ON Semiconductor’s CAT4101 – End of Life, Discontinued

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 … Continue reading MicroCrystal RV-8803 – A Really Accurate RTC
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 … Continue reading Analog Devices’ LTM2887 – If a Digital Bus Needs Galvanic Isolation
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 … Continue reading AVAGO APDS-9008 or APDS-9005-020 – Keeping an Eye on Ambient Light
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. … Continue reading STMicroelectronics’ LIS2DH12 – Low Power Motion Sensing
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 … Continue reading Panasonic AMG8833 – FLIR for cheap
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 … Continue reading DipTronics DTS-62R-V – Small Switch, Very Big (and Very Cheap)

Around 2010, ON Semiconductor introduced the world to the CAT4101 family of LED drivers. Sadly, the sands of time leave no one untouched – which is why we must channel Steve Jobs while mourning the death of our beloved friend, CAT4101TV-T75.

As shown in the figure, the CAT4101 was a relatively simple constant current shunt regulator. This meant that its efficiency was limited, but that no inductors were needed – without switching action, there are no LED bulb EMI concerns to worry about.

Using the part to drive a set of LEDs could not be easier. Our figure shows an example where a set of LEDs is driven by a CAT4101TV-T75 with a guaranteed current of 1A. The main issue is that a regulated 5V supply is needed to power the logic, while a second supply with higher voltage is required to actually keep the LEDs happy. The resistor shown on the right-hand side, then, is used to determine the LED current desired.

Driving LEDs with constant current is not difficult

ON Semiconductor apparently planned to offer an entire product line for LED driving; its life, sadly, seems to have been cut short. Thus, no in-house replacement will be provided for the end-of-life CAT4101 – other vendors do, however, offer similar components.

While the part is no longer being produced by ON Semiconductor, there still is quite a bit of stock to be had. Use OEMSecrets to find CAT4101TV distributors, and stock up in a last-time-buying frenzy to keep units in the field!