10 Watt WD Dual “Low Input” Series DC/DC Converters Features � Universal 9 to 36 Volt Input Range. � Up to 10 Watts of PCB Mounted Power � Efficiencies to > 80% � Optional ON/OFF Control Pin � Fully Isolated, Filtered Design � Low Noise Outputs � Very Low I/O Capacitance, 350 pF Typical � Water Washable Shielded Copper Case � Five Year Warranty Selection Chart Description Input Range Output The universal input of the WD Dual series spans 9 to 36 volts. VDC Model This makes these converters ideal for 12, 24 and 28 volt Power Mx in MC a VA D m W battery and process control applications. 29 4D5.850WD 356 ±0±9 85 Coupled with these features is a low output noise of 29 4D12.400WD 326 ±0 1 ±0 40 1 typically less than 80 mV peak to peak. The noise is also fully specified for RMS value and if even these impressive noise 29 4D15.320WD 356 ±0 1 ±0 32 1 figures aren’t enough, our applications section shows a What all this means to you is a tighter, more compact simple add on circuit that can reduce the output noise to less overall system that has the capability of being universally than 10 mV p-p. powered. Full application information is provided to make Full isolation is provided to help cut ground loops in integrating this supply in your system a snap. industrial systems, where unknown input power quality could Other input and output voltage combinations may be create havoc with sensitive, high precision analog circuitry. factory ordered, contact CALEX applications engineering at No extra components or heatsinking are required for most 1-800-542-3355 for more information. applications saving you design time and valuable PCB space. 10 Watt Dual WD Series Block Diagram A 2401 Stanwell Drive • Concord, California 94520  Ph: 925/687-4411 or 800/542-3355  Fax: 925/687-3333  www.calex.com  Email: sales@calex.com eco#030327-1, eco#040308-2, eco# 041007-1 1 10 Watt WD Dual “Low Input” Series DC/DC Converters Input Parameters* MD odel 2D 4D5.850W2D 4D12.400W 2s 4D15.320W Unit MIN 9 Voltage Range VDC MAX 36 Input Current Full Load TYP 450 510 510 mA No Load TYP 10 15 15 EP fficiency T9 Y 78787% SP witching FrequencyT0 Y 1z 0 kH Maximum Input Overvoltage,M0 AX 4C VD 100ms Maximum Turn-on Time, T0 YP10202s m 1% Output Error Recommended Fuse (2) Output Parameters* MD odel 2D 4D5.850W2D 4D12.400W 2s 4D15.320W Unit O5 utput Voltage ±2±5 1 ±C 1 VD MIN ±4.950 ±11.900 ±14.900 Output Voltage Accuracy TYP ±5.000 ±12.000 ±15.000 VDC MAX ±5.050 ±12.100 ±15.100 MIN 0 0 0 Rated Load Range (3) mA MAX ±850 ±400 ±320 Load Regulation (4) TYP 0.1 0.1 0.1 25% Max load to % MAX 0.5 0.5 0.5 Max Load CP ross Regulation (5)T5 Y 22 . 10 . 1% . Line Regulation TYP 0.1 0.1 0.1 % Vin = 9 - 36 VDC MAX 0.7 0.3 0.3 SP hort Term Stability (6)T1 Y 20 dB of absorption loss to both electric and magnetic fields at 100 Ultra Low Noise Output Circuit kHz, while at the same time providing 20 to 40 % better heat The circuit shown in figure 3 can be used to reduce the output sinking over competitive thin steel, aluminum or plastic designs. noise to below 10 mV p-p over a 20 MHz bandwidth. Size The case shield is tied to the CMN output pin. This inductor L1 appropriately for the maximum expected load connection is shown on the block diagram. The case is current. All of the ground connections must be as short as floating from the input sections. The input is coupled to the possible back to the CMN pin. The filter should be placed as outputs only by the low 350 pF of isolation capacitance. This close to the WD Dual as possible, even if your load is at some low I/O capacitance insures that any AC common mode noise distance from the converter. on the inputs is not coupled to your output circuits. Compare this isolation to the more usual 1000 - 2000 pF found on competitive designs and you will see that CALEX provides the very best DC and AC isolation available. After all, you are buying an isolated DC/DC to cut ground loops. Don’t L1 = 20µH let the isolation capacitance add them back in. C1 = 22µF/20V, TANTALUM Figure 3. C2 = 0.01µF/100V, CERAMIC Temperature Derating This circuit can reduce the output noise to below 10 mV p-p over a 20 MHz bandwidth. Size inductor L1 appropriately for the maximum The WD Dual series can operate up to 85 °C case temperature expected load current. The filter should be constructed as close as without derating. Case temperature may be roughly calculated possible to the converter and all of the ground connections must be from ambient by knowing that the case temperature rise is as short as possible back to the CMN pin. approximately 16°C per package watt dissipated. For example: If a WD Dual converter is delivering 8 Watts Single Ended Loads with a 24 volt input, at what ambient could it expect to run with no moving air and no extra heatsinking? The WD Dual may be operated as a single ended output to get either 10, 24 or 30 volts output as shown in figure 1. If the Efficiency of the converter is approximately 76% at 8 watts output is operated single ended then the CMN pin should be of output power, this leads to an input power of about 10.5 A left floating. Watts. The case temperature rise would be 10.5 - 8 Watts or 2.5 Watts × 16 = 40°C. This number is subtracted from the Full power is available when operating single ended. For maximum case temperature of 85°C to get: 45°C. example: If a 24D5.850WD is operated as a 10 volt output then a full 0.850 amps is available at 10 volts. This example calculation is for a WD Dual without any extra heat sinking or appreciable air flow. Both of these factors can Operation With Very Light Loads greatly effect the maximum ambient temperature (see below). Exact efficiency depends on input line and load conditions, Dynamic response and cross regulation of the WD Dual will check the efficiency curves for exact information. degrade when the unit is operated with less than about 25% This is a rough approximation to the maximum ambient of full rated power. If this is a problem the most lightly loaded temperature. Because of the difficulty of defining ambient output may be “Pre-Loaded” with a resistor to common as temperature and the possibility that the loads dissipation may needed. The exact amount of preloading required is dependent actually increase the local ambient temperature significantly, on your system requirements, so some experimentation is these calculations should be verified by actual measurement necessary to arrive at the optimum value. before committing to a production design. Grounding Remember, it is the system designers responsibility to be sure that the case temperature of the WD Dual does not The input and output sections are fully floating from each exceed 85°C for maximum reliability in operation. other. They may be operated fully floating or with a common 2401 Stanwell Drive  Concord, California 94520  Ph: 925/687-4411 or 800/542-3355  Fax: 925/687-3333  www.calex.com  Email: sales@calex.com eco#030327-1, eco#040308-2, eco# 041007-1 5 10 Watt WD Dual “Low Input” Series DC/DC Converters Typical Performance (Tc=25°C, Vin=Nom VDC, Rated Load). INPUT CURRENT Vs. LINE INPUT VOLTAGE EFFICIENCY Vs. LOAD 2.5 85 LINE = 9VDC 80 2.0 75 1.5 70 100% LOAD 1.0 65 0.5 LINE = 24VDC 60 50% LOAD LINE = 36VDC 0.0 55 0 5 10 15 20 25 30 35 40 0 10 2030 405060 7080 90 100 LINE INPUT (VOLTS) LOAD (%) EFFICIENCY Vs. LINE INPUT VOLTAGE RMS INPUT CURRENT Vs. LINE INPUT VOLTAGE 90 1.0 85 0.8 50% FULL LOAD 80 0.6 100% FULL LOAD 75 100% LOAD 0.4 75% LOAD 70 0.2 65 50% LOAD 60 0.0 8 121620 24283236 8 121620 24283236 LINE INPUT(VOLTS) LINE INPUT (VOLTS) A 2401 Stanwell Drive  Concord, California 94520  Ph: 925/687-4411 or 800/542-3355  Fax: 925/687-3333  www.calex.com  Email: sales@calex.com eco#030327-1, eco#040308-2, eco# 041007-1 6 EFFICIENCY(%) INPUT CURRENT (AMPS) RMS INPUT CURRENT (ARMS) EFFICIENCY (%)