MicroCrystal RV-8803 – A Really Accurate RTCJune 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 IsolationJune 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 LightJune 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 SensingJune 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 cheapJune 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 […]
Texas Instruments offers engineers a set of switching regulator evergreens which combine high efficiency with simple PCB layouts. The highly efficient LM2653, first introduced in 1999, usually stands in the shadow of his SimpleSwitch-branded brothers.
While the letter are expensive and don’t deliver high efficiency, the LM2653 performs efficiently and affordably over a wide range of output currents.
…the part at hand is efficient at both low and high currents.
From a technical point of view, there is not much to say about the part. It is a switching regulator which boasts a working frequency of 300kHz, and uses a coil and an inductor to perform a bucking operation. An example schematic presents itself like figure two.
…setting up the advanced features requires a set of capacitors and resistors
The relative complexity of the example can be explained by looking at the block diagram. In addition to the thermal and overcurrent protection available in almost all switching regulators, the part contains a set of delay circuits which perform additional safety checks.
Hot feature number one is the soft start capacitor, which usually gets connected to pin SS. The IC charges it with the current of about 2 µA, and watches the voltage level until it reaches 2V. That way, the system starts up slowly, which can be helpful when charging capacitors and other elements.
Secondarily, the system has undervoltage and overvoltage protection. Should the load be able to sink the voltage to less than 80% of the desired value, a delay capacitor is charged slowly but surely – when it reaches a voltage level of 2V, the part switches off the supply to prevent short circuit and similar damages.
From a technical point of view, the part at hand is relatively docile. The datasheet contains detailed information on capacitor and diode selection, and comes with a few precalculated examples. The IC itself is available in TSSOP housing with sixteen pins.