PRELIMINARY V•I Chip Voltage Transformation Module BCM V•I Chip – BCM Bus Converter Module TM B048K120T30 K indicates BGA configuration. For other mounting options see Part Numbering below. • 48 V to 12 V V•I Chip Converter • 96% efficiency • 300 Watt (450 Watt for 1 ms) • 125°C operation • High density – 1200 W/in3 © • <1 µs transient response • Small footprint – 280 W/in2 • 3.5 million hours MTBF • Low weight – 0.5 oz (14 g) • No output filtering required • ZVS/ZCS isolated sine amplitude converter • Surface mount BGA or J-Lead packages Product Description Vin = 38 - 55 V Vout = 9.5 - 13.7 V Iout = 25 A K = 1/4 Rout = 13.9 mΩ max Absolute Maximum Ratings The V•I Chip Bus Converter Module (BCM) is a high efficiency (>96%), narrow input range Sine Amplitude Converter (SAC) operating from a 38 to 55 Vdc primary bus to deliver an isolated 9.5 V to 13.7 V secondary. The BCM may be used to power non-isolated POL converters or as an independent 9.5 – 13.7 V source. Due to the fast response time and low noise of the BCM, the need for limited life aluminum electrolytic or tantalum capacitors at the input of POL converters is reduced—or eliminated—resulting in savings of board area, materials and total system cost. The BCM achieves a power density of 1200 W/in3 and may be surface mounted with a profile as low as 0.16" (4 mm) over the PCB. Its V•I Chip power package is compatible with onboard or inboard surface mounting. The V•I Chip package provides flexible thermal management through its low Junction-to-Case and Junction-to-BGA thermal resistance. Owing to its high conversion efficiency and safe operating temperature range, the BCM does not require a discrete heat sink in typical applications. It is also available with heat sink options, assuring low junction temperatures and long life in the harshest environments. Parameter Values Unit -1.0 to 60 Vdc +In to -In 100 Vdc PC to -In -0.3 to 7.0 Vdc +Out to -Out -0.5 to 30.0 Vdc 2,250 Vdc 25 A Continuous 37.5 A For 1 ms +In to -In Isolation voltage Output current Peak output current Notes For 100 ms Input to Output Output power 300 W Continuous Peak output power 450 W For 1 ms Case temperature 208 °C During reflow Operating junction temperature (1) -40 to 125 -55 to 125 °C °C T - Grade M - Grade Storage temperature -40 to 150 °C -65 to 150 °C T - Grade M - Grade Note: (1) The referenced junction is defined as the semiconductor having the highest temperature. This temperature is monitored by a shutdown comparator. Part Numbering B 048 Bus Converter Module K Input Voltage Designator Configuration Options F = Onboard (Figure 20) K = Inboard (Figure 19) vicorpower.com Actual size 800-735-6200 V•I Chip Bus Converter Module 120 Output Voltage Designator (=VOUT x10) T 30 Output Power Designator (=POUT/10) Product Grade Temperatures (°C) Grade Storage Operating T -40 to150 -40 to125 M -65 to150 -55 to125 B048K120T30 Rev. 1.0 Page 1 of 16 PRELIMINARY Specifications V•I Chip Voltage Transformation Module Input (Conditions are at 48 Vin, full load, and 25°C ambient unless otherwise specified) Parameter Input voltage range Input dV/dt Input undervoltage turn-on Input undervoltage turn-off Input overvoltage turn-on Input overvoltage turn-off Input quiescent current Inrush current overshoot Input current Input reflected ripple current No load power dissipation Internal input capacitance Internal input inductance Recommended external input capacitance Min Typ Max Unit 38 48 55 1 37.4 Vdc V/µs Vdc Vdc Vdc Vdc mA A Adc mA p-p W µF nH µF 32.6 55 59 2.5 2.0 6.8 170 4.7 4 20 47 5.7 Note PC low Using test circuit in Figure 21; See Figure 1 Using test circuit in Figure 21; See Figure 4 200 nH maximum source inductance; See Figure 21 Input Waveforms Figure 1— Inrush transient current at full load and 48 Vin with PC enabled Figure 2— Output voltage turn-on waveform with PC enabled at full load and 48 Vin Figure 3—Output voltage turn-on waveform with input turn-on at full load and 48 Vin Figure 4— Input reflected ripple current at full load and 48 Vin vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 2 of 16 PRELIMINARY Specifications V•I Chip Voltage Transformation Module (continued) Output (Conditions are at 48 Vin, full load, and 25°C ambient unless otherwise specified) Parameter Min Typ 9.5 9.2 0 Output voltage Rated DC current Peak repetitive current DC current limit Current share accuracy Efficiency Half load Full load Internal output inductance Internal output capacitance Load capacitance Output overvoltage setpoint Output ripple voltage No external bypass 10 µF bypass capacitor Average short circuit current Effective switching frequency Line regulation K Load regulation ROUT Transient response Voltage overshoot Response time Recovery time Output overshoot Input turn-on PC enable Output turn-on delay From application of power From release of PC pin 25.5 30.0 5 95.0 95.0 Max Unit Note 13.7 13.4 25 Vdc Vdc Adc 37.5 A No load Full load Module will shut down when current limit is reached or exceeded Max pulse width 1ms, max duty cycle 10%, baseline power 50% 36.3 10 Adc % 95.5 96.0 1.1 55 1,000 13.8 214 2.5 144 12.8 0.16 2.8 0.2475 1/4 0.2525 11.7 13.9 3.2 See Parallel Operation on Page 12 % % nH µF µF Vdc See Figure 5 See Figure 5 mV mV A MHz See Figures 7 and 9 See Figure 8 Effective value Fixed, 1.4 MHz per phase VOUT = K•VIN at no load mΩ 355 200 1 mV ns µs 100% load step; See Figures 10 and 11 See Figures 10 and 11 See Figures 10 and 11 0 0 mV mV No output filter; See Fig.3 No output filter; See Fig.2 308 80 ms ms No output filter; See Fig.3 No output filter Output Waveforms Power Dissipation vs. Output Power 14 96 12 Power Dissipation (W) Efficiency (%) Efficiency vs. Output Power 98 94 92 90 88 86 84 10 8 6 4 2 0 0 30 60 90 120 150 180 210 240 270 300 0 30 60 Output Power (W) 120 150 180 210 240 270 300 Output Power (W) Figure 5— Efficiency vs. output power at 48 Vin vicorpower.com 90 Figure 6—Power dissipation as a function of output power 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 3 of 16 PRELIMINARY Specifications V•I Chip Voltage Transformation Module (continued) Figure 7— Output voltage ripple at full load and 48 Vin; without any external bypass capacitor. Figure 8—Output voltage ripple at full load and 48 Vin with 10 µF ceramic external bypass capacitor and 20 nH of distribution inductance. Ripple Voltage vs. Output Power 160 Output Ripple (mVpk-pk) 140 120 100 80 60 40 20 0 0 30 60 90 120 150 180 210 240 270 300 Output Power (W) Figure 9— Output voltage ripple vs. output power at 48 Vin line without any external bypass capacitor. Figure 10— 0 -25 A load step with 47 µF input capacitor and no output capacitor. Figure 11— 25- 0 A load step with 47 µF input capacitance. vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 4 of 16 PRELIMINARY Specifications V•I Chip Voltage Transformation Module (continued) General Parameter Min Typ Max Unit Note 25°C, GB MTBF MIL-HDBK-217F 3.5 Mhrs Telcordia TR-NT-000332 4.2 Mhrs Isolation specifications Voltage 2,250 Capacitance 3,000 Resistance 10 Agency approvals (pending) Vdc Input to Output pF Input to Output MΩ Input to Output cTÜVus UL/CSA 60950, EN 60950 CE Mark Low voltage directive Mechanical parameters See Mechanical Drawing, Figures 15 and 17 Weight 0.50 / 14 oz / g Dimensions Length 1.26 / 32 in / mm Width 0.85 / 21.5 in / mm Height 0.23 / 6 in / mm Auxiliary Pins (Conditions are at 48 Vin, full load, and 25°C ambient unless otherwise specified) Parameter Min Typ Max Unit DC voltage 4.8 5.0 5.2 Vdc Module disable voltage 2.4 2.5 2.6 Vdc 2.5 2.9 mA Note Primary control (PC) Module enable voltage Current limit 2.4 2.5 Vdc Enable delay time 80 ms Disable delay time 10 µs Figure 12— VOUT at full load vs. PC disable vicorpower.com Source only See Fig.12 time from PC low to output low Figure 13— PC signal during fault 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 5 of 16 PRELIMINARY Specifications V•I Chip Voltage Transformation Module (continued) Thermal Symbol Parameter Min Typ Max Unit Over temperature shutdown 125 130 135 °C Thermal capacity 0.61 Ws/°C RθJC Junction-to-case thermal impedance 1.1 1.5 RθJB Junction-to-BGA thermal impedance 2.1 2.5 °C/W RθJA Junction-to-ambient (1) 6.5 7.2 °C/W RθJA Junction-to-ambient (2) 5.0 5.5 °C/W Note Junction temperature BGA package °C/W Notes: (1 B048K120T30 surface mounted in-board to a 2" x 2" FR4 board, 4 layers 2 oz Cu, 300 LFM. (2) B048K120T30 with optional 0.25"H Pin Fins surface mounted on FR4 board, 300 LFM. V•I Chip Stress Driven Product Qualification Process Test Standard Environment High Temperature Operational Life (HTOL) Temperature cycling High temperature storage Moisture resistance Temperature Humidity Bias Testing (THB) Pressure cooker testing (Autoclave) Highly Accelerated Stress Testing (HAST) Solvent resistance/marking permanency Mechanical vibration Mechanical shock Electro static discharge testing – human body model Electro static discharge testing – machine model JESD22-A-108-B JESD22-A-104B JESD22-A-103A JESD22-A113-B EIA/JESD22-A-101-B JESD22-A-102-C JESD22-A-110B JESD22-B-107-A JESD22-B-103-A JESD22-B-104-A EIA/JESD22-A114-A EIA/JESD22-A115-A Per Vicor Internal Test Specification(1) 125°C, Vmax, 1,008 hrs -55°C to 125°C, 1,000 cycles 150°C, 1,000 hrs Moisture sensitivity Level 5 85°C, 85% RH, Vmax, 1,008 hrs 121°C, 100% RH, 15 PSIG, 96 hrs 130°C, 85% RH, Vmax, 96 hrs Solvents A, B & C as defined 20g peak, 20-2,000 Hz, test in X, Y & Z directions 1,500g peak 0.5 ms pulse duration, 5 pulses in 6 directions Meets or exceeds 2,000 Volts Meets or exceeds 200 Volts Highly Accelerated Life Testing (HALT) Per Vicor internal test specification(1) Dynamic cycling Operation limits verified, destruct margin determined Constant line, 0-100% load, -20°C to 125°C Note: (1) For details of the test protocols see Vicor’s website. V•I Chip Ball Grid Array Interconnect Qualification Test BGA solder fatigue evaluation Solder ball shear test vicorpower.com Standard Environment IPC-9701 Cycle condition: TC3 (-40 to +125°C) IPC-SM-785 Test duration: NTC-B (500 failure free cycles) IPC-9701 Failure through bulk solder or copper pad lift-off 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 6 of 16 PRELIMINARY Pin/Control Functions V•I Chip Voltage Transformation Module +IN/-IN – DC Voltage Input Ports The V•I Chip input voltage range should not be exceeded. An internal under/over voltage lockout-function prevents operation outside of the normal operating input range. The BCM turns ON within an input voltage window bounded by the “Input under-voltage turn-on” and “Input over-voltage turn-off” levels, as specified. The V•I Chip may be protected against accidental application of a reverse input voltage by the addition of a rectifier in series with the positive input, or a reverse rectifier in shunt with the positive input located on the load side of the input fuse. The connection of the V•I Chip to its power source should be implemented with minimal distribution inductance. If the interconnect inductance exceeds 100 nH, the input should be bypassed with a RC damper to retain low source impedance and stable operation. With an interconnect inductance of 200 nH, the RC damper may be a 47 µF in series with 0.3Ω. A single electrolytic or equivalent low-Q capacitor may be used in place of the series RC bypass. 4 3 +Out -Out +Out -Out 21 A B C D E F G H J K L M N P R T U V W Y AA AB AC AD AE AF AG AH AJ AK AL A B C D E F G H J K L M N P R T U V W Y AA AB AC AD AE AF AG AH AJ AK AL +In TM RSV PC -In Bottom View PC – Primary Control The Primary Control port is a multifunction node that provides the following functions: Enable/Disable – If the PC port is left floating, the BCM output is enabled. Once this port is pulled lower than 2.4 Vdc with respect to –In, the output is disabled. This action can be realized by employing a relay, opto-coupler, or open collector transistor. Refer to Figures 1-3, 12 and 13 for the typical Enable/Disable characteristics. This port should not be toggled at a rate higher than 1 Hz. The PC port should also not be driven by or pulled up to an external voltage source. Primary Auxiliary Supply – The PC port can source up to 2.4 mA at 5.0 Vdc. The PC port should never be used to sink current. Alarm – The BCM contains circuitry that monitors output overload, input over voltage or under voltage, and internal junction temperatures. In response to an abnormal condition in any of the monitored parameters, the PC port will toggle. Refer to Figure 13 for PC alarm characteristics. Signal NameDesignation +In –In TM RSV PC +Out –Out BGA A1-L1, A2-L2 AA1-AL1, AA2-AL2 P1, P2 T1, T2 V1, V2 A3-G3, A4-G4, U3-AC3, U4-AC4 J3-R3, J4-R4, AE3-AL3, AE4-AL4 Figure 14—BCM BGA configuration TM and RSV – Reserved for factory use. +OUT/-OUT – DC Voltage Output Ports Two sets of contacts are provided for the +Out port. They must be connected in parallel with low interconnect resistance. Similarly, two sets of contacts are provided for the –Out port. They must be connected in parallel with low interconnect resistance. Within the specified operating range, the average output voltage is defined by the Level 1 DC behavioral model of Figure 25. The current source capability of the BCM is rated in the specifications section of this document. The low output impedance of the BCM, reduces or eliminates the need for limited life aluminum electrolytic or tantalum capacitors at the input of POL converters. Total load capacitance at the output of the BCM should not exceed the specified maximum. Owing to the wide bandwidth and low output impedance of the BCM, low frequency bypass capacitance and significant energy storage may be more densely and efficiently provided by adding capacitance at the input of the BCM. vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 7 of 16 PRELIMINARY Mechanical Drawings V•I Chip Voltage Transformation Module 1,00 0.039 5,9 0.23 21,5 0.85 SOLDER BALL #A1 INDICATOR 0.020 (106) X Ø 0.51 1,00 0.039 18,00 0.709 9,00 0.354 SOLDER BALL SOLDER BALL #A1 OUTPUT 28,8 1.13 30,00 1.181 INPUT OUTPUT 32,0 1.26 INPUT 1,00 TYP 0.039 C L 15,00 0.591 16,0 0.63 C L 1,6 0.06 TOP VIEW (COMPONENT SIDE) 1,00 0.039 BOTTOM VIEW 3,9 0.15 15,6 0.62 NOTES: mm 1- DIMENSIONS ARE inch . 2- UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X/[.XX] = +/-0.25/[.01]; .XX/[.XXX] = +/-0.13/[.005] 3- PRODUCT MARKING ON TOP SURFACE SEATING PLANE Figure 15— BCM BGA mechanical outline; Inboard mounting IN-BOARD MOUNTING BGA surface mounting requires a cutout in the PCB in which to recess the V•I Chip 1,50 0.059 ( 1,00 ) 0.039 (ø 0,51 ) 0.020 0,50 0.020 SOLDER MASK DEFINED PADS ø 0,53 PLATED VIA 0.021 CONNECT TO INNER LAYERS 0,50 0.020 ( 1,00 ) 0.039 1,00 0.039 1,00 0.039 18,00 0.709 1,00 0.039 9,00 0.354 SOLDER PAD #A1 1 (4) X 6,00 0.236 +IN +OUT1 (2) X 10,00 0.394 -OUT1 (COMPONENT SIDE SHOWN) 29,26 1.152 RSV TM RECOMMENDED LAND AND VIA PATTERN PCB CUTOUT 24,00 0.945 16,00 0.630 NOTES: mm 1- DIMENSIONS ARE inch . 2- UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X/[.XX] = +/-0.25/[.01]; .XX/[.XXX] = +/-0.13/[.005] 8,00 0.315 -OUT2 -IN PC +OUT2 20,00 0.787 17,00 0.669 15,00 13,00 0.591 0.512 31 0,51 (106) X ø 0.020 SOLDER MASK DEFINED PAD 0,37 0.015 8,08 0.318 16,16 0.636 1,6 (4) X R 0.06 Figure 16—BCM BGA PCB land/VIA layout information; Inboard mounting vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 8 of 16 PRELIMINARY Mechanical Drawings (continued) V•I Chip Voltage Transformation Module 6,1 0.24 22,0 0.87 15,99 0.630 3,01 0.118 3,01 0.118 INPUT OUTPUT 11,10 (2) PL. 0.437 24,00 0.945 OUTPUT 32,0 1.26 INPUT (4) PL. 7,10 0.280 CL 16,00 0.630 15,55 0.612 12,94 0.509 8,00 0.315 20,00 0.787 C L 0,45 0.018 TOP VIEW (COMPONENT SIDE) 14,94 0.588 16,94 0.667 BOTTOM VIEW NOTES: 1- DIMENSIONS ARE mm/[INCH]. 2- UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X/[.XX] = +/-0.25/[.01]; .XX/[.XXX] = +/-0.13/[.005] 3- PRODUCT MARKING ON TOP SURFACE. Figure 17— BCM J-Lead mechanical outline; Onboard mounting 3,26 0.128 3,26 0.128 15,74 0.620 0,51 TYP 0.020 (2) X14,94 0.588 -OUT2 12,94 (2) X 0.509 -IN 20,00 (2) X 0.787 (2) X16,94 0.667 +OUT2 PC RSV TM 1,60 0.063 7,48 (8) X 0.295 -OUT1 (6) X +OUT1 (4) X 11,48 0.452 +IN 1,38 0.054 TYP (2) X 24,00 0.945 (2) X 16,00 0.630 8,00 (2) X 0.315 RECOMMENDED LAND PATTERN (COMPONENT SIDE SHOWN) NOTES: 1- DIMENSIONS ARE mm/[INCH]. 2- UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X/[.XX] = +/-0.25/[.01]; .XX/[.XXX] = +/-0.13/[.005] Figure 18— BCM J-Lead PCB land layout information; Onboard mounting vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 9 of 16 PRELIMINARY Configuration Options V•I Chip Voltage Transformation Module Configuration Inboard (1) (Package K) Onboard (1) (Package F) Inboard with 0.25" Pin Fins (2) Onboard with 0.25" Pin Fins (2) Effective power density 1750 W/in3 1090 W/in3 680 W/in3 550 W/in3 2.1 °C/W 2.4 °C/W 2.1 °C/W 2.4 °C/W 1.1 °C/W 1.1 °C/W N/A N/A 6.5 °C/W 6.8 °C/W 5.0 °C/W 5.0 °C/W Junction-Board thermal resistance Junction-Case thermal resistance Junction-Ambient thermal resistance 300LFM Notes: (1) Surface mounted to a 2" x 2" FR4 board, 4 layers 2 oz Cu (2) Pin Fin heat sink available as a separate item 21.5 0.85 22.0 0.87 32.0 1.26 32.0 1.26 4.0 0.16 6.3 0.25 ONBOARD MOUNT INBOARD MOUNT (V•I Chip recessed into PCB) mm in mm in Figure 20— Onboard mounting – package F Figure 19—Inboard mounting – package K Input reflected ripple measurement point F1 15 A Fuse +Out +In + Enable/Disable Switch -Out C1 47 µF R2 2K Ω electrolytic SW1 TM RSV PC D1 -In BCM K Ro R3 10 mΩ typ. +Out -Out Load C3 10 µF – Notes: Source inductance should be no more than 200 nH. If source inductance is greater than 200 nH, additional bypass capacitance may be required. C3 should be placed close to the load. R3 may be ESR of C3 or a seperate damping resistor. D1 power good indicator will dim when a module fault is detected. Figure 21—BCM test circuit vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 10 of 16 PRELIMINARY Application Note V•I Chip Voltage Transformation Module Parallel Operation The BCM will inherently current share when properly configured in an array of BCMs. Arrays may be used for higher power or redundancy in an application. Current sharing accuracy is maximized when the source and load impedance presented to each BCM within an array are equal. The recommended method to achieve matched impedances is to dedicate common copper planes within the PCB to deliver and return the current to the array, rather than rely upon traces of varying lengths. In typical applications the current being delivered to the load is larger than that sourced from the input, allowing traces to be utilized on the input side if necessary. The use of dedicated power planes is, however, preferable. CASE 2—Conduction to the PCB The low thermal resistance Junction-to-BGA, RθJB, allows use of the PCB to exchange heat from the V•I Chip, including convection from the PCB to the ambient or conduction to a cold plate. For example, with a V•I Chip surface mounted on a 2" x 2" area of a multi-layer PCB, with an aggregate 8 oz of effective copper weight, the total Junction-to-Ambient thermal resistance, RθJA, is 6.5°C/W in 300 LFM air flow (see Thermal Resistance section, Page 1). Given a maximum junction temperature of 125°C and 13 W dissipation at 300 W of output power, a temperature rise of 85°C allows the V•I Chip to operate at rated output power at up to 41°C ambient temperature. The BCM power train and control architecture allow bi-directional power transfer, including reverse power processing from the BCM output to its input. Reverse power transfer is enabled if the BCM input is within its operating range and the BCM is otherwise enabled. The BCM’s ability to process power in reverse improves the BCM transient response to an output load dump. Output Power 300 Thermal Management The high efficiency of the V•I Chip results in relatively low power dissipation and correspondingly low generation of heat. The heat generated within internal semiconductor junctions is coupled with low effective thermal resistances, RθJC and RθJB, to the V•I Chip case and its Ball Grid Array allowing thermal management flexibility to adapt to specific application requirements (Figure 22). 0 -40 -20 0 20 40 60 80 100 120 140 Operating Junction Temperature CASE 1 Convection via optional Pin Fins to air. Figure 23— Thermal derating curve BCM with 0.25'' optional Pin Fins 10 9 8 Tja If the application is in a typical environment with forced convection over the surface of the PCB and greater than 0.4" headroom, a simple thermal management strategy is to procure V•I Chips with the Pin Fin option. The total Junction-to-Ambient thermal resistance, RθJA, of a surface mounted V•I Chip with optional 0.25" Pin Fins is 4.8 °C/W in 300 LFM air flow (Figure 24). At full rated output power of 300 W, the heat generated by the BCM is approximately 13 W (Figure 6). Therefore, the junction temperature rise to ambient is approximately 62°C. Given a maximum junction temperature of 125°C, a temperature rise of 62°C allows the V•I Chip to operate at rated output power at up to 63°C ambient temperature. At 100 W of output power, operating ambient temperature extends to 103°C. 7 6 5 4 3 θJC = 1.1°C/W 0 100 200 300 400 500 600 Airflow (LFM) θJB = 2.1°C/W Figure 22—Thermal resistance Figure 24—Junction-to-ambient thermal resistance of BCM with 0.25" Pin Fins (Pin Fins available as a separate item.) vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 11 of 16 PRELIMINARY Application Note (continued) V•I Chip Voltage Transformation Module The TM (Temperature Monitor) port monitors the V•I Chip junction temperature and provides feedback and validation of the thermal management of V•I Chips, as applied in diverse power systems and environments. The thermal resistance of the PCB to the surrounding environment in proximity to V•I Chips may be reduced by low profile heat sinks surface mounted to the PCB.The PCB may also be coupled to a cold plate by low thermal resistance standoff elements as a means of achieving effective cooling for an array of V•I Chips, without a direct interface to their case. CASE 3—Combined direct convection to the air and conduction to the PCB. Parallel use of the V•I Chip internal thermal resistances (including Junctionto-Case and Junction-to-BGA) in series with external thermal resistances provides an efficient thermal management strategy as it reduces total thermal resistance. This may be readily estimated as the parallel network of two pairs of series configured resistors. V•I Chip Bus Converter Level 1 DC Behavioral Model for 48 V to 12 V, 300 W ROUT IOUT + + 11.7 mΩ 1/4 • Iout VIN V•I + + – IQ 99 mA 1/4 • Vin VOUT – K – – © Figure 25—This model characterizes the DC operation of the V•I Chip bus converter, including the converter transfer function and its losses. The model enables estimates or simulations of output voltage as a function of input voltage and output load, as well as total converter power dissipation or heat generation. V•I Chip Bus Converter Level 2 Transient Behavioral Model for 48 V to 12 V, 300 W 8.5 nH ROUT IOUT L IN = 20 nH + 11.7 mΩ RCIN 2.5 mΩ CIN VIN Lout = 1.1 nH V•I 1/4 • Iout + + – 4µF IQ 99 mA RCOUT 40 mΩ + 1 mΩ 1/4 • Vin COUT 55 µF VOUT – K – – © Figure 26—This model characterizes the AC operation of the V•I Chip bus converter including response to output load or input voltage transients or steady state modulations. The model enables estimates or simulations of input and output voltages under transient conditions, including response to a stepped load with or without external filtering elements. vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 12 of 16 PRELIMINARY Application Note (continued) V•I Chip Voltage Transformation Module Input Impedance Recommendations Input Fuse Recommendations To take full advantage of the BCM capabilities, the impedance presented to its input terminals must be low from DC to approximately 5 MHz. The source should exhibit low inductance (less than 100 nH) and should have a critically damped response. If the interconnect inductance exceeds 100 nH, the BCM input pins should be bypassed with an RC damper (e.g., 47 µF in series with 0.3 ohm) to retain low source impedance and stable operations. Given the wide bandwidth of the BCM, the source response is generally the limiting factor in the overall system response. V•I Chips are not internally fused in order to provide flexibility in configuring power systems. However, input line fusing of V•I Chips must always be incorporated within the power system. A fast acting fuse should be placed in series with the +IN port. Anomalies in the response of the source will appear at the output of the BCM multiplied by its K factor. The DC resistance of the source should be kept as low as possible to minimize voltage deviations. This is especially important if the BCM is operated near low or high line as the over/under voltage detection circuitry could be activated. Application Circuits Vo = 9.5 - 13.7 V +Out +In -Out 48 Vin (38 - 55 Vdc) BCM TM RSV PC -In K Ro +Out -Out NiPOL 1 NiPOL 2 NiPOL 3 NiPOL 4 LOAD 1 LOAD 2 LOAD 3 LOAD 4 Figure 27—The BCM provides an isolated output from a narrow range input ideal for driving non-isolated point of load converters (niPOLs) In the following figure; K = BCM Transformation Ratio RO = BCM Output Resistance VO = BCM Output Vf = PRM Output (Factorized Bus Voltage) VL = Desired Load Voltage VS = PRM Output Set Point Voltage FPA Local Loop Vo = VL – IO • RO VC PC TM IL NC PR PRM-AL +In VH SC SG OS NC CD ROS Factorized Power Bus +Out 48 Vin (36 - 75 Vdc) Vf = –In VL K –Out +Out +In -Out TM RSV PC -In BCM K Ro +Out L O A D -Out VS range = 38 - 55 Vdc B048K120T30 (K = 1/4 : RO = 11.7 mΩ) Figure 28—The PRM regulates its output to provide a constant factorized bus voltage. The output voltage is the nominal load voltage, Vo, at no load and decreases with load at a constant rate equal to the BCM output resistance Ro. vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 13 of 16 PRELIMINARY Application Note (continued) V•I Chip Voltage Transformation Module V•I Chip soldering recommendations Removal and rework V•I Chip modules are intended for reflow soldering processes. The following information defines the processing conditions required for successful attachment of a V•I Chip to a PCB. Failure to follow the recommendations provided can result in aesthetic or functional failure of the module. V•I Chip modules can be removed from PCBs using special tools such as those made by Air-Vac. These tools heat a very localized region of the board with a hot gas while applying a tensile force to the component (using vacuum). Prior to component heating and removal, the entire board should be heated to 80-100ºC to decrease the component heating time as well as local PCB warping. If there are adjacent moisture-sensitive components, a 125ºC bake should be used prior to component removal to prevent popcorning. V•I Chip modules should not be expected to survive a removal operation. Storage V•I Chip modules are currently rated at MSL 5. Exposure to ambient conditions for more than 72 hours requires a 24 hour bake at 125ºC to remove moisture from the package. Solder paste stencil design 239 Solder paste is recommended for a number of reasons, including overcoming minor solder sphere co-planarity issues as well as simpler integration into overall SMD process. 63/37 SnPb, either no-clean or water-washable, solder paste should be used. Pb-free development is underway. The recommended stencil thickness is 6 mils. The apertures should be 20 mils in diameter for the Inboard (BGA) application and 0.9-0.9:1 for the Onboard (J-Leaded). Joint Temperature, 220ºC Case Temperature, 208ºC 183 165 degC 91 Pick and place Inboard (BGA) modules should be placed as accurately as possible to minimize any skewing of the solder joint; a maximum offset of 10 mils is allowable. Onboard (J-Leaded) modules should be placed within ±5 mils. 16 Soldering Time Figure 29—Thermal profile diagram To maintain placement position, the modules should not be subjected to acceleration greater than 500 in/sec2 prior to reflow. Reflow There are two temperatures critical to the reflow process; the solder joint temperature and the module’s case temperature. The solder joint’s temperature should reach at least 220ºC, with a time above liquidus (183ºC) of ~30 seconds. The module’s case temperature must not exceed 208 ºC at anytime during reflow. Because of the ∆T needed between the pin and the case, a forced-air convection oven is preferred for reflow soldering. This reflow method generally transfers heat from the PCB to the solder joint. The module’s large mass also reduces its temperature rise. Care should be taken to prevent smaller devices from excessive temperatures. Reflow of modules onto a PCB using Air-Vac-type equipment is not recommended due to the high temperature the module will experience. Figure 30— Properly reflowed V•I Chip J-Lead Inspection For the BGA-version, a visual examination of the post-reflow solder joints should show relatively columnar solder joints with no bridges. An inspection using x-ray equipment can be done, but the module’s materials may make imaging difficult. The J-Lead versions solder joints should conform to IPC 12.2 • Properly wetted fillet must be evident. • Heel fillet height must exceed lead thickness plus solder thickness. vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 Page 14 of 16 Warranty Vicor products are guaranteed for two years from date of shipment against defects in material or workmanship when in normal use and service. This warranty does not extend to products subjected to misuse, accident, or improper application or maintenance. Vicor shall not be liable for collateral or consequential damage. This warranty is extended to the original purchaser only. EXCEPT FOR THE FOREGOING EXPRESS WARRANTY, VICOR MAKES NO WARRANTY, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Vicor will repair or replace defective products in accordance with its own best judgement. For service under this warranty, the buyer must contact Vicor to obtain a Return Material Authorization (RMA) number and shipping instructions. Products returned without prior authorization will be returned to the buyer. The buyer will pay all charges incurred in returning the product to the factory. Vicor will pay all reshipment charges if the product was defective within the terms of this warranty. Information published by Vicor has been carefully checked and is believed to be accurate; however, no responsibility is assumed for inaccuracies. Vicor reserves the right to make changes to any products without further notice to improve reliability, function, or design. Vicor does not assume any liability arising out of the application or use of any product or circuit; neither does it convey any license under its patent rights nor the rights of others. Vicor general policy does not recommend the use of its components in life support applications wherein a failure or malfunction may directly threaten life or injury. Per Vicor Terms and Conditions of Sale, the user of Vicor components in life support applications assumes all risks of such use and indemnifies Vicor against all damages. Vicor’s comprehensive line of power solutions includes high density AC-DC and DC-DC modules and accessory components, fully configurable AC-DC and DC-DC power supplies, and complete custom power systems. Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor components are not designed to be used in applications, such as life support systems, wherein a failure or malfunction could result in injury or death. All sales are subject to Vicor’s Terms and Conditions of Sale, which are available upon request. Specifications are subject to change without notice. Intellectual Property Notice Vicor and its subsidiaries own Intellectual Property (including issued U.S. and Foreign Patents and pending patent applications) relating to the products described in this data sheet. Interested parties should contact Vicor's Intellectual Property Department. Vicor Corporation 25 Frontage Road Andover, MA, USA 01810 Tel: 800-735-6200 Fax: 978-475-6715 email Vicor Express: [email protected] Technical Support: [email protected] vicorpower.com 800-735-6200 V•I Chip Bus Converter Module B048K120T30 Rev. 1.0 01/05