NCX10S SERIES Isolated 10W Single Output DC/DC Converters Nominal Input Voltage Output Voltage Output Current Power Consumption at 0% Load Power Consumption at Shutdown Efficiency (MIN) Isolation Capacitance SELECTION GUIDE1 V 24 24 48 48 24 24 48 48 V 3.4 5.1 3.4 5.1 3.4 5.1 3.4 5.1 A 3.1 2.0 3.1 2.0 3.1 2.0 3.1 2.0 mW 270 280 500 510 270 280 500 510 mW 26 25 44 45 26 25 44 45 % 78 82 79 82 78 82 79 82 pF 23 26 29 32 23 26 29 32 Order Code NCX10S24033 NCX10S24050 NCX10S48033 FEATURES NCX10S48050 ■ High Efficiency to 82% NCX10S24033Y ■ 500V Input to Output Isolation ■ Industry Standard Pinout ■ UL 60950 Recognition Pending ■ Non Latching Current Limit ■ Constant 400kHz Frequency ■ Versatile Control Options ■ Continuous Rating to 10W @85°C ■ Operation to Zero Load ■ Protected Against Load Faults ■ Internal Over Temperature Protection ■ Uses No Electrolytic Capacitors DESCRIPTION The NCX10S series of DC/DC Converters combines ease of application with versatility and is available in two pin patterns based on popular industry standards. High efficiency enables full rating to be achieved in a small package without heatsinking, and a high surge capability will provide for start-up and transient loads, whilst being thermally protected against sustained overload. The NCX10S series is currently undergoing testing by Underwriters Laboratory (UL) to UL 60950 for functional insulation. NCX10S24050Y NCX10S48033Y NCX10S48050Y INPUT CHARACTERISTICS1 Parameter Conditions Voltage Range Continuous operation, 24V input types Continuous operation, 48V input types MIN NOM MAX Units 18 36 24 48 36 75 V OUTPUT CHARACTERISTICS1 Parameter Conditions MIN TYP Voltage Set Point Error 50% load Substrate temperature –40 to 110°C Overall Load 0% - 100% Voltage Error Input specified range Temperature Coefficient of Output Voltage (slope) Deviation of Temperature MIN - MAX Output Voltage Current Limit Continuous short circuit causes no damage NCX10S24033 Overload 95% of nominal NCX10S24050 Output Current output voltage NCX10S48033 NCX10S48050 Line Regulation Operating voltage range, 50% load Load Regulation 0% - 100% rated load2 Ripple rms MAX Units 1.0 % 2.5 % 250 ppm°C 1.0 % 153 170 148 164 % of rated Output Current 0.1 0.5 1.0 % % % TYP MAX Units -0.3 0 1.5 2.6 5.0 6.1 10 ms 360 400 440 kHz CONTROL CHARACTERISTICS Parameter Conditions Voltage Trimming Range Remote Switch Input (voltage relative to input negative) At rated load, Trim control at either output Not operating Operating, open circuit voltage VIN MIN to MAX Time from application of valid input voltage to output being in specification Start Delay Switching Frequency MIN ±10 % V ABSOLUTE MAXIMUM RATINGS Input voltage, 24V input types Input voltage, 48V input types Output Voltage Output trim control Shutdown control www.cdpoweronline.com –0.3V to 40V –0.3V to 80V –0.3V to regulated voltage –1V to +30V relative to output return –0.3V to 6V relative to input return 1 Specifications typical at TA=25°C, nominal input voltage and rated output current unless otherwise specified. 2 A minimum load of 10% of rating is recommended for typical applications, see application notes. NCX10S SERIES Isolated 10W Single Output DC/DC Converters ISOLATION CHARACTERISTICS Parameter Conditions Isolation Voltage Resistance Flash tested for 1 second VISO=500VDC MIN TYP MAX 1000 1 Units VDC GΩ ENVIRONMENTAL CHARACTERISTICS Parameter Conditions MIN Substrate Temp. Full load Storage Absolute MAX internal temperature Thermal Protection Operates at substrate temperature TYP MAX Units 125 125 °C °C °C –40 –40 150 THERMAL PERFORMANCE NCX10S24050 NCX10S48033 11 11 10 10 10 9 8 7 6 5 4 -40 Still Air 100lfm 200lfm 300lfm 400lfm 10 60 Ambient Temperature (°C) 110 Ambient Power (W) 11 Ambient Power (W) Ambient Power (W) NCX10S24033 9 8 7 6 Still Air 100lfm 200lfm 300lfm 5 4 -40 10 60 Ambient Temperature (°C) 9 8 Still Air 100lfm 200lfm 7 6 5 4 -40 110 10 60 Ambient Temperature (°C) 110 NCX10S48050 11 Ambient Power (W) 10 UL 60950 RECOGNITION (Maximum permissable load in still air) 9 8 7 6 Still Air 100lfm 5 4 -40 10 60 Ambient Temperature (°C) Part Number -40°C 25°C 70°C 75°C 80°C 85°C 90°C Units NCX10S24033 NCX10S24050 NCX10S48033 NCX10S48050 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 9.0 10.0 9.5 10.0 7.9 8.9 8.4 10.0 6.5 7.2 7.1 9.6 5.0 5.2 5.5 8.0 W 110 APPLICATION NOTES In a typical application, the NCX10S series of DC/DC converters require nothing more than a dc supply of correct polarity and voltage to generate its specified output. These notes are intended to offer help in the use of other facilities offered by these converters, and to provide assistance in achieving their full potential. VOLTAGE TRIMMING The trimming (adjust) input on the secondary side allows output voltage adjustment within the capability of the power circuit. When open circuit, the trimming pin ADJ operates at near half the output voltage. A basic trimming arrangement consists of a potentiometer of 10kΩ to 100kΩ connected across the output, with its wiper connected to the ADJ pin (see figure 1). Dependent on model, the output will be reduced by about 15% when the wiper is at the positive output, or increased by about 24% when at the negative rail. Regulation will be maintained to at least 10% adjustment either way. If finer adjustment is required, a resistor may be included between the wiper and the pin. For example, 62kΩ will restrict a 3.3V model to ±5% adjustment range. The corresponding values for the 5V model is 56kΩ. +VIN +VOUT DC ADJ 100KΩ –VIN Figure 1: Voltage Trimming DC 0V NCX10S SERIES Isolated 10W Single Output DC/DC Converters APPLICATION NOTES OTHER TRIMMING FUNCTIONS The voltage applied to the trim pin need not be from a potentiometer. The trim facility may be driven electronically to provide “margining”, remote sense, active load sharing, current control or remote programming (There is a minimum output voltage below which control is not possible). SHUTDOWN & UNDER VOLTAGE TRIM When the shutdown pin (Pin 11) is shorted to the negative input, the converter will stop. Its current consumption will then be less than 1mA at nominal supply voltage. The shutdown/UV adjust pin serves the dual function of shutting the converter down into a low power state, and allowing adjustment of the under voltage start threshold. To shut the unit down this pin should be taken to below 1.5V, using either an isolating diode (figure 2) with the anode connected to the shutdown pin or using an open collector pulldown (figure 3). The UV threshold can be controlled either via a resistor connected between the pin and 0V, or by connecting a series 1MΩ resistor to a voltage of between 0V and 2.5V. in figures 4 & 5. Note that voltage should not be applied directly to the pin without a series resistor or diode. If the shutdown pin is to be connected to a long wire, it is recommended that a capacitor decouples the pin to the supply common in order to avoid the risk of injecting noise into the converter circuit. A series resistor may also be helpful. Values of 10nF and 1kΩ may be used. Many converters may be switched together simply by linking the primary control pins via a schottky signal diode anode to the control pin. The primary common pins must also be linked, see figure 6. FILTERING The module includes a basic level of filtering, sufficient for many applications. Where lower noise levels are desired, filters can easily be added to achieve any required noise performance. A DC/DC converter generates noise in two principle forms: that which is radiated from its body and that conducted on its external connections. There are three separate modes of conducted noise: input differential, output differential and input-output. This last appears as common mode at the input and the output, and cannot therefore be removed by filtering at the input or output alone. The first level of filtering is to connect a capacitor between input and output returns, The variation of startup voltage with either parallel resistor or applied voltage is shown SD DC Less than 0.8V for Shutdown If no filtering is required, the inductance of long supply wiring could also cause a problem, requiring an input decoupling capacitor for stability. An electrolytic will perform well in these situations. See figure 7 for a recommended configuration to reduce all three conducted modes. The component values and ratings will depend on the converter rating and voltage, and the required noise performance. The input-output filtering is performed by the common-mode choke on the primary. This could be placed on the output, but would then degrade the regulation and produce less 15 2.0 1.5 1.0 17 –VIN Figure 2: Shutdown with Isolating Diode Input ripple is a voltage developed across the internal input decoupling capacitor. It is therefore measured with a defined supply source impedance. Although simple series inductance will provide filtering, on its own it can degrade the stability. A shunt capacitor is therefore recommended across the converter input terminals, so that it is fed from a low impedance. 2.5 Applied Voltage (V) e.g. BAT42 DC to reduce this form of noise. It typically contains high harmonics of the switching frequency, which tend to appear as spikes on surrounding circuits. The voltage rating of this capacitor must match the required isolation voltage. (Due to the great variety in isolation voltage and required noise performance, this capacitor has not been included within the converter.) Shutdown Resistor (MΩ) SET VOLTAGE The output voltage is set to 100mV above nominal, to offset resistive losses and thus assist with worst case error calculations. This allowance can be altered with a single fixed resistor, connected from the trimming pin to one of the output pins. 17.5 18 18.5 19 Startup Voltage (V) 19.5 10K 0.25W Greater than 1.5V for Shutdown DC –VIN Figure 3: Shutdown with Open Collector Pulldown 7 5 3 17.5 18 18.5 19 Startup Voltage (V) 19.5 20 15 Shutdown Resistor (MΩ) DC 9 Figure 4: NCX10S24XXX Startup Voltage Vs Startup Pin Resistor/Voltage Applied Voltage (V) e.g. BC546 11 1 17 20 2.5 SD 13 2.0 1.5 1.0 32.5 33 33.5 34 34.5 35 35.5 Startup Voltage (V) 36 13 11 9 7 5 3 1 32 33 34 35 Startup Voltage (V) Figure 5: NCX10S48XXX Startup Voltage Vs Startup Pin Resistor/Voltage 36 NCX10S SERIES Isolated 10W Single Output DC/DC Converters APPLICATION NOTES benefit for a given size, cost, and power loss. Radiated noise is present in magnetic and electrostatic forms. Thanks to the small size of these units, neither form of noise will be radiated “efficiently”, so will not normally cause a problem. Any question of this kind usually better repays attention to conducted signals. Optional Open Collector Transistor In applications where large transient load swings are expected, for example 10-60% or 25-75%, the fitting of an external electrolytic output capacitor is recommended to reduce voltage over/under shoot. 200µF capacitance will typically reduce a peak excursion to 350mV settling to within 1% VNOM in 1.2ms. Additional externally fitted capacitance will further reduce over/under shoot. DC DC SD SD Less than 0.8V for Shutdown DC DC –VIN –VIN PROTECTION The “absolute maximum” ratings in the specification define conditions which may degrade life but will not result in immediate damage. This section of the application notes deals with those unavoidable or accidental occasions when the ratings are exceeded. The unit will protect itself against a wide range of abnormal conditions. In others, where failure is inevitable, the consequent hazards have been minimised. If the supply polarity is reversed, the unit is unable to protect itself. The simple preventative measure of a series diode would add unacceptable power loss for the basic product, but it may be appropriate in some applications to fit this diode externally. With no polarity protection, tracks and components will safely fail to high impedance, disconnecting the power. A large fault current will occur in this process. FUSING Figure 6: Shutdown with Isolating Diode 100µH Part Number Recommended Fuses1 NCX10S24XX NCX10S48XX 1.6A 1.0A 10µH DC 2.2µF 1mH 10µH 2.2µF DC 100µH 10µF, 250Vac Y Rated Figure 7: Recommended Configuration to Reduce Noise 1 Anti surge T-type fuses are recommended 10µF, 250Vac Y Rated NCX10S SERIES Isolated 10W Single Output DC/DC Converters MECHANICAL DIMENSIONS 18 Pin SMD Package Style 1.75 (44.56) 1.58 (40.03) 18 17 16 15 14 13 12 11 10 1.12 ±0.016 (28.4 ±0.4) 0.82 (20.75) Detail A REFERENCE PLANE 0.197 (0.50) 1 2 3 4 5 6 7 8 0.20 (5.0) 0.049±0.008 (1.24±0.2) x18 Pins 9 0.10±0.004 (2.59±0.1) ±5.00° 0.008(0.2) M P S 0.008(0.2) M 0.31 (7.75) MAX P S 0.09±0.001 (2.27±0.25) S 0.315±0.004 (8.00±0.10) 18 Pins 0.01 (2.51) MAX DETAIL A 0.010±0.002 (0.25±0.05) 0.004(0.1) S Recommended Footprint Details Pin Connections 0.94 (24.0) 1.17 (29.6) PIN NCX10SXXXXX NCX10SXXXXXY 1 +VOUT +VOUT 2 –VOUT –VOUT 3-7 NC NC 8 VADJ VADJ 9-10 NC NC 11 SD SD 12-16 NC NC 17 –VIN +VIN 18 +VIN –VIN Package Weight: 8.3g 0.20 (5.00) 0.14 (3.60) All pins on a 0.1(2.54) pitch and within ±0.01(0.25) of true position. 1.57 (40.0) Unless otherwise stated all dimensions in inches(mm) ±0.01(0.25). C&D Technologies (NCL) Limited reserve the right to alter or improve the specification, internal design or manufacturing process at any time, without notice. Please check with your supplier or visit our web site to ensure that you have the current and complete specification for your product before use. © C&D Technologies (NCL) Limited 2003 NDC NCX10S.1 No part of this publication may be copied, transmitted or stored in a retrieval system or reproduced in any way including, but not limited to, photography, photocopy, magnetic or other recording means, without prior written permission from C&D Technologies (NCL) Limited. 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