB input bias current (Q500nA) do not affect the output voltage accuracy. With lower value resistors, the DC error is reduced, but the amount of power consumed in the resistor-divider increases. A typical value for R2 is 10kI, but values between 5kI and 50kI are acceptable. Once R2 is chosen, calculate R1 using: V R1 = R2 x OUT - 1 V FB where the feedback threshold voltage, VFB = 0.6V (typ). When regulating for an output of 0.6V in skip mode, short FB to OUT and keep R2 connected from FB to GND. Inductor Selection A high-valued inductor results in reduced inductor ripple current, leading to a reduced output ripple voltage. However, a high-valued inductor results in either a larger physical size or a high series resistance (DCR) and a lower saturation current rating. Typically, choose an inductor value to produce a current ripple equal to 30% of load current. Choose the inductor with the following formula: = L V VOUT x 1 - OUT fSW x LIR x ILOAD VIN where fSW is the internally fixed 1MHz switching frequency, and LIR is the desired inductor current ratio (typically Maxim Integrated 12 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator FEEDBACK DIVIDER ERROR AMPLIFIER POWER MODULATOR SLOPE COMPENSATION RAMP OUTPUT FILTER AND LOAD VIN VOUT C gMC FB R1 *CFF VFB COMP R2 QHS PWM CONTROL LOGIC VCOMP gMV ROUT DCR QLS COMPARATOR RC IL L VOUT IOUT ESR RLOAD COUT CC VCOMP REF ROUT = 10AVEA(dB)/20/gMV GMOD IOUT NOTE: THE GMOD STAGE SHOWN ABOVE MODELS THE AVERAGE CURRENT OF THE INDUCTOR, IL, INJECTED INTO THE OUTPUT LOAD, IOUT, e.g., IL = IOUT. THIS CAN BE USED TO SIMPLIFY/MODEL THE MODULATION/CONTROL/POWER STATE CIRCUITRY SHOWN WITHIN THE BOXED AREA. *NOTE: CFF IS OPTIONAL AND DESIGNED TO EXTEND THE REGULATOR'S GAIN BANDWIDTH AND INCREASED PHASE MARGIN FOR SOME LOW-DUTY CYCLE APPLICATIONS. Figure 1. Peak Current-Mode Regulator Transfer Model set to 0.3). In addition, the peak inductor current, IL_PK, must always be below the minimum high-side currentlimit value, IHSCL, and the inductor saturation current rating, IL_SAT. Ensure that the following relationship is satisfied: 1 IL_PK = ILOAD + IL < min IHSCL, IL_SAT 2 ( ) Input Capacitor Selection The input capacitor reduces the peak current drawn from the input power supply and reduces switching noise in the device. The total input capacitance must be equal to or greater than the value given by the following equation to keep the input ripple voltage within the specification and minimize the high-frequency ripple current being fed back to the input source: ILOAD V = CIN x OUT fSW x VIN_RIPPLE VIN where DVIN_RIPPLE is the maximum-allowed input ripple voltage across the input capacitors and is recommended to be less than 2% of the minimum input voltage, fSW is www.maximintegrated.com the switching frequency (1MHz), and ILOAD is the output load. The impedance of the input capacitor at the switching frequency should be less than that of the input source so high-frequency switching currents do not pass through the input source, but are instead shunted through the input capacitor. The input capacitor must meet the ripple current requirement imposed by the switching currents. The RMS input ripple current is given by: V OUT x (VIN - VOUT ) IRIPPLE = ILOAD VIN where IRIPPLE is the input RMS ripple current. Output Capacitor Selection The key selection parameters for the output capacitor are capacitance, ESR, ESL, and voltage rating. The parameters affect the overall stability, output ripple voltage, and transient response of the DC-DC converter. The output ripple occurs due to variations in the charge stored in the output capacitor, the voltage drop due to the capacitor's ESR, and the voltage drop due to the capacitor's Maxim Integrated 13 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator ESL. Estimate the output-voltage ripple due to the output capacitance, ESR, and ESL as follows: VOUT = VOUT VOUT 1 x 1 - x RESR_COUT + fSW x L VIN 8 x fSW x C OUT For ceramic capacitors, ESR contribution is negligible: R ESR_OUT << 1 8 x fSW x C OUT For tantalum or electrolytic capacitors, ESR contribution is dominant: R ESR_OUT >> 1 8 x fSW x C OUT Use these equations for initial output-capacitor selection. Determine final values by testing a prototype or an evaluation circuit. A smaller ripple current results in less output-voltage ripple. Since the inductor ripple current is a factor of the inductor value, the output-voltage ripple decreases with larger inductance. Use ceramic capacitors for low ESR and low ESL at the switching frequency of the converter. The ripple voltage due to ESL is negligible when using ceramic capacitors. Load-transient response also depends on the selected output capacitance. During a load transient, the output instantly changes by ESR x DILOAD. Before the controller can respond, the output deviates further, depending on the inductor and output capacitor values. After a short time, the controller responds by regulating the output voltage back to the predetermined value. Use higher COUT values for applications that require light load operation or transition between heavy load and light load, triggering skip mode, causing output undershooting or overshooting. When applying the load, limit the output undershoot by sizing COUT according to the following formula: C OUT ILOAD 3fCO x VOUT where DILOAD is the total load change, fCO is the regulator unity-gain bandwidth (or zero crossover frequency), and DVOUT is the desired output undershooting. When removing the load and entering skip mode, the device cannot control output overshooting, since it has no sink current capability; see the Skip Mode Frequency and Output Ripple section to properly size COUT. Skip Mode Frequency and Output Ripple In skip mode, the switching frequency (fSKIP) and output ripple voltage (VOUT-RIPPLE) shown in Figure 2 are calculated as follows: tON is a fixed time (300ns, typ); the peak inductor current reached is: I= SKIP -LIMIT VIN - VOUT x t ON L IL ISKIP-LIMIT ILOAD tON tOFF1 tOFF2 = n x tCK VOUT VOUT-RIPPLE Figure 2. Skip Mode Waveform www.maximintegrated.com Maxim Integrated 14 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator tOFF1 is the time needed for inductor current to reach the zero-current crossing limit (~ 0A): t OFF1 = L x I SKIP -LIMIT VOUT During tON and tOFF1, the output capacitor stores a charge equal to (see Figure 2): 1 1 2 + L x (I SKIP -LIMIT - ILOAD ) x VIN - VOUT VOUT Q OUT = 2 During tOFF2 (= n x tCK, number of clock cycles skipped), output capacitor loses this charge: = t OFF2 Q OUT ILOAD 1 1 2 L x (I SKIP - LIMIT - ILOAD ) x + - V V V OUT OUT IN t OFF2 = 2 xILOAD Finally, frequency in skip mode is: fSKIP = 1 t ON + t OFF1 + t OFF2 emulates a controlled current source. As a result, the inductor's pole frequency is shifted beyond the gain bandwidth of the regulator. System stability is provided with the addition of a simple series capacitor-resistor from COMP to GND. This pole-zero combination serves to tailor the desired response of the closed-loop system. The basic regulator loop consists of a power modulator (comprising the regulator's pulse-width modulator, current sense and slope compensation ramps, control circuitry, MOSFETs, and inductor), the capacitive output filter and load, an output feedback divider, and a voltage-loop error amplifier with its associated compensation circuitry. See Figure 1. The average current through the inductor is expressed as: = IL G MOD x VCOMP where IL is the average inductor current and GMOD is the power modulator's transconductance. For a buck converter: = VOUT R LOAD x IL where RLOAD is the equivalent load resistor value. Combining the above two relationships, the power modulator's transfer function in terms of VOUT with respect to VCOMP is: VOUT R LOAD x IL = = RLOAD x G MOD VCOMP IL G MOD Output ripple in skip mode is: = VOUT -RIPPLE VCOUT -RIPPLE + VESR-RIPPLE -I (I ) x t ON = SKIP -LIMIT LOAD C OUT + RESR,COUT x (I SKIP -LIMIT - ILOAD ) L x ISKIP -LIMIT = VOUT -RIPPLE + R ESR,COUT C x V - V OUT ) OUT ( IN x (I SKIP -LIMIT - ILOAD ) To limit output ripple in skip mode, size COUT based on the above formula. All the above calculations are applicable only in skip mode. Compensation Design Guidelines The MAX15053 uses a fixed-frequency, peak-current-mode control scheme to provide easy compensation and fast transient response. The inductor peak current is monitored on a cycle-by-cycle basis and compared to the COMP voltage (output of the voltage error amplifier). The regulator's duty cycle is modulated based on the inductor's peak current value. This cycle-by-cycle control of the inductor current www.maximintegrated.com The peak current-mode controller's modulator gain is attenuated by the equivalent divider ratio of the load resistance and the current-loop gain's impedance. GMOD becomes: 1 G MOD (DC = ) gMC x R LOAD x K S x (1 - D) - 0.5 1 + x f L SW where RLOAD = VOUT/IOUT(MAX), fSW is the switching frequency, L is the output inductance, D is the duty cycle (VOUT/VIN), and KS is a slope compensation factor calculated from the following equation: S V xf x L x g MC KS = 1 + SLOPE = 1 + SLOPE SW SN (VIN - VOUT ) where: S= SLOPE VSLOPE = VSLOPE x fSW t SW SN = (VIN - VOUT ) L x g MC Maxim Integrated 15 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator 1ST ASYMPTOTE R2 x (R1 + R2)-1 x 10AVEA(dB)/20 x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 2ND ASYMPTOTE R2 x (R1 + R2)-1 x gMV x (2GCC)-1 x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 GAIN 3RD ASYMPTOTE R2 x (R1 + R2)-1 x gMV x (2GCC)-1 x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 x (2GCOUT x {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1)-1 4TH ASYMPTOTE R2 x (R1 + R2)-1 x gMV x RC x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 x (2COUT x {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1)-1 3RD POLE (DBL) 2ND ZERO 0.5 x fSW (2GCOUTESR)-1 UNITY 1ST POLE [2GCC x (10AVEA(dB)/20 - gMV-1)]-1 FREQUENCY fCO 2ND POLE fPMOD* 5TH ASYMPTOTE R2 x (R1 + R2)-1 x gMV x RC x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 x (2GCOUT x {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1)-1 x (0.5 x fSW)2 x (2Gf)-2 1ST ZERO (2GCCRC)-1 NOTE: ROUT = 10AVEA(dB)/20 x gMV-1 fPMOD = [2GCOUT x (ESR + {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1)]-1 WHICH FOR ESR << {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 6TH ASYMPTOTE R2 x (R1 + R2)-1 x gMV x RC x gMC x RLOAD x {1 + RLOAD x [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 x ESR x {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1 x (0.5 x fSW)2 x (2Gf)-2 BECOMES fPMOD = [2GCOUT x {RLOAD-1 + [KS x (1 - D) - 0.5] x (L x fSW)-1}-1]-1 fPMOD = (2GCOUT x RLOAD)-1 + [KS x (1 - D) - 0.5] x (2GCOUT x L x fSW)-1 Figure 3. Asymptotic Loop Response of Current-Mode Regulator As previously mentioned, the power modulator's dominant pole is a function of the parallel effects of the load resistance and the current-loop gain's equivalent impedance: fPMOD = 1 -1 1 K S x (1 - D) - 0.5 2 x C OUT x ESR + + RLOAD fSW x L And knowing that the ESR is typically much smaller than the parallel combination of the load and the current loop: K x (1 - D) - 0.5 + ESR << R LOAD fSW x L fPMOD www.maximintegrated.com fPMOD K S x (1 - D) - 0.5 + 2 x C OUT x R LOAD 2 x fSW x L x C OUT 1 Note: Depending on the application's specifics, the amplitude of the slope compensation ramp could have a significant impact on the modulator's dominate pole. For low duty-cycle applications, it provides additional damping (phase lag) at/near the crossover frequency (see the Closing the Loop: Designing the Compensation Circuitry section). There is no equivalent effect on the power modulator zero, fZMOD. fZMOD = fZESR = 1 1 K S x (1 - D) - 0.5 2 x C OUT x + RLOAD fSW x L which can be expressed as: 1 2 x C OUT x ESR -1 Maxim Integrated 16 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator The effect of the inner current loop at higher frequencies is modeled as a double-pole (complex conjugate) frequency term, GSAMPLING(s), as shown: s2 ( x fSW ) 2 + s +1 x fSW x Q C where the sampling effect quality factor, QC, is: 1 x K S x (1 - D) - 0.5 And the resonant frequency is: SAMPLING(s) = x fSW or: f fSAMPLING = SW 2 Having defined the power modulator's transfer function, the total system transfer can be written as follows (see Figure 3): Gain(s) = GFF(s) x GEA(s) x GMOD(DC) x GFILTER(s) x GSAMPLING(s) where: G = FF (s) (sC FFR1 + 1) R2 x R1 + R2 sC FF (R1|| R2) + 1 Leaving CFF empty, GFF(s) becomes: R2 G FF (s) = R1 + R2 Also: = G EA (s) 10 A VEA (dB)/20 x (sC CR C + 1) 10 A VEA (dB)/20 sC C R C + + 1 gMV which simplifies to: = G EA (s) 10 A VEA (dB)/20 x when R C << (sC CR C + 1) 10 A VEA (dB)/20 sC C + 1 gMV 10 A VEA (dB)/20 gMV G FILTER = (s) RLOAD x fP1 = 1 G SAMPLING (s) = QC = The dominant poles and zeros of the transfer loop gain are shown below: (sC OUTESR + 1) -1 1 sC K S x (1 - D) - 0.5 + 1 + OUT R fSW x L LOAD www.maximintegrated.com fP2 = gMV 2 x 10 A VEA (dB)/20 x C C 1 1 K S x (1-D) -0.5 -1 2 x C OUT + R fSW x L LOAD 1 (fSW ) 2 1 fZ1 = 2 x C CR C fP3 = fZ2 = 1 2 x C OUTESR The order of pole-zero occurrence is: fP1 < fP2 fZ1 < fCO fP3 < fZ2 Under heavy load, fP2, approaches fZ1. Figure 3 shows a graphical representation of the asymptotic system closed-loop response, including dominant pole and zero locations. The loop response's fourth asymptote (in bold, Figure 3) is the one of interest in establishing the desired crossover frequency (and determining the compensation component values). A lower crossover frequency provides for stable closed-loop operation at the expense of a slower loadand line-transient response. Increasing the crossover frequency improves the transient response at the (potential) cost of system instability. A standard rule of thumb sets the crossover frequency between 1/10 and 1/5 of the switching frequency. First, select the passive power and decoupling components that meet the application's requirements. Then, choose the small-signal compensation components to achieve the desired closed-loop frequency response and phase margin as outlined in the Closing the Loop: Designing the Compensation Circuitry section. Closing the Loop: Designing the Compensation Circuitry 1) Select the desired crossover frequency. Choose fCO approximately 1/10 to 1/5 of the switching frequency (fSW). 2) Determine RC by setting the system transfer's fourth asymptote gain equal to unity (assuming fCO > fZ1, fP2, and fP1) where: Maxim Integrated 17 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator R LOADK S (1 - D) - 0.5 1 + L x fSW R1 + R2 x 2f C RC = x CO OUT x R2 g MV x g MC x R LOAD 1 ESR + K S (1 - D) - 0.5 1 + R LOAD L x fSW and where the ESR is much smaller than the parallel combination of the equivalent load resistance and the current loop impedance, e.g.,: ESR << 1 1 K S (1 - D) - 0.5 + R LOAD L x fSW RC becomes: RC = R1 + R2 2fCO x C OUT x R2 g MV x g MC 3) Determine CC by selecting the desired first system zero, fZ1, based on the desired phase margin. Typically, setting fZ1 below 1/5 of fCO provides sufficient phase margin. = fZ1 f 1 CO 2 x C CR C 5 therefore: CC 5 2 x fCO x R C 4) For low duty-cycle applications, the addition of a phase-leading capacitor (CFF in Figure 1) helps mitigate the phase lag of the damped half-frequency double pole. Adding a second zero near to but below the desired crossover frequency increases both the closed-loop phase margin and the regulator's unitygain bandwidth (crossover frequency). Select the capacitor as follows: 1 C FF = 2 x fCO x (R1|| R2) This guarantees the additional phase-leading zero occurs at a frequency lower than fCO from: 1 fPHASE_LEAD = 2 x C FF x R1 www.maximintegrated.com Using CFF the zero-pole order is adjusted as follows: fP1 < fP2 fZ1 < 1 1 < 2C FFR1 2C FF (R1|| R2) fCO fP3 < fZ2 Confirm the desired operation of CFF empirically. The phase lead of CFF diminishes as the output voltage is a smaller multiple of the reference voltage, e.g., below about 1V. Do not use CFF when VOUT = VFB. Setting the Soft-Start Time The soft-start feature ramps up the output voltage slowly, reducing input inrush current during startup. Size the CSS capacitor to achieve the desired soft-start time, tSS, using: I xt C SS = SS SS VFB ISS, the soft-start current, is 10FA (typ) and VFB, the output feedback voltage threshold, is 0.6V (typ). When using large COUT capacitance values, the high-side current limit can trigger during the soft-start period. To ensure the correct soft-start time, tSS, choose CSS large enough to satisfy: C SS >> C OUT x VOUT x I SS (IHSCL - IOUT ) x VFB IHSCL is the typical high-side MOSFET current-limit value. An external tracking reference with steady-state value between 0V and VIN - 1.8V can be applied to SS/REFIN. In this case, connect an RC network from external tracking reference and SS/REFIN, as shown in Figure 4. The recommended value for RSS is approximately 1kI. RSS is needed to ensure that, during hiccup period, SS/REFIN can be internally pulled down. When an external reference is connected to SS/REFIN, the soft-start must be provided externally. VREF_EXT RSS SS/REFIN CSS MAX15053 Figure 4. RC Network for External Reference at SS/REFIN Maxim Integrated 18 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator INPUT 2.7V TO 5.5V LOUT 1H IN CIN 22F LX 1.2I RPULL 20kI MAX15053 1nF PGOOD ON ENABLE OUTPUT 1.8V AT 2A EN OFF SKIP SS/REFIN CSS 22nF COUT 22F CFF 100pF R1 8.06kI GND FB R2 4.02kI COMP RC 2.32kI CC 3.3nF Figure 5. Application Circuit for PWM Mode Operation Power Dissipation The MAX15053 is available in a 9-bump WLP package and can dissipate up to 1127mW at TA = +70NC. When the die temperature exceeds +150NC, the thermal-shutdown protection is activated (see the Thermal-Shutdown Protection section). Layout Procedure Careful PCB layout is critical to achieve clean and stable operation. It is highly recommended to duplicate the MAX15053 Evaluation Kit layout for optimum performance. If deviation is necessary, follow these guidelines for good PCB layout: 1) Connect the signal and ground planes at a single point immediately adjacent to the GND bump of the IC. www.maximintegrated.com 2) Place capacitors on IN and SS/REFIN as close as possible to the IC and the corresponding pad using direct traces. 3) Keep the high-current paths as short and wide as possible. Keep the path of switching current short and minimize the loop area formed by LX, the output capacitors, and the input capacitors. 4) Connect IN, LX, and GND separately to a large copper area to help cool the IC to further improve efficiency. 5) Ensure all feedback connections are short and direct. Place the feedback resistors and compensation components as close as possible to the IC. 6) Route high-speed switching nodes (such as LX) away from sensitive analog areas (such as FB and COMP). Maxim Integrated 19 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator INPUT 2.7V TO 5.5V LOUT 1H IN CIN 22F LX 1.2I RPULL 20kI MAX15053 1nF PGOOD ON ENABLE OUTPUT 1.8V AT 2A COUT 22F CFF 100pF R1 8.06kI GND FB EN OFF R2 4.02kI COMP SKIP RC 2.32kI SS/REFIN CSS 22nF CC 3.3nF Figure 6. Application Circuit for Skip Mode Operation Typical Operating Circuit Chip Information PROCESS: BiCMOS INPUT 2.7V TO 5.5V IN LX MAX15053 GND PGOOD FB ENABLE OFF ON EN SKIP SS/REFIN www.maximintegrated.com COMP OUTPUT 1.8V/2A Package Information For the latest package outline information and land patterns, go to www.maximintegrated.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 9 WLP W91E1Z+1 21-0508 Refer to Application Note 1891 Maxim Integrated 20 MAX15053 High-Efficiency, 2A, Current-Mode Synchronous, Step-Down Switching Regulator Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 5/10 Initial release -- 1 3/11 Revised Package Information section. -- 2 7/11 Changed the 1.65mm x 1.65mm, 9-bump package information to 1.5mm x 1.5mm, 9-bump package information. Inserted Typical Operating Circuit on page one. 3 4/15 Updated Benefits and Features section DESCRIPTION 1, 11 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated's website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2015 Maxim Integrated Products, Inc. 21