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15 Mar 2014

obr1490_1

If you have in your “drawer” a universal 1000V diode in a miniature SOD123FL package, you have a solution for many circuits. 

Small/ bigger, with a lower- or rather with a higher cut-off voltage, solderable by wave or by reflow … these are for example some of the criteria when selecting a universal rectifying diode. However if you already know, that 1A current and a middle speed are sufficient for you, then we can say, that only one type will be sufficient for you in majority of cases – SL1M from company Diotec.

Standard silicon diodes show only a minimal dependency of VF from a cut-off voltage – in opposite to Schottky diodes, where a choice according a cut-off voltage is important in order to reach low losses (as a forward voltage – VF is noticeably higher at types with a higher cut-off voltage).

In other words, if a Schottky diode transfers for example 1A current, there´s a significant difference in a VF between types with a lower cut-off voltage in comparison to types with a higher cut-off voltage. However common silicon diodes don´t have this dependency, thus in general it dosen´t matter, whether we´ll use a „100V“ diode or a „1000V“ diode on a given place (if we don´t use a possible breakdown intentionally). So if can choose between a 400V and 1000V type for a similar price, nothing prevents us to better buy a 1000V type and to have a surety of universal usage – for example even for a direct rectification of a mains voltage. As a result we´ll gain for example a higher resistance to various overvoltages.

SL1M offers such versatility thanks to a very good price and also thanks to its dimensions, because it belongs to the smallest 1A diodes in the market. The only requirement if we want to use a maximum current of 1A is, that it´s necessary to observe a minimal pad dimensions (copper area) of approx. 5x5mm at both sides. This won´t be a problem for the most of applications, as to this area also contribute surrounding solder pads of other components (if they don´t generate heat). Naturally, in this case we mustn´t use at the PCB design a thermal isolation of pads (so called thermals), but only a non-solderable layer (solder resist).

Detailed description contains the Diotec SL1 datasheet and many useful documents can be found in our recent article “Do you need diodes? – Diotec has them“.

SL1M – when one diode can replace several types - [Link]

28 Jan 2014

obr1469_1

If you don´t have enough space on a PCB, maybe you´ll benefit from dual connectors for SIM cards and memory cards.

Usually there are more than enough reasons why to save space. Especially at handheld devices it´s almost always desirable that they were miniature and lightweight. We bring you two useful SMT connectors able to solve a problem with insufficient PCB space:

  • microSD+SIM card socket – 112G-TA00-R, 2×8 pinov, push-push for uSD/ push-pull for SIM, SIM/SD cards are mutually rotated in 90°
  • 2x SIM card socket – 115H-BA00, push-pull

Both sockets are made of a stainless steel and the plastic part is from an LCP (liquid crystal polymer) class UL94-V0 (self-extinguishing). Compact construction of both connectors is also reflected in a low profile of 2.7/ 3 mm.

“Doubledecker” can be found not only in London - [Link]

5 Jan 2014

obr1463_1

Xeno Lithium batteries offer high capacity at extremely low self-discharge and are able to supply your device for many years.

Primary Lithium batteries (Lithium thionyl-chloride, LiSOCl2) represent batteries with the highest energy density (Wh/kg), moreover able to operate without problems even in strong frosts. Perhaps their only technical “drawback” is the fact, that they´re only suitable for appliances with low current demands (up to tens of mA). However this “drawback” is already considerably overcome, because with modern components it´s easily possible to design devices with miliWatts power consumption. In principle are the Lithium primary (non-rechargeable) batteries suitable for backup (for example memories) and for power supplying devices with low power consumption, where it´s possible to reach even more than 10 years lifetime. This is naturally a huge benefit, as it enables to construct a device fully independent from external power supply, or without necessity of an external power supply and similar. At the same time it will also eliminate necessity to use an adapter or further electric installation.

These Lithium batteries operate on a principle of reaction Li+SOCl2. Arrising LiCl film on an anode has insulating properties. It provides excellent storage properties and energy preservation, because this passivation layer blocks auto reaction of Li+SOCl2 (self-discharging). Properties of Lithium batteries are also affected by the way and the length of stocking, and it´s possible, that after loading a battery, a short-time voltage drop will occur because of this passivation layer. Maximum capacity usage can be reached at a certain range of discharge currents (according to a diagram at every battery type). If a Lithium battery is intended to supply circuits with a short-time pulse demands, it´s very suitable to use a large capacitor or a supercapacitor connected in parallel with a battery. A capacitor in these cases will supply a bigger energy amount for a fraction of time and from the battery point of view a circuit then appears as one with significantly lower power consumption peaks. This contributes significantly to a maximum capacity usage and it´s also beneficial for a device itself thanks to minimum voltage drop at pulse power consumption.

Nominal voltage of LiSOCl2 batteries is 3,6V and a big advantage is a wide operating temperature range -55 to +85°C (max 150°C). Company Xeno Energy is a producer specializing in Lithium batteries and as one of few in the world they an ISO13485 certification for usage of batteries in medical devices. Further information will provide you the Xeno short form catalogue as well as detailed datasheets of Xeno batteries. In the Xeno production portfolio can also be found special batteries with a higher pulse capacity and type for extra high temperatures -55 to +130°C.

10 years of operation on 1 battery? - [Link]

21 Dec 2013

International Rectifier’s IR3846 is a member of the Gen3 SupIRBuck family of highly integrated synchronous voltage regulators. IR3846 is a compact DC-DC regulator with a single input supply without the need of an external VCC with its internal LDO and has a high current output of up to 35 A. Being part of the Gen3 SupIRBuck family, it has a corrective and unique modulation feature that gives a jitter-free and noise-free operation allowing higher frequency and higher bandwidth operation for better transient response. The device is very efficient and ideal for power applications of enterprises requiring space such as netcom server/storage, distributed point-of-load power architecture, and embedded telecom systems that involve high power density.

With a market price of $29, IRDC3846 evaluation board is highly efficient and cost-effective having multiple features. The PCB is a 200 mm^2, 6-layer board mounted with few passive components. Some of the important features of the board include: digital soft-start up, power good operation, overvoltage protection, thermal shutdown, and programmable switching frequency, which is flexible for different applications ranging from 300 kHz-1.5 Mhz. It is designed to a well-regulated input supply of +12V and configured for remote differential sensing.

The IRDC3846 evaluation board is very easy-to-use. Simply connect a +12V input supply at VIN+ and VIN- and a maximum of 35 A load should be connected to VOUT+ and VOUT-. If external VCC is required in an operation, Vin and VCC pins should be shorted together by installing a 0 ohm resistor. Other than remote sensing, the board can also be configured for local sensing by changing the resistors needed for operation. The length of the on-board power ground is minimized for better efficiency. Using separate power ground and analog ground, both can be connected together using a 0 Ohm resistor.

If you need a low voltage, high current regulator, IR3846 definitely should be considered. Having a small footprint, the device has exceptional capability offering high density. It is likely suitable for many applications in network communication and storage systems.

International Rectifier SupIRBuckTM IRDC3846 Evaluation - [Link]


4 Dec 2013

LT8614

The LT8614 is a 4A, 42V input capable synchronous step-down switching regulator. A unique Silent Switcher architecture reduces EMI/EMC emissions by more than 20dB, well below the CISPR 25 Class 5 limit. Even with switching frequencies in excess of 2MHz, synchronous rectification delivers efficiency as high as 96% while Burst Mode operation keeps quiescent current under 2.5μA in no-load standby conditions. Its 3.4V to 42V input voltage range makes it ideal for automotive and industrial applications.

LT8614 – 42V, 4A Synchronous Step-Down Silent Switcher with 2.5μA Quiescent Current - [Link]

2 Dec 2013

ap_vco_handsfree_car_kit

Locally broadcast your cell phone through FM band using MAX2606 from Maxim:

This design idea presents an integrated IF voltage-controlled oscillator (VCO) that can retransmit the audio signal from a cell phone to the FM broadcast band. By placing the cell phone’s speaker near the microphone, the user can use the phone as a hands-free device while driving.

[via]

VCO enables a hands-free car kit for cell phones - [Link]

27 Nov 2013

MAX21002

Industry’s Smallest Footprint Package (3mm x 3mm LGA16) and a Low Power Supply (1.8V) Gyroscope

The MAX21002 is a low-power, low-noise, dual-axis angular rate sensor that delivers unprecedented accuracy and sensitivity over temperature and time. It operates with a supply voltage as low as 1.71V for minimum power consumption. It includes a sensing element and an IC interface that provides the measured angular rate to the external world through a digital interface (I2C/SPI).

The IC has a full scale of ±31.25/±62.50/±125/±250/ ±500/±1000 degrees per second (dps) and measures rates with a finely tunable user-selectable bandwidth. The high ODR and the large BW, the low noise at highest FS, together with the low phase delay, make the IC suitable for optical image stabilization (OIS) applications.

The IC is a highly integrated solution available in a compact 3mm x 3mm x 0.9mm plastic land grid array (LGA) package and does not require any external components other than supply bypass capacitors. It can operate over the -40°C to +85°C temperature range.

MAX21002 – Ultra-Accurate, Low Power, Dual-Axis Digital Output Gyroscope - [Link]

27 Nov 2013

8217

Industry’s Only 60V, 2.5A Internal FET Synchronous Buck Converter

The MAX17503 high-efficiency, high-voltage, synchronously rectified step-down converter with dual integrated MOSFETs operates over a 4.5V to 60V input. It delivers up to 2.5A and 0.9V to 90%VIN output voltage. Built-in compensation across the output voltage range eliminates the need for external components. The feedback (FB) regulation accuracy over -40°C to +125°C is ±1.1%. The device is available in a compact (4mm x 4mm) TQFN lead(Pb)-free package with an exposed pad. Simulation models are available.

The device features a peak-current-mode control architecture with a MODE feature that can be used to operate the device in pulse-width modulation (PWM), pulse-frequency modulation (PFM), or discontinuous-conduction mode (DCM) control schemes. PWM operation provides constant frequency operation at all loads, and is useful in applications sensitive to switching frequency. PFM operation disables negative inductor current and additionally skips pulses at light loads for high efficiency. DCM features constant frequency operation down to lighter loads than PFM mode, by not skipping pulses but only disabling negative inductor current at light loads. DCM operation offers efficiency performance that lies between PWM and PFM modes. The low-resistance, on-chip MOSFETs ensure high efficiency at full load and simplify the layout.

4.5V-60V, 2.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter with Internal Compensation - [Link]

27 Nov 2013

ROHM Semiconductor’s SiC (Silicon Carbide) MOSFET offers cost-effective, breakthrough performance in providing low switching loss during high frequency operation. Released by ROHM with designations SCT2080KE and SCH2080KE, these SiC MOSFETs are both 80-milliohm devices, with the SCH2080KE being the industry’s first SiC MOSFET co-packaged with a discrete anti-parallel SiC Schottky Barrier Diode (SBD). The SiC Schottky Barrier Diode (SBD) comprises a forward voltage level three times smaller than that of the body diode. The SCH2080KE is especially popular since it allows board space saving and thus eventually reduces BOM costs.

Compared to its silicon device counterpart such as a Silicon IGBT, the SiC MOSFET has reached a reduced turn-off switching loss of up to 90% because of the absence of tail current, yielding a 70-90ns ON/OFF times and allowing for switching frequencies in the hundreds of kilohertz (kHz) range. The fast recovery performance of the device’s body diode has reduced the switching loss by 73%, minimizing its chip size and cost. Furthermore, the SiC MOSFET provides simultaneous high voltage resistance, low-on resistance, and high speed switching in applications ranging from industrial equipment such as solar and 3-phase inverters, DC/DC converters, uninterruptible power supplies (UPS), and motor drives to power systems and conditioning. These features enable designers and end users to maximize the SiC MOSFET’s benefit of achieving high efficiency performance during operations.

ROHM’s series of SiC MOSFETs featuring low on-resistance being maintained at high temperature condition have been available in mass production since July of this year. The SCT2080KE and SCH2080KE are available in the TO-247 MOSFET Class package, with the SCT2080KE also available in die form.

ROHM Semiconductor’s SiC Mosfet Technology - [Link]

16 Nov 2013

obr1432_3

Low losses, precise design, low power consumption and moreover a very affordable price are one of several reasons saying for the signal relays from Fujitsu.

Despite a big advance in a segment of semiconductors, there are still many reasons for usage of electromechanical relays. Galvanic isolation of a driving signal from a switched signal, resistance to surges, minimum crosstalk among switched signals and a minimal or no distortion are main arguments for a classic relay.
In fact a word “classic” even isn´t appropriate, because development of relays is still in progress and it brings results in a form of small dimensions, higher lifetime, low power consumption, high isolation strength etc., that´s why many modern types overcome their predecessors quite significantly.

We´d like to focus your attention for example to series FTR-B3 and FTR-B4. Both are ultra- miniature with a low power consumption and highly reliable bifurcated gold-plated contacts. A big advantage is, that both series also contain latching types with a „zero“ power consumption, thus requiring only a short pulse at switching. In respect to miniature dimensions and an affordable price, their usage is beneficial not only for a signal transmission, but also for example for driving/ switching of various processes and similar.

Detailed information will provide you the FTR-B3 and FTR-B4.

Connect a signal without distortion – via a Fujitsu relay - [Link]



 
 
 

 

 

 

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