EP5368QI 600mA Synchronous Buck Regulator With Integrated Inductor 3mm x 3mm x 1.1mm Package April 2008 RoHS Compliant Halogen Free Product Overview Featuring Integrated Inductor Technology Product Highlights • Integrated Inductor • 3mm x 3mm x 1.1mm QFN package • Only two low cost MLCC caps required • 4 MHz switching frequency • High efficiency, up to 94% • Up to 700mA continuous output current • Wide 2.4V to 5.5V input range • VOUT Range 0.603V to VIN – 0.4V • 100% duty cycle capable • Less than 1 µA standby current • Low VOUT ripple for RF compatibility • Short circuit and over current protection • UVLO and thermal protection • Stable over entire operating range • RoHS compliant; MSL 3 260°C reflow Typical Application Circuit VSense ENABLE VIN Vin 4.7µF 0603 Voltage Select EP5368QI VFB VS0 V S1 VS2 VOUT Vout GND Figure 1. Typical application circuit. 22µF 0805 The EP5368QI is a synchronous buck converter with integrated Inductor, PWM controller, MOSFETS, and Compensation providing the smallest possible solution size. The EP5368QI requires only two small MLCC capacitors to make a complete solution. Integration of the inductor greatly simplifies design, contains noise, reduces part count, and reduces solution footprint. Low output ripple ensures compatibility with RF systems. The EP5368QI operates at a switching frequency of 4 MHz, enabling this unprecedented level of integration and small external components. Type III voltage mode control is used to provide high noise immunity and wide control loop bandwidth. The device is stable over all input and output voltages . It can source 600mA of current over the industrial temperature range and up to 700mA over the commercial temperature range. The small footprint makes this part ideal for space constrained portable applications. Shutdown current of <1uA extends battery life Output voltage level is programmed via a 3-pin VID selector providing seven pre-programmed output voltages along with an option for external resistor divider. Applications • • • • • • Noise sensitive RF applications Area constrained applications Smart phones and PDAs Portable gaming devices Personal Media Players Advanced Mobile Processors, DSP, IO, Memory, Video, Multimedia Engines April 2008 EP5368QI Pin Description VSENSE (Pin 5): Sense pin for preset output voltages. When using preset voltages connect this to VLOAD or as close to VLOAD as possible to ensure the best regulation. When using external divider, connect this pin to VOUT. AGND: (Pin 6):Analog ground. This is the quiet ground for the internal control circuitry VOUT (Pin 7,8): Regulated output voltage. VS0,VS1,VS2 (Pin 10, 11, 12): Output voltage select. VS2=pin10 VS1=pin11, VS0=pin12. Selects one of seven preset output voltages or choose external divider by connecting pins to logic high or low. Logic low is defined as VLOW ≤ 0.4V. Logic high is defined as VHIGH ≥ 1.4V. Any level between these two values is indeterminate. (refer to section on output voltage select for more detail). Figure 2. EP5368QI Package Pin-out. NC (Pins 1,3,9,15,16): These pins should not be electrically connected to each other or to any external signal, voltage, or ground. One or more of these pins may be connected internally. ENABLE (Pin 13): Output enable. Enable = logic high, disable = logic low. Logic low is defined as VLOW ≤ 0.4V. Logic high is defined as VHIGH ≥ 1.4V. Any level between these two values is indeterminate. PGND: (Pin 2): Power ground. VFB (Pin 4): Feed back pin for external divider option. When using the external divider option (VS0=VS1=VS2= high) connect this pin to the center of the external divider. Set the divider such that VFB = 0.6V. The “ground” side of the external divider should be connected to AGND. ©Enpirion 2008 all rights reserved, E&OE VIN (Pin 14): Input voltage pin. Supplies power to the IC. VIN can range from 2.4V to 5.5V. 2 www.enpirion.com April 2008 EP5368QI Functional Block Diagram VIN UVLO Thermal Limit Current Limit ENABLE NC(SW) Soft Start P-Drive (-) Logic VOUT PWM Comp (+) N-Drive GND VSENSE Sawtooth Generator Compensation Network (-) Switch Error Amp VFB (+) DAC Voltage Select VREF Package Boundry VS0 VS1 VS2 Figure 3. Functional block diagram. ©Enpirion 2008 all rights reserved, E&OE 3 www.enpirion.com April 2008 EP5368QI Absolute Maximum Ratings CAUTION: Absolute Maximum ratings are stress ratings only. Functional operation beyond recommended operating conditions is not implied. Stress beyond absolute maximum ratings may cause permanent damage to the device. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. PARAMETER Input Supply Voltage Voltages on: ENABLE, VSENSE, VS0-VS2 Voltage on: VFB Storage Temperature Range Reflow Temp, 10 Sec, MSL3 JEDEC J-STD-020C ESD Rating (based on Human Body Model) SYMBOL MIN MAX UNITS VIN -0.3 -0.3 -0.3 -65 7.0 VIN + 0.3 2.7 150 260 2000 V V V °C °C V TSTG Recommended Operating Conditions PARAMETER SYMBOL MIN MAX UNITS VIN TA TJ 2.4 -40 -40 5.5 +85 +125 V Input Voltage Range Operating Ambient Temperature Operating Junction Temperature °C °C Thermal Characteristics PARAMETER SYMBOL TYP UNITS θJA TJ-TP 100 +150 15 °C/W °C °C Thermal Resistance: Junction to Ambient (0 LFM) Thermal Overload Trip Point Thermal Overload Trip Point Hysteresis 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 0603 MLCC, COUT = 22uF 0805 MLCC. PARAMETER Operating Input Voltage Output Voltage (presets) SYMBOL (VS pins must not be left floating) Vo Output Voltage (external divider) Dynamic Voltage Slew Rate Continuous Output Current TEST CONDITIONS VIN MIN 2.4 0.6 IOUT Shut-Down Current PFET OCP Threshold ISD ILIM ©Enpirion 2008 all rights reserved, E&OE VIN = 5V, 0.603V <VOUT < 3.3V TA = -40°C to +85°C VIN = 5V, 0.603V <VOUT < 3.3V TA = -10°C to +85°C; (Application Circuit Figure 5.) Enable = Low 2.4V ≤ VIN ≤ 5.5V, 0.6V ≤ VIN ≤ 3.3V 4 UNITS V V VIN-0.4 1.5 Vslew Continuous Output Current MAX 5.5 Vout 3.3 2.5 1.8 1.5 1.25 1.2 0.8 ext. VS2 VS1 VS0 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 Vo IOUT TYP V mV/µS 600 mA 700 mA 1.4 0.75 2 µA A www.enpirion.com April 2008 EP5368QI PARAMETER Feedback Pin Voltage Feedback Pin Input Current VS0-VS1, Enable Voltage Threshold VS0-VS2 Pin Input Current Operating Frequency PFET On Resistance NFET On Resistance VOUT Accuracy SYMBOL TEST CONDITIONS MIN VFB IFB VTH Pin = Low Pin = High Line Regulation Load Regulation Soft-Start Operation Soft-Start Slew Rate Time to 90% Vout Vss Tss MAX 100 0.4 VIN 0.0 1.4 IVSX FOSC RDS(ON) RDS(ON) VOUT TYP 0.603 1 4 340 270 TA = 25°C 2.4V ≤ VIN ≤ 5.5V -40°C ≤ TA ≤ +85°CV (all causes) 2.4V ≤ VIN ≤ 5.5V 0A ≤ ILOAD ≤ 700mA Vout = 3.3V -2% -3% UNITS V nA nA MHz mΩ mΩ +2% +3% 0.0566 0.0003 %/V %/ mA 1.5 2.2 mV/µS mS 100 100 95 95 90 90 85 85 Efficiency (%) Efficiency (%) Typical Performance Characteristics 80 75 70 80 75 70 65 65 60 60 55 55 50 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 50 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 Load Current (A) Load Current (A) Efficiency, VIN = 3.3V, VOUT = 1.2V, 1.5V,1.8V, 2.5V Efficiency, VIN = 3.7V, VOUT = 1.2V, 1.5V,1.8V, 2.5V 100 95 90 Efficiency (%) 85 80 75 70 65 60 55 50 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 Load Current (A) Efficiency, VIN = 5V, VOUT = 1.2V, 1.5V,1.8V, 2.5V, 3.3V ©Enpirion 2008 all rights reserved, E&OE Transient, VIN = 3.6V, VOUT = 1.2V, Load = 0-500mA 5 www.enpirion.com April 2008 EP5368QI Startup, VIN = 3.6V, VOUT = 1.5V, Load = 500mA Shutdown, VIN = 3.6V, VOUT = 1.5V, Load = 500mA Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 0mA COUT = 1x 22uF 0805, 2.0mV/Div. Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 600mA COUT = 1x 22uF 0805, 2.0mV/Div. Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 0mA COUT = 2x 10uF 0805, 2.0mV/Div. Voltage Ripple, VIN = 3.3V, VOUT = 1.8V, Load = 600mA COUT = 2x 10uF 0805, 2.0mV/Div. Detailed Description ©Enpirion 2008 all rights reserved, E&OE 6 www.enpirion.com April 2008 EP5368QI Integrated Inductor Functional Overview Enpirion has introduced the world’s first product family featuring integrated inductors. The EP5368QI utilizes a proprietary low loss integrated inductor. The use of an internal inductor localizes the noises associated with the output loop currents. The inherent shielding and compact construction of the integrated inductor reduces the radiated noise that couples into the traces of the circuit board. Further, the package layout is optimized to reduce the electrical path length for the AC ripple currents that are a major source of radiated emissions from DCDC converters. The integrated inductor significantly reduces parasitic effects that can harm loop stability, and makes layout very simple. The EP5368QI is a complete DCDC converter solution requiring only two low cost MLCC capacitors. MOSFET switches, PWM controller, Gate-drive, compensation, and inductor are integrated into the tiny 3mm x 3mm x 1.1mm package to provide the smallest footprint possible while maintaining high efficiency, low ripple, and high performance. The converter uses voltage mode control to provide the simplest implementation and high noise immunity. The device operates at a 4MHz switching frequency. The high switching frequency allows for a wide control loop bandwidth providing excellent transient performance. The high switching frequency further enables the use of very small components making possible this unprecedented level of integration. Stable Over Wide Range of Operating Conditions Enpirion’s proprietary power MOSFET technology provides very low switching loss at frequencies of 4 MHz and higher, allowing for the use of very small internal components, and high performance. Integration of the magnetics virtually eliminates the design/layout issues normally associated with switch-mode DCDC converters. All of this enables much easier and faster incorporation into various applications to meet demanding EMI requirements. The EP5368QI utilizes an internal type III compensation network and is designed to provide a high degree of stability over a wide range of operating conditions. The device operates over the entire input and output voltage range with no external modifications required. The very high switching frequency allows for a very wide control loop bandwidth. 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 soft start ramp rate is nominally 1.5V/mS. Output voltage is chosen from seven preset values via a three pin VID voltage select scheme. An external divider option enables the selection of any voltage in VIN to 0.6V range. This reduces the number of components that must be qualified and reduces inventory burden. The VID pins can be toggled on the fly to implement glitch free dynamic voltage scaling. Protection features include under-voltage lockout (UVLO), over-current protection (OCP), short circuit protection, and thermal overload protection. ©Enpirion 2008 all rights reserved, E&OE 7 www.enpirion.com April 2008 EP5368QI Over Current/Short Circuit Protection Enable 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 a period of 1mS and then a normal soft start is initiated. If the over current condition still persists, this cycle will repeat in a “hiccup” mode. 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. In shutdown mode, the device quiescent current will be less than 1 uA. NOTE: This pin must not be left floating. Thermal Shutdown Under Voltage Lockout 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. 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. Application Information hardwired to VIN or GND or alternatively can be driven by standard logic levels. Logic low is defined as VLOW ≤ 0.4V. Logic high is defined as VHIGH ≥ 1.4V. Any level between these two values is indeterminate. These pins must not be left floating. Output Voltage Select To provide the highest degree of flexibility in choosing output voltage, the EP5368QI uses a 3 pin VID, or Voltage ID, output voltage select arrangement. This allows the designer to choose one of seven preset voltages, or to use an external voltage divider. 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. Table 1. VID voltage select settings. VS2 0 0 0 0 1 1 1 1 Table 1 shows the various VS0-VS2 pin logic states and the associated output voltage levels. A logic “1” indicates a connection to VIN or to a “high” logic voltage level. A logic “0” indicates a connection to ground or to a “low” logic voltage level. These pins can be either ©Enpirion 2008 all rights reserved, E&OE 8 VS1 0 0 1 1 0 0 1 1 VS0 0 1 0 1 0 1 0 1 VOUT 3.3V 2.5V 1.8V 1.5V 1.25V 1.2V 0.8V User Selectable www.enpirion.com April 2008 EP5368QI External Voltage Divider Input and Output Capacitors As described above, the external voltage divider option is chosen by connecting the VS0, VS1, and VS2 pins to VIN or logic “high”. The EP5368QI uses a separate feedback pin, VFB, when using the external divider. VSENSE must be connected to VOUT as indicated in Figure 4. VSense ENABLE VIN Vin 4.7uF 0603 The input capacitance requirement is 4.7uF 0603 MLCC. The input capacitor must be a X5R/X7R MLCC. Y5V or equivalent dielectric formulations lose capacitance with frequency, bias, and with temperature, and are not suitable for switch-mode DC-DC converter input filter applications. VOUT Vout Ra EP5368QI The output capacitance requirement is approximately 20uF. Enpirion recommends a single 22uF 0805 MLCC. Ripple performance can be improved by using 2 x 10uF 0805 MLC capacitors. 22µF 0805 VFB VS0 VS1 Rb VS2 GND The output capacitor must be a X5R/X7R or equivalent MLCC. Y5V or equivalent dielectric formulations lose capacitance with frequency, bias, and temperature and are not suitable for switch-mode DC-DC converter output filter applications. Figure 4. External Divider application circuit. The output voltage is selected by the following formula: VOUT = 0.603V (1 + Ra Rb ) Please consult Enpirion Applications Support for other capacitor case size combinations. Ra must be chosen as 200KΩ to maintain loop gain. Then Rb is given as: Rb = 1.206 x10 5 Ω VOUT − 0.603 Operation at 700mA Output Current VOUT can be programmed over the range of 0.603V to VIN-0.4V. Operation at 700mA is supported by using the application circuit shown in Figure 5. The modification in the compensation is to ensure stability over the entire set of input and output voltage conditions. Dynamically Adjustable Output The EP5368QI is designed to allow for dynamic switching between the predefined VID voltage levels The inter-voltage slew rate is optimized to prevent excess undershoot or overshoot as the output voltage levels transition. The slew rate is identical to the softstart slew rate of 1.5V/mS. VSense ENABLE VIN Vin 4.7uF 0603 Ca 22µF 0805 VFB VS0 VS1 Dynamic transitioning between internal VID settings and the external divider is not allowed. Ra EP5368QI VS2 VOUT Vout Rb GND Figure 5. Applications circuit for operation at 700mA. ©Enpirion 2008 all rights reserved, E&OE 9 www.enpirion.com April 2008 EP5368QI For 700mA operation, use the following component values: VOUT can be programmed over the range of 0.603V to VIN-0.4V. Ra = 249KΩ. Ca = 15pF 0402 MLCC capacitor. Stability cannot be assured if these guidelines are not followed. Then Rb is given as: Rb = 1.501x10 5 Ω VOUT − 0.603 Recommended PCB Footprint ©Enpirion 2008 all rights reserved, E&OE 10 www.enpirion.com April 2008 EP5368QI Package Dimensions ©Enpirion 2008 all rights reserved, E&OE 11 www.enpirion.com April 2008 EP5368QI Contact Information Enpirion, Inc. 685 US Route 202/206 Suite 305 Bridgewater, NJ 08807 Phone: +1 908-575-7550 Fax: +1 908-575-0775 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 2008 all rights reserved, E&OE 12 www.enpirion.com