EP53A7LQI/EP53A7HQI 1000mA Synchronous Buck Regulator with Integrated Inductor RoHS Compliant; Halogen Free Description Features The EP53A7xQI (x = L or H) is a 1000mA PowerSOC. The EP53A7xQI integrates MOSFET switches, control, compensation, and the magnetics in an advanced 3mm x 3mm QFN Package. • Integrated Inductor Technology • 3mm x 3mm x 1.1mm QFN package • Total Solution Footprint < 21mm2 • 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 21mm2. • High efficiency, up to 94% • 1000mA 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 EP53A7xQI 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 – 0.5V • 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. EP53A7LQI further has the option to use an external voltage divider. The EP53A7xQI offers the optimal combination of very small solution footprint and advanced performance features. 3.5mm Application • Portable wireless and RF applications • Solid state storage applications • Space constrained applications requiring high efficiency and very small solution size 100 ohm 4.7uF 100 Ohm VIN 6mm 4.7μF EP53A7xQI PVIN VOUT AVIN VSENSE ENABLE LLM VS0 VFB VOUT 10μF VS1 VS2 PGND AGND 10uF Figure 2: Typical Application Schematic Figure 1: Total Solution Footprint www.enpirion.com 01543 11/11/2009 Rev:B EP53A7LQI/EP53A7HQI Ordering Information Part Number Pin Assignments (Top View) Comment Package EP53A7LQI LOW VID Range 16-pin QFN T&R EP53A7HQI HIGH VID Range 16-pin QFN T&R EP53A7LQI-E EP53A7LQI Evaluation Board EP53A7HQI-E EP53A7HQI Evaluation Board Figure 3: EP53A7LQI Pin Out Diagram (Top View) Figure 4: EP53A7HQI Pin Out Diagram (Top View) Pin Description PIN NAME 1, 15, 16 NC(SW) 2 PGND 3 LLM 5 VFB NC VSENSE 6 AGND 7, 8 VOUT 4 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. EP53A7LQI: Feed back pin for external resistor divider option. EP53A7HQI: No Connect Sense pin for preset output voltages. Refer to application section for proper configuration. 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. ©Enpirion 2009 all rights reserved, E&OE 01543 2 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI PIN NAME 9, 10, 11 VS2, VS1, VS0 12 13 14 ENABLE AVIN PVIN FUNCTION Output voltage select. VS2 = pin 9, VS1 = pin 10, VS0 = pin 11. EP53A7LQI: Selects one of seven preset output voltages or an external resistor divider. EP53A7HQI: 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. Connect to PVIN through a 100 Ohm resistor. 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 (EP53A7LQI) -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 2009 all rights reserved, E&OE 01543 3 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 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 Operating Input Voltage 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 EP53A7LQI (VDO = ILOAD X RDO) EP53A7HQI Dynamic Voltage Slew Rate VSLEW EP53A7LQI EP53A7HQI ΔVOUT TA = 25°C, VIN = 3.6V; ILOAD = 100mA ; 0.8V ≤ VOUT ≤ 3.3V -2 Feedback Pin Voltage Initial Accuracy VFB TA = 25°C, VIN = 3.6V; ILOAD = 100mA ; 0.8V ≤ VOUT ≤ 3.3V .588 Line Regulation ΔVOUT_LINE 2.4V ≤ VIN ≤ 5.5V 0.03 %/V Load Regulation ΔVOUT_LOAD 0A ≤ ILOAD ≤ 1000mA 0.6 %/A Temperature Variation ΔVOUT_TEMPL -40°C ≤ TA ≤ +85°C 30 ppm/°C Output Current IOUT Shut-down Current ISD Enable = Low EP53A7HQI Operating Quiescent Current IQ EP53A7LQI Operating Quiescent Current VID Preset VOUT Initial Accuracy TEST CONDITIONS MIN TYP 2.4 350 0.6 1.8 MAX UNITS 5.5 V 500 VIN-VDO 3.3 4 8 mΩ V V/mS 0.6 +2 % 0.612 V 1000 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 1.4 A Feedback Pin Input Current IFB Note 1 <100 nA 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 Note 1 <100 LLM Pin Logic Low VLLMLO LLM Pin Logic High VLLMHI ©Enpirion 2009 all rights reserved, E&OE nA 0.3 1.4 Note 1 nA 700 mV 0.3 1.4 4 11/11/2009 V V <100 Minimum difference between VIN and VOUT to ensure proper LLM operation LLM Engage Headroom 01543 1.25 V V www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNITS LLM Pin Current ILLM <100 nA Operating Frequency FOSC 5 MHz 4 8 V/mS Soft Start Operation Soft Start Slew Rate ΔVSS EP53A7LQI (VID only) EP53A7HQI (VID only) Soft Start Rise Time ΔTSS EP53A7LQI (VFB mode); Note 2 170 225 280 μS Note 1: Parameter guaranteed by design Note 2: Measured from when VIN ≥ VUVLO_R & ENABLE pin crosses its logic High threshold. 95 90 85 80 75 70 65 60 55 50 45 LLM Efficiency (%) Efficiency (%) Typical Performance Characteristics VOUT=1.2V PWM 10 100 Load Current (mA) Efficiency (%) Efficiency (%) VOUT=2.5V PWM 100 Load Current (mA) 01543 PWM 95 90 85 80 75 70 65 60 55 50 45 100 Load Current (mA) 1000 LLM VOUT=3.3V PWM 10 1000 Efficiency vs. Load Current: VOUT = 2.5V, VIN (from top to bottom) = 3.3, 3.7, 4.3, 5.0V ©Enpirion 2009 all rights reserved, E&OE VOUT=1.8V Efficiency vs. Load Current: VOUT = 1.8V, VIN (from top to bottom) = 2.5, 3.3, 3.7, 4.3, 5.0V LLM 10 LLM 10 1000 Efficiency vs. Load Current: VOUT = 1.2V, VIN (from top to bottom) = 2.5, 3.3, 3.7, 4.3, 5.0V 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: VOUT = 3.3V, VIN (from top to bottom) = 3.7, 4.3, 5.0V 5 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 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 = 1000mA, PWM 5mV/Div 50mV/Div Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 10mA LLM enabled ©Enpirion 2009 all rights reserved, E&OE 01543 Output Ripple: VIN = 5.0V, VOUT = 1.2V, Load = 1A 6 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 50mV/Div 5mV/Div Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 1A Output Ripple: VIN = 5.0V, VOUT = 3.3V, Load = 10mA LLM enabled 50mV/Div 5mV/Div Output Ripple: VIN = 3.3V, VOUT = 1.8V, Load = 10mA LLM enabled Output Ripple: VIN = 3.3V, VOUT = 1.8V Load = 1A 5mV/Div 50mV/Div Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 1A Output Ripple: VIN = 3.3V, VOUT = 1.2V, Load = 10mA LLM enabled ©Enpirion 2009 all rights reserved, E&OE 01543 7 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Load Transient: VIN = 5.0V, VOUT = 3.3V Load stepped from 0mA to 1000mA Load Transient: VIN = 5.0V, VOUT = 3.3V Load stepped from 10mA to 1000mA, LLM enabled Load Transient: VIN = 5.0V, VOUT = 1.2V Load stepped from 0mA to 1000mA Load Transient: VIN = 5.0V, VOUT = 1.2V Load stepped from 10mA to 1000mA, LLM enabled ©Enpirion 2009 all rights reserved, E&OE 01543 8 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Load Transient: VIN = 3.7V, VOUT = 1.2V Load stepped from 0mA to 1000mA Load Transient: VIN = 3.7V, VOUT = 1.2V Load stepped from 10mA to 1000mA, LLM enabled Load Transient: VIN = 3.3V, VOUT = 1.8V Load stepped from 0mA to 1000mA Load Transient: VIN = 3.3V, VOUT = 1.8V Load stepped from 10mA to 1000mA, LLM enabled ©Enpirion 2009 all rights reserved, E&OE 01543 9 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 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 2009 all rights reserved, E&OE 01543 10 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Detailed Description Functional Overview Integrated Inductor The EP53A7xQI requires only 2 small MLCC capacitors and an 0201 resistor for a complete DC-DC converter solution. The device integrates MOSFET switches, PWM controller, Gate-drive, compensation, and inductor into a tiny 3mm x 3mm x 1.1mm QFN package. Advanced package design, along with the high level of integration, provides very low output ripple and noise. The EP53A7xQI 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 EP53A7xQI comes with two VID output voltage ranges. The EP53A7HQI provides VOUT settings from 1.8V to 3.3V, the EP53A7LQI 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-0.5V range. The EP53A7xQI provides the industry’s highest power density of any 1A DCDC converter solution. The EP53A7xQI utilizes a proprietary low loss integrated inductor. The integration of the inductor greatly simplifies the power supply design process. 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 seamless 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 2009 all rights reserved, E&OE 01543 Voltage Mode Control The EP53A7xQI 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 EP53A7xQI 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 exit LLM operation and begin normal PWM operation. Figure 6 demonstrates VOUT behavior during transition into and out of LLM operation. 11 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI LLM Ripple VMAX LLM Threshold Current vs. VOUT 250 VNOM VMIN LLM Threshold (mA) PWM Ripple VOUT Load Step 200 150 VIN=5V (top curve) 100 VIN=4.2V VIN=3.7V 50 VIN=3.3V (bottom curve) 0 IOUT 0.8 1.1 1.4 1.7 2.0 2.3 2.6 2.9 3.2 VOUT (V) 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 (shown in Figure 6). 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 EP53A7xQI 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 reenters LLM, as shown in Figure 7. 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 ©Enpirion 2009 all rights reserved, E&OE 01543 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 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 complete; disable LLM before VIN ramp down. For applications with ENABLE control, tie LLM to ENABLE; enable device after VIN ramp up complete and disable device before VIN ramp 12 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 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 EP53A7xQI requires a minimum difference between VIN and VOUT of 700mV. 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 EP53A7HQI has a soft-start slew rate that is twice that of the EP53A7LQI. When the EP53A7LUI 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: EP53A7LQI: COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 200uF EP53A7HQI: EP53A7LUI 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 25C°, the device will go through the normal startup process. COUT_TOTAL_MAX = COUT_Filter + COUT_BULK = 100uF ©Enpirion 2009 all rights reserved, E&OE 01543 13 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Application Information 100 ohm VIN 4.7μF PVIN VOUT AVIN VSENSE ENABLE LLM VOUT 10μF VS0 NOTE: The VID pins must not be left floating. VS1 VS2 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. PGND AGND EP53A7L Low VID Range Programming Figure 9: Application Circuit, EP53A7HQI. Note that all control signals should be connected to an external control signal, AVIN or AGND. 100 ohm VIN 4.7μF PVIN VOUT AVIN VSENSE ENABLE LLM VS0 VFB VOUT 10μF The EP53A7LQI 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. VS1 VS2 Table 2: EP53A7LQI VID Voltage Select Settings PGND AGND VS2 0 0 0 0 1 1 1 1 Figure 10: Application Circuit, EP53A7LQI showing the VFB function. Output Voltage Programming The EP53A7xQI 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 an external control signal, AVIN or to AGND to avoid noise coupling into the device. The VID pins must not be left floating. 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 EP53A7LQI. 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 EP53A7HQI. Internally, the output of the VID multiplexer sets the value for the voltage reference DAC, ©Enpirion 2009 all rights reserved, E&OE 01543 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 EP53A7LQI 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. EP53A7LQI External Voltage Divider The external divider option is chosen by connecting VID pins VS2-VS0 to AVIN or a logic “1” or “high”. The EP53A7LQI uses a separate feedback pin, VFB, when using the external divider. VSENSE must be connected to VOUT as indicated in Figure 11. 14 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI 100 Ohm PVIN VIN AVIN ENABLE VS0 VS1 VS2 EP53A7L 4.7uF VSense VOUT VOUT Ra 10μF VFB LLM 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. Table 3: EP53A7HQI VID Voltage Select Settings Rb VS2 0 0 0 0 1 1 1 1 PGND AGND Figure 11: EP53A7LQI using external divider 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: R = b 142.2 x10 3 Ω VOUT − 0.6 VOUT can be programmed over the range of 0.6V to (VIN – 0.5V). 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 when using this option. EP53A7HQI High VID Range Programming The EP53A7HQI 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 EP53A7HQI does not have an external divider option. As with the EP53A7LQI, the VID pin settings can be changed while the device is enabled. Table 3 shows the VS0-VS2 pin logic states for the EP53A7HQI 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 ©Enpirion 2009 all rights reserved, E&OE 01543 VS1 0 0 1 1 0 0 1 1 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 Input Filter Capacitor The input filter capacitor requirement is a 4.7µF 0402 or 0603 low ESR MLCC capacitor. Output Filter Capacitor The output filter capacitor requirement is a minimum of 10µF 0805 MLCC. Ripple performance can be improved by using 2x10µF 0603 or 2x10µF 0805 MLCC capacitors. 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 EP53A7xQI. 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. The separation provides an inductance that isolates the control loop from the bulk capacitance. NOTE: Excess total capacitance on the output (Output Filter + Bulk) can cause an overcurrent condition at startup. Refer to the section on Soft-Start for the maximum total capacitance on the output. NOTE: The Input and Output capacitors 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 switch-mode DC-DC converter filter applications. 15 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Recommended PCB Footprint Figure 12: EP53A7xQI Package PCB Footprint ©Enpirion 2009 all rights reserved, E&OE 01543 16 11/11/2009 www.enpirion.com Rev:B EP53A7LQI/EP53A7HQI Package and Mechanical Figure 13: EP53A7xQI Package Dimensions Contact Information Enpirion, Inc. Perryville III 53 Frontage Road Suite 210 Hampton, NJ 08827 Tel..908.894.6000 Fax: 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 2009 all rights reserved, E&OE 01543 17 11/11/2009 www.enpirion.com Rev:B