MicroCrystal RV-8803 – A Really Accurate RTC June 17, 2019- RTC chips traditionally were the domain of Maxim and NXP. Switzerland-based MicroCrystal recently made quite a buzz with its RV-8803, which offers simple integration, an I2C interface and extreme accuracy. Let us start out by looking at a system overview. Figure one shows how this I2C RTC is made up internally – interested observers note […] Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation June 15, 2019- In theory, digital buses are intended to connect things to one another. Sadly, one sometimes wants but a logical connection – in many cases, galvanic isolation helps out. Should you ever feel like isolating very fast buses, definitely give the LTM2887 a chance. From a technical point of view, Linear Technologies attempt at entering the […] AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light June 14, 2019- Recent times saw quite a bit of interest for part numbers such as the APDS-9008 or APDS-9005-020 – they are a very interesting type of ambient light sensor. One of the oldest questions in regards to light sensors involves their spectral sensitivity. If a part is to output but one voltage level, the conversion between […] STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing June 12, 2019- Apple’s iPhone introduced gyroscopic sensors to a wider range – before that, accelerometers were not commonly found in consumer hardware. STM sells excellent parts which, however, get little media attention – time to take a look at the LIS2DH12. Integrating the part into your circuit as an MPU6500 alternative or MPU9500 alternative is not difficult. […] Panasonic AMG8833 – FLIR for cheap June 7, 2019- FLIR made infrared thermal sensors cool – sadly, their parts are all but cheap (and suffer from export control problems). Panasonic’s Grid-EYE family is a low-resolution alternative which comes at significantly lower cost. From a technical point of view, Panasonic’s image sensor could not be simpler. We are looking at an 8×8 sensor with an […] DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap) June 5, 2019- When yours truly was but a lowly cadet, various US manufacturers produced (pricey but quite reliable) switches. Chinese vendors recently started to catch up – seeing the DTS-62R-V top our customer interest list shows that the run stage of the crawl-walk-run cycle is reached. DipTronics has been around the Asian switch market for ages, exhibiting […]
Be it a fan, a turbine or any other kind of inductive or resistive load – keeping an eye on safety becomes difficult if large amounts of current flow. STM’s VND5004B and VND5004BSP30 high-side drivers are a nice way to work around the problem.
Understanding the part is best accomplished by looking at figure one. It shows an example of the VND5004 being interfaced to a microcontroller of choice. The resistors next to the GPIO pins are required to prevent latch-ups of the GPIO interface, as inductive loads can wreak all kinds of havoc in your circuit during switch-off.
Interfacing the VND5004 to a microcontroller is easy…
Driving large currents – the datasheet maximum of the part is at 100A – requires both security precautions and careful PCB design. ST tries to make designer’s life easier with the pinout – figure two shows that the output pins are multiplied.
Furthermore, a pad at the bottom provides both Vcc and a first-class opportunity to attach a PCB heatsink directly to the ICs die. This, sadly, is a problem for hand assembly – if you don’t have a reflow oven in-house, pass assembly to another firm or buy one.
“Doubling” pins spreads current across the PCB…
While undervoltage shutoff, thermal and short-circuit protection are relatively simple to understand, the official datasheet of the part does not provide any information on the actual voltage levels found at the sense pins – when used with an ADC; they are intended to provide feedback on the current drawn by the load.
More answers on this topic can be found in application note AN1596, which describes both the semiconductor topology used and gives practical advice on component behavour. When driving serious inductive loads, definitely do take a look at it before finishing your circuit.