QM48T25050-NDA0

The QM Series of high current single output DC-DC converters sets new standards for thermal performance and power density in the quarter-brick package. The QM48T/S25050 converters of the QM Series provide thermal performance in high temperature environments that is comparable to or exceeds the industry’s leading 5 V half-bricks. This is accomplished through the use of patent pending circuit, packaging and processing techniques to achieve ultrahigh efficiency, excellent thermal management, and a very low body profile. Low body profile and the preclusion of heat sinks minimize impedance to system airflow, thus enhancing cooling for both upstream and downstream devices. The use of 100% automation for assembly, coupled with advanced electric and thermal design, results in a product with extremely high reliability. Operating from a 36-75 V input, the QM Series converters provide outputs that can be trimmed from –20% to +10% of the nominal output voltage, thus providing outstanding design flexibility. • • • • • • • • • • • • • • • • • • • • • • • • RoHS lead-free solder and lead-solder-exempted products are available Delivers up to 25 A @ 5.0 V Industry-standard quarter brick pinout On-board input differential LC-filter High efficiency – no heat sink required Start-up into pre-biased output No minimum load required Available in through-hole and surface-mount packages Low profile: 0.28” [7.1 mm] SMT version, 0.31” [7.9 mm] TH version Low weight: 1.1 oz [31.5 g] typical Meets Basic Insulation requirements of EN 60950-1 Withstands 100 V input transient for 100 ms Fixed-frequency operation Fully protected Remote output sense Output voltage trim range: +10%/−20% with industry-standard trim equations High reliability: MTBF of 2.6 million hours, calculated per Telcordia TR-332, Method I Case 1 Positive or negative logic ON/OFF option Approved to the following safety standards: UL/CSA 60950-1, EN 62368-1, IEC 60950-1 & IEC 62368-1 Meets conducted emissions requirements of FCC Class B and EN 55022 Class B with external filter All materials meet UL94, V-0 flammability rating QM48T25050/QM48S25050 2 Conditions: TA = 25ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified. PARAMETER CONDITIONS / DESCRIPTION MIN TYP MAX UNITS Absolute Maximum Ratings Input Voltage 0 80 VDC Operating Ambient Temperature Continuous -40 85 °C Storage Temperature -55 125 °C Input Characteristics Operating Input Voltage Range 36 48 75 VDC Input Under Voltage Lockout Turn-on Threshold Non-latching 33 34 35 VDC Input Under Voltage Lockout Turn-off Threshold 31 32 33 VDC 100 VDC Input Voltage Transient 100 ms Maximum Input Current 25 ADC, 5 VDC Out @ 36 VDC In Input Stand-by Current Vin = 48 V, converter disabled 2.65 mADC Input No Load Current (0 load on the output) Vin = 48 V, converter enabled 52 mADC Input Reflected-Ripple Current 25 MHz bandwidth 12.5 mAPK-PK Input Voltage Ripple Rejection 120 Hz TBD dB 3.9 ADC Output Characteristics External Load Capacitance Plus full load (resistive) Output Current Range 0 Current Limit Inception Non-latching Peak Short-Circuit Current Non-latching. Short = 10 mΩ. RMS Short-Circuit Current Non-latching Output Voltage Set Point (no load) 27.75 31 4.950 10,000 μF 25 ADC 36.9 A 50 A 6.5 Arms 5.000 5.050 VDC Output Regulation Over Line ±2 ±5 mV Output Regulation Overload ±2 ±5 mV 5.075 VDC 50 mVPK-PK Output Voltage Range Over line, load and temperature2 Output Ripple and Noise - 25 MHz bandwidth Full load + 10 μF tantalum + 1 μF ceramic 4.925 30 Isolation Characteristics I/O Isolation 2000 Isolation Capacitance VDC 1.4 Isolation Resistance nF 10 MΩ Feature Characteristics Switching Frequency 340 Output Voltage Trim Range1 Industry-std. equations Remote Sense Compensation1 Percent of VOUT(nom) Output Over-Voltage Protection Non-latching Auto-Restart Period Applies to all protection features Turn-On Time -20 117 128 kHz +10 % +10 % 140 % 100 ms 4 ms tech.support@psbel.com QM48T25050/ QM48S25050 3 ON/OFF Control (Positive Logic) Converter Off -20 0.8 VDC Converter On 2.4 20 VDC Converter Off 2.4 20 VDC Converter On -20 0.8 VDC ON/OFF Control (Negative Logic) Dynamic Response Load Change 25% of Iout Max, di/dt = 1 A/μs Co = 470 μF tantalum + 1 μF ceramic 120 mV 40 µs 100% Load 89.5 % 50% Load 90.5 % Setting Time to 1% Efficiency 1) 2) Vout can be increased up to 10% via the sense leads or up to 10% via the trim function, however total output voltage trim from all sources should not exceed 10% of VOUT(nom), in order to insure specified operation of over-voltage protection circuitry. -40ºC to 85ºC 2.1 These power converters have been designed to be stable with no external capacitors when used in low inductance input and output circuits. However, in many applications, the inductance associated with the distribution from the power source to the input of the converter can affect the stability of the converter. The addition of a 33 µF electrolytic capacitor with an ESR < 1 across the input helps ensure stability of the converter. In many applications, the user has to use decoupling capacitance at the load. The power converter will exhibit stable operation with external load capacitance up to 2,200 µF on 5 V output. 2.2 The ON/OFF pin is used to turn the power converter on or off remotely via a system signal. There are two remote control options available, positive logic and negative logic and both are referenced to Vin(-). Typical connections are shown in Fig. 1. Vin (+) QmaX TM Series Converter (Top View) ON/OFF Vin Vout (+) SENSE (+) TRIM Rload SENSE (-) Vin (-) Vout (-) CONTROL INPUT Figure 1. Circuit configuration for ON/OFF function. The positive logic version turns on when the ON/OFF pin is at logic high and turns off when at logic low. The converter is on when the ON/OFF pin is left open. The negative logic version turns on when the pin is at logic low and turns off when the pin is at logic high. The ON/OFF pin can be hard wired directly to Vin(-) to enable automatic power up of the converter without the need of an external control signal. Asia-Pacific +86 755 298 85888 Europe, Middle East +353 61 49 8941 North America +1 866 513 2839 © 2022 Bel Power Solutions & Protection BCD.00631_AB4 QM48T25050/QM48S25050 4 ON/OFF pin is internally pulled-up to 5 V through a resistor. A mechanical switch, open collector transistor, or FET can be used to drive the input of the ON/OFF pin. The device must be capable of sinking up to 0.2 mA at a low level voltage of  0.8 V. An external voltage source of ±20 V max. may be connected directly to the ON/OFF input, in which case it should be capable of sourcing or sinking up to 1 mA depending on the signal polarity. See the Start-up Information section for system timing waveforms associated with use of the ON/OFF pin. 2.3 The remote sense feature of the converter compensates for voltage drops occurring between the output pins of the converter and the load. The SENSE(-) (Pin 5) and SENSE(+) (Pin 7) pins should be connected at the load or at the point where regulation is required (see Fig. 2). Vin (+) QmaX TM Series Converter Vout (+) Rw 100 (Top View) ON/OFF Vin SENSE (+) TRIM Rload SENSE (-) 10 Vin (-) Vout (-) Rw Figure 2. Remote sense circuit configuration If remote sensing is not required, the SENSE(-) pin must be connected to the Vout(-) pin (Pin 4), and the SENSE(+) pin must be connected to the Vout(+) pin (Pin 8) to ensure the converter will regulate at the specified output voltage. If these connections are not made, the converter will deliver an output voltage that is slightly higher than the specified value. Because the sense leads carry minimal current, large traces on the end-user board are not required. However, sense traces should be located close to a ground plane to minimize system noise and ensure optimum performance. When wiring discretely, twisted pair wires should be used to connect the sense lines to the load to reduce susceptibility to noise. The converter’s output overvoltage protection (OVP) senses the voltage across Vout(+) and Vout(-), and not across the sense lines, so the resistance (and resulting voltage drop) between the output pins of the converter and the load should be minimized to prevent unwanted triggering of the OVP. When utilizing the remote sense feature, care must be taken not to exceed the maximum allowable output power capability of the converter, equal to the product of the nominal output voltage and the allowable output current for the given conditions. When using remote sense, the output voltage at the converter can be increased by as much as 10% above the nominal rating in order to maintain the required voltage across the load. Therefore, the designer must, if necessary, decrease the maximum current (originally obtained from the derating curves) by the same percentage to ensure the converter’s actual output power remains at or below the maximum allowable output power. 2.4 The output voltage can be adjusted up 10% or down 20% relative to the rated output voltage by the addition of an externally connected resistor. The TRIM pin should be left open if trimming is not being used. To minimize noise pickup, a 0.1 µF capacitor is connected internally between the TRIM and SENSE(-) pins. To increase the output voltage, refer to Fig. 3. A trim resistor, RT-INCR, should be connected between the TRIM (Pin 6) and SENSE(+) (Pin 7), with a value of: RT−INCR = 5.11(100 + Δ)VO−NOM − 626 − 10.22 [kΩ] 1.225Δ where, RT-INCR = Required value of trim-up resistor k] VO-NOM = Nominal value of output voltage [V] Δ= (VO-REQ − VO-NOM) X 100 [%] VO -NOM tech.support@psbel.com QM48T25050/ QM48S25050 5 Vo-REQ = Desired (trimmed) output voltage [V]. When trimming up, care must be taken not to exceed the converter‘s maximum allowable output power. See previous section for a complete discussion of this requirement. QmaX TM Vin (+) Series Converter (Top View) Vin Vout (+) SENSE (+) R T-INCR ON/OFF TRIM Rload SENSE (-) Vin (-) Vout (-) Figure 3. Configuration for increasing output voltage. To decrease the output voltage (Fig. 4), a trim resistor, RT-DECR, should be connected between the TRIM (Pin 6) and SENSE(-) (Pin 5), with a value of: RT−DECR = 511 − 10.22 |Δ | [kΩ] where, RT-DECR Required value of trim-down resistor [k] and Δ is as defined above. Note: The above equations for calculation of trim resistor values match those typically used in conventional industry-standard quarter-bricks. More information can be found in Output Voltage Trim Feature Application Note. Vin (+) QmaX TM Series Converter (Top View) Vin ON/OFF Vout (+) SENSE (+) TRIM Rload R T-DECR SENSE (-) Vin (-) Vout (-) Figure 4. Configuration for decreasing output voltage. Trimming/sensing beyond 110% of the rated output voltage is not an acceptable design practice, as this condition could cause unwanted triggering of the output overvoltage protection (OVP) circuit. The designer should ensure that the difference between the voltages across the converter’s output pins and its sense pins does not exceed 0.50 V, or: [VOUT(+) − VOUT(−)] − [VSENSE (+) − VSENSE (−)]  0.50 [V] This equation is applicable for any condition of output sensing and/or output trim. Asia-Pacific +86 755 298 85888 Europe, Middle East +353 61 49 8941 North America +1 866 513 2839 © 2022 Bel Power Solutions & Protection BCD.00631_AB4 6 QM48T25050/QM48S25050 Input undervoltage lockout is standard with this converter. The converter will shut down when the input voltage drops below a pre-determined voltage. The input voltage must be at least 35 V for the converter to turn on. Once the converter has been turned on, it will shut off when the input voltage drops below 31 V. This feature is beneficial in preventing deep discharging of batteries used in telecom applications. The converter is protected against overcurrent or short-circuit conditions. Upon sensing an overcurrent condition, the converter will switch to constant current operation and thereby begin to reduce output voltage. When the output voltage drops below 60% of the nominal value of output voltage, the converter will shut down. Once the converter has shut down, it will attempt to restart nominally every 100 ms with a typical 3% duty cycle. The attempted restart will continue indefinitely until the overload or short circuit conditions are removed or the output voltage rises above 60% of its nominal value. The converter will shut down if the output voltage across Vout(+) (Pin 8) and Vout(-) (Pin 4) exceeds the threshold of the OVP circuitry. The OVP circuitry contains its own reference, independent of the output voltage regulation loop. Once the converter has shut down, it will attempt to restart every 100 ms until the OVP condition is removed. The converter will shut down under an overtemperature condition to protect itself from overheating caused by operation outside the thermal derating curves, or operation in abnormal conditions such as system fan failure. After the converter has cooled to a safe operating temperature, it will automatically restart. The converters meet North American and International safety regulatory requirements per UL/CSA 60950-1, EN 62368-1, IEC 60950-1 & IEC 62368-1. Basic Insulation is provided between input and output. To comply with safety agencies’ requirements, an input line fuse must be used external to the converter. A fuse with rating of 7 A is recommended for use with this product. EMC requirements must be met at the end-product system level, as no specific standards dedicated to EMC characteristics of board mounted component dc-dc converters exist. However, Bel Power Solutions tests their converters to several system level standards, primary of which is the more stringent EN 55022, Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement. Effective internal LC differential filter significantly reduces input reflected ripple current and improves EMC. With the addition of a simple external filter, all versions of the QM Series of converters pass the requirements of Class B conducted emissions per EN 55022 and FCC, and meet at a minimum, Class A radiated emissions per EN 55022 and Class B per FCC Title 47CFR, Part 15-J. Please contact Bel Power Solution Applications Engineering for details of this testing. Figure 5. Location of the thermocouple for thermal testing tech.support@psbel.com QM48T25050/ QM48S25050 VIN Scenario #1: Initial Startup From Bulk Supply ON/OFF function enabled, converter started via application of VIN. See Figure 6. Time t0 t1 t2 t3 7 Comments ON/OFF pin is ON; system front-end power is toggled on, VIN to converter begins to rise. VIN crosses Under-Voltage Lockout protection circuit threshold; converter enabled. Converter begins to respond to turn-on command (converter turn-on delay). Converter VOUT reaches 100% of nominal value ON/OFF STATE OFF ON VOUT For this example, the total converter startup time (t3- t1) is typically 4 ms. t0 t1 t2 t t3 Figure 6. Start-up scenario #1. Scenario #2: Initial Startup Using ON/OFF Pin With VIN previously powered, converter started via ON/OFF pin. See Figure 7. Time t0 t1 t2 t3 Comments VINPUT at nominal value. Arbitrary time when ON/OFF pin is enabled (converter enabled). End of converter turn-on delay. Converter VOUT reaches 100% of nominal value. VIN ON/OFF STATE OFF ON For this example, the total converter startup time (t3- t1) is typically 4 ms. VOUT t0 t1 t2 t t3 Figure 7. Startup scenario #2. Scenario #3: Turn-off and Restart Using ON/OFF Pin With VIN previously powered, converter is disabled and then enabled via ON/OFF pin. See Figure 8. Time t0 t1 t2 t3 t4 t5 VIN Comments VIN and VOUT are at nominal values; ON/OFF pin ON. ON/OFF pin arbitrarily disabled; converter output falls to zero; turn-on inhibit delay period (100 ms typical) is initiated, and ON/OFF pin action is internally inhibited. ON/OFF pin is externally re-enabled. If (t2- t1) ≤ 100 ms, external action of ON/OFF pin is locked out by startup inhibit timer. If (t2- t1) > 100 ms, ON/OFF pin action is internally enabled. Turn-on inhibit delay period ends. If ON/OFF pin is ON, converter begins turn-on; if off, converter awaits ON/OFF pin ON signal; see Figure 7. End of converter turn-on delay. Converter VOUT reaches 100% of nominal value. 100 ms ON/OFF STATE OFF ON VOUT t0 For the condition, (t2- t1) ≤ 100 ms, the total converter startup time (t5- t2) is typically 104 ms. For (t2- t1) > 100 ms, startup will be typically 4 ms after release of ON/OFF pin. t1 t2 t3 t4 t t5 Figure 8. Startup scenario #3. Asia-Pacific +86 755 298 85888 Europe, Middle East +353 61 49 8941 North America +1 866 513 2839 © 2022 Bel Power Solutions & Protection BCD.00631_AB4 QM48T25050/QM48S25050 8 The converter has been characterized for many operational aspects, to include thermal derating (maximum load current as a function of ambient temperature and airflow) for vertical and horizontal mounting, efficiency, start-up and shutdown parameters, output ripple and noise, transient response to load step-change, overload, and short circuit. The following pages contain specific plots or waveforms associated with the converter. Additional comments for specific data are provided below. All data presented were taken with the converter soldered to a test board, specifically a 0.060” thick printed wiring board (PWB) with four layers. The top and bottom layers were not metalized. The two inner layers, comprising two-ounce copper, were used to provide traces for connectivity to the converter. The lack of metalization on the outer layers as well as the limited thermal connection ensured that heat transfer from the converter to the PWB was minimized. This provides a worstcase but consistent scenario for thermal derating purposes. All measurements requiring airflow were made in vertical and horizontal wind tunnel facilities using Infrared (IR) thermography and thermocouples for thermometry. Ensuring components on the converter do not exceed their ratings is important to maintaining high reliability. If one anticipates operating the converter at or close to the maximum loads specified in the derating curves, it is prudent to check actual operating temperatures in the application. Thermographic imaging is preferable; if this capability is not available, then thermocouples may be used. Bel Power Solutions recommends the use of AWG #40 gauge thermocouples to ensure measurement accuracy. Careful routing of the thermocouple leads will further minimize measurement error. Refer to Figure H for optimum measuring thermocouple location. Load current vs. ambient temperature and airflow rates are given in Figs. 9-12 for vertical and horizontal converter mounting both through-hole and surface mount version. Ambient temperature was varied between 25°C and 85°C, with airflow rates from 30 to 500 LFM (0.15 to 2.5 m/s). For each set of conditions, the maximum load current was defined as the lowest of: (i) The output current at which either any FET junction temperature did not exceed a maximum specified temperature (120°C) as indicated by the thermographic image, or (ii) The nominal rating of the converter (25 A) During normal operation, derating curves with maximum FET temperature less than or equal to 120 °C should not be exceeded. Temperature on the PCB at the thermocouple location shown in Fig. 13 should not exceed 118 °C in order to operate inside the derating curves. 4.4 Fig.13 shows the efficiency vs. load current plot for ambient temperature of 25 ºC, airflow rate of 300 LFM (1.5 m/s) with vertical mounting and input voltages of 36 V, 48 V and 72 V. Also, a plot of efficiency vs. load current, as a function of ambient temperature with Vin = 48 V, airflow rate of 200 LFM (1 m/s) with vertical mounting is shown in Fig. 14. Fig. 15 shows the power dissipation vs. load current plot for Ta = 25ºC, airflow rate of 300 LFM (1.5 m/s) with vertical mounting and input voltages of 36 V, 48 V and 72 V. Also, a plot of power dissipation vs. load current, as a function of ambient temperature with Vin = 48 V, airflow rate of 200 LFM (1 m/s) with vertical mounting is shown in Fig. 16. Output voltage waveforms, during the turn-on transient using the ON/OFF pin for full rated load currents (resistive load) are shown without and with external load capacitance in Fig. 17 and Fig. 18, respectively. Figure 20 shows the output voltage ripple waveform, measured at full rated load current with a 10 µF tantalum and 1 µF ceramic capacitor across the output. Note that all output voltage waveforms are measured across a 1 F ceramic capacitor. The input reflected ripple current waveforms are obtained using the test setup shown in Fig 21. The corresponding waveforms are shown in Figs. 22 and 23. tech.support@psbel.com 9 30 30 25 25 Load Current [Adc] Load Current [Adc] QM48T25050/ QM48S25050 20 15 500 LFM (2.5 m/s) 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 100 LFM (0.5 m/s) 30 LFM (0.15 m/s) 10 5 30 40 15 500 LFM (2.5 m/s) 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 100 LFM (0.5 m/s) 30 LFM (0.15 m/s) 10 5 0 20 20 50 60 70 80 0 90 20 30 40 Ambient Temperature [°C] 30 30 25 25 20 15 500 LFM (2.5 m/s) 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 100 LFM (0.5 m/s) 30 LFM (0.15 m/s) 10 5 70 80 90 20 15 500 LFM (2.5 m/s) 400 LFM (2.0 m/s) 300 LFM (1.5 m/s) 200 LFM (1.0 m/s) 100 LFM (0.5 m/s) 30 LFM (0.15 m/s) 10 5 0 0 20 30 40 50 60 70 80 20 90 30 40 50 60 70 80 90 Ambient Temperature [°C] Ambient Temperature [°C] Figure 11. Available load current vs. ambient temperature and airflow rates for QM48S25050 converter mounted vertically with Vin = 48 V, air flowing from pin 3 to pin 1 and maximum FET temperature  120C. Figure 12. Available load current vs. ambient temperature and airflow rates for QM48S25050 converter mounted horizontally with Vin = 48 V, air flowing from pin 3 to pin 1 and maximum FET temperature  120C. 0.95 0.95 0.90 0.90 0.85 0.85 Efficiency Efficiency 60 Figure 10. Available load current vs. ambient air temperature and airflow rates for QM48T25050 converter with B height pins mounted horizontally with air flowing from pin 3 to pin 1, MOSFET temperature  120C, Vin = 48 V. Load Current [Adc] Load Current [Adc] Figure 9. Available load current vs. ambient air temperature and airflow rates for QM48T25050 converter with B height pins mounted vertically with air flowing from pin 3 to pin 1, MOSFET temperature  120 Cº, Vin = 48 V. 50 Ambient Temperature [°C] 0.80 0.75 72 V 48 V 36 V 0.80 0.75 0.70 70 C 55 C 40 C 0.70 0.65 0.65 0 5 10 15 20 25 30 0 Load Current [Adc] 5 10 15 20 25 30 Load Current [Adc] Figure 13. Efficiency vs. load current and input voltage for converter mounted vertically with air flowing from pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25C. Figure 14. Efficiency vs. load current and ambient temperature for converter mounted vertically with Vin = 48 V and air flowing from pin 3 to pin 1 at a rate of 200 LFM (1.0 m/s). Asia-Pacific +86 755 298 85888 Europe, Middle East +353 61 49 8941 North America +1 866 513 2839 © 2022 Bel Power Solutions & Protection BCD.00631_AB4 QM48T25050/QM48S25050 20.00 20.00 16.00 16.00 Power Dissipation [W] Power Dissipation [W] 10 12.00 8.00 72 V 48 V 36 V 4.00 12.00 8.00 70 C 55 C 40 C 4.00 0.00 0.00 0 5 10 15 20 25 30 Load Current [Adc] 0 5 10 15 20 25 30 Load Current [Adc] Figure 15. Power dissipation vs. load current and input voltage for converter mounted vertically with air flowing from pin 3 to pin 1 at a rate of 300 LFM (1.5 m/s) and Ta = 25C. Figure 16. Power dissipation vs. load current and ambient temperature for converter mounted vertically with Vin = 48 V and air flowing from pin 3 to pin 1 at a rate of 200 LFM (1.0 m/s). Figure 17. Turn-on transient at full rated load current (resistive) with no output capacitor at Vin = 48 V, triggered via ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output voltage (2 V/div.) Time scale: 2 ms/div. Figure 18. Turn-on transient at full rated load current (resistive) plus 10,000 F at Vin = 48 V, triggered via ON/OFF pin. Top trace: ON/OFF signal (5 V/div.). Bottom trace: output voltage (2 V/div.). Time scale: 2 ms/div. Figure 19. Output voltage response to load current stepchange (12.5 A – 18.75 A – 12.5 A) at Vin = 48 V. Top trace: output voltage (100 mV/div.). Bottom trace: load current (5 A/div). Current slew rate: 1 A/s. Co = 470 F tantalum + 1 F ceramic. Time scale: 0.2 ms/div. Figure 20. Output voltage ripple (20 mV/div.) at full rated load current into a resistive load with Co = 10 F tantalum + 1uF ceramic and Vin = 48 V. Time scale: 1 s/div. tech.support@psbel.com QM48T25050/ QM48S25050 iS 11 iC 10 H source inductance 33 F ESR