M series consists of three types (M, M2 and M3) to match different customer and application requirements. Multimedia is just one application field, but the IRM meets many requirements for this segment, like high immunity against TFT screen backlight noise, high immunity against artificial light, low current consumption, low operating voltage and compatibility to all protocols used in the markt. All three new types fullfill these requirements. The main difference between M, M2 and M3 is the protocol compatibility. M is specially designed for high data rate and short burst protocols. It can match all fast multimedia protocols in the market which are used for STB and keyboard applications. M2 is specially designed for protocols using normal burst length but fast repetition times. Both M and M2 also can handle continuous data transmission. M3 is designed to support the most common IR protocols combined with highest immunity against any kind of optical noise including plasma TVs.
The main difference to previous products and other IR receivers in the market is the improved bandpass filter of the M series. Due to a more narrow bandwidth, the noise rejection could be improved. Especially for multimedia applications this is a very important factor because the frequency of optical noise from TFT backlight and lamps is often very close to the carrier frequency of the IR protocol. Additionally, the M series is equipped with enhanced AGC algorithms to further improve the TFT noise immunity.
Another benefit of the new M, M2 and M3 series, is the improved output pulse stability. All IR receivers have output pulse variations depending on transmission distance and noise. If this variation is too big, the decoding IC will no longer be able to detect the signal correctly. As a result the end device (TV, STB, etc.) either doesn't react on the command of the remote control or in worst case it interprets the command wrong. Due to the improved output pulse stability of M series, this scenario can be avoided.
The M series is available in the standard DIP package with two different pinout constellations (IRM-36xxMx pinout Out-Gnd-Vcc, IRM-37xxMx pinout Out-Vcc-Gnd).
Main features of the IRM M series are:
- Low current consumption typ. 400µA @ 3V
- Operating voltage from 2.7V to 5.5V
- Highest immunity against TFT backlight noise
- High immunity against lamp noise
- Improved output pulse stability
- Enhanced band pass filter for improved noise rejection
- Optimized type for fast multimedia protocols
- TV sets
- Set Top Boxes
- DVD and Blu Ray player
- Audio systems