BCM(R) Bus Converter BCM48Bx120y300A00 S (R) US C C NRTL US Isolated Fixed Ratio DC-DC Converter Features & Benefits Product Ratings * 48VDC - 12VDC 300W Bus Converter * High efficiency (>96%) reduces system power consumption * High power density (>1022W/in3) reduces power system footprint by >40% VIN = 48V (38 - 55V) POUT= up to 300W VOUT = 12V (9.5 - 13.8V) (no load) K = 1/4 Description The VI Chip(R) bus converter is a high efficiency (>96%) Sine Amplitude ConverterTM (SACTM) operating from a 38 to 55VDC primary bus to deliver an isolated, ratiometric output voltage from 9.5 to 13.8VDC. The Sine Amplitude Converter offers a low AC impedance beyond the bandwidth of most downstream regulators; therefore capacitance normally at the load can be located at the input to the Sine Amplitude Converter. Since the transformation ratio of the BCM48Bx120y300A00 is 1/4, the capacitance value can be reduced by a factor of 16x, resulting in savings of board area, materials and total system cost. * Contains built-in protection features: n Undervoltage n Overvoltage Lockout n Overcurrent Protection n Short circuit Protection n Overtemperature Protection * Provides enable/disable control, internal temperature monitoring * Can be paralleled to create multi-kW arrays The BCM48BF120y300A00 is provided in a VI Chip package compatible with standard pick-and-place and surface mount assembly processes. The co-molded VI Chip package provides enhanced thermal management due to a large thermal interface area and superior thermal conductivity. The high conversion efficiency of the BCM48Bx120y300A00 increases overall system efficiency and lowers operating costs compared to conventional approaches. Typical Applications * High End Computing Systems * Automated Test Equipment * High Density Power Supplies Part Numbering * Communications Systems Product Number BCM48Bx120y300A00 Package Style (x) Product Grade (y) F = J-Lead T = -40 to 125C T = Through hole M = -55 to 125C For Storage and Operating Temperatures see General Characteristics Typical Application enable / disable switch SW1 F1 PC TM L O A D BCM(R) Bus Converter +IN +OUT -IN -OUT VIN BCM(R) Bus Converter Page 1 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 Pin Configuration 4 3 2 1 A A +OUT B B C C D D E E -OUT F G H H J J +OUT -OUT +IN K K L L M M N N P P R R TM RSV PC -IN T T Bottom View Pin Descriptions Pin Number Signal Name Type Function A1-E1, A2-E2 +IN INPUT POWER Positive input power terminal L1-T1, L2-T2 -IN INPUT POWER RETURN Negative input power terminal H1, H2 TM OUTPUT J1, J2 RSV NC Temperature monitor, input side referenced signal No connect K1, K2 PC OUTPUT/INPUT A3-D3, A4-D4, J3-M3, J4-M4 +OUT OUTPUT POWER Positive output power terminal E3-H3, E4-H4, N3-T3, N4-T4 -OUT OUTPUT POWER RETURN Negative output power terminal BCM(R) Bus Converter Page 2 of 20 Rev 1.8 08/2016 Enable and disable control, input side referenced signal vicorpower.com 800 927.9474 BCM48Bx120y300A00 Absolute Maximum Ratings The absolute maximum ratings below are stress ratings only. Operation at or beyond these maximum ratings can cause permanent damage to the device. Parameter Comments Min Max -1 60 V -1 1 V/s 2250 V -1 16 V -3 37.5 A -2 30 A PC to -IN -0.3 20 V TM to -IN -0.3 7 V +IN to -IN VIN slew rate Operational Isolation voltage, input to ouput +OUT to -OUT Output current transient 10ms, 10% DC Output current average BCM(R) Bus Converter Page 3 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 Unit BCM48Bx120y300A00 Electrical Specifications Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of -40C TCASE 100C (T-Grade); all other specifications are at TCASE = 25C unless otherwise noted. Attribute Symbol Conditions / Notes Min Typ Max Unit 38 55 V 38 55 V Powertrain Input voltage range, continuous Input voltage range, transient VIN_DC VIN_TRANS Quiescent current IQ VIN to VOUT time TON1 Full current or power supported, 50ms max, 10% duty cycle max Disabled, PC Low VIN = 48V, PC floating 340 VIN = 48V, TCASE = 25C No load power dissipation PNL At POUT = 300W POUT_PK Output current (average) IOUT_AVG Output current (peak) IOUT_PK 6.5 15 17 IIN_DC Output power (peak) 5.3 VIN = 38V to 55V DC input current POUT_AVG ms 9 IINR_P Output power (average) mA VIN = 38V to 55V, TCASE = 25C Inrush current peak K 1.0 620 3 VIN = 48V Worse case of: VIN = 55V, COUT = 1000F, RLOAD = 391m Transformation ratio 0.5 450 10 K = VOUT / VIN, at no load 20 A 8.8 A 1/4 10ms max, POUT_AVG 300W 10ms max, IOUT_AVG 30A VIN = 48V, IOUT = 25A; TCASE = 25C 95.0 VIN = 38V to 55V, IOUT = 25A; TCASE = 25C 93.5 W V/V 300 W 450 W 30 A 37.5 A 96.0 Efficiency (ambient) hAMB VIN = 48V, IOUT = 12.5A; TCASE = 25C 94.5 95.5 Efficiency (hot) hHOT VIN = 48V, IOUT = 25A; TCASE = 100C 94.5 95.6 Efficiency (over load range) h20% 5A < IOUT < 25A 80 ROUT_COLD IOUT = 25A, TCASE = -40C 4.9 6.7 12.0 ROUT_AMB IOUT = 25A, TCASE = 25C 6.3 9.0 14.0 ROUT_HOT IOUT = 25A, TCASE = 100C 8.8 11.5 16.0 1.85 1.95 2.05 MHz 285 mV Output resistance % % % m Switching frequency FSW Output voltage ripple VOUT_PP COUT = 0F, IOUT = 25A, VIN = 48V, 20MHz BW 150 Output inductance (parasitic) LOUT_PAR Frequency up to 30MHz, Simulated J-lead model 600 pH Output capacitance (internal) COUT_INT Effective value at 12VOUT 47 F Output capacitance (external) COUT_EXT BCM(R) Bus Converter Page 4 of 20 0 Rev 1.8 08/2016 vicorpower.com 800 927.9474 1000 F BCM48Bx120y300A00 Electrical Specifications (Cont.) Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of -40C TCASE 100C (T-Grade); all other specifications are at TCASE = 25C unless otherwise noted. Attribute Symbol Conditions / Notes Min Typ Max Unit Protection Input overvoltage lockout threshold VIN_OVLO+ 55.1 58.5 60 V Input overvoltage recovery threshold VIN_OVLO- 55.1 58.0 60 V Input overvoltage lockout hysteresis VIN_OVLO_HYST 1.2 V Overvoltage lockout response time TOVLO 8 s TAUTO_RESTART 240 300 380 ms Input undervoltage lockout threshold VIN_UVLO- 28.5 31.1 37.4 V Input undervoltage recovery threshold VIN_UVLO+ 28.5 33.7 37.4 V Input undervoltage lockout hysteresis VIN_UVLO_HYST 1.6 V TUVLO 8 s Undervoltage lockout response time Output overcurrent trip threshold IOCP Output overcurrent response time constant TOCP Short circuit protection trip threshold ISCP Short circuit protection response time TSCP Output Power (W) Thermal shutdown threshold 30 Effective internal RC filter 39 55 A 5.3 ms 30 A 1 s 125 TJ_OTP C 375 50.00 350 43.75 325 37.50 300 31.25 275 25.00 250 18.75 225 12.50 200 6.25 8.70 9.23 9.76 10.29 10.82 11.36 11.89 12.42 12.95 Output Voltage (V) P (ave) P (pk), < 10ms I (ave) Figure 1 -- Safe operating area BCM(R) Bus Converter Page 5 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 I (pk), < 10ms 13.48 14.01 Output Current (A) Fault recovery time BCM48Bx120y300A00 Signal Characteristics Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of -40C TCASE 100C (T-Grade); all other specifications are at TCASE = 25C unless otherwise noted. Primary Control: PC * The PC pin enables and disables the BCM. When held low, the BCM is disabled. * In an array of BCM modules, PC pins should be interconnected to synchronize start up and permit start up into full load conditions. * PC pin outputs 5V during normal operation. PC pin internal bias level drops to 2.5V during fault mode, provided VIN remains in the valid range. SIGNAL TYPE STATE Regular Operation ANALOG OUTPUT Standby Transition Start Up DIGITAL INPUT / OUTPUT ATTRIBUTE SYMBOL MIN TYP MAX UNIT VPC 4.7 5.0 5.3 V PC available current IPC_OP 2.0 3.5 5.0 mA PC source (current) IPC_EN 50 100 PC resistance (internal) RPC_INT 50 150 PC capacitance (internal) CPC_INT PC voltage PC load resistance RPC_S Regular Operation PC enable threshold VPC_EN PC disable threshold VPC_DIS Standby PC disable duration TPC_DIS_T Transition CONDITIONS / NOTES PC threshold hysteresis VPC_HYSTER PC enable to VOUT time TON2 PC disable to standby time TPC_DIS PC fault response time TFR_PC Internal pull down resistor To permit regular operation A 400 k 1000 pF 60 2.0 Minimum time before attempting re-enable 1 VIN = 48V for at least TON1 ms 50 k 2.5 3.0 V 1.95 V s 50 From fault to PC = 2V mV 100 150 s 4 10 s 100 s Temperature Monitor: TM * The TM pin monitors the internal temperature of the controller IC within an accuracy of 5C. * Can be used as a "Power Good" flag to verify that the BCM module is operating. * Is used to drive the internal comparator for Overtemperature Shutdown. SIGNAL TYPE STATE ATTRIBUTE TM voltage range TM voltage reference ANALOG OUTPUT DIGITAL INPUT / OUTPUT Regular Operation Transition Standby SYMBOL CONDITIONS / NOTES TM available current ITM TM gain ATM TM voltage ripple VTM_PP TM capacitance (external) CTM_EXT TM fault response time TFR_TM TM voltage VTM_DIS TM pull down (internal) RTM_INT TJ controller = 27C 3.00 UNIT 4.04 V 3.05 V 100 CTM = 0pF, VIN = 48V, IOUT = 25A 120 From fault to TM = 1.5V 200 mV 50 pF 10 vicorpower.com 800 927.9474 25 40 A mV/C s 0 Internal pull down resistor Reserved for factory use. No connection should be made to this pin. Rev 1.8 08/2016 2.95 MAX 10 Reserved: RSV BCM(R) Bus Converter Page 6 of 20 TYP 2.12 VTM VTM_AMB MIN V 50 k BCM(R) Bus Converter Page 7 of 20 NL 5V 2.5 V 5V 3V PC VUVLO+ VUVLO- Rev 1.8 08/2016 vicorpower.com 800 927.9474 1 A E: TON2 F: TOCP G: TPC-DIS H: TSCP** B D 1: Controller start 2: Controller turn off 3: PC release C *Min value switching off **From detection of error to power train shut down A: TON1 B: TOVLO* C: TAUTO_RESTART D:TUVLO 0.4 V 3 V @ 27C TM LL * K VOUT C 500mS before retrial 3V VIN VOVLO+ VOVLO- 2 F 4: PC pulled low 5: PC released on output SC 6: SC removed IOCP ISSP IOUT E 3 G 4 Notes: H 5 - Timing and signal amplitudes are not to scale - Error pulse width is load dependent 6 BCM48Bx120y300A00 Timing Diagram BCM48Bx120y300A00 Application Characteristics The following values, typical of an application environment, are collected at TCASE = 25C unless otherwise noted. See associated figures for general trend data. 96.5 12 Full Load Efficiency (%) Power Dissipation (W) 11 10 9 8 7 6 5 4 96.0 95.5 95.0 94.5 94.0 38 40 42 44 46 47 49 51 53 55 -40 -20 0 Input Voltage (V) TCASE: -40C 100C V IN: 80 100 38V 48V 55V Power Dissipation (W) 30 92 Efficiency (%) 60 Figure 3 -- Full load efficiency vs. temperature; Vin 97 87 82 77 72 0 5 10 15 20 25 20 15 10 5 0 25 Load Current (A) VIN: 38V 48V 0 5 10 15 20 25 Load Current (A) VIN: 55V Figure 4 -- Efficiency at TCASE = -40C 38V 48V 55V Figure 5 -- Power dissipation at TCASE = -40C 98 24 Power Dissipation (W) Efficiency (%) 40 Case Temperature (C) 25C Figure 2 -- No load power dissipation vs. Vin 67 20 93 88 83 78 18 12 6 0 0 5 VIN: 10 15 20 38V 48V 55V Load Current (A) Figure 6 -- Efficiency at TCASE = 25C BCM(R) Bus Converter Page 8 of 20 25 0 5 10 15 VIN: 38V 48V Figure 7 -- Power dissipation at TCASE = 25C Rev 1.8 08/2016 20 Load Current (A) vicorpower.com 800 927.9474 55V 25 BCM48Bx120y300A00 Application Characteristics (Cont.) 24 Power Dissipation (W) Efficiency (%) 98 93 88 83 78 0 5 10 15 20 18 12 6 0 25 0 5 Load Current (A) 38V VIN: 48V 55V VIN: 14 145 12 125 10 8 6 -40 -20 0 20 40 12.5A 60 80 25 38V 48V 55V 100 85 65 45 25 0 Rev 1.8 08/2016 5 10 15 20 25 Load Current (A) VIN: 25A Figure 10 -- ROUT vs. temperature; nominal input BCM(R) Bus Converter Page 9 of 20 20 105 Case Temperature (C) IOUT: 15 Figure 9 -- Power dissipation at TCASE = 100C Ripple (mV pk-pk) ROUT (m) Figure 8 -- Efficiency at TCASE = 100C 4 10 Load Current (A) 48V Figure 11 -- Vripple vs. Iout: No external Cout, board mounted module, scope setting : 20MHz analog BW vicorpower.com 800 927.9474 BCM48Bx120y300A00 Application Characteristics (Cont.) Figure 12 -- Full load ripple, 330F Cin: No external Cout, Board mounted module, scope setting : 20MHz analog BW Figure 13 -- Start up from application of PC; Vin pre-applied Cout = 1000F Figure 14 -- 0A - 25A transient response: Cin = 330F, Iin measured prior to Cin , no external Cout Figure 15 -- 25A - 0A transient response: Cin = 330F, Iin measured prior to Cin, no external Cout BCM(R) Bus Converter Page 10 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 General Characteristics Specifications apply over all line and load conditions, unless otherwise noted; boldface specifications apply over the temperature range of -40C TCASE 100C (T-Grade); All other specifications are at TCASE = 25C unless otherwise noted. Attribute Symbol Conditions / Notes Min Typ Max Unit Mechanical Length L 32.25 / [1.270] 32.50 / [1.280] 32.75 / [1.289] mm / [in] Width W 21.75 / [0.856] 22.00 / [0.866] 22.25 / [0.876] mm / [in] Height H Volume Vol Weight W 6.48 / [0.255] No heat sink Lead Finish 6.73 / [0.265] 6.98 / [0.275] mm / [in] 4.81 / [0.294] cm3/ [in3] 14.5 / [0.512] g / [oz] Nickel 0.51 2.03 Palladium 0.02 0.15 Gold 0.003 0.051 BCM48Bx120T300A00 (T-Grade) -40 125 BCM48Bx120M300A00 (M-Grade) -55 125 m Thermal Operating temperature TJ Thermal resistance fJC Isothermal heatsink and isothermal internal PCB Thermal capacity C 1 C/W 5 Ws/C Assembly Peak compressive force applied to case (Z-axis) Storage Temperature Supported by J-lead only TST lbs lbs/ in2 BCM48Bx120T300A00 (T-Grade) -40 125 C BCM48Bx120M300A00 (M-Grade) -65 125 C ESDHBM Human Body Model, "JEDEC JESD 22-A114D.01"Class 1D 1000 ESDCDM Charge Device Model, "JEDEC JESD 22-C101-D" 400 ESD Withstand 6 5.41 V Soldering Peak temperature during reflow MSL 4 (Datecode 1528 and later) 245 C Peak time above 217C 60 90 s Peak heating rate during reflow 1.5 3 C/s Peak cooling rate post reflow 1.5 6 C/s 60 VDC Safety Working voltage (IN - OUT) VIN_OUT Isolation voltage (hipot) VHIPOT Isolation capacitance CIN_OUT Unpowered unit Isolation resistance RIN_OUT At 500VDC MTBF 2250 2500 VDC 3200 10 MIL-HDBK-217Plus Parts Count - 25C Ground Benign, Stationary, Indoors / Computer Profile 6.03 MHrs Telcordia Issue 2 - Method I Case III; 25C Ground Benign, Controlled 7.94 MHrs cURus CE Marked for Low Voltage Directive and ROHS recast directive, as applicable. BCM(R) Bus Converter Page 11 of 20 pF M cTUVus Agency approvals / standards 3800 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 Using the Control Signals PC, TM Primary Control (PC) pin can be used to accomplish the following functions: n Logic enable and disable for module: Once TON1 time has been satisfied, a PC voltage greater than VPC_EN will cause the module to start. Bringing PC lower than VPC_DIS will cause the module to enter standby. n Auxiliary voltage source: Once enabled in regular operational conditions (no fault), each BCM module PC provides a regulated 5V, 3.5mA voltage source. n Synchronized start up: In an array of parallel modules, PC pins should be connected to synchronize start up across units. This permits the maximum load and capacitance to scale by the number of paralleled modules. n Output disable: PC pin can be actively pulled down in order to disable the module. Pull down impedance shall be lower than 60. n Fault detection flag: The PC 5V voltage source is internally turned off as soon as a fault is detected. n Note that PC can not sink significant current during a fault condition. The PC pin of a faulted module will not cause interconnected PC pins of other modules to be disabled. Temperature Monitor (TM) pin provides a voltage proportional to the absolute temperature of the converter control IC. It can be used to accomplish the following functions: n Monitor the control IC temperature: The temperature in Kelvin is equal to the voltage on the TM pin scaled by 100. (i.e. 3.0V = 300K = 27C). If a heat sink is applied, TM can be used to protect the system thermally. n Fault detection flag: The TM voltage source is internally turned off as soon as a fault is detected. For system monitoring purposes microcontroller interface faults are detected on falling edges of TM signal. BCM(R) Bus Converter Page 12 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 Sine Amplitude ConverterTM Point of Load Conversion 973pH + VinIN V Rout 9.0m ROUT out IIOUT Lin = 5.7nH RRcCin IN 0.57m CIN C IN 2F IIQQ 109mA + + - - K RRC cout OUT 3.13 V*I 1/4 * Iout Lout = 600pH + 430 1/4 * Vin CCOUT out VVOUT out 47F - - Figure 16 -- VI Chip(R) module AC model The Sine Amplitude Converter (SACTM) uses a high frequency resonant tank to move energy from input to output. The resonant LC tank, operated at high frequency, is amplitude modulated as a function of input voltage and output current. A small amount of capacitance embedded in the input and output stages of the module is sufficient for full functionality and is key to achieving power density. The BCM48Bx120y300A00 SAC can be simplified into the preceeding model. ROUT represents the impedance of the SAC, and is a function of the RDSON of the input and output MOSFETs and the winding resistance of the power transformer. IQ represents the quiescent current of the SAC control, gate drive circuitry, and core losses. The use of DC voltage transformation provides additional interesting attributes. Assuming that ROUT = 0 and IQ = 0A, Eq. (3) now becomes Eq. (1) and is essentially load independent, resistor R is now placed in series with VIN. At no load: R VOUT = VIN * K (1) VVin in + - SACTM SAC 1/4 KK==1/32 Vout V out K represents the "turns ratio" of the SAC. Rearranging Eq (1): VOUT (2) K= VIN Figure 17 -- K = 1/4 Sine Amplitude Converter with series input resistor The relationship between VIN and VOUT becomes: In the presence of load, VOUT is represented by: VOUT = VIN * K - IOUT * ROUT (3) (5) Substituting the simplified version of Eq. (4) (IQ is assumed = 0A) into Eq. (5) yields: and IOUT is represented by: IIN - IQ IOUT = K BCM(R) Bus Converter Page 13 of 20 VOUT = (VIN - IIN * R) * K (4) Rev 1.8 08/2016 VOUT = VIN * K - IOUT * R * K2 vicorpower.com 800 927.9474 (6) BCM48Bx120y300A00 This is similar in form to Eq. (3), where ROUT is used to represent the characteristic impedance of the SACTM. However, in this case a real R on the input side of the SAC is effectively scaled by K 2 with respect to the output. Assuming that R = 1, the effective R as seen from the secondary side is 62.5m, with K = 1/4. A similar exercise should be performed with the additon of a capacitor or shunt impedance at the input to the SAC. A switch in series with VIN is added to the circuit. This is depicted in Figure 18. S VVin in + - C SACTM SAC K = 1/4 K = 1/32 VVout out Low impedance is a key requirement for powering a highcurrent, low-voltage load efficiently. A switching regulation stage should have minimal impedance while simultaneously providing appropriate filtering for any switched current. The use of a SAC between the regulation stage and the point of load provides a dual benefit of scaling down series impedance leading back to the source and scaling up shunt capacitance or energy storage as a function of its K factor squared. However, the benefits are not useful if the series impedance of the SAC is too high. The impedance of the SAC must be low, i.e. well beyond the crossover frequency of the system. A solution for keeping the impedance of the SAC low involves switching at a high frequency. This enables small magnetic components because magnetizing currents remain low. Small magnetics mean small path lengths for turns. Use of low loss core material at high frequencies also reduces core losses. The two main terms of power loss in the BCM module are: n No load power dissipation (PNL): defined as the power used to power up the module with an enabled powertrain at no load. Figure 18 -- Sine Amplitude ConverterTM with input capacitor A change in VIN with the switch closed would result in a change in capacitor current according to the following equation: n Resistive loss (PR ): refers to the power loss across OUT the BCM module modeled as pure resistive impedance. PDISSIPATED = PNL + PROUT (10) Therefore, IC(t) = C dVIN (7) dt Assume that with the capacitor charged to VIN, the switch is opened and the capacitor is discharged through the idealized SAC. In this case, IC = IOUT * K (8) substituting Eq. (1) and (8) into Eq. (7) reveals: POUT = PIN - PDISSIPATED = PIN - PNL - PROUT The above relations can be combined to calculate the overall module efficiency: POUT PIN - PNL - PROUT h = = P P IN IN = VIN * IIN - PNL - (IOUT)2 * ROUT VIN * IIN IOUT = C * dVOUT K2 dt (9) = 1 - (PNL + (IOUT)2 * ROUT) VIN * IIN The equation in terms of the output has yielded a K 2 scaling factor for C, specified in the denominator of the equation. A K factor less than unity results in an effectively larger capacitance on the output when expressed in terms of the input. With a K = 1/4 as shown in Figure 18, C = 1F would appear as C = 16F when viewed from the output. BCM(R) Bus Converter Page 14 of 20 Rev 1.8 08/2016 (11) vicorpower.com 800 927.9474 (12) BCM48Bx120y300A00 Input and Output Filter Design A major advantage of SACTM systems versus conventional PWM converters is that the transformers do not require large functional filters. The resonant LC tank, operated at extreme high frequency, is amplitude modulated as a function of input voltage and output current and efficiently transfers charge through the isolation transformer. A small amount of capacitance embedded in the input and output stages of the module is sufficient for full functionality and is key to achieve power density. This paradigm shift requires system design to carefully evaluate external filters in order to: 1. Guarantee low source impedance: Within this frequency range, capacitance at the input appears as effective capacitance on the output per the relationship defined in Eq. 13. COUT = CIN K2 This enables a reduction in the size and number of capacitors used in a typical system. Thermal Considerations To take full advantage of the BCM module's dynamic response, the impedance presented to its input terminals must be low from DC to approximately 5MHz. The connection of the bus converter module to its power source should be implemented with minimal distribution inductance. If the interconnect inductance exceeds 100nH, the input should be bypassed with a RC damper to retain low source impedance and stable operation. With an interconnect inductance of 200nH, the RC damper may be as high as 1F in series with 0.3. A single electrolytic or equivalent low-Q capacitor may be used in place of the series RC bypass. 2. Further reduce input and/or output voltage ripple without sacrificing dynamic response: Given the wide bandwidth of the module, the source response is generally the limiting factor in the overall system response. Anomalies in the response of the source will appear at the output of the module multiplied by its K factor. This is illustrated in Figures 14 and 15. VI Chip(R) products are multi-chip modules whose temperature distribution varies greatly for each part number as well as with the input / output conditions, thermal management and environmental conditions. Maintaining the top of the BCM48Bx120y300A00 case to less than 100C will keep all junctions within the VI Chip module below 125C for most applications. The percent of total heat dissipated through the top surface versus through the J-lead is entirely dependent on the particular mechanical and thermal environment. The heat dissipated through the top surface is typically 60%. The heat dissipated through the J-lead onto the PCB surface is typically 40%. Use 100% top surface dissipation when designing for a conservative cooling solution. It is not recommended to use a VI Chip module for an extended period of time at full load without proper heat sinking. 3. Protect the module from overvoltage transients imposed by the system that would exceed maximum ratings and cause failures: The module input/output voltage ranges shall not be exceeded. An internal overvoltage lockout function prevents operation outside of the normal operating input range. Even during this condition, the powertrain is exposed to the applied voltage and power MOSFETs must withstand it. A criterion for protection is the maximum amount of energy that the input or output switches can tolerate if avalanched. Total load capacitance at the output of the BCM module shall not exceed the specified maximum. Owing to the wide bandwidth and low output impedance of the module, low-frequency bypass capacitance and significant energy storage may be more densely and efficiently provided by adding capacitance at the input of the module. At frequencies <500kHz the module appears as an impedance of ROUT between the source and load. BCM(R) Bus Converter Page 15 of 20 (13) Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 Current Sharing Fuse Selection The performance of the SACTM topology is based on efficient transfer of energy through a transformer without the need of closed loop control. For this reason, the transfer characteristic can be approximated by an ideal transformer with a positive temperature coefficient series resistance. In order to provide flexibility in configuring power systems VI Chip(R) modules are not internally fused. Input line fusing of VI Chip products is recommended at system level to provide thermal protection in case of catastrophic failure. This type of characteristic is close to the impedance characteristic of a DC power distribution system both in dynamic (AC) behavior and for steady state (DC) operation. When multiple BCM modules of a given part number are connected in an array they will inherently share the load current according to the equivalent impedance divider that the system implements from the power source to the point of load. Some general recommendations to achieve matched array impedances include: n Dedicate common copper planes within the PCB to deliver and return the current to the modules. n Apply same input / output filters (if present) to each unit. For further details see AN:016 Using BCM Bus Converters in High Power Arrays. ZIN_EQ1 BCM(R)1 ZOUT_EQ1 R0_1 ZIN_EQ2 BCM(R)2 n Current rating (usually greater than maximum current of BCM module) n Maximum voltage rating (usually greater than the maximum possible input voltage) n Ambient temperature n Nominal melting I2t n Recommend fuse: 10A Littlefuse Nano2 Fuse. Reverse Operation n Provide as symmetric a PCB layout as possible among modules VIN The fuse shall be selected by closely matching system requirements with the following characteristics: The BCM48Bx120y300A00 has not been qualified for continuous operation in a reverse power condition. Furthermore fault protections which help protect the module in forward operation will not fully protect the module in reverse operation. VOUT Transient operation in reverse is expected in cases where there is significant energy storage on the output and transient voltages appear on the input. Transient reverse power operation of less than 10ms, 10% duty cycle is permitted and has been qualified to cover these cases. ZOUT_EQ2 R0_2 + DC BCM modules are capable of reverse power operation. Once the unit is started, energy will be transferred from secondary back to the primary whenever the secondary voltage exceeds VIN * K. The module will continue operation in this fashion for as long as no faults occur. Load ZIN_EQn BCM(R)n ZOUT_EQn R0_n Figure 19 -- BCM module array BCM(R) Bus Converter Page 16 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 J-Lead Package Mechanical Drawing mm (inch) NOTES: mm 1. DIMENSIONS ARE inch . 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. NOTES: PRODUCT MARKING ON mmTOP SURFACE 1. DIMENSIONS ARE inch . DXF and PDF files are available on vicorpower.com 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com J-Lead Package Recommended Land Pattern NOTES: mm 1. DIMENSIONS ARE inch . 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. NOTES: PRODUCT MARKING ON mmTOP SURFACE 1. DIMENSIONS ARE inch . DXF and PDF files are available on vicorpower.com 2. UNLESS OTHERWISE SPECIFIED, TOLERANCES ARE: .X / [.XX] = +/-0.25 / [.01]; .XX / [.XXX] = +/-0.13 / [.005] 3. PRODUCT MARKING ON TOP SURFACE DXF and PDF files are available on vicorpower.com BCM(R) Bus Converter Page 17 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 Through Hole Package Mechanical Drawing mm (inch) TOP VIEW ( COMPONENT SIDE ) TOP VIEW ( COMPONENT SIDE ) NOTES: NOTES:1. DIMENSIONS ARE (mm). inch (mm) 2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE: 1. DIMENSIONS ARE inch . X.X [X.XX] = 0.25 [0.01]; X.XX [X.XXX] = 0.13 [0.005] 2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE: 3. RoHS COMPLIANT PER[X.XXX] CST-0001 LATEST REVISION X.X [X.XX] = 0.25 [0.01]; X.XX = 0.13 [0.005] 3. RoHSDXF COMPLIANT PERare CST-0001 REVISION and PDF files availableLATEST on vicorpower.com DXF and PDF files are available on vicorpower.com Through Hole Package Recommended Land Pattern NOTES: NOTES:1. DIMENSIONS ARE (mm). inch (mm) 2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE: 1. DIMENSIONS ARE inch . X.X [X.XX] = 0.25 [0.01]; X.XX [X.XXX] = 0.13 [0.005] 2. UNLESS OTHERWISE SPECIFIED TOLERANCES ARE: 3. RoHS COMPLIANT PER[X.XXX] CST-0001 LATEST REVISION X.X [X.XX] = 0.25 [0.01]; X.XX = 0.13 [0.005] RECOMMENDED HOLE PATTERN ( COMPONENT SHOWN ) RECOMMENDED HOLESIDE PATTERN ( COMPONENT SIDE SHOWN ) 3. RoHSDXF COMPLIANT PERare CST-0001 REVISION and PDF files availableLATEST on vicorpower.com DXF and PDF files are available on vicorpower.com BCM(R) Bus Converter Page 18 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474 BOTTOM VIEW BOTTOM VIEW BCM48Bx120y300A00 Recommended Heat Sink Push Pin Location (NO GROUNDING CLIPS) (WITH GROUNDING CLIPS) Notes: 1. Maintain 3.50 (0.138) Dia. keep-out zone free of copper, all PCB layers. 2. (A) Minimum recommended pitch is 39.50 (1.555). This provides 7.00 (0.275) component edge-to-edge spacing, and 0.50 (0.020) clearance between Vicor heat sinks. (B) Minimum recommended pitch is 41.00 (1.614). This provides 8.50 (0.334) component edge-to-edge spacing, and 2.00 (0.079) clearance between Vicor heat sinks. BCM(R) Bus Converter Page 19 of 20 3. VI Chip(R) module land pattern shown for reference only; actual land pattern may differ. Dimensions from edges of land pattern to push-pin holes will be the same for all full-size VI Chip(R) products. 5. Unless otherwise specified: Dimensions are mm (inches) tolerances are: x.x (x.xx) = 0.3 (0.01) x.xx (x.xxx) = 0.13 (0.005) 4. RoHS compliant per CST-0001 latest revision. 6. Plated through holes for grounding clips (33855) shown for reference, heat sink orientation and device pitch will dictate final grounding solution. Rev 1.8 08/2016 vicorpower.com 800 927.9474 BCM48Bx120y300A00 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 makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication. Vicor reserves the right to make changes to any products, specifications, and product descriptions at any time without notice. Information published by Vicor has been checked and is believed to be accurate at the time it was printed; however, Vicor assumes no responsibility for inaccuracies. Testing and other quality controls are used to the extent Vicor deems necessary to support Vicor's product warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. Specifications are subject to change without notice. Vicor's Standard Terms and Conditions All sales are subject to Vicor's Standard Terms and Conditions of Sale, which are available on Vicor's webpage or upon request. Product Warranty In Vicor's standard terms and conditions of sale, Vicor warrants that its products are free from non-conformity to its Standard Specifications (the "Express Limited Warranty"). This warranty is extended only to the original Buyer for the period expiring two (2) years after the date of shipment and is not transferable. UNLESS OTHERWISE EXPRESSLY STATED IN A WRITTEN SALES AGREEMENT SIGNED BY A DULY AUTHORIZED VICOR SIGNATORY, VICOR DISCLAIMS ALL REPRESENTATIONS, LIABILITIES, AND WARRANTIES OF ANY KIND (WHETHER ARISING BY IMPLICATION OR BY OPERATION OF LAW) WITH RESPECT TO THE PRODUCTS, INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OR REPRESENTATIONS AS TO MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, INFRINGEMENT OF ANY PATENT, COPYRIGHT, OR OTHER INTELLECTUAL PROPERTY RIGHT, OR ANY OTHER MATTER. This warranty does not extend to products subjected to misuse, accident, or improper application, maintenance, or storage. Vicor shall not be liable for collateral or consequential damage. Vicor disclaims any and all liability arising out of the application or use of any product or circuit and assumes no liability for applications assistance or buyer product design. Buyers are responsible for their products and applications using Vicor products and components. Prior to using or distributing any products that include Vicor components, buyers should provide adequate design, testing and operating safeguards. Vicor will repair or replace defective products in accordance with its own best judgment. 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. Life Support Policy VICOR'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF VICOR CORPORATION. As used herein, life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Per Vicor Terms and Conditions of Sale, the user of Vicor products and components in life support applications assumes all risks of such use and indemnifies Vicor against all liability and damages. 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. No license, whether express, implied, or arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Interested parties should contact Vicor's Intellectual Property Department. The products described on this data sheet are protected by the following U.S. Patents Numbers: 5,945,130; 6,403,009; 6,710,257; 6,911,848; 6,930,893; 6,934,166; 6,940,013; 6,969,909; 7,038,917; 7,145,186; 7,166,898; 7,187,263; 7,202,646; 7,361,844; D496,906; D505,114; D506,438; D509,472; and for use under 6,975,098 and 6,984,965. Vicor Corporation 25 Frontage Road Andover, MA, USA 01810 Tel: 800-735-6200 Fax: 978-475-6715 email Customer Service: custserv@vicorpower.com Technical Support: apps@vicorpower.com BCM(R) Bus Converter Page 20 of 20 Rev 1.8 08/2016 vicorpower.com 800 927.9474