Application Note EP5358xUI Evaluation Board Enpirion EP5358xUI DC/DC Converter Module Evaluation Board Introduction Thank you for choosing Enpirion, the source for Ultra small foot print power converter products! This application note describes how to test the EP5358xUI (EP5358LUI, EP5358HUI) converters using the Enpirion 2.5mmx2.25mm Module EVAL BOARD shown in Fig. 1. In addition to this document you will also need the device datasheet for a thorough evaluation of the power converter module. The EP5358xUI converters are part of a new class of DC/DC converter products, a complete power system on chip (PowerSoC): * * * * * * * These devices are complete modules including magnetics, and require only ceramic input and output capacitors. The evaluation board is designed to offer a wide range of engineering evaluation capabilities. This includes the base configuration of an 0603 input capacitor and an 0805 output capacitor. Pads are available to add up to one additional input capacitor and up to one additional output capacitor for evaluation of performance over a wide range of input/output capacitor combinations. Pads are available to populate an external resistor divider to enable output voltage programming of values not available using the VID. The pads are labeled R1 and R2. Pads are also available for placing an optional feedforward capacitor (labeled C9) across resistor R1. NOTE: The External voltage divider option is available only with EP5358LUI. Jumpers are provided for easy programming of the following signals: o Enable o VS0-VS2 output voltage selection pins Test points are provided as well as clip leads for input and output connections The board comes with input decoupling, and input reverse polarity protection to safeguard the device from common setup mishaps. Enpirion 2010 all rights reserved, E&OE 03371 Page 1 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Quick Start Guide Jumper STEP 1: Before applying power to the board, set the "ENABLE" jumper to the Disable Position. Set VS0, VS1 and VS2 pins for the desired output setting. Output Disabled CAUTION: the signal pins, ENA, VS0, VS1 and VS2 must be connected to a logic "high", jumper to the left, or a logic "low", jumper to the right. It may not be left floating as the pin state would then be in an indeterminate state. STEP 2: Connect a power supply to the input test points, TP8 (VIN) and TP5 (GND) as indicated in Figure 1. The same test points can also be used to measure the input voltage. CAUTION: be mindful of the polarity and the voltage magnitude. If VIN is greater than 6V, the board may get damaged. If the input voltage polarity is wrong, diode D1 will conduct, and draw excessive input current. STEP 3: Set the output voltage select pins for the desired output voltage. Refer to Tables 1 and 2 to determine the setting. CAUTION: the external resistor divider is not populated in the standard board configuration. Choosing the "EXT" option for the EP5358LUI without the external resistors R1 and R2 will result in unpredictable behavior. "1" "0" STEP 4: Connect the load to the output connectors TP7 (VOUT) and TP6 (GND), as indicated in Figure 1.The same test points are also used to measure the DC output voltage. STEP 5: Move the ENABLE jumper to the enabled position, and power up the board. The EP5358xUI should now be operational. Enpirion 2010 all rights reserved, E&OE 03371 Page 2 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Figure 1. Evaluation Board silk screen. Enpirion 2010 all rights reserved, E&OE 03371 Page 3 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Output Voltage Select The EP5358xUI utilizes a 3 pin output voltage select scheme. The output voltage is programmed by setting the VSx jumpers to either a logic "1" or a logic "0" as described in the Quick Start section Tables 1 and 2 show the logic table for VOUT selection. There are seven preset output voltage levels and an externally programmable option for the EP5358LQI. The EP5358HQI has eight preset output voltage levels and no external programming capability. Table 1: EP5358LUI Output Voltage Select Logic Table VS2 0 0 0 0 1 1 1 1 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: EP5358HUI Output Voltage Select Logic Table VS2 0 0 0 0 1 1 1 1 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 Test Recommendations Recommendations To guarantee measurement accuracy, the following precautions should be observed: 1. Make all input and output voltage measurements at the board using the test points provided. This will eliminate voltage drop across the line and load cables that can produce inaccurate measurements - especially efficiency. Enpirion 2010 all rights reserved, E&OE 03371 Page 4 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board 2. Measure input and output current with series ammeters or accurate shunt resistors. This is especially important when measuring efficiency. 3. Use a balanced impedance probe tip as shown in Figure 2, and through-hole test point pair TP2 to measure the output voltage ripple to avoid noise coupling into the probe ground lead and for load transient response measurements. Figure 2: Balanced-impedance oscilloscope probe. Wrap bare wire around the ground shaft and bring the wire close to the probe tip. This minimizes probe loop inductance and stray noise pickup by the probe. Using The External Voltage Divider The EP5358xUI evaluation board is designed to provide a great deal of flexibility in evaluating the performance of the Enpirion DC/DC module. Pre-tinned pads are provided to place 0805 sized 1% resistors on the board to implement an external resistor divider for the EP5358LUI to choose an output voltage other than one of the seven pre-set voltages available on the VID. See Figure 3 for the basic circuit. 2.2uF 0603 PVIN AVIN ENABLE VS0 VS1 VS2 EP5358LUI VIN VSense VOUT VOUT R1 10F 0805 VFB R2 PGND AGND Figure 3. External divider schematic for the EP5358LUI. Enpirion 2010 all rights reserved, E&OE 03371 Page 5 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board The output voltage is selected by the following formula: VOUT = 0.6V (1 + R1 R2 ) R1 must be chosen as 237k to maintain control loop stability. Then R2 is given as: 142.2 x10 3 R2 = VOUT - 0.6 The external voltage divider option is chosen by setting the jumpers VS0 - VS2 to a logic "high". Note: The VSENSE pin should be tied to the Output pin even in external feedback mode to access the internal phase lead capacitor that is situated between the VSENSE and VFB pads. This phase lead capacitor is integral to the loop compensation and the power supply stability. Dynamically Adjustable Output The EP5358xUI is designed to allow for dynamic switching between the predefined voltage levels by toggling the VID pins. The inter-voltage slew rate is optimized to prevent excess undershoot or overshoot as the output voltage levels transition. The slew rate is defined in the datasheet. This feature can be tested by connecting the VSx jumper center pins to logic driver to toggle between the various VOUT states. Note: Dynamic switching between a predefined output and an externally programmed output is not allowed. This could result excess current flow and damage the device. Enpirion 2010 all rights reserved, E&OE 03371 Page 6 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Input and Output Capacitors Input Filter Capacitor For ILOAD 500mA, CIN = 2.2uF For ILOAD > 600mA 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 temperature, and are not suitable for switch-mode 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 2x10F 0603 MLCC capacitors (for any allowed VIN). The maximum output filter capacitance next to the output pins of the device is 60F low ESR MLCC capacitance. VOUT has to be sensed at the last output filter capacitor next to the EP5358xUI. 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 overcurrent 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 switch-mode DC-DC converter output filter applications. Enpirion 2010 all rights reserved, E&OE 03371 Page 7 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Board, BOM, Schematic Figure 4. Photo of EVB. Table 3. EVB Bill of Materials. Item Description 2.2UF 10V X7R 0603 CAPACITOR CERAMIC CAP, 10UF 0805 X7R 10% 10V CERAMIC EP5358xUI 2.5MM X 2.25MM CAP 47UF 16V ELECT FC SMD S2A DIODE CAP, 10UF 0805 X7R 10% 10V CERAMIC MULTILAYER SMD FERRITE BEAD 4000MA 0805 CONNECTOR, CUSTOM, VERTICAL HEADER, SMT COMPONENT NOT USED ** DO NOT INSTALL ** TEST POINT SURFACE MOUNT RESISTOR ZERO OHM 1/10W 5% 0402 SMD Qty 1 2 1 1 1 1 1 1 8 4 1 Ref Des C2 C3 U1 C8 D1 C10 FB1 J1 C1,C4,C5,C9,R1,R2,R3,U2 TP5,TP6,TP7,TP8 R4 Enpirion 2010 all rights reserved, E&OE 03371 Item Type Capacitor Capacitor Device-GTP Capacitor Diode Capacitor Ferrite Bead Connector/Contact Function Input Capacitor Output Capacitor Enpirion EP5358xUI Board Input Decoupling Capacitor Reverse Polarity Protection Connector Decoupling Connector Decoupling Jumper/Connector Array Not Used Connector/Contact Test Point Resistor Zero Ohm Jumper Page 8 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Figure 5. 2.5mmx2.25mm Module Evaluation Board Schematic Enpirion 2010 all rights reserved, E&OE 03371 Page 9 of 10 05/26/2010 Rev: B Application Note EP5358xUI Evaluation Board Contact Information Enpirion, Inc. Perryville III 53 Frontage Rd ; Suite 210 Hampton, NJ 08827 Phone: 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 2010 all rights reserved, E&OE 03371 Page 10 of 10 05/26/2010 Rev: B