EP5357LUI/EP5357HUI 600mA Synchronous Buck Regulator with Integrated Inductor RoHS Compliant; Halogen Free Description Features The EP5357xUI (x = L or H) is a 600mA PowerSOC. The EP5357xUI integrates MOSFET switches, control, compensation, and the magnetics in an advanced 2.5mm x 2.25mm QFN Package. • Integrated Inductor Technology • 2.5mm x 2.25mm x 1.1mm package • Total Solution Footprint 10mm2 • Low VOUT ripple for RF compatibility Integrated magnetics enables a tiny solution footprint, low output ripple, low part-count, and high reliability, while maintaining high efficiency. The complete solution can be implemented in as little as 10mm2. • High efficiency, up to 93% • 600mA continuous output current • 55µA quiescent current • Less than 1µA standby current A proprietary light load mode (LLM) provides high efficiency in light load conditions. • 5 MHz switching frequency • 3 pin VID for glitch free voltage scaling The EP5357xUI uses a 3-pin VID to easily select the output voltage setting. Output voltage settings are available in 2 optimized ranges providing coverage for typical VOUT settings. • VOUT Range 0.6V to VIN – 0.25V • Short circuit and over current protection • UVLO and thermal protection • IC level reliability in a PowerSOC solution The VID pins can be changed on the fly for fast dynamic voltage scaling. EP5357LUI further has the option to use an external voltage divider. • Wireless and RF applications • Wireless broad band data cards • Smart phone and portable media players • Advanced Low Power Processors, DSP, IO, Memory, Video, Multimedia Engines EP5357xUI 10uF AVIN 4.7uF 2.25mm Application VOUT PVIN EP5357LUI 4.7uF VSO VS1 VS2 ENABLE LLM 10uF VSENSE VFB AGND PGND 4.75mm Figure 1: Total Solution Footprint. Figure 2: Typical Application Schematic. www.enpirion.com 03409 September 12, 2012 Rev: D EP5357LUI/EP5357HUI LOW VID Range 16-pin QFN T&R EP5357HUI HIGH VID Range 16-pin QFN T&R EP5357LUI-E EP5357LUI Evaluation Board NC(SW) 1 EP5357HUI-E EP5357HUI Evaluation Board PGND 2 LLM 3 VFB 4 VSENSE 5 AGND 6 NC(SW) EP5357LUI 16 15 7 8 VOUT Package NC(SW) Comment EP5357LUI Part Number Pin Assignments (Top View) VOUT Ordering Information 14 PVIN 13 AVIN 12 ENABLE 11 VS0 10 VS1 9 VS2 2 LLM 3 NC 4 VSENSE 5 AGND 6 NC(SW) 7 8 VOUT PGND 15 EP5357HUI 1 16 VOUT NC(SW) NC(SW) Figure 3: EP5357LUI Pin Out Diagram (Top View) 14 PVIN 13 AVIN 12 ENABLE 11 VS0 10 VS1 9 VS2 Figure 4: EP5357HUI Pin Out Diagram (Top View) Pin Description PIN NAME 1, 15, 16 NC(SW) 2 PGND 3 LLM 4 VFB/NC 5 VSENSE FUNCTION NO CONNECT – These pins are internally connected to the common switching node of the internal MOSFETs. NC (SW) pins are not to be electrically connected to any external signal, ground, or voltage. However, they must be soldered to the PCB. Failure to follow this guideline may result in part malfunction or damage to the device. Power ground. Connect this pin to the ground electrode of the Input and output filter capacitors. LLM (Light Load Mode – “LLM”) pin. Logic-High enables automatic LLM/PWM and logiclow places the device in fixed PWM operation. LLM pin should be connected to ENABLE, or should be disabled before ENABLE is pulled low. EP5357LUI: Feed back pin for external divider option. EP5357HUI: No Connect Sense pin for preset output voltages. Refer to application section for proper configuration. ©Enpirion 2012 all rights reserved, E&OE 03409 2 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI PIN NAME 6 AGND 7, 8 VOUT 9, 10, 11 VS2, VS1, VS0 12 13 14 ENABLE AVIN PVIN FUNCTION Analog ground. This is the quiet ground for the internal control circuitry, and the ground return for external feedback voltage divider Regulated Output Voltage. Refer to application section for proper layout and decoupling. Output voltage select. VS2 = pin 9, VS1 = pin 10, VS0 = pin 11. EP5357LUI: Selects one of seven preset output voltages or an external resistor divider. EP5357HUI: Selects one of eight preset output voltages. (Refer to section on output voltage select for more details.) Output Enable. Enable = logic high; Disable = logic low Input power supply for the controller circuitry. Input Voltage for the MOSFET switches. Absolute Maximum Ratings CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond the recommended operating conditions is not implied. Stress beyond the absolute maximum ratings may cause permanent damage to the device. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. PARAMETER SYMBOL MIN MAX UNITS VIN -0.3 6.0 V Voltages on: ENABLE, VSENSE, VSO – VS2 -0.3 VIN+ 0.3 V Voltages on: VFB (EP5357LUI) -0.3 2.7 V 150 °C 150 °C Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020C 260 °C ESD Rating (based on Human Body Mode) 2000 V Input Supply Voltage Maximum Operating Junction Temperature TJ-ABS Storage Temperature Range TSTG -65 Recommended Operating Conditions PARAMETER SYMBOL MIN MAX UNITS Input Voltage Range VIN 2.4 5.5 V Operating Ambient Temperature TA -40 +85 °C Operating Junction Temperature TJ -40 +125 °C Thermal Characteristics PARAMETER Thermal Resistance: Junction to Ambient –0 LFM (Note 1) Thermal Overload Trip Point Thermal Overload Trip Point Hysteresis SYMBOL TYP UNITS θJA 85 °C/W TJ-TP +155 °C 25 °C Note 1: Based on a four layer copper board and proper thermal design per JEDEC EIJ/JESD51 standards ©Enpirion 2012 all rights reserved, E&OE 03409 3 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Electrical Characteristics NOTE: TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C, VIN = 3.6V. CIN = 4.7µF MLCC, COUT = 10µF MLCC PARAMETER SYMBOL TEST CONDITIONS MIN TYP Operating Input Voltage Range VIN Under Voltage Lock-out – VIN Rising VUVLO_R 2.0 V Under Voltage Lock-out – VIN Falling VUVLO_F 1.9 V Drop Out Resistance RDO Input to Output Resistance Output Voltage Range VOUT EP5357LUI (VDO = ILOAD X RDO) EP5357HUI Dynamic Voltage Slew Rate VSLEW EP5357LUI (VID MODE) EP5357HUI (VID MODE) VID Preset VOUT Initial Accuracy ΔVOUT TA = 25°C, VIN = 3.6V; ILOAD = 100mA ; 0.8V ≤ VOUT ≤ 3.3V Line Regulation ΔVOUT_LINE 2.4V ≤ VIN ≤ 5.5V 0.03 %/V Load Regulation ΔVOUT_LOAD 0A ≤ ILOAD ≤ 600mA 0.48 %/A Temperature Variation ΔVOUT_TEMPL -40°C ≤ TA ≤ +85°C 24 ppm/°C Output Current IOUT Shut-down Current ISD Enable = Low EP5357HUI Operating Quiescent Current IQ EP5357LUI Operating Quiescent Current 2.4 350 0.6 1.8 MAX UNITS 5.5 V 500 VIN-VDO 3.3 4 8 mΩ V V/mS -2 +2 600 % mA 0.75 µA ILOAD=0; Preset Output Voltages, LLM=High 55 µA IQ ILOAD=0; Preset Output Voltages, LLM=High 65 µA OCP Threshold ILIM 2.4V ≤ VIN ≤ 5.5V 0.6V ≤ VOUT ≤ 3.3V 1.25 1.4 A Feedback Pin Voltage Initial Accuracy VFB TA = 25°C, VIN = 3.6V; ILOAD = 100mA ; 0.8V ≤ VOUT ≤ 3.3V .588 0.6 0.612 V .582 0.6 0.618. V -40°C ≤ TA ≤ +85°C; 2.4V ≤ VIN ≤ 5.5V Feedback Pin Voltage variation over Line, Load, and Temperature VFB Feedback Pin Input Current IFB VS0-VS2, Pin Logic Low VVSLO 0.0 0.3 V VS0-VS2, Pin Logic High VVSHI 1.4 VIN V VS0-VS2, Pin Input Current IVSX Enable Pin Logic Low VENLO Enable Pin Logic High VENHI Enable Pin Current IENABLE 0mA ≤ ILOAD ≤ 600mA ©Enpirion 2012 all rights reserved, E&OE 03409 Note 1 <100 Note 1 nA <100 nA 0.3 1.4 Note 1 V <100 4 September 12, 2012 V nA www.enpirion.com Rev: D EP5357LUI/EP5357HUI PARAMETER SYMBOL TEST CONDITIONS MIN Minimum VIN-VOUT to ensure proper LLM operation LLM Engage Headroom TYP MAX 600 UNITS mV LLM Pin Logic Low VLLMLO 0.3 LLM Pin Logic High VLLMHI LLM Pin Current ILLM <100 nA Operating Frequency FOSC 5 MHz 8 4 V/mS 250 uSec 1.4 V V Soft Start Operation Soft Start Slew Rate ΔVSS EP5357HUI (VID MODE) EP5357LUI (VID MODE) VOUT Rise Time TRISE Time to 90% VOUT (VFB MODE) 180 Note 1: Parameter guaranteed by design 95 90 85 80 75 70 65 60 55 50 45 LLM Efficiency (%) Efficiency (%) Typical Performance Characteristics PWM 10 100 Load Current (mA) 1000 Efficiency (%) LLM PWM 10 Efficiency vs. Load Current: VIN = 5.0V, VOUT (from top to bottom) = 3.3, 2.5, 1.8, 1.2V 95 90 85 80 75 70 65 60 55 50 45 95 90 85 80 75 70 65 60 55 50 45 100 Load Current (mA) 1000 Efficiency vs. Load Current: VIN = 3.7V, VOUT (from top to bottom) = 2.5, 1.8, 1.2V LLM PWM 10 100 Load Current (mA) 1000 Efficiency vs. Load Current: VIN = 3.3V, VOUT (from top to bottom) = 2.5, 1.8, 1.2V ©Enpirion 2012 all rights reserved, E&OE 03409 5 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Start Up Waveform: VIN = 5.0V, VOUT = 3.3V; ILOAD = 10mA (VID MODE) Start Up Waveform: VIN = 5.0V, VOUT = 3.3V; ILOAD = 1000mA (VID MODE) Shut-down Waveform: VIN = 5.0V, VOUT = 3.3V; ILOAD = 10mA, PWM Shut-down Waveform: VIN = 5.0V, VOUT = 3.3V; ILOAD = 500mA, PWM 5mV/Div 50mV/Div Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 500mA Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 10mA LLM enabled ©Enpirion 2012 all rights reserved, E&OE 03409 6 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI 50mV/Div 5mV/Div Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 10mA LLM enabled Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 500mA 50mV/Div 5mV/Div Output Ripple: VIN = 3.3V, VOUT = 1.8V Load = 500mA Output Ripple: VIN = 3.3V, VOUT = 1.8V, Load = 10mA LLM enabled 5mV/Div 50mV/Div Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 10mA LLM enabled ©Enpirion 2012 all rights reserved, E&OE 03409 Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 500mA 7 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Load Transient: VIN = 5.0V, VOUT = 1.2V Load stepped from 0mA to 500mA, LLM enabled Load Transient: VIN = 5.0V, VOUT = 1.2V Load stepped from 10mA to 500mA Load Transient: VIN = 3.3V, VOUT = 1.8V Load stepped from 0mA to 500mA, LLM enabled Load Transient: VIN = 3.3V, VOUT = 1.8V Load stepped from 10mA to 500mA ©Enpirion 2012 all rights reserved, E&OE 03409 8 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Functional Block Diagram LLM PVIN UVLO Mode Logic Thermal Limit Current Limit ENABLE NC(SW) Soft Start P-Drive (-) Logic VOUT PWM Comp (+) N-Drive PGND VSENSE Sawtooth Generator Compensation Network (-) Switch VFB Error Amp (+) DAC Voltage Select VREF Package Boundry AVIN VS0 VS1 VS2 AGND Figure 5: Functional Block Diagram ©Enpirion 2012 all rights reserved, E&OE 03409 9 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Detailed Description Functional Overview Integrated Inductor The EP5357xUI requires only 2 small MLCC capacitors for a complete DC-DC converter solution. The device integrates MOSFET switches, PWM controller, Gate-drive, compensation, and inductor into a tiny 2.5mm x 2.25mm x 1.1mm QFN package. Advanced package design, along with the high level of integration, provides very low output ripple and noise. The EP5357xUI uses voltage mode control for high noise immunity and load matching to advanced ≤90nm loads. A 3-pin VID allows the user to choose from one of 8 output voltage settings. The EP5357xUI comes with two VID output voltage ranges. The EP5357HUI provides VOUT settings from 1.8V to 3.3V, the EP5357LUI provides VID settings from 0.8V to 1.5V, and also has an external resistor divider option to program output setting over the 0.6V to VIN-0.25V range. The EP5357xUI provides the industry’s highest power density of any 600mA DCDC converter solution. The EP5357xUI utilizes a proprietary low loss integrated inductor. The integration of the inductor greatly simplifies the power supply design process. The inherent shielding and compact construction of the integrated inductor reduces the conducted and radiated noise that can couple into the traces of the printed circuit board. Further, the package layout is optimized to reduce the electrical path length for the high di/dT input AC ripple currents that are a major source of radiated emissions from DC-DC converters. The integrated inductor provides the optimal solution to the complexity, output ripple, and noise that plague low power DCDC converter design. The key enabler of this revolutionary integration is Enpirion’s proprietary power MOSFET technology. The advanced MOSFET switches are implemented in deep-submicron CMOS to supply very low switching loss at high switching frequencies and to allow a high level of integration. The semiconductor process allows seem-less integration of all switching, control, and compensation circuitry. The proprietary magnetics design provides high-density/high-value magnetics in a very small footprint. Enpirion magnetics are carefully matched to the control and compensation circuitry yielding an optimal solution with assured performance over the entire operating range. Protection features include under-voltage lockout (UVLO), over-current protection (OCP), short circuit protection, and thermal overload protection. ©Enpirion 2012 all rights reserved, E&OE 03409 Voltage Mode Control The EP5357xUI utilizes an integrated type III compensation network. Voltage mode control is inherently impedance matched to the sub 90nm process technology that is used in today’s advanced ICs. Voltage mode control also provides a high degree of noise immunity at light load currents so that low ripple and high accuracy are maintained over the entire load range. The very high switching frequency allows for a very wide control loop bandwidth and hence excellent transient performance. Light Load Mode (LLM) Operation The EP5357xUI uses a proprietary light load mode to provide high efficiency in the low load operating condition. When the LLM pin is high, the device is in automatic LLM/PWM mode. When the LLM pin is low, the device is in PWM mode. In automatic LLM/PWM mode, when a light load condition is detected, the device will (1) step VOUT up by approximately 1.5% above the nominal operating output voltage setting, VNOM, and then (2) shut down unnecessary circuitry, and (3) monitor VOUT. When VOUT falls below VNOM, the device will repeat (1), (2), and (3). The voltage step up, or pre-positioning, improves transient droop when a load transient causes a transition from LLM mode to PWM mode. If a load transient occurs, causing VOUT to fall below the threshold VMIN, the device will 10 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI exit LLM operation and begin normal PWM operation. Figure 6 demonstrates VOUT behavior during transition into and out of LLM operation. LLM Threshold Current vs. VOUT LLM Threshold (mA) 250 LLM Ripple VMAX PWM Ripple VNOM VMIN 200 150 VIN=5V (top curve) 100 VIN=4.2V VIN=3.7V 50 VIN=3.3V (bottom curve) VOUT 0 0.8 1.1 1.4 1.7 2.0 2.3 2.6 2.9 3.2 VOUT (V) Load Step IOUT Figure 6: VOUT Behavior in LLM Operation Figure 8: Typical load current for LLM engage and disengage versus VOUT for selected input voltages Table 1: Load current below which the device can be certain to be in LLM operation. These values are guaranteed by design VIN Device exits LLM, tests load current Figure 7: VOUT Droop during Periodic LLM Exit Many multi-mode DCDC converters suffer from a condition that occurs when the load current increases only slowly so that there is no load transient driving VOUT below the VMIN threshold. In this condition, the device would never exit LLM operation. This could adversely affect efficiency and cause unwanted ripple. To prevent this from occurring, the EP5357xUI periodically exits LLM mode into PWM mode and measures the load current. If the load current is above the LLM threshold current, the device will remain in PWM mode. If the load current is below the LLM threshold, the device will re-enter LLM operation. There will be a small droop in VOUT at the point where the device exits and re-enters LLM, as shown in Figure 7. ©Enpirion 2012 all rights reserved, E&OE 03409 VOUT 3.30 3.00 2.90 2.60 2.50 2.20 2.10 1.80 1.50 1.45 1.20 1.15 1.10 1.05 0.80 3.3 3.7 56 69 101 105 111 111 111 105 103 101 99 87 62 89 106 111 120 122 124 120 119 111 108 106 104 89 4.3 105 122 126 136 138 141 141 138 130 128 117 114 111 108 92 5.0 147 156 158 162 162 160 158 150 138 136 122 119 116 113 94 The load current at which the device will enter LLM mode is a function of input and output voltage. Figure 8 shows the typical value at which the device will enter LLM operation. The actual load current at which the device will enter LLM operation can vary by +/-30%. Table 1 shows the minimum load current below which the device is guaranteed to be in LLM operating mode. To ensure normal LLM operation, LLM mode should be enabled/disabled with specific sequencing. For applications with explicit LLM pin control, enable LLM after VIN ramp up is complete; disable LLM before VIN ramp down. 11 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI For applications with ENABLE control, tie LLM to ENABLE; enable device after VIN ramp up is complete and disable device before VIN ramp down begins. For devices with ENABLE and LLM tied to VIN, contact Enpirion Applications engineering for specific recommendations Increased output filter capacitance and/or increased bulk capacitance at the load will decrease the magnitude of the LLM ripple. Refer to the section on output filter capacitance for maximum values of output filter capacitance and the Soft-Start section for maximum bulk capacitance at the load. NOTE: For proper LLM operation the EP5357xUI requires a minimum difference between VIN and VOUT of 600mV. If this condition is not met, the device cannot be assured proper LLM operation. NOTE: Automatic LLM/PWM is not available when using the external resistor divider option for VOUT programming. Soft Start Internal soft start circuits limit in-rush current when the device starts up from a power down condition or when the “ENABLE” pin is asserted “high”. Digital control circuitry limits the VOUT ramp rate to levels that are safe for the Power MOSFETS and the integrated inductor. The EP5357HUI has a soft-start slew rate that is twice that of the EP5357LUI. When the EP5357LUI is configured in external resistor divider mode, the device has a fixed VOUT ramp time. Therefore, the ramp rate will vary with the output voltage setting. Output voltage ramp time is given in the Electrical Characteristics Table. Excess bulk capacitance on the output of the device can cause an over-current condition at startup. The maximum total capacitance on the output, including the output filter capacitor and bulk and decoupling capacitance, at the load, is given as: EP5357LUI: COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 200uF COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 100uF EP5357LUI in external divider mode: COUT_TOTAL_MAX = 2.25x10-4/VOUT Farads The nominal value for COUT is 10uF. See the applications section for more details. Over Current/Short Circuit Protection The current limit function is achieved by sensing the current flowing through a sense PMOSFET which is compared to a reference current. When this level is exceeded the PFET is turned off and the N-FET is turned on, pulling VOUT low. This condition is maintained for approximately 0.5mS and then a normal soft start is initiated. If the over current condition still persists, this cycle will repeat. Under Voltage Lockout During initial power up an under voltage lockout circuit will hold-off the switching circuitry until the input voltage reaches a sufficient level to insure proper operation. If the voltage drops below the UVLO threshold the lockout circuitry will again disable the switching. Hysteresis is included to prevent chattering between states. Enable The ENABLE pin provides a means to shut down the converter or enable normal operation. A logic low will disable the converter and cause it to shut down. A logic high will enable the converter into normal operation. NOTE: The ENABLE pin must not be left floating. Thermal Shutdown When excessive power is dissipated in the chip, the junction temperature rises. Once the junction temperature exceeds the thermal shutdown temperature the thermal shutdown circuit turns off the converter output voltage thus allowing the device to cool. When the junction temperature decreases by 15C°, the device will go through the normal startup process. EP5357HUI: ©Enpirion 2012 all rights reserved, E&OE 03409 12 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Application Information VIN 4.7μF PVIN VOUT AVIN VSENSE ENABLE LLM VOUT 10μF VS0 VS1 VS2 PGND AGND Internally, the output of the VID multiplexer sets the value for the voltage reference DAC, which in turn is connected to the non-inverting input of the error amplifier. This allows the use of a single feedback divider with constant loop gain and optimum compensation, independent of the output voltage selected. NOTE: The VID pins must not be left floating. EP5357L Low VID Range Programming Figure 9: Application Circuit, EP5357HUI, configured for LLM Enabled. Note that all control signals should be connected to AVIN or AGND. VIN μF PVIN VOUT AVIN VSENSE ENABLE LLM VS0 VFB VOUT 10μF VS1 VS2 The EP5357LUI is designed to provide a high degree of flexibility in powering applications that require low VOUT settings and dynamic voltage scaling (DVS). The device employs a 3-pin VID architecture that allows the user to choose one of seven (7) preset output voltage settings, or the user can select an external voltage divider option. The VID pin settings can be changed on the fly to implement glitchfree voltage scaling. PGND AGND Table 2: EP5357LUI VID Voltage Select Settings VS2 0 0 0 0 1 1 1 1 Figure 10: Application Circuit, EP5357LUI, configured for LLM Enabled, showing the VFB function. Output Voltage Programming The EP5357xUI utilizes a 3-pin VID to program the output voltage value. The VID is available in two sets of output VID programming ranges. The VID pins should be connected either to AVIN or to AGND to avoid noise coupling into the device. The “Low” range is optimized for low voltage applications. It comes with preset VID settings ranging from 0.80V and 1.5V. This VID set also has an external divider option. To specify this VID range, order part number EP5357LUI. The “High” VID set provides output voltage settings ranging from 1.8V to 3.3V. This version does not have an external divider option. To specify this VID range, order part number EP5357HUI. ©Enpirion 2012 all rights reserved, E&OE 03409 VS1 0 0 1 1 0 0 1 1 VS0 0 1 0 1 0 1 0 1 VOUT 1.50 1.45 1.20 1.15 1.10 1.05 0.8 EXT Table 2 shows the VS2-VS0 pin logic states for the EP5357LUI and the associated output voltage levels. A logic “1” indicates a connection to AVIN or to a “high” logic voltage level. A logic “0” indicates a connection to AGND or to a “low” logic voltage level. These pins can be either hardwired to AVIN or AGND or alternatively can be driven by standard logic levels. Logic levels are defined in the electrical characteristics table. Any level between the logic high and logic low is indeterminate. 13 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI connection to AVIN or to a “high” logic voltage level. A logic “0” indicates a connection to AGND or to a “low” logic voltage level. These pins can be either hardwired to AVIN or AGND or alternatively can be driven by standard logic levels. Logic levels are defined in the electrical characteristics table. Any level between the logic high and logic low is indeterminate. These pins must not be left floating. EP5357LUI External Voltage Divider The external divider option is chosen by connecting VID pins VS2-VS0 to VIN or a logic “1” or “high”. The EP5357LUI uses a separate feedback pin, VFB, when using the external divider. VSENSE must be connected to VOUT as indicated in Figure 11. The output voltage is selected by the following formula: VOUT = 0.6V (1 + Ra Rb ) Ra must be chosen as 237KΩ to maintain loop gain. Then Rb is given as: Rb = Table 3: EP5357HUI VID Voltage Select Settings VS2 0 0 0 0 1 1 1 1 142.2 x10 3 Ω VOUT − 0.6 VOUT can be programmed over the range of 0.6V to (VIN – 0.25V). NOTE: Dynamic Voltage Scaling is not allowed between internal preset voltages and external divider. NOTE: LLM is not functional when using the external divider option. Tie the LLM pin to AGND. VIN VSense AVIN ENABLE VS0 VS1 VS2 EP5357L 4.7uF PVIN VS0 0 1 0 1 0 1 0 1 VOUT 3.3 3.0 2.9 2.6 2.5 2.2 2.1 1.8 Power-Up/Down Sequencing VOUT VOUT Ra VS1 0 0 1 1 0 0 1 1 10μF VFB Rb PGND AGND During power-up, ENABLE should not be asserted before PVIN, and PVIN should not be asserted before AVIN. The PVIN should never be powered when AVIN is off. During power down, the AVIN should not be powered down before the PVIN. Tying PVIN and AVIN or all three pins (AVIN, PVIN, ENABLE) together during power up or power down meets these requirements. Pre-Bias Start-up Figure 11: EP5357LUI using external divider EP5357HUI High VID Range Programming The EP5357HUI VOUT settings are optimized for higher nominal voltages such as those required to power IO, RF, or IC memory. The preset voltages range from 1.8V to 3.3V. There are eight (8) preset output voltage settings. The EP5357HUI does not have an external divider option. As with the EP5357LUI, the VID pin settings can be changed while the device is enabled. Table 3 shows the VS0-VS2 pin logic states for the EP5357HUI and the associated output voltage levels. A logic “1” indicates a ©Enpirion 2012 all rights reserved, E&OE 03409 The EP5357xUI does not support startup into a pre-biased condition. Be sure the output capacitors are not charged or the output of the EP5357xUI is not pre-biased when the EP5357xUI is first enabled. Input Filter Capacitor For ILOAD ≤ 500mA, CIN = 2.2uF For ILOAD > 500mA CIN = 4.7uF. 0402 capacitor case size is acceptable. The input capacitor must use a X5R or X7R or equivalent dielectric formulation. Y5V or equivalent dielectric formulations lose capacitance with frequency, bias, and with 14 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI temperature, and are not suitable for switchmode DC-DC converter input filter applications. Output Filter Capacitor For VIN ≤ 4.3V, COUT_MIN = 10uF 0603 MLCC. For VIN > 4.3V, COUT_MIN = 10uF 0805 MLCC. Ripple performance can be improved by using 2x10µF 0603 MLCC capacitors (for any allowed VIN). The maximum output filter capacitance next to the output pins of the device is 60µF low ESR MLCC capacitance. VOUT has to be sensed at the last output filter capacitor next to the EP5357xUI. Additional bulk capacitance for decoupling and bypass can be placed at the load as long as there is sufficient separation between the VOUT Sense point and the bulk capacitance. Excess total capacitance on the output (Output Filter + Bulk) can cause an over-current condition at startup. Refer to the section on Soft-Start for the maximum total capacitance on the output. The output capacitor must use a X5R or X7R or equivalent dielectric formulation. Y5V or equivalent dielectric formulations lose capacitance with frequency, bias, and temperature and are not suitable for switchmode DC-DC converter output filter applications. Recommended PCB Footprint Figure 12: EP5357 Package PCB Footprint ©Enpirion 2012 all rights reserved, E&OE 03409 15 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Package and Mechanical Figure 13: EP5357xUI Package Dimensions ©Enpirion 2012 all rights reserved, E&OE 03409 16 September 12, 2012 www.enpirion.com Rev: D EP5357LUI/EP5357HUI Contact Information Enpirion, Inc. Perryville III 53 Frontage Road Suite 210 Hampton, NJ 08827 Phone: +1 908-894-6000 Fax: +1 908-894-6090 Enpirion reserves the right to make changes in circuit design and/or specifications at any time without notice. Information furnished by Enpirion is believed to be accurate and reliable. Enpirion assumes no responsibility for its use or for infringement of patents or other third party rights, which may result from its use. Enpirion products are not authorized for use in nuclear control systems, as critical components in life support systems or equipment used in hazardous environment without the express written authority from Enpirion. ©Enpirion 2012 all rights reserved, E&OE 03409 17 September 12, 2012 www.enpirion.com Rev: D