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19 May 2015

In digital electronics, fan-out is defined as the number of gate inputs that the output of a single logic gate can feed. It is very important in digital systems for a single logic gate to drive other gates or devices. In this case, a buffer can be used between the logic gate and the devices it will drive. Clock buffer is also called as fan-out buffer. The IDT clock buffer clock divider and clock multiplexer portfolio includes devices with up to 27 outputs. Differential outputs such as LVPECL, LVDS, HCSL, CML, HSTL, as well as selectable outputs, are supported for output frequencies up to 3.2 GHz and single-ended LVCMOS outputs for frequencies up to 350MHz.

Modern digital systems often require many high quality clocks at logic levels that are different from the logic level of the clock source. Extra buffering may be required to guarantee accurate distribution to other circuit components without loss of integrity. Many systems require low jitter multiple system clocks for mixed signal processing and timing. The circuit shown in interfaces the ADF4351 integrated phase-locked loop (PLL) and voltage-controlled oscillator (VCO) to the ADCLK948, which provides up to eight low voltage differential signaling (LVDS) outputs from one differential output of the IDT 8SLVD1208-33. The IDT8SLVD1208-33I is characterized to operate from a 3.3V power supply. Guaranteed output-to-output and part-to-part skew characteristics make the IDT8SLVD1208-33I ideal for those clock distribution applications demanding well-defined performance and repeatability. Two selectable differential inputs and eight low skew outputs are available. The integrated bias voltage reference enables easy interfacing of single-ended signals to the device inputs. The device is optimized for low power consumption and low additive phase noise.

Fan-out buffers and clock dividers are general-purpose clock building block devices that can be used in any number of applications. They are ideal for clock and signal distribution in a large variety of systems, from personal computers to consumer electronics or industrial systems, as well as high-performance networking and communications systems.

Increasing Outputs from a Clock Source – [Link]

14 May 2015

LDMOS

Nowadays, laterally diffused metal oxide semiconductor (LDMOS) transistors are widely used for RF Power Amplification and in many applications. A simplified circuit of an LDMOS amplifier bias circuit is shown in the schematic diagram above. The DC Bias on these amplifiers is set by applying a DC voltage to the gate (VGS) and by monitoring the Drain current (IDD). Ideally, this IDD will be constant over temperature, but since the VGS of LDMOS amplifier devices varies with temperature, some type of temperature compensation is required.

The ISL21400 features a precision voltage reference combined with a temperature sensor whose output voltage varies linearly with temperature. The precision 1.20V reference has a very low temperature coefficient, and its output voltage is scaled by an internal DAC (VREF) to produce a temperature stable output voltage that is programmable from 0V to 1.20V. The output voltage from the temperature sensor (VTS) is summed with VREF to produce a temperature dependent output voltage. The maximum voltage supply of the ISL21400 is 5.5V, and the LP2950 voltage regulator drops the LDMOS voltage to 5.5V for the ISL21400 supply. An LC filter is then added to the output of the voltage regulator to ensure no RF energy present on the supply line. The ISL21400 can be tied to a microcontroller or to any I/O connector for PC control and programming.

The RFPA bias control using the ISL21400 is very straightforward. The RFPA uses the Freescale AFT21S140W02GSR3. LDMOS are useful devices for many applications including commercial FM broadcasting and TV power transmitters, cellular and paging communication systems, and military RF and microwave hand-held transceivers.

LDMOS Transistor Bias Control in RF Power Amplifiers – [Link]

17 Apr 2015

obr1688_uvod

Higher RF power, GMSK modulation and extra low power consumption make a new communication module interesting even for rough conditions.

At cars, chip-tuning usually results in a higher power of a motor. Even the new communication module (transceiver) TR72D from IQRF has passed such „chip-tuning“ of RF portion, resulting in a higher max. RF output (up to 12mW). New RF chip – Spirit1, used at TR72D also provides excellent sensitivity and GMSK modulation (Gaussian Minimum Shift Keying) with high resistance to interference. That´s why the new module is able to transfer data at much higher distance than previous types (up to 600m on a free space). This improvement has one limitation – the new module is usable with applications originally developed for previous types, but it´s not usable in one RF network simultaneously with older types (because of a different modulation).Basically the new module TR72D offers the same straightforward development of devices with a wireless communication as previous modules. The best idea about differences among particular types will give you the attached table. TR72D is a hot novelty from which we have first engineering samples. Version „DAx“ also contains built-in antenna.

Features of IQRF technology, description of the development environment and other features can be found in a record of our webinar Wireless MESH networks without programming.

Detailed information will provide you the Wago 2059-2060-2061 brochure.

IQRF module TR72D communicates at up to 600m distance – [Link]

7 Apr 2015

KSC-LoRa

by elektor.com:

KCS BV, based in Dordrecht (NL) has extended their successful TraceME product line with an advanced module, targeted for worldwide mobility in the Internet of Things era.

The latest development of the TraceME GPS/GPRS Track and Trace module will combine the RF location based positioning solution with the LoRa™ technology. This combination offers ‘smart objects’ being even smarter, since LoRa™ enables long range, battery friendly communication in a wide variety of (M2M) applications.

Supporting GPRS/SMS and optional 3G, Wi-Fi, Bluetooth LE, ANT/ANT+ and iBeacon™ provides easy integration with existing wireless networks and mobile apps. The module will be available in Q2/2015 and other variants in the high/mid-range and budget-line will follow shortly after.

KCS TraceME expands Internet of Things era by integrating LoRa™ – [Link]


26 Mar 2015

IMG_20150326_09360122-600x450

Martin writes:

The rumors for RFM12B’s end-of-life two years ago seem to have been highly exaggerated now and the popular RF module is still available in abundance. HopeRF has introduced a pin-compatible upgrade, the RFM69CW. The module itself offers improved sensitivity and range compared to the RFM12B (+30%) at the cost of increased power consumption, making it probably a good choice for the receiving end (RFM2Pi), and probably less suited for low power battery operated nodes. The new module supports RSSI for those interested in measuring it.

The new module is more power hungry, and simply replacing a RFM12B on the RFM2Pi v2 or a Funky v3 with it didn’t work; The boards browned out so I had to swap C4 and C7 on the RFM2Pi with 10uF caps and populate the 0805 10uF on Funky v3’s boost regulator circuitry to get it to work. I’ll ship the boards with these refinements from now on so that they are compatible with both the RFM12B and RFM69CW.

[via]

Using RFM69CW instead of RFM12B – [Link]

25 Feb 2015

3042

The LT®3042 is a high performance low dropout linear regulator featuring LTC’s ultralow noise and ultrahigh PSRR architecture for powering noise sensitive RF applications. Designed as a precision current reference followed by a high performance voltage buffer, the LT3042 can be easily paralleled to further reduce noise, increase output current and spread heat on the PCB.

The device supplies 200mA at a typical 350mV dropout voltage. Operating quiescent current is nominally 2mA and drops to <<1μA in shutdown. The LT3042’s wide output voltage range (0V to 15V) while maintaining unitygain operation provides virtually constant output noise, PSRR, bandwidth and load regulation, regardless of the programmed output voltage. Additionally, the regulator features programmable current limit, fast start-up capability and programmable power good to indicate output voltage regulation.

LT3042 – 20V, 200mA, Ultralow Noise, Ultrahigh PSRR RF Linear Regulator – [Link]

21 Feb 2015

Teardown, Analysis & Part-Salvage from an HP 70001A Series Optical Microwave Analyzer – [Link]

12 Feb 2015

42020-Switch-Press_WEB

The UltraCMOS® PE42020 Integrates RF, Digital and Analog Functions in a Monolithic Die to Preserve Signal Integrity From DC to 8 GHz

Peregrine Semiconductor announces the availability of the UltraCMOS® PE42020, the industry’s first and only RF integrated switch to operate at true DC, zero Hz. This True DC RF switch features high power handling and maintains excellent RF performance and linearity from DC through 8000 MHz. A reliable alternative to problematic mechanical relays and micro-electro-mechanical systems (MEMS), the PE42020 is ideal for test-and-measurement (T&M) and automated-test-equipment (ATE) applications.

“For the first time, an integrated RF switch can operate at DC and truly cover the signal over the entire frequency spectrum,” says Kinana Hussain, Peregrine’s senior manager of marketing. “Until now, only mechanical relays and MEMS switches allowed DC pass through, and these products are plagued with reliability issues and lack of integration. Today’s release of the UltraCMOS PE42020 is another example of Peregrine solving the RF industry’s biggest challenges.”

Peregrine Semiconductor Ships Industry’s First True DC Switch – [Link]

12 Feb 2015

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by Tim @ timleland.com:

Have you ever wanted to wirelessly control power outlets from your phone? You could buy a Belkin WeMo Switch for over $40 for 1 outlet or build your own with 5 outlets for under $35 if you already own a Raspberry Pi. Hopefully this post will guide you in the right direction.

Wireless Power Outlets RF from Raspberry Pi – [Link]

22 Jan 2015

QFN-46

With a focus on the 2.4 GHz RF application area, Holtek is delighted to announce its new I/O Type Full Speed USB Flash MCU, the BC68FB540. This device forms one of a series of new generation 8-bit Flash USB RF MCUs. The 2.4 GHz RF Transceiver includes the features of low power consumption, high performance and high noise immunity characteristics and has a data rate of up to 2 MBPS.

The BC68FB540 is compatible with the USB 2.0 specification and has an operating voltage of 2.2 V to 5.5 V, and with an operating temperature of –40 °C to +85 °C it meets with industrial specifications. The RF circuitry derives its system clock from an externally connected 16 MHz crystal while the MCU system clock is derived from a fully internal 12 MHz HIRC oscillator.

Holtek New BC68FB540 2.4GHz Full Speed USB Flash Type RF TRX MCU – [Link]



 
 
 

 

 

 

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