For more information, please visit the product page. rev. PART NUMBER: VPOL16A-12-SMT page 1 of 14 date 08/2007 DESCRIPTION: point of load converter features * industry standard pin out * high efficiency to 94% * 300 KHz switching frequency * 9.0-14 VDC wide input range * 0.75-5.0 VDC wide output range * over temperature protection * continuous short circuit protection * remote on/off * cost-efficient open frame design * UL/C-UL60950 certified * output voltage sequencing (tracking) * power good signal 1. INTRODUCTION 2. VPOL16A-12W-SMT CONVERTER FEATURES 6. SAFETY 6.1 Input Fusing and Safety Considerations. 3. GENERAL DESCRIPTION 3.1 Electrical Description 7. APPLICATIONS 7.1 Layout Design Challenges. 3.2 Thermal Packaging and Physical Design. 7.2 Convection Requirements for Cooling 4. TECHNICAL SPECIFICATIONS 7.3 Thermal Considerations 5. MAIN FEATURES AND FUNCTIONS 5.1 Operating Temperature Range 7.4 Power De-Rating Curves 5.2 Over-Temperature Protection (OTP) 7.6 Input Capacitance at the Power Module 5.3 Output Voltage Adjustment 7.7 Test Set-Up 5.4 Safe Operating Area (SOA) 7.8 Remote Sense Compensation 5.5 Over Current Protection 7.9 VPOL16A-12W-SMT Series Output Voltage Adustment. 5.6 Remote ON/OFF 7.10 Output Ripple and Noise Measurement 5.7 UVLO (Under-Voltage Lockout) 7.11 Output Capacitance 7.5 Efficiency vs Load Curves 7.12 VPOL16A-12W-SMT Reflow Profile 8. MECHANICAL OUTLINE DIAGRAMS 8.1 VPOL16A-12W-SMT Mechanical Outline Diagrams 8.2 VPOL16A-12W-SMT Tape and Reel Dimensions 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. PART NUMBER: VPOL16A-12-SMT 1. Introduction are highly efficient, reliable and compact, high power density, single 2 of 14 date 08/2007 DESCRIPTION: point of load converter converter is also protected against over-temperature conditions. If the converter is overloaded or the ambient temperature gets too high, the converter will shut down to protect the unit. This application note describes the features and functions of CUI INC's VPOL16A-12W-SMT series of Non Isolated DC-DC Converters. These page L1 Q1 +VIN output DC/DC converters. These “Point of Load” modules serve the +VO C1 needs specifically of the fixed and mobile telecommunications and Q2 D1 C2 R sense +SENSE computing market, employing economical distributed Power Architectures. The VPOL16A-12W-SMT series provide precisely regulated output voltage range from 0.7525V to 5.0Vdc over a wide COM COM range of input voltage (Vi=6.0 – 14Vdc) and can operate over an ambient temperature range of –40°C to +85°C. Ultra-high efficiency operation is achieved through the use of synchronous rectification and drive control techniques. PGood ON/OFF PWM IC ERR AMP SEQ R1 R trim TRIM R2 The modules are fully protected against short circuit and overtemperature conditions. CUI INC's world class automated Figure 1. Electrical Block Diagram manufacturing methods, together with an extensive testing and qualification program, ensure that all VPOL16A-12W-SMT series converters are extremely reliable. 3.2 Thermal Packaging and Physical Design. 2. VPOL16A-12W-SMT Converter Features The VPOL16A-12W-SMT series uses a multi-layer FR4 PCB High efficiency topology, typically 94% at 5.0Vdc Industry standard footprint Wide ambient temperature range, -40C to +85C Cost efficient open frame design Programmable output voltage via external resistor from 0.7525 to 5.0Vdc No minimum load requirement (Stable at all loads) Remote ON/OFF Remote sense compensation Fixed switching frequency Continuous short-circuit protection and over current protection Over-temperature protection (OTP) Monotonic Startup with pre-bias at the output. UL/IEC/EN60950 Certified. Output Voltage Sequencing( Tracking ) Power Good Signal (Option) construction. All surface mount power components are placed on one side of the PCB, and all low-power control components are placed on the other side. Thus, the Heat dissipation of the power components is optimized, ensuring that control components are not thermally stressed. The converter is an open-frame product and has no case or case pin. The open-frame design has several advantages over encapsulated closed devices. Among these advantages are: Efficient Thermal Management: the heat is removed from the heat generating components without heating more sensitive, small signal control components. Environmental: Lead free open-frame converters are more easily re-cycled. Cost Efficient: No encapsulation. Cost efficient open-frame construction. Reliable: Efficient cooling provided by open frame construction offers high reliability and easy diagnostics. 3. General Description 3.1 Electrical Description A block diagram of the VPOL16A-12W-SMT Series converter is shown in Figure 1. Extremely high efficiency power conversion is achieved through the use of synchronous rectification and drive techniques. Essentially, the powerful VPOL16A-12W-SMT series topology is based on a non-isolated synchronous buck converter. The control loop is optimized for unconditional stability, fast transient response and a very tight line and load regulation. In a typical pre-bias application the VPOL16A-12W-SMT series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.7525 to 5.0vdc, using the TRIM pin with a external resistor. The converter can be shut down via a remote ON/OFF input that is referenced to ground. This input is compatible with popular logic devices; a 'positive' logic input is supplied as standard. Positive logic implies that the converter is enabled if the remote ON/OFF input is high (or floating), and disabled if it is low. The 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 3 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 4. Technical Specifications (All specifications are typical at nominal input, full load at 25°C unless otherwise noted.) PARAMETER ABSOLUTE MAXIMUM RATINGS Input Voltage Continuous Operating Temp erature See Thermal Considerations Section NOTES and CONDITIONS Operating Input Voltage Min. Typical Max. Units ALL 0 16 Vdc ALL -40 +85 ° ALL -55 +125 °C ALL 6.0 6.5 14 14 Vdc Storage Temperature INPUT CHARACTERISTICS Device Vo=4.5V Vo=5.0V Input Under-Voltage Lockout Turn -On Voltag e Threshold Turn -Off Voltag e Threshold Lockout Hysteresis Voltage ALL ALL ALL ALL 12 12 5.0 4.0 1.0 Vdc Vdc Vdc Maximum Input Current Vin=0 to 14Vdc , Io=Io,max. No-Load Input Current Vo=0.7525V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V Vo=5.0V ALL Off Converter Input Current Shutdown input idle current ALL 10 mA ALL 0.4 As 2 Inrush Current (I t) Input Reflected-Ripple Current 15 40 40 50 60 60 65 75 95 A mA 2 P-P thru 1uH inductor, 5Hz to 20MHz ALL 200 mA Output Voltage S et Point Vin=Nominal Vin , Io=Io.max, Tc=25° ALL -1.5% Vo,set +1.5% Vdc Output Voltage Trim Adjustment Range Selected by an extern al resistor ALL 0.7525 Vdc OUTPUT CHARACTERISTIC 5.0 Output Voltage Regulation Load Regulation Io=Io.min to Io.max ALL -0.5 +0.5 % Line Regulation Vin=low line to high line ALL -0.2 +0.2 % Tempera ture Coefficient Ta=-40° Cto 85°C ALL -0.03 +0.03 %/° Output Voltage Ripple and Noise 5Hz to 20MHz bandwidth 75 mV Peak-to-Peak RMS External C apacitive Load Full Load, 1uF ceramic and 10uF tantalum ALL Full Load, 1uF ceramic and 10uF tantalum ALL 30 mV Lo w ESR ALL 8000 uF 16 A 32 A 1.0 V/ms Operating Output Current Range Output DC Current-Limit Inception Output Voltage =90% Nominal Output Voltage Shout Circuit Protection Continuous with Hiccup Mode Sequenc y Sle w Rate Capability dVSEQ/dt ALL 0 ALL 19.2 0.1 Sequencing Delay Time 25 10 Tracking Accuracy Power up Power down Power Good Signal Asserted Logic High Vo ms ALL Suffix “P” 90 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 200 400 mV 110 % For more information, please visit the product page. rev. page 4 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT Error Brand 50% Step Load Change, di/dt=2.5A/us ALL 200 mV Setting Time (within 1% Vout nominal) 50% Step Load Change, di/dt=2.5A/us ALL 200 us EFFICIENCY 100% Load ISOLATION CHARACTERISTICS Input to Output Vo=0.7525V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V Vo=5.0V ALL Non-isolation ALL 80 85 88 89 90 91 93 94 % 0 Vdc FEATURE CHARACTERISTICS Switching Frequency ON/OFF Control, Positive Logic Remote On/Off Logic Low (Module Off) Logic High (Module On) ALL or Open Circuit ON/OFF Control, Negative Logic Remote On/Off Logic Low (Module On) or Open Circuit Logic High (Module Off) ON/OFF Current (for both remote on/off logic) Leakage Current (for both remote on/off logic) Turn -On Delay and Rise Time Turn -On Delay Time, From On/Off Control Turn -On Delay Time, From I nput Output Voltage Rise Time Over Temperature Protection GENERAL SPECIFICATIONS MTBF Weight Dimensions 1.3x0.53 300 KHz VPOL16A-12W-SMT 0 0.4 Vin Vdc Vdc VPOL16A-12W-SMT 0 2.8 0.4 Vin Vdc Vdc 1 1 mA mA Ion/off at Von/off =0.0V Logic High, Von/off=14V ALL ALL Von/off to 10 %Vo,set Vin,min. to 10%V o,set 10%Vo,set to 90 %Vo,set ALL ALL ALL ALL 3 3 4 130 ms ms ms °C ALL 0.92 M hours ALL 8.5 grams Io=100%of Io.max;Ta=2 5°C per MIL-HDBK217F x0.3 46 inches(33.0x13.4 6x8.8 mm ) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 5 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 5. Main Features and Functions 5.1 Operating Temperature Range removed. The power module will supply up to 150% of rated current. In the event of an over current converter will go into a hiccup mode protection. CUI INC's VPOL16A-12W-SMT series converters highly efficient converter design has resulted in its ability to operate over a wide ambient temperature environment ( -40°C to 85°C). Due consideration must be given to the de-rating curves when ascertaining maximum power that can be drawn from the converter. The maximum power drawn is influenced by a number of factors, such as: 5.6 Remote ON/OFF The remote ON/OFF input feature of the converter allows external circuitry to turn the converter ON or OFF. Active-high remote ON/OFF is available as standard. The VPOL16A-12W-SMT are turned on if the remote ON/OFF pin is high(=Vin), or left open. Setting the pin low(<0.4Vdc) will turn the converter ‘Off’. The signal level of the remote Input voltage range. on/off input is defined with respect to ground. If not using the remote Output load current. Air velocity (forced or natural convection). Mounting orientation of converter PCB with respect to the Airflow. Motherboard PCB design, especially ground and power planes. These can be effective heat sinks for the converter. 5.2 Over-Temperature Protection (OTP) on/off pin, leave the pin open (module will be on). The part number suffix “N” is Negative remote ON/OFF version. The unit is guaranteed OFF over the full temperature range if this voltage level exceeds 2.8Vdc. The converters are turned on If the on/off pin input is low (<0.4Vdc) or left open. The recommended VPOL16A-12W-SMT remote on/off drive circuit as shown as figure 3, 4. The VPOL16A-12W-SMT Series converters are equipped with nonlatching over-temperature protection. A temperature sensor monitors the +Vin temperature of the hot spot (typically, top switch). If the temperature exceeds a threshold of 130°C (typical) the converter will shut down, disabling the output. When the temperature has decreased the converter will automatically restart. The over-temperature condition can be induced by a variety of reasons ON/OFF Control +Vo Remote ON/OFF Q1 VPOL16A-12W-SMT such as external overload condition or a system fan failure. Common 5.3 Output Voltage Adjustment Section 7.8 describes in detail as to how to trim the output voltage with respect to its set point. The output voltage on all models is trimmable in Common Figure 3. Positive Remote ON/OFF Input Drive Circuit the range 0.7525 – 5.0Vdc. 5.4 Safe Operating Area (SOA) +Vin Figure 2 provides a graphical representation of the Safe Operating Area (SOA) of the converter. This representation assumes ambient operating conditions such as airflow are met as per thermal guidelines provided in Sections 7.2 and 7.3. Q1 ON/OFF Control +Vo VPOL16A-12W-SMT Remote ON/OFF Vo Common VOLTAGE (V) Vo,nom Common Figure 4. Negative Remote ON/OFF Input Drive Circuit Safe Operating Area CURRENT (A) Io,max Io,CL Io Figure 2. Maximum Output Current Safe Operating Area 5.5 Over Current Protection All different voltage models have a full continuous short-circuit protection. The unit will auto recover once the short circuit is removed. To provide protection in a fault condition, the unit is equipped with internal overcurrent protection. The unit operates normally once the fault condition is 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 6 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 5.7 UVLO (Under-Voltage Lockout) The voltage on the Vcc pin determines the start of the operation of the Converter. When the input Vcc rises and exceeds about 5.0V the Power start up with SEQ signal Input Voltage=12Vdc Master DC/DC output voltage (CH1) = 5Vdc Salve DC/DC output voltage (CH2)=3.3Vdc Sequencing voltage= 0.6V/msec converter initiates a soft start. The UVLO function in the converter has a hysteresis (about 1V) built in to provide noise immunity at start-up. 5.8 Output Voltage Sequencing (Tracking) The VPOL16A-12W-SMT series including a sequencing feature. It is able implement various types of output voltage sequencing in customer applications, VPOL16A-12W-SMT series is accomplishable through an additional sequencing pin. When not using the sequencing feature, tie the SEQ pin to +Vin. When the signal voltage is applied to the SEQ pin, the output voltage tracks this voltage until the output reaches the set point voltage. The SEQ voltage needs to be set higher than the set point of the module. The output voltage will be follow by the voltage on the SEQ pin. On the multiple modules application, we can connect SEQ pin and input signal voltage together to apply on the SEQ pin. Customers can get multiple modules to track their output voltages to follow the voltage of the SEQ pin. To control this module for sequen cing, when the input voltage Figure 6. Example testing circuit of sequencing function applied to the module. The on/off pin is left unconnected so that the module is ON by default. After applying input voltage to the module, a minimum of 10msec delay is required before applying voltage on the SEQ pin and slew rate of the voltage on the SEQ pin see technical Power turn off with SEQ signal voltage Input Voltage=12Vdc (CH1) Master DC/DC output voltage (CH2) = 5Vdc Salve DC/DC output voltage (CH3)=3.3Vdc specifications “ dVSEQ/dt “. After 10msec delay, an Analog voltage is applied to the SEQ pin and the output voltage of the module will track this voltage until output voltage reaches the set point voltage. To initiate simultaneous shutdown of the modules, the SEQ pin voltage is lowered in a controlled manner. Output voltage of the modules track the voltages below their set-point voltage voltages. A valid input voltage must be maintained until the tracking and output voltages reach ground potential to ensure a controlled shutdown of the modules. A typical example testing circuit used master DC/DC converter and SIP/SMT Module as shown as below: +Vin Power + C1 +Vo CH1 R1 Load Master DC/DC Converter Supply Common Common Figure 7. Example testing circuit of sequencing function +Vin +Vo SEQ CH2 VPOL16A-12W-SMT Common C2 CH3 R2 Load Common Figure 5. Example testing circuit of sequencing function 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. PART NUMBER: VPOL16A-12-SMT 7. Applications 6.1 Input Fusing and Safety Considerations. 7.1 Layout Design Challenges. Agency Approvals: The power Supply shall be submitted to and receive 1.The power supply shall be approved by a nationally recognized testing rd laboratory to UL/CSA 60950 3 Edition (North America) and EN60950 (International) 7 of 14 date 08/2007 DESCRIPTION: point of load converter 6. Safety formal approval from the following test agencies. page In optimizing thermal design the PCB is utilized as a heat sink. Also some heat is transferred from the VPOL16A-12W-SMT module to the main board through connecting pins. The system designer or the end user must ensure that other components and metal in the vicinity of the VPOL16A-12W-SMT series meet the spacing requirements to which the system is approved. 2. CB Certificate from an internationally recognized test house in Low resistance and low inductance PCB layout traces are the norm and accordance with EN 60950. should be used where possible. Due consideration must also be given to The VPOL16A-12W-SMT series converters do not have an internal fuse. However, to achieve maximum safety and system protection, always use an input line fuse. The safety agencies require a time-delay fuse proper low impedance tracks between power module, input and output grounds. The recommended VPOL16A-12W-SMT footprint is shown as figure 8. with a maximum rating of 20A. Recommended Pad Layout Dimensions are in millimetes and(inches) 7.54(0.297) 4.83 4.83 4.83 3.05 (0.120) 4.83 4.83 (0.190) (0.190) (0.190) (0.190) (0.190) PGood +SENSE TRIM +VO 10.29 (0.405) COM 10.92 (0.430) Top Vie w of Board ON/OFF 0.64 (0.025) SEQ +VIN 29.90 (1.177) PAD SIZE MIN:3.556x2.413(0.140x0.095) MAX:4.19x2.79(0.165x0.110) Figure 9. Recommended VPOL16A-12W-SMT Footprint 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 8 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 7.2 Convection Requirements for Cooling To predict the ap proximate cooling needed for the module, refer to the Power De-rating curves in Figure 11. These de -rating curves are approximations of the ambient temperatures and airflows required to keep the power module temperature below its maximum rating. Once the module is assembled in the actual system, the module’s temperature should be checked as shown in Figure 9 to ensure it does not exceed 120°C. Proper cooling can be verified by measuring the power module’s temperature at “ Tref ” as shown in Figure 10. Wind Tunnel 25.4(1.0) PWBs Power Module Figure 10. Temperature Measurement Location for VPOL16A12W-SMT 76.2(3.0) Thermocuple Location for measuring ambient temperature and airflow 12.7(0.5) 7.3 Thermal Considerations The power module operates in a variety of thermal environments; however, sufficient cooling should be provided to help ensure reliable operation of the unit. Heat is removed by conduction, convection, and radiation to the surrounding environment. The thermal data presented is based on measurements taken in a set-up as shown in Figure 9. Figure 11 represents the test data. Note that the airflow is parallel to the long Air flow axis of the module as shown in Figure 10 for the VPOL16A-12W-SMT. The temperature at “ Tref ” location should not exceed 120 °C. The output power of the module should not exceed the rated power for the module (VO, set x IO, max). The thermal data presented is based on Note : Dimensions are in millimeters and (inches) Figure 9. Thermal Test Setup measurements taken in a wind tunnel. The test setup shown in Figure 7 and EUT need to solder on 33mm x 40.38mm(1.300'' x 1.59'') test pcb. Note that airflow is parallel to the long axis of the module as shown in Fig 10. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT TYPICAL POWER DERATING FOR 5 Vin 3.3 Vout 18 16 Output Current(A) 14 12 10 0LFM 100LFM 200LFM 300LFM 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100 Ambient Temperature(o C) NOTE: 1. specific input & output derating curves available, please contact CUI INC for detail 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 page 9 of 14 date 08/2007 For more information, please visit the product page. rev. page 10 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 7.5 Efficiency vs Load Curves VPOL16A-12W-SMT Vo=5.0V (Eff Vs Io) VPOL16A-12W-SMT Vo=3.3V (Eff Vs Io) 95% 95% Efficincy (%) 100% 100% Efficincy (%) 90% 90% 85% 85% 6.5V 12V 14V 80% 75% 6.0V 12V 14V 80% 75% 70% 70% 0 1 2 3 4 5 6 7 8 0 9 10 11 12 13 14 15 16 Current Load (A) VPOL16A-12W-SMT Vo=2.5V (Eff Vs Io) 95% 95% 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) VPOL16A-12W-SMT Vo=2.0V (Eff Vs Io) Efficincy (%) 100% Efficincy (%) 100% 1 90% 90% 85% 85% 6.0V 12V 14V 80% 75% 6.0V 12V 14V 80% 75% 70% 70% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 11 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT VPOL16A-12W-SMT Vo=1.8V (Eff Vs Io) VPOL16A-12W-SMT Vo=1.5V (Eff Vs Io) 95% 95% 90% 90% Efficincy (%) 100% Efficincy (%) 100% 85% 85% 80% 80% 75% 6.0V 12V 14V 70% 65% 75% 6.0V 12V 14V 70% 65% 60% 60% 0 1 2 3 4 5 6 7 8 0 9 10 11 12 13 14 15 16 Current Load (A) VPOL16A-12W-SMT Vo=1.2 V (Eff Vs Io) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) VPOL16A-12W-SMT Vo=0.75V (Eff Vs Io) 100% 100% 95% 95% 90% 90% Efficincy (%) Efficincy (%) 85% 85% 80% 75% 80% 75% 6.0V 12V 14V 70% 65% 60% 70% 6.0V 12V 14V 65% 60% 55% 50% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Current Load (A) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. Line.reg = 7.6 Input Capacitance at the Power Module The VPOL16A-12W-SMT converters must be connected to a low AC source impedance. To avoi d problems with loop stability source inductance should be low. Also, the input capacitors should be placed close to the converter input pins to de-couple distribution inductance. However, the external input capacitors are chosen for suitable ripple handling capability. Low ESR polymers are a good choice. They have high capacitance, high ripple rating and low ESR (typical <100mohm). Electrolytic capacitors should be avoided. Circuit as shown in Figure 12 represents typical measurement methods for ripple current. Input reflected-ripple current is measured with a simulated source Inductance of 1uH. Current is measured at the input of the module. L1 +Vin 1uH + 2*100uF Tantalum +Vo VPOL16A-12W-SMT R1 C2 1000uF Electronlyic ESR<0.1ohm Com Load Com Figure 12. Input Reflected-Ripple Test Setup 7.7 Test Set-Up The basic test set-up to measure parameters such as efficiency and load regulation is shown in Figure 13. Things to note are that this converter is non-isolated, as such the input and output share a common ground. These grounds should be connected together via low impedance ground plane in the application circuit. When testing a converter on a bench set-up, ensure that -Vin and -Vo are connected together via a low impedance short to ensure proper efficiency and load regulation measurements are being made. When testing the CUI INC's VPOL16A-12W-SMT series under any transient conditions please ensure that the transient response of the source is sufficient to power the equipment under test. We can calculate the Efficiency Load regulation and line regulation. The value of efficiency is defined as: Vo x Io x100% ç= Vin x Iin Where: Vo is output voltage, Io is output current, Vin is input voltage, Iin is input current. The value of load regulation is defined as: Load .reg = date 08/2007 VHL _ VLL x 100% VLL Where: VHL is the output voltage of maximum input voltage at full load. VLL is the output voltage of minimum input voltage at full load. Current Meter A Power Supply +Vin A +Vo +Sense + V 100uF Voltage Meter VPOL16A-12W-SMT Common V Load Common Figure 13. VPOL16A-12W-SMT Series Test Setup 7.8 Remote Sense Compensation To Oscilloscope Supply 12 of 14 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT Power page Remote Sense regulates the output voltage at the point of load. It minimizes the effects of distribution losses such as drops across the connecting pin and PCB tracks (see Figure 14). Please note however, the maximum drop from the output pin to the point of load should not exceed 500mV for remote compensation to work. The amount of power delivered by the module is defined as the output voltage multiplied by the output current (VO x IO). When using TRIM UP, the output voltage of the module will increase which, if the same output current is maintained, increases the power output by the module. Make sure that the maximum output power of the module remains at or below the maximum rated power. When the Remote Sense feature is not being used, leave sense pin disconnected. Figure 14. Circuit Configuration for Remote Sense Operation Distribution Losses +Vin +Vo +Sense VPOL16A-12W-SMT Common Common R-Load Distribution Losses VFL _ VNL x100% VNL Where: VFL is the output voltage at full load VNL is the output voltage at no load The value of line regulation is defined as: 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 13 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 7.11 Output Capacitance 7.9 VPOL16A-12W-SMT Series Output Voltage Adustment. The output Voltage of the VPOL16A-12W-SMT can be adjusted in the range 0.7525V to 5.0V by connecting a single resistor on the motherboard (shown as Rtrim) in Figure 15. When Trim resistor is not connected the output voltage defaults to 0.7525V +Vin R trim-up Common Figure 15. Trim-up Voltage Setup The value of Rtrim-up defined as: Vo 10500 _ 1000 ) _ 0.7525 Where: Rtri m-up is the external resistor in ohm, Vo is the desired output voltage To gi ve an example of the above calculation, to set a voltage of 3.3Vdc, Rtrim is given by: Rtrim = ( 10500 _ 1000 ) 3.3 _ 0.7525 Rtrim = 3.122K ohm CUI INC's VPOL16A-12W-SMT series converters provide unconditional stability with or without external capacitors. For good transient response low ESR output capacitors should be located close to the point of load. For high current applications point has already been made in layout considerations for low resistance and low inductance tracks. Output capacitors with its associated ESR values have an impact on loop stability and bandwidth. CUI INC's converters are designed to work with load capacitance up-to 8,000uF. It i s recommended that any additional capacitance, typically 1,000uF and low ESR (<20mohm), be connected close to the point of load and outside the remote compensation point. 7.12 VPOL16A-12W-SMT Reflow Profile An example of the VPOL16A-12W-SMT reflow profile is given in Fig 17. Equipment used: SMD HOT AIR REFLOW HD-350SAR Alloy: AMQ-M293TA or N C-SMQ92 IND-82088 SN63 REFLOW PROFILE 240 200 TEMPERATURE (C) For various output values various resistors are calculated and provided in Tabl e 3 for convenience. Vo,set (V) 0.7525 1.2 1.5 1.8 2.0 2.5 3.3 5.0 + LOAD COM VPOL16A-12W-SMT R-Load VPOL16A-12W-SMT Rtrim = ( 100uF ESR<0.1Ohm 1uF VIN Trim Common SCOPE 10uF Power Supply +Vo VO COPPER STRIPS Rtrim (Kohm) Open 22.46 13.05 9.024 7.417 5.009 3.122 1.472 160 120 80 40 0 0 30 60 90 120 150 180 210 240 TIME (SECONDS) Figure 17 VPOL16A-12W-SMT Reflow Profile Table 3 – Trim Resistor Values 7.10 Output Ripple and Noise Measurement The test set-up for noise and ripple measurements is shown in Figure 16. a coaxial cable with a 50ohm termination was used to prevent impedance mismatch reflections disturbing the noise readings at higher frequencies. The Output Ripple & Noise is measured with 1uf ceramic and 10uf tantalum. The measured position are 50mm to 75mm(2” to 3”) from the module. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 For more information, please visit the product page. rev. page 14 of 14 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL16A-12-SMT 8. Mechanical Outline Diagrams 8.2 VPOL16A-12W-SMT Tape and Reel Dimensions 8.1 VPOL16A-12W-SMT Mechanical Outline Diagrams Po P2 P D t E F Dimensions are in millimeters and inches Tol erance: x.xx ±0.02 in. (0.5mm) , x.xxx ±0.010 in. (0.25 mm) unless otherwise noted The Ta pe Reel dimensions for the VPOL16A-12W-SMT module is shown in Figure 19. 1.30 (33.0) 0.12 (3.05) 0.19 0.19 0.19 0.297 (7.54) 0.19 0.19 0.065 (1.65) (4.83) (4.83) (4.83) (4.83) (4.83) SEQ COM +VO TRIM +SENSE PGood (Option) 0.346 (8.80) max. Ao 0.405 0.530 (10.29) (13.46) ON/OFF +VIN 0.063 (1.60) W Bo BOTTOM VIEW OF BOARD SURFACE MOUNT CONTACT 0.112 (2.84) 0.048 (1.22) 0.075(1.91) L1 INDUCTOR Dimensions are in Inches(millimeters) Tolerances :X.XX¡ Ó0.02in(0.5mm),X.XXX¡ Ó0.010in(0.25mm),unless otherwise noted. Figure 18 VPOL16A-12W-SMT Mechanical Outline Diagram W Ao Bo Ko P F E D D1 Po P2 t Figure 19 – VPOL16A-12W-SMT Tape and Reel Dimensions 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 Ko