VPOL15A-5-SMT

rev. rev. page date 1 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter features * industry standard pin out * high efficiency to 94% * 300 KHz switching frequency * 3.0-5.5 VDC input range * 0.9-3.63 VDC wide output range * over temperature protection * continuous short circuit protection * remote on/off * cost-efficient open frame design * UL/C-UL60950 (E222736) certified 1. INTRODUCTION 2. VPOL15A-5-SMT CONVERTER FEATURES 3. GENERAL DESCRIPTION 3.1 Electrical Description 3.2 Thermal Packaging and Physical Design. 7. APPLICATIONS 7.1 Layout Design Challenges. 7.2 Convection Requirements for Cooling 7.3 Thermal Considerations 7.4 Power De-Rating Curves 7.5 Efficiency vs Load Curves 7.6 Input Capacitance at the Power Module 7.7 Test Set-Up 7.8 Remote Sense Compensation 7.9 VPOL15A-5-SMT Series Output Voltage Adustment. 7.10 Output Ripple and Noise Measurement 7.11 Output Capacitance 7.12 VPOL15A-5-SMT Reflow Profile 4. TECHNICAL SPECIFICATIONS 5. MAIN FEATURES AND FUNCTIONS 5.1 Operating Temperature Range 5.2 Over-Temperature Protection (OTP) 5.3 Output Voltage Adjustment 5.4 Safe Operating Area (SOA) 5.5 Over Current Protection 5.6 Remote on/off 5.7 UVLO (Under-Voltage Lockout) 8. MECHANICAL OUTLINE DIAGRAMS 8.1 VPOL15A-5-SMT Mechanical Outline Diagrams 8.2 VPOL15A-5-SMT Tape and Reel Dimensions 6. SAFETY 6.1 Input Fusing and Safety Considerations. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 2 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter 1. Introduction This application note describes the features and functions of V-Infinity’s VPOL15A-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 specifically of the fixed and mobile telecommunications and computing market, employing economical distributed power architectures. The VPOL15A-5-SMT series provide precisely regulated output voltage range from 0.9V to 3.63Vdc over a wide range of input voltage (Vi=3.0 – 5.5Vdc) and can operate over an ambient temperature range of –40°C to +85°C. Ultr a-high efficiency operation is achieved through the use of synchronous rectification and drive control techniques. The modules are fully protected against short circuit and overtemperature conditions. V-Infinity’s world class automated manufacturing methods, together with an extensive testing and qualification program, ensure that all VPOL15A-5-SMT series converters are extremely reliable. 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. Q1 +VIN L1 +VO C1 Q2 D1 C2 R sense +SENSE COM COM R1 PWM IC ON/OFF R trim TRIM ERR AMP R2 Figure 1. Electrical Block Diagram 2. VPOL15A-5-SMT Converter Features High efficiency topology, typically 94% at 3.3Vdc Industry standard footprint Wide ambient temperature range, -40°C to +85°C Cost efficient open frame design Programmable output voltage via external resistor from 0.9 to 3.63Vdc 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. 3.2 Thermal Packaging and Physical Design. The VPOL15A-5-SMT series uses a multi-layer FR4 PCB 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 VPOL15A-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 VPOL15A-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 VPOL15A-5-SMT series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.9 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. 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 3 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter 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 Storage Temperature NOTES and CONDITIONS ALL ALL Device Min. Typical Max. Units 0 -40 ALL -55 5.8 +85 +125 Vdc °C °C INPUT CHARACTERISTICS Operating Input Voltage Input Under-Voltage Lockout Turn-On Voltage Threshold Turn-Off Voltage Threshold Lockout Hysteresis Voltage Maximum Input Current Vin=3.0 to 5.5Vdc , Io=Io,max. Vo=1.0V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V Shutdown input idle current Vo=2.7V Vo=3.0V ALL ALL ALL ALL ALL 3.0 4.5 5.0 5.0 2.8 2.7 0.1 5.5 5.5 Vdc Vdc Vdc Vdc 15.5 60 60 60 70 70 70 70 5 10 0.4 150 A No-Load Input Current ALL mA Off Converter Input Current Inrush Current (I t) Input Reflected-Ripple Current 2 ALL ALL mA As mA 2 P-P thru 1uH inductor, 5Hz to 20MHz ALL OUTPUT CHARACTERISTIC Output Voltage Set Point Output Voltage Trim Adjustment Range Output Voltage Regulation Load Regulation Line Regulation Tempera ture Coefficient Output Voltage Ripple and Noise Peak-to-Peak RMS External Capacitive Load Operating Output Current Range Output DC Current-Limit Inception Shout Circuit Protection Output Voltage =90% Nominal Output Voltage Continuous with Hiccup Mode Io=Io.min to Io.max Vin=low line to high line Ta=-40°C to 85°C 5Hz to 20MHz bandwidth Full Load, 1uF ceramic and 10uF tantalum Full Load, 1uF ceramic and 10uF tantalum Low ESR ALL ALL ALL ALL ALL 0 18 22 50 20 10000 15 28 mV mV uF A A ALL VPOL15A-5SMT ALL -0.5 -0.2 -0.4 +0.5 +0.2 +0.4 ±0.03 % % %/°C Vin=Nominal Vin , Io=Io.max, Tc=25°C Selected by an external resistor ALL ALL -1.5% Vo,set +1.5% 0.9 3.63 Vdc Vdc 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 4 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter PARAMETER DYNAMIC CHARACTERISTICS Output Voltage Transient Response Error Brand Setting Time (within 1% Vout nominal) NOTES and CONDITIONS Device Min. Typical Max. Units 25% Step Load Change, di/dt=0.1A/us 25% Step Load Change, di/dt=0.1A/us ALL ALL ±5 200 % us EFFICIENCY Vo=1.0V Vo=1.2V Vo=1.5V Vo=1.8V Vo=2.0V Vo=2.5V Vo=3.3V Non-isolation 82 84 87 88 89 92 94 0 100% Load ALL % ISOLATION CHARACTERISTICS Input to Output 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 Ion/off at Von/off=0.0V Logic High, Von/off=5V Von/off to 10%Vo,set Vin,min. to 10%Vo,set 10%Vo,set to 90%Vo,set 1 1 3.5 120 1.5 6.8 ALL 0 2.8 0 300 0.4 Vin 0.4 Vin 1 1 KHz Vdc Vdc Vdc Vdc mA mA ms ms ms °C M hours grams 6 GENERAL SPECIFICATIONS MTBF Weight Io=100%of Io.max;Ta=25 °C per MIL-HDBK-217F 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 5 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter current protection. The unit operates normally once the fault condition is 5. Main Features and Functions 5.1 Operating Temperature Range V-Infinity’s VPOL15A-5-SMT series converters highly efficient converter design has resulted in its ability to operate over a wide ambient temperature environment ( -40° to 85°C). Due consideration must be C 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: Input voltage range. 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. 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 VPOL15A-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 2.8Vdc. The converters are turned on If the on/off pin input is low or left open. The recommended VPOL15A-5SMT remote on/off drive circuit is shown as figures 3 & 4. 5.2 Over-Temperature Protection (OTP) The VPOL15A-5-SMT series converters are equipped with non-latching over-temperature protection. A te mperature sensor monitors the temperature of the hot spot (typically, top switch). If the temperature 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 7.9 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 0.9 – 3.63Vdc. 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. Vo Vo,nom VOLTAGE (V) Safe Operating Area Io,max Io,CL Io CURRENT (A) 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 over- 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 6 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter +Vin Remote ON/OFF +Vo 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 VPOL15A-5-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 VPOL15A-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 proper low impedance tracks between power module, input and output grounds. The recommended VPOL15A-5-SMT footprint is shown as figure 5. ON/OFF Control Q1 VPOL15A-5-SMT Common Common Figure 3. Positive Remote on/off Input Drive Circuit +Vin +Vo Q1 VPOL15A-5-SMT ON/OFF Control Remote ON/OFF Common Common Recommended Pad Layout Dimensions are in millimetes and(inches) Figure 4. Negative Remote on/off Input Drive Circuit 7.54 (0.297) 4.83 4.83 4.83 7.87 (0.310) 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 2.8V 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. 10.29 (0.405) (0.190) (0.190) (0.190) +SENSE TRIM +VO COM 10.92 (0.430) +VIN Top View of Board ON/OFF 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 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 VPOL15A-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 20A. rd 0.64 (0.025) 29.90 (1.177) PAD SIZE MIN:3.556x2.413(0.140x0.095) MAX:4.19x2.79(0.165x0.110) Figure 5. Recommended VPOL15A-5-SMT Footprint 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 7 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter TYPICAL POWER DERATING FOR 5 Vin 3.3 Vout SMT15-05S33A Derating Curve 16 14 12 Output Current(A) 10 8 6 4 2 0 0 10 20 30 40 50 60 70 Ambient Temperature( oC) 80 90 100 0LFM 100LFM 200LFM 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 date 8 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter 7.5 Efficiency vs Load Curves (Fig. 10) VPOL15A-5-SMT Vo=3.3V (Eff Vs Io) 100% 95% 100% 95% VPOL15A-5-SMT Vo=2.5V (Eff Vs Io) Efficincy (%) Efficincy (%) 90% 85% 80% 75% 70% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 90% 85% 80% 75% 70% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 4.5V 5.0V 5.5V 3.0V 5.0V 5.5V Current Load (A) VPOL15A-5-SMT Vo=1.8V (Eff Vs Io) 100% 95% 90% 85% 80% 75% 70% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Current Load (A) VPOL15A-5-SMT Vo=1.5V (Eff Vs Io) 100% 95% Efficincy (%) Efficincy (%) 90% 85% 80% 75% 70% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 3.0V 5.0V 5.5V 3.0V 5.0V 5.5V Current Load (A) Current Load (A) VPOL15A-5-SMT Vo=1.2V (Eff Vs Io) 100% 95% 90% 100% 95% 90% VPOL15A-5-SMT Vo=1.0V (Eff Vs Io) Efficincy (%) 85% 80% 75% 70% 65% 60% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Efficincy (%) 85% 80% 75% 70% 65% 60% 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 3.0V 5.0V 5.5V 3.0V 5.0V 5.5V Current Load (A) Current Load (A) 20050 SW 112th Ave. Tualatin, Oregon 97062 phone 503.612.2300 fax 503.612.2382 rev. page date 9 of 11 08/2007 PART NUMBER: VPOL15A-5-SMT DESCRIPTION: point of load converter VNL is the output voltage at no load 7.6 Input Capacitance at the Power Module The VPOL15A-5-SMT converters must be connected to a low AC source impedance. To avoid probl ems 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