High Reliability, High Isolation Single-Pole-Double-Throw RF switch

In telecommunications, ideal RF switches require low insertion loss, high isolation and linearity. The IDT F2912 is a single-pole-double throw RF switch capable of having low insertion of loss of 0.4dB at 1GHz and a RF1 to RF2 Isolation of 74dB at 1GHz with extended temperature of -55C to +125C making it highly reliable. In addition, this covers a broad frequency range from 300kHz to 8000MHz.

As a switch, it’s capable of 3 types of controls namely switch control, mode control, and logic control. The switch control includes (3 states and 2-pin control input) or (2 states and 1-pin control input). The 3 states and 2-pin control input operates like a XOR logic gate, if there is a high value input from the control pin either CTL1/CTL2 will trigger RF1 to RF Com if CTL1 is High or RF2 to RF Com if CTL2 is High. While the 2 states and 1-pin control input, a high value CTL2 will trigger RF2 to RF com and a low value CTL2 triggers RF1 to RF Com leaving the CTL1 a “don’t care”. The mode control use either (2-pi

n control: CTL1 and CTL2) or (1-pin control: CTL2). When RF1 and RF2 ports are both open (State 1), all 3 RF ports are terminated to an internal 50Ω termination resistor. When RF1 or RF2 port is open (State 2 or State 3 OFF condition), the open port is connected to an internal 50Ω termination resistor. When RF1 or RF2 port is closed (State 2 or State 3 ON condition), the closed port is connected to the RF Com port. The logic control operates using logic voltage 1.8V and 3.3V to operate logic CTL (pin18) VCC and GND respectively.

This circuit design can be applied more on base station 2G, 3G, 4G, portable wireless, repeaters and E911 systems, digital pre-distortion point to point infrastructure, public safety infrastructure WIMAX receivers and transmitters, military systems, JTRS radios, RFID handheld and portable readers, cable Infrastructure, wireless LAN, test/ ATE Equipment.

High Reliability, High Isolation Single-Pole-Double-Throw RF switch – [Link]

Data Logger Deluxe Version


An update on LuckyResistor’s data logger project:

Just to let you know the deluxe version of the data logger is almost done. The hardware is ready and tested – currently I finish the menu based software for the data logger.
Menu based control with 5 capacitive inputs
Record, view records, send records to serial, erase all, settings
Wireless charging

Data Logger Deluxe Version – [Link]

1A, 2 MHz, 60V boost/SEPIC/inverting DC/DC converter, 6µA Iq


by Graham Prophet:

LT8330 is a current mode, 2 MHz step-up DC/DC converter with an internal 1A, 60V switch. It operates from an input voltage range of 3V to 40V, making it suitable for applications with input sources ranging from a single-cell Li-Ion to automotive inputs.

The device can be configured as either a boost, SEPIC or an inverting converter. It uses a fixed 2 MHz switching frequency, enabling designers to minimise external component sizes and avoid critical frequency bands, such as AM radio. Burst Mode operation reduces quiescent current to 6 µA while keeping output ripple below 15 mVP-P. The combination of a 3 x 2 mm DFN or TSOT-23 package and tiny externals ensures a very compact footprint while minimising overall cost.

1A, 2 MHz, 60V boost/SEPIC/inverting DC/DC converter, 6µA Iq – [Link]

Freeze 75 – and you have a temperature under control


Freeze 75 spray will enable you to find faulty component or also to protect components from overheating during soldering.

A device operates OK until it reaches stable operating temperature … a typical situation in praxis usually caused by a faulty component or faulty (cold) joint. Localization of such a fault is easy only if we can cool down (locally) a given component or a given joint. It´s often possible to suppose a source of malfunction, but to be able to localize it exactly, we´d need to change temperature of only one component or only a small PCB area. Right for this purpose a well known spray Freeze 75, is designed, able to cool down (freeze) a given component very significantly – in laboratory testing down to -52°C. And what about other possibilities of usage?
There are a lot of them. For example a local (preventive) cooling at soldering of temperature-sensitive components like temperature fuses or cooling of sensitive components near a soldered joint (for example soldering of a relatively bulky RF connector at a sensitive RF component, protection of plastic parts etc.) Another unusual help is at removing a rubber-like sticky substances from various places and textile. A typical example is removing of a chewing gum. Freeze 75 is also used in medicine, in machine engineering for shrinkage of small components etc.

How does the Freeze 75 function?
Again we´ll call for help a grammar school physics. When we go out of a swimming pool, we usually feel cold, even though there´s a warm weather outside. The reason is the water evaporating from our skin. Evaporating liquid consumes heat from a given surface. This is also a case of Freeze 75, which is filled by liquids with boiling point deeply below the frost point thus taking a lot of heat from a surface on which it is applied. Freeze 75 is non-flammable, non-explosive at all usual conditions and it also doesn´t attack plastics. It´s only advisable to be careful at components sensitive to sudden temperature changes. For absolutely highest safety in critical applications, the Freeze 75 Super is available, which is non-explosive at any circumstances.

After application of Freeze 75 in moisty environment a small amount of water can condense on a given component, consequently freezing into a whitish coating. This coating will gradually defreeze and evaporate or it can be readily removed by a water miscible solvent like for example Kontakt WL. Freeze 75 (originally marked as Kalte 75) we keep on stock in 200ml as well as 400 ml package. Detailed information will give you the Freeze 75 datasheet.

Freeze 75 – and you have a temperature under control – [Link]

Measure small currents without adding resistive insertion loss


by Maciej Kokot @ edn.com:

In most cases, you measure current by converting it into a proportional voltage and then measuring the voltage. Figure 1 shows two typical methods of making the conversion. In one method, you insert a probing resistor, RP, in series with the current path and use differential amplifier IC1 to measure the resulting voltage drop (Figure 1a). A second method is a widely known operational amplifier current-to-voltage converter in which inverted IC1’s output sinks the incoming current through the feedback resistor (Figure 1b).

Measure small currents without adding resistive insertion loss – [Link]

PCI-Express Clock Generator

This reference design is a frequency generator for use in synchronizing a circuit’s operation. It consumes less than 50mW of power that specifically uses the IDT’s 9FGV0241 PCI-Express Clock Generator which is the lowest-power PCI Express timing family. It is a two output clock generator with programmable output amplitude allowing tuning for various application environments.

The circuit reduces heat dissipation to ease cooling requirements in large scale cloud computing applications. It has a programmable slew rate allowing tuning for various line lengths with an integrated output termination of 100Ω, providing maximum flexibility when working in a non-homogenous timing environment. In addition, the device has an external 25MHz crystal that supports tight parts per million (ppm) with 0 ppm synthesis error.

These clock synthesizers have various applications such as communications, computing, and consumer goods. Most members of IDT timing family feature a selectable SMBus address so that multiple devices can seamlessly share the same SMBus segment without the cumbersome additional logic that is often required with other solutions.

PCI-Express Clock Generator – [Link]

A Connected Lamp to Wake Me Up


Limpkin has modified his IKEA lamp to use 10W LEDs.

So for some reason I bought 2 IKEA lamps at a flea market. As IKEA furniture has a long history of being hacker-friendly, I figured they shouldn’t be an exception to the rule.
My plan? Fit a few 10W RGB LEDs in there together with an ESP8266 to use the final result as an alarm clock.

When you are dealing with a LED consuming that much current, you can’t simply use a series resistor as the latter would need to dissipate R*I² in heat. I’m therefore using a dedicated LED driver that automatically adjusts the LED voltage to match a given current. As you can guess, it isn’t much different than a standard step-down and just uses a shunt resistor to measure the current flowing through the LED.

A Connected Lamp to Wake Me Up – [Link]

Fake TV Security Light


by Marcus Jenkins:

This gadget steps up the game from leaving a light on at home when you’re out. Place it near a window to make it look like somebody’s at home watching TV.

The idea of leaving a light on at home while you’re out is to give the burglar an uneasy feeling that somebody’s at home and it might be worth trying the next house along instead. A TV on at night plays a constantly-changing light-show against your window which really does say I’m at home and I’m awake. Of course, you could leave a real TV on but that’s an eco-disaster since TV’s consume 50W at best and hundreds at worst. Plus you might not want to be burning your TV in for days on end if you’re not at home.

Fake TV Security Light – [Link]

Graphics on Nokia 5110 Lcd using Arduino

by Akshay Jha @ instructables.com:

In this short instructable I am gonna displ some graphics on Nokia 5110 LCD using ARDUINO UNO R3 this is very helpful for beginners`s here is a testing video .

Graphics on Nokia 5110 Lcd using Arduino – [Link]

Sit.Up – alerts the user if sitting to long


electrobob.com has build a device that alerts you if sitting to long:

Sitting for long periods has become more common in today’s jobs causing serious health issues. Unfortunately the plethora of activity trackers fail to address the issue: being rather active while sitting does not provide a good picture of the amount of time spent sitting.

Sit.Up is a simple device that attaches to the chair and alerts the user by vibration if sitting for too long while also tracking the sitting time. It aims to be easy to install and forget on any chair and work with any person. On top of that, it is very low cost and has months to years of battery life. With an optional WiFi connection, the data can be uploaded and you can track your sitting times.

Sit.Up – alerts the user if sitting to long – [Link]