Search Results for "REC"

RECOM prides itself on having a comprehensive certification portfolio, with full third party UL/IEC/EN certifications (not just 'designed to meet'). Certifications cover Industrial, Medical, LED lighting, Household, Railway and Automotive standards, depending on the application area of the converter.

We provide many medical grade converters with UL/IEC/ EN-60601-1 certifications (3rd Ed.), including risk assessment documentation.

The UKCA (UK Conformity Assessed) marking is a new UK product marking that is used for products being placed on the market in Great Britain (England, Wales and Scotland). It applies to the same products that are currently CE marked. The circumstances in which self-declaration of conformity for UKCA marking can be used are the same as for CE marking. Based on current UK rules, RECOM is eligible to self-declare for the UKCA Declaration of Conformity (DoC) as long as the EU and UK regulations remain aligned.
RECOM will make available a separate UKCA Declaration of Conformity (DoC) based on the existing CE Declaration of Conformity (DoC) and test reports (self-declaration). CE marking remains valid for goods placed on the market in Great Britain until 1 January 2023. The UKCA marking must be used for placing goods on the market in Great Britain after this date. RECOM will continue to actively monitor any changes to the UKCA rules based on UK government guidance and react accordingly.
We will also instigate a program to successively add the UKCA mark to our CE marked products to fulfil our obligations as manufacturer. For further information or enquiries regarding our UKCA policy, contact TechSupport

As with all electronic devices, strongly reactive or abrasive cleaners can attack the encapsulating material and the pins, hence cleaning is recommended with inert solutions (e.g. alcohol or water based solvents) suitable for electronic components and at the temperatures recommended by the cleanser manufacturer. Jet washing or ultrasonic cleaning is not recommended.

Refer to the instructions given by the conformal coating supplier regarding the recommended process for washing and drying the boards before applying the conformal coating. We have never received any complaints of chemical incompatibility or any other problems with conformal coating our products.

All RECOM production batches are burn-in tested in our factory before being shipped to the customer.

The inrush current is dependent on the converter, the load (especially the capacitive load) and the impedance of the primary power supply. Therefore, there is no recommended value for the inrush limiting inductor as this need to be individually worked out for each application. Having said that, usually 22µH~100µH is a good starting point.
A CMC is a good inrush current limiter because the core does not go into saturation with high currents (the +ve inrush current is balanced out by the -ve inrush current), so it has a dual purpose: EMC filter and inrush limiting. However, for high power converters it is sometimes better to use a low inductance, high current, choke that is selected to reduce inrush rather than a high inductance choke selected for the best EMC filtering because otherwise too much power could be lost through the choke's resistance during normal operation.

Recom does not offer this feature in any of its DC/DC converters. Synchronizing the oscillators in several converters is a useful technique where beat frequencies must be avoided at the cost of an increased amount of interference at the main frequency. Usually effective results can be achieved by individually filtering each converter without creating a strongly interfering main frequency.

In theory, yes, but in practice it is very non-linear. Adjusting the output voltage using an external voltage or current can also affect the regulation and short circuit behaviour, so it is not recommended.

Reverse polarity protection is not built inside any of the converters. It needs to be added externally. We recommend adding an external MOSFET for higher power converters or a simple blocking diode for lower power, non-critical applications.

RECOM has one of the largest selection of non-isolated DC/DC products on the market. Our search engine allows searches for non-isolated converters only.

The main problem with a 12 battery as a power source is that it can deliver very high inrush currents. Normally with lower power converters (under 20W), this is not a problem, but for the higher power converters the inrush current can damage the converters or extzernal components. The other issue with batteries is if the end-user connects the battery the wrong way around, this will instantly destroy any converter. To avoid these problems, an external blocking diode or FET can be fitted and either a soft-start circuit or an inrush current filter can be added. Please contact Recom Technical Support for suggested circuits and component values.

RECOM prides itself on having comprehensive datasheets, but there may be a parameter or operating characteristic that it not listed.

We offer local Technical Support through our offices in Austria, Germany, USA, Singapore, Japan and China, or you can contact your local RECOM contact or distributor to ask us for more information.

The sense pins (Sense + and Sense-) are used by the DC/DC converter to regulate the output voltage as delivered to the load, not as measuresd directly across the output pins. The converter uses four connections, Vout+ and Vout- delivering a high current and two low current connections, Sense+ and Sense- for feedback. The advantage of using the sense pins compared with simply trimming up the output voltage to compensate for the volt-drop along the connection is that sense pins regulate the load voltage at both low and high load currents, thus avoiding too high a load voltage when lightly loaded. Sense pins can also be used by some load sharing controllers to allow two or more DC/DC converters to be connected in parallel to increase the power.

Some RECOM converters, like the R-78AA series, have a two level control pin function. If the control pin voltage drops below 2.6V, the main power stage is switched off, but the internal oscillator and voltage regulator is kept running. This allows a very rapid restart from standby to full power. For ultra-low power mode, the control pin voltage must be below 1.6V. Then the main oscillator is also turned off and the converter draws only 20µA from the input. Start-up will be slower from deep sleep than from standby.

All RECOM products will not be damaged if used without s load, although in some families some specifications may be out of range below 10% load.

An unregulated converter is a cheaper solution but offers less output voltage stability. The output voltage can change depending on both the load and the input voltage variations. Therefore, the input voltage range is restricted to +/-5% or +/-10% , so it is recommended to use unregulated DC/DC cpnverters only with a regulated supply voltage. The output voltage can rise substantially during no-load conditions, but, even an unregulated converter offers a low output voltage variation over a 20% to 100% load range.

Regulated converters offer a much better load and line voltage regulation, typically less than 1%, so the output voltage is not dependant on the load or input voltage. In particular, the output voltage remains stable under low load or no load conditions. In addition, the input voltage range is higher (2:1, 4:1 or up to 7:1 with non-isolated converters), so regulated converters are suitable for use with variable input voltage supplies such a batteries or multiple supply voltages (e.g, 12V or 24V supplies)

Low power converters that uses post-regulation must be designed so that at the minimum input voltage there is enough output voltage headroom that the linear regulator can regulate properly. This means that with the nominal input voltage, there will be a higher voltage drop across the linear regulator, which in turn will increase the quiescent current drawn by the converter.

Higher power converters often use synchronous rectification on the output. The switching transistors still run at full power even under no-load conditions, so this can lead to a high quiescent current.

The enable pin on the ROF-78 has a max voltage of 5VDC.
1.25V is the threshold voltage, below that voltage the converter should be OFF. Above 1.25 the converter will be ON. The 0.9V and 1.55V values are recommended safety values to ensure that below 0.9 it will be OFF, and 1.55V it will be ON.
In short, if you want to ensure that the device is on continuously, apply >1.55V to the EN pin all the time

It is recommended that the R-78 series of switching converters is used with a minimum load of 6mA to guarantee that the output is stable under all operating conditions.

All of our DC/DC converters contain a built-in input capacitor filter, so an external capacitor is not required for normal operation, unless specified in the datasheet. An input capacitor may also be required to meet surge requirements or to smooth the DC supply at the point of load. If several DC/DCs are powered from the same rail, then input capacitors placed close to the input pins are recommended.

No external components are needed. An input capacitor is recommended only if the input voltage exceeds 26V. An output capacitor helps reduce output ripple further, but the ripple is relatively low anyway.

Type is not critical. Actually, a lower quality, relatively high ESR capacitor on the input is actually an advantage as its internal resistance helps damp down any switch-on surge oscillations.
A combination of tantalum or electrolytic in parallel with an MLCC on the input or output combines the advantages of both types (high ESR to reduce ringing, low ESR to filter noise).

A four-wire communication protocol, e.g. RS485 Modbus. Differential transmit and receive data are sent on separate twisted pairs.

Safety certification defines various levels of accessibility. Anything that is easily accessible must be safer than something that has restricted access (behind a locked door, at an unreachable height or requiring tools to gain entry, for example).

The definitions include:

• Operator Accessible – access can be gained without the use of a tool
• Restricted Access – access is through use of a tool or lock and key and the service person has been instructed about the necessary precautions
• Service Access – same as restricted access, but where it may be necessary for the equipment to be kept powered while adjusting or calibrating the system

Temperature of the air surrounding equipment such as a power supply. The operating temperature given in datasheets of RECOM parts is always the ambient temperature. The maximum case temperature may also be specified (temperature of the case or baseplate). Ambient temperature is measured close to, but not directly above the converter.

Automated Test Equipment. Commonly used in a production line to check the correct functionality of each product manufactured (100% test).

Relating to a device that accommodates signals traveling in either direction though a single channel. A bidirectional DC/DC converter can transfer power in either direction.

Cloud-Based Manufacturing (CBM) is a networked manufacturing model that forms temporary, reconfigurable production lines according to demand – both within and across different manufacturing sites - an example of Industry 4.0.

When a wanted phenomenon: Fluctuating or jittering the frequency of a clock of a power converter to reduce EMI by spreading the main clock frequency over a wider range which reduces the EMI power in a standard measuring receiver bandwidth, indicating lower EMI levels. (also called spread spectrum). When an unwanted phenomenon: the inaccuracy of a timing clock pulse.

The Cloud is an on-demand system of interconnected computers that can share resources without direct active management by the user, relying on the Cloud Service Provider (CSP) to manage data traffic and secure the system.

An ESD test method where the ESD generator makes direct contact with the device under test (DUT).

Digital-to-Analog Converter (DAC): A data converter that receives digital data and outputs a voltage or current proportional to the binary value of the data.

Direct Current: Current that is unidirectional e.g. from a battery or voltage regulator.

A device that passes current in one direction only.

The minimum input-output differential voltage which is required for a non-isolated DC/DC converter to operate correctly.

End of Life: After a product has reached End of Life status, it will be removed from the standard product range and is no longer for sale. The datasheet is still available on the RECOM website. In a period before this, the product will be designated as ‘No longer Recommended for New Designs (NRND)’.

Energy-related Products: A term used in the EU Eco-design directive. Previously EuP, Energy-using Products.

Energy Recovery System. Typically refers to methods of recovering electrical energy from kinetic energy such as from a car braking system.

Electric Vehicle. A plug-in EV (PEV) is a pure EV. A hybrid EV (HEV) has both an internal combustion engine and an electric motor. If the internal battery can also be recharged from the mains, it is a plug-in HEV (PHEV). In Asia, EVs are commonly called New Energy Vehicles (NEV).

A control loop where negative feedback compares an output with a reference and generates an error signal to correct the output if it drifts. Such feedback loops are the heart of any regulated power converter. Positive feedback is generally avoided in power converters, although it has some uses in oscillator circuits and hysteretic control power converters.

Global Positioning System: A satellite-based navigation system in which two or more signals, received from satellites, are used to determine a receiver's position on the globe.

Data transmission over a circuit capable of transmitting in either direction, but not simultaneously.

Abbreviation for High Potential test: The standard test for insulation breakdown voltage. A high voltage is applied across an isolation barrier for 1 second or 1 minute and no arc-over should occur. All RECOM products are 100% Hi-Pot tested in production.

A product with the designation NRND (Not Recommended for New Designs) can also have a last time buy date found in the header of the datasheet. The product can be ordered up to this date but no later. The product has then reached EoL status.

Lithium-ion (Li+, Li-Ion, Lion) cells are generally used as power sources for portable equipment. They are usually rechargeable. Lithium-ion and Nickel-Metal-Hydride (NiMH) have displaced Nickel-Cadmium (NiCd or nicad) as the dominant rechargeable chemistry for portable applications.

Manchester encoding is a form of Binary Phase-Shift Keying (BPSK) used for low-cost radio-frequency (RF) transmission of digital data. Its main characteristic is that it encodes data in a way that ensures that there are never long strings of continuous zeros or ones. The presence of guaranteed transitions means that a clock can be recovered from the transmitted data, allowing the link to function with variable signal strengths from transmitters with imprecise, low-cost, data-rate clocks.

In radio transmission, multipath refers to the simultaneous reception of two copies of a signal that arrive via separate paths with different delays. A common example is when a signal bounces off a building or other object and is received along with the direct (unbounced) signal. In television reception, this causes 'ghosting', a faded echo is seen on the screen horizontally displaced from the main image. One of the main reasons why GPS does not work well in large cities is multipath signals bouncing off tall buildings.

Non-Recurring Engineering cost: One-time engineering costs associated with a project (usually for the design effort or for tooling or certifications).

A product Not Recommended for New Designs will be withdrawn at some future date. The NRND status can be found on the RECOM website and on the datasheet of the relevant series and/or product. If an alternative product is available, a button will indicate this.

Power Factor Correction: A passive or active circuit that synchronises and shapes the AC mains input current to better match the mains input voltage. When current and voltage are perfectly aligned, the power factor (PF) is unity. Passive PFC circuits can typically improve the PF from around 0.4 to 0.7, active PFC circuits can achieve >0.99. PFC is required by the EMC standards for AC/DC power supplies of >75W, but for LED drivers, the limit is 25W.

Power-over-Ethernet: A means for delivering power to a remote device using the same cable lines used to deliver Ethernet data. Can be used to power remote devices (cameras, LED-lighting, door entry systems) over a single combined power and bi-directional data cable. The nominal PoE voltage supply is 44-57VDC, so a DC/DC converter is typically required at the end device. This DC/DC must negotiate with the primary power supply to release enough current for its needs (available power is restricted between 4W and 100W depending on a complex sequence of signature resistances offered by the DC/DC negotiation IC). The relevant standard defining this interface is IEEE 802.3af /at/bt. Many think that PoE is the future for indoor LED lighting.

Reverse recovery charge: the charge that accumulates on a PN junction when it is forward biased. The current needed to overcome the Qrr when a transistor or diode is reverse biased causes significant losses.

When switching from the conducting to the blocking state, a diode junction has stored charge that must first be ‘recovered’. This discharge takes a finite amount of time known as the Reverse Recovery Time, during which the diode does not block the reverse current. When dealing with high frequency oscillators or very steeply rising signals, the reverse recovery time can lead to significant losses in a circuit, as high current and high reverse voltage can be present simultaneously.

Also known as Euro-connector, a 21-pin connector commonly used in Europe to interconnect satellite receivers, television sets, and other AV equipment. Sometimes needs a DC/DC converter to supply a 10-12V ‘Device present’ signal.

Silicon-Controlled Rectifier: A semiconductor switch that once activated by a gate voltage, stays on until the input voltage turns off or reverses and therefore can be used as a latch. Typical uses include fault protection (OVP, OTP) which forces the user to turn off the device to reset the SCR.

A digital interface in which data is sent in a single stream of bits, usually on a single wire-plus-ground, wire-pair, or single wireless channel (or two sets, one for each direction). Examples include USB, RS-232 and I²C

Set Top Box: Typically a cable or satellite TV receiver.

A technique used in switch-mode power supplies, in which the output rectifier diode is replaced with a MOSFET switch to reduce losses and thereby increase efficiency. The MOSFET is turned synchronously on and off with the main switch(es) to reproduce the effect of a diode.

An inductive electrical device for changing the voltage of alternating current, consisting of two magnetically coupled coils. Alternating current in one (called the ‘primary’) creates a changing magnetic field which induces a current in the second coil (the ‘secondary’). Multiple secondary coils can be energised from a single primary winding. There is no such thing as a DC transformer, so an isolated DC/DC converter has to convert the DC input to an AC signal for the transformer primary and then rectify the resulting AC on the transformer secondary to a DC output.

AC/DC power supplies that are non-isolated and use switched capacitors, high voltage regulators or switching converters to generate a low voltage DC output which is directly referenced to the AC input. These may only be used where human access to the secondary connections is prevented.

An ISO Technical Specification that aligns various automotive quality systems standards within the global automotive industry. Together with ISO 9001:2000, ISO/TS 16949:2002 specifies the quality system requirements for the design/development, production, installation and servicing of automotive related products. RECOM’s factories in Taiwan are ISO/TS 16949 certified.

Universal Asynchronous Receiver-Transmitter: An IC that converts parallel data to serial and converts received serial data to parallel data.