rev. PART NUMBER: VPOL5A-5-SMT page 1 of 11 date 08/2007 DESCRIPTION: point of load converter features * high efficiency topology, typically 94% at 3.3 Vdc * industry standard footprint * wide ambient temperature range, -40C to +85C * cost efficient open frame design * programmable output voltage via external resistor from 0.75 to 3.63 Vdc * 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/EN60950-1 (E222736) certified. 1. INTRODUCTION 2. VPOL5A-5-SMTCONVERTER 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 VPOL5A-5-SMT Series Output Voltage Adustment. 5.5 Over Current Protection 7.9 Output Ripple and Noise Measurement 5.6 Remote On/Off 7.10 Output Capacitance 5.7 UVLO (Under-Voltage Lockout) 7.11 SMT Reflow Profile 7.5 Efficiency vs Load Curves 8. MECHANICAL OUTLINE DIAGRAMS 8.1 SIP/SMT05 Mechanical Outline Diagrams 8.2 SMT Tape and Reel Dimensions 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page 2 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT L1 Q1 +VIN +VO 1. Introduction Q2 C1 This application note describes the features and functions of V-Infinity’s D1 C2 VPOL5A-5-SMT series of Non Isolated DC-DC Converters. These are highly efficient, reliable and compact, high power density, single output dc-dc converters. These “Point of Load” modules serve the needs COM COM specifically of the fixed and mobile telecommunications and computing R1 market, employing economical distributed Power Architectures. The VPOL5A-5-SMT series provide precisely regulated output voltage range PWM IC ON/OFF from 0.75V to 3.63 Vdc over a wide range of input voltage (Vi=3.0 – 5.5 Vdc) and can operate over an ambient temperature range of –40 +85 R trim TRIM ERR AMP R2 to . Ultra-high efficiency operation is achieved through the use of Figure 1. Electrical Block Diagram synchronous rectification and drive control techniques. The modules are fully protected against short circuit and overtemperature conditions. V-Infinity’s world class automated 3.2 Thermal Packaging and Physical Design. manufacturing methods, together with an extensive testing and The VPOL5A-5-SMT series uses a multi-layer FR4 PCB construction. qualification program, ensure that all VPOL5A-5-SMT series converters All surface mount power components are placed on one side of the are extremely reliable. PCB, and all low-power control components are placed on the other 2. VPOL5A-5-SMTConverter Features High efficiency topology, typically 94% at 3.3 Vdc Industry standard footprint Wide ambient temperature range, -40 °C to +85 °C 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: Cost efficient open frame design Efficient Thermal Management: the heat is removed from the Programmable output voltage via external resistor from 0.75 to heat generating components without heating more sensitive, small 3.63 Vdc signal control components. No minimum load requirement (Stable at all loads) Environmental: Lead free open-frame converters are more easily Remote ON/OFF re-cycled. Remote sense compensation Cost Efficient: No encapsulation. Cost efficient open-frame Fixed switching frequency construction. Continuous short-circuit protection and over current protection Reliable: Efficient cooling provided by open frame construction Over-temperature protection (OTP) offers high reliability and easy diagnostics. Monotonic Startup with pre-bias at the output. UL/IEC/EN60950 Certified. 3. General Description 3.1 Electrical Description A block diagram of the VPOL5A-5-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 VPOL5A-5-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 VPOL5A-5SMT series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.75 to 3.63vdc, 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 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. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page 3 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT 4. Technical Specifications (All specifications are typical at nominal input, full load at 25 PARAMETER ABSOLUTE MAXIMUM RATINGS Input Voltage Continuous Operating Temp erature See Thermal Considerations Section unless otherwise noted.) NOTES and CONDITIONS Device Min. Typical Max. ALL 0 5.8 ALL -40 +85 -55 +125 Storage Temperature ALL Units Vdc INPUT CHARACTERISTICS Operating Input Voltage Input Under-Voltage Lockout Turn-On Voltage Threshold Turn-Off Voltage Threshold Lockout Hysteresis Voltage Vo,set Vin-0.5 Vdc ALL 3.0 5 ALL ALL ALL ALL 5.5 2.0 Vdc Vdc Vdc Vdc 1.9 0.1 Maximum Input Current Vin=0 to 5.5 Vdc , Io=Io,max. No-Load Input Current Vo=0.75V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V ALL Off Converter Input Current Shutdown input idle current ALL 10 mA ALL 0.1 As 2 Inrush Current (I t) Input Reflected-Ripple Current 5 25 30 30 35 35 35 35 A mA 2 P-P thru 1uH inductor, 5Hz to 20MHz ALL 150 mA Output Voltage Set 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 external resistor ALL OUTPUT CHARACTERISTIC 0.75 3.63 Vdc 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 -0.4 +0.4 % Tempera ture Coefficient Ta=-40 ALL -0.03 +0.03 Output Voltage Ripple and Noise 5Hz to 20MHz bandwidth to 85 %/ Peak-to-Peak Full Load, 1uF ceramic and 10uF tantalum ALL 50 mV RMS Full Load, 1uF ceramic and 10uF tantalum ALL 20 mV Low ESR ALL 3000 uF ALL 0 Output DC Current-Limit Inception Output Voltage =90% Nominal Output Voltage ALL 6 Shout Circuit Protection Continuous with Hiccup Mode External Capacitive Load Operating Output Current Range 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 9.5 5 A 15 A rev. 4 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT PARAMETER DYNAMIC CHARACTERISTICS page NOTES and CONDITIONS Device Min. Typical Max. Units Output Voltage Transient Response Error Brand 50% Step Load Change, di/dt=0.1A/us ALL 200 mV Setting Time (within 1% Vout nominal) 50% Step Load Change, di/dt=0.1A/us ALL 200 us EFFICIENCY 100% Load Vo=0.75V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V ALL Non-isolation ALL 79 85 87 89 90 92 94 % ISOLATION CHARACTERISTICS Input to Output 0 Vdc FEATURE CHARACTERISTICS Switching Frequency On/Off Control, Positive Logic Remote On/Off Logic Low (Module Off) Logic High (Module On) On/Off Control, Negative Logic Remote On/Off Logic Low (Module On) 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 Input Output Voltage Rise Time Over Temperature Protection ALL or Open Circuit or Open Circuit 300 Standard Model 0 Suffix “N” Model 0 2.8 Vin KHz 0.4 Vdc Vdc 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%Vo,set 10%Vo,set to 90%Vo,set ALL ALL ALL ALL 2 2 4.5 120 ms ms ms ALL 1.5 M hours ALL 2.3 grams GENERAL SPECIFICATIONS MTBF Weight Dimensions SIP packages SMT packages Io=100%of Io.max;Ta=25 217F per MIL-HDBK- 0.9x0.4x0.22 inches (22.9x10.16x5.6 mm) 0.8x0.45x0.24 inches(20.3x11.43x6.09 mm) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. PART NUMBER: VPOL5A-5-SMT 5. Main Features and Functions 5.1 Operating Temperature Range V-Infinity’s VPOL5A-5-SMT series converters highly efficient converter design has resulted in its ability to operate over a wide ambient temperature environment ( -40 to 85 ). Due consideration must be page 5 of 11 date 08/2007 DESCRIPTION: point of load converter 5.4 Safe Operating Area (SOA) 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. given to the de-rating curves when ascertaining maximum power that can Vo be drawn from the converter. The maximum power drawn is influenced by a number of factors, such as: Input voltage range. Vo,nom 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) VOLTAGE (V) Output load current. Safe Operating Area The VPOL5A-5-SMT Series converters are equipped with non-latching over-temperature protection. A te mperature sensor monitors the Io,max Io,CL Io temperature of the hot spot (typically, top switch). If the temperature CURRENT (A) exceeds a threshold of 120 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 such as external overload condition or a system fan failure. 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 the range 0.75 – 3.63 Vdc. 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 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. 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 VPOL5A-5-SMT series converters are turned on if the remote on/off pin is high, or left open or floating. Setting the pin low will turn the converter ‘Off’. The signal level of the remote on/off input is defined with respect to ground. If not using the remote 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 2.8 Vdc. The converters are turned on If the on/off pin input is low or left open. The recommended SMTremote on/off drive circuit as shown as figure 3, 4. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page 6 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT proper low impedance tracks between power module, input and output +Vin ON/OFF Control +Vo grounds. The recommended SMT footprint as shown as figure 5. Recommended Pad Layout Remote ON/OFF Dimensions are in Inches ( millimetes ) Q1 VPOL5A-5-SMT Common 0.180 (4.57) 0.160 (4.06) 0.160 (4.06) 0.190 (4.83) Common VOUT TRIM GND 0.340 (8.64) 0.350 (8.89) Figure 3. Positive Remote On/Off Input Drive Circuit +Vin +Vo Q1 VPOL5A-5-SMT ON/OFF Control Remote ON/OFF Common ON/OFF 0.06 (1.5) 0.05 (1.3) 0.010 (0.25) VIN 0.690 (17.53) PAD SIZE MIN : 0.120" x 0.095 " MAX : 0.135" x 0.110 " Figure 5. Recommended SMT Footprint (Top View) Common Figure 4. Negative Remote On/Off Input Drive Circuit 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 2.0V the converter initiates a soft start. The UVLO function in the converter has a hysteresis (about 100mV) built in to provide noise immunity at start-up. 6. Safety 6.1 Input Fusing and Safety Considerations. Agency Approvals: The power Supply shall be submitted to and receive formal approval from the following test agencies. 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) 2. CB Certificate from an internationally recognized test house in accordance with EN 60950. The VPOL5A-5-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 with a maximum rating of 10A. 7. Applications 7.1 Layout Design Challenges. In optimizing thermal design the PCB is utilized as a heat sink. Also some heat is transferred from the 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 VPOL5A-5-SMT series meet the spacing requirements to which the system is approved. Low resistance and low inductance PCB layout traces are the norm and should be used where possible. Due consideration must also be given to 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. TYPICAL POWER DERATING FOR 5Vin 3.3Vout 6.0 Output Current(A) 5.0 4.0 0LFM 100LFM 2.0 200LFM 1.0 0.0 0 10 20 30 40 50 7 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT 3.0 page 60 70 80 90 100 o Ambient Temperature( C) Figure 3. Typical Power De-rating for 5V IN 3.3Vout NOTE: 1. specific input & output derating curves available, please contact V-Infinity for detail 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page 8 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT 7.5 Efficiency vs Load Curves VPOL5A-5-SMT Vo=2.5V (Eff Vs Io) VPOL5A-5-SMT Vo=3.3V (Eff Vs Io) 95% 95% Efficincy (%) 100% Efficincy (%) 100% 90% 85% 4.5V 5.0V 5.5V 80% 75% 90% 85% 3.0V 5.0V 5.5V 80% 75% 70% 70% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 Current Load (A) VPOL5A-5-SMT Vo=1.8V (Eff Vs Io) 95% Efficincy (%) 95% Efficincy (%) 2.5 3 3.5 4 4.5 5 VPOL5A-5-SMT Vo=1.5V (Eff Vs Io) 100% 90% 85% 3.0V 5.0V 5.5V 75% 2 Current Load (A) 100% 80% 1.5 90% 85% 3.0V 5.0V 5.5V 80% 75% 70% 70% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 0.5 1 Current Load (A) 1.5 2 2.5 3 3.5 4 4.5 5 Current Load (A) VPOL5A-5-SMT Vo=1.2V (Eff Vs Io) VPOL5A-5-SMT Vo=0.75V (Eff Vs Io) 100% 100% 95% 95% Efficincy (%) Efficincy (%) 90% 90% 85% 3.0V 5.0V 5.5V 80% 75% 85% 80% 3.0V 5.0V 5.5V 75% 70% 65% 70% 60% 0 0.5 1 1.5 2 2.5 3 3.5 Current Load (A) 4 4.5 5 0 0.5 1 1.5 2 2.5 3 3.5 Current Load (A) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 4 4.5 5 rev. page 9 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT VNL is the output voltage at no load 7.6 Input Capacitance at the Power Module The SMTconvert ers must be connected to a low AC source impedance. To a void 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 10 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. The value of line regulation is defined as: Line.reg = 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 +Sense + V 100uF Voltage Meter VPOL5A-5-SMT Common Common To Oscilloscope Figure 11. VPOL5A-5-SMT Test Setup L1 +Vin 1uH Power + 2*100uF Tantalum Supply VPOL5A-5-SMT 220uF ESR<0.1ohm Common Figure 10. 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 11. Things to not e 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 V-Infinity’s VPOL5A-5-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: ç= Vo x Io x 100% 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 = A +Vo VFL _ VNL =100% VNL 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 V Load rev. page 10 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT 7.8 VPOL5A-5-SMT Series Output Voltage Adustment. 7.9 Output Ripple and Noise Measurement The output Voltage of the VPOL5A-5-SMTS33A can be adjusted in the range 0.75V to 3.63V by connecting a single resistor on the motherboard (shown as Rtrim) in Figure 12. When Trim resistor is not connected the output voltage defaults to 0.75V The test set-up for noise and ripple measurements is shown in Figure 13. a coaxial cable with a 50ohm termination was used to prevent impedance mismatch reflections disturbing the noise readings at higher frequencies +Vin +Vin +Vo Common Figure 12. Trim-up Voltage Setup The value of Rtrim-up defined as: 21070 _ 5110 ) Vo _ 0.75 Rtrim-up is the external resistor in ohm, Vo is the desired output voltage To give an exa mple of the above calculation, to set a voltage of 3.3 Vdc, Rtrim is given by: Where: 21070 _ 5110 ) Vo _ 0.75 Rtrim = 3153 ohm Common 7.10 Output Capacitance V-Infinity’s VPOL5A-5-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. V-Infinity’s converters are designed to work with load capacitance up-to 3,000uF. It is reco mmended that any additional capacitance, Maximum 3,000uF and low ESR, be connected close to the point of load and outside the remote compensation point. 7.11 SMT Reflow Profile An example of the SMT reflow profile is given in Figure 14. Equipment used: SMD HOT AIR REFLOW HD-350SAR Alloy: AMQ-M293TA or N C-SMQ92 IND-82088 SN63 Table 3 – Trim Resistor Values REFLOW PROFILE 240 200 TEMPERATURE (C) Rtrim (Kohm) Open 41.71 22.98 14.96 11.75 6.93 3.15 2.20 Common Figure 13. Output Voltage Ripple and Noise Measurement Set-Up For various output values various resistors are calculated and provided in Table 3 for co nvenience. Vo,set (V) 0.75 1.20 1.50 1.80 2.00 2.50 3.30 3.63 R-Load Test Jack R trim-up Rtrim = ( 1uF Ceramic R-Load VPOL5A-5-SMT Rtrim = ( 10uF Tant. VPOL5A-5-SMT Trim Common +Vo 160 120 80 40 0 0 30 60 90 120 150 180 210 240 TIME (SECONDS) Figure 14 SMT Reflow Profile 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page 11 of 11 date 08/2007 DESCRIPTION: point of load converter PART NUMBER: VPOL5A-5-SMT 8. Mechanical Outline Diagrams 8.2 SMT Tape and Reel Dimensions 8.1 VPOL5A-5-SMT Mechanical Outline Diagrams The Ta pe Reel dimensions for the SMT module is shown in Figure 16. Dimensions are in millimeters and inches Tolerance: x.xx ±0.02 in. (0.5mm) , x.xxx ±0.010 in. (0.25 mm) unless otherwise noted BOTTOM VIEW OF BOARD 0.80 (20.3) 0.190 (4.83) 0.160 (4.06) GND 0.35 (8.9) 0.160 (4.06) TRIM 0.180 (4.06) VOUT 0.062 (1.57) 0.24 (6.09) 0.340 (8.64) 0.450 (11.43) VIN 0.062 (1.57) ON/OFF Surface Mount Contact 5 Places 0.090 0.05 (1.3) (2.29) Dimensions are in Inches (millimeters) 0.06 (1.5) Toleranc es :x.xx ¡ Ó0.02in.( x.x ¡ Ó0.5mm) , unless otherwise noted x.xxx ¡ Ó0.010in. ( x.xx ¡ Ó0.25mm) Figure 15 VPOL5A-5-SMT Mechanical Outline Diagram W Ao Bo Ko P F E D D1 Po P2 t Figure 16 – SMT Tape a nd Reel Dimensions 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382