The ULN2003A 7-way (or ULN2803A 8-way) darlington driver is usually the go-to chip of choice when you need to switch any high current load from a microcontroller’s GPIO. It provides seven darlington driver stages to give low-side switching and even includes seven common-cathode clamp diodes to snub voltage spikes when high inductance loads are used. Texas instruments have recently introduced an alternative device which is said to be the industry’s first seven-channel, NMOS low-side driver chip.
The TPL7407L is a high-current NMOS transistor array. It contains seven NMOS transistors that feature high-voltage outputs also with built-in clamp diodes. The input stage is compatible with GPIO logic levels ranging from 1.8 to 5.0 V and the maximum rating of each NMOS channel is 600 mA. Several outputs can be paralleled if it is necessary to sink higher levels of load current. The TPL7407L’s key benefit is its improved power efficiency and lower leakage compared to bipolar darlington drivers.
Efficient NMOS Driver Array - [Link]
by Henrik’s Blog @ hforsten.com:
Nowadays many of the most “exiting” chips come only in leadless packages, such as BGA and QFN which are hard or impossible to solder just by soldering iron, because leads are under the chip where they can’t be reached. These kinds of chips are usually soldered using reflow soldering. In reflow process solder paste is used instead of solder wire. It contains very small balls of solder in flux, diameter of the balls is just few micrometers. First this paste is put on the contact pads, then components are placed on the pads and whole board is heated in reflow oven where solder balls in the paste melt and attaches the components firmly in place.
Toaster oven reflow controller - [Link]
Discovering of overheating and joints with a high resistance has never been easier and safer. With the type Flir i3 now moreover price-affordable.
Thermal cameras, i.e. cameras sensitive in infrared range bring a useful information – picture with virtual colors responding to a temperature of a scanned surface. Maybe, at the word “thermal camera” you too get an idea about a well known usage in buildings – inspection of a heat leakage (thermal bridges) = status of a thermal insulation of buildings. But that´s only one of many ways to use these devices. In electronics and power engineering it´s far more interesting for example:
- searching for faults on a PCB, optimizing of layout in respect to an even heat distribution
- inspection of distribution boxes with cables, terminal blocks and circuit breakers
- inspection of motors and transformers
- inspection of cables interconnections (overheating caused by a high resistance)
- inspection of cooling efficiency – heatsinks, fans, …
- inspection of solar panels
…and all this at full operation and under (often high) voltage.
„I have an infrared thermometer, thus I need no camera” – this is a frequent opinion – until the time, you once try working with a camera. The joke is, that one picture from for example camera Flir i3 with resolution of “only” 60×60 pixels equals to 3600 measurements of an IR thermometer. It can be said, that one picture taken by the camera even exceeds 3600 measurements (done by an IR thermometer), because a spatial resolution of the thermal camera is usually better (surface measured by one pixel is smaller) than that of IR thermometers. This way it can happen, that a small source of heat (for example a small overheated component) can´t be discovered by an IR thermometer, while with a camera it will be clearly visible. Naturally, there are many applications where only an IR thermometer is sufficient, but cameras are far better for a professional usage and a maximum work efficiency.
That´s why we decided to incorporate into our offer the world renowned cameras from company FLIR, which is on the edge of development in this segment. As a standard stock item can be found type Flir i3 (3600 px) with resolution of 0.15°C and a viewing angle 12,5°x 12,5°. Big 2,8“ TFT display shows all necessary information and settings. Very advantageous is a possibility to store up to 5000 snapshots into a uSD card (2GB, jpg) and a consequent transfer of files into a PC through a USB. Further detailed information will provide you the Flir i3 datasheet.
Upon order we´re able to supply you any other type from company FLIR in a short leadtime..
Even hidden faults can be found with FLIR thermal cameras - [Link]
by Henrik’s Blog @ hforsten.com:
All of the best integrated circuits today come in hard to solder BGA packages. Because BGA packages have connections under the chip soldering is harder and it needs to be done using a reflow oven or hot plate. Another problem is with designing the PCB, vias and traces need to be small enough to fit between the solder balls and there needs to be usually quite many layers in the board to make room for all the closely packed traces. This means that a cheap Chinese two layer board doesn’t have enough room and more layers are needed. Adding layers increases the cost of the board dramatically when ordering only a few copies.
Making embedded Linux computer - [Link]
Dan over at HackAday documented his single chip computer project with the PCBs from DirtyPCBs:
A single AVR microcontroller (the ATmega 1284P) has been used to create a standalone computer system which runs the BASIC programming language. The 1284P runs TinyBASIC Plus, generates RCA video signals (using TVout) and reads PS/2 keyboard input. A single sided PCB was used to hold all the components meaning it is easy to manufacture the computer at home using processes such as photo-etching. Additionally, the component count is fairly low and only one IC is required (the 1284P).
Single chip AVR BASIC computer - [Link]
Linear Technology Corp have introduced the LTC3124 which is a two phase 3 MHz current-mode synchronous boost DC/DC converter featuring output disconnect and inrush current limiting. Dual phase operation has the benefit of reducing peak inductor and capacitor ripple currents allowing equivalent performance to be achieved in the power supply design with smaller valued inductors and capacitors.
The LTC3124 incorporates low resistance MOSFETs with an RDS(ON) of 130mΩ (N-channel) and 200mΩ (P-channel) to deliver efficiencies as high as 95%. The output disconnect feature allows the output to be completely discharged at shutdown and reduces switch-on inrush. An input pin can be used to configure the LTC3124 for continuous frequency mode to give low-noise operation. Additional features include external synchronization, output overvoltage protection, and robust short-circuit protection.
Dual-Phase Boosts Step-Up Efficiency - [Link]
What’s inside a 1991 vintage IBM PS/2 L40SX 80386SX laptop?
EEVblog #639 – IBM L40SX Retro Laptop Teardown - [Link]
By Darren Quick @ gizmag.com:
After unveiling the world’s first flexible OLED TV at CES earlier this year, LG has gone a step further with the unveiling of two new 18-inch OLED panels: the first is a transparent display, while the second can be rolled up. Although both fall short of the 77-inch flexible TV on show at CES, the company says the new panels prove that it has the technology to bring rollable TVs with screens in excess of 50 inches to market in the future.
LG “rolls out” latest flexible and transparent OLED panels - [Link]
Anandtech tears down the LG G Watch and Samsung Gear Live:
The G Watch turns out to be pretty easy to take apart. There are four Torx T5 screws on the back, removing them gives you access to its internals. The 400mAh battery is integrated into the back cover. ARM’s teardown confirms 3.8V chemistry, resulting in a 1.52Wh total capacity.
The logic board in the Gear Live is a bit more complex. There’s a second layer stacked on the main logic board that also acts as an RF can.
LG G Watch and Samsung Gear Live Teardowns - [Link]
by Avago Technologies:
Analog isolation is still widely used in motor drives, power monitoring, etc whereby applications typically use inexpensive analog voltage control for speed, intensity or other adjustments.
The HCNR201/200 analog optocoupler is commonly added to isolate the analog signal in the front end module of an application circuitry. The optocoupler will be placed between the analog input and the A/D converter to provide isolation of the analog input from the mixed signal ADC and other digital circuitries. The HCNR201/200 is an excellent solution for many of the analog isolation problems.
Fast analog isolation with linear optocouplers - [Link]