With the growth in demand of modern day electronics, analog has now become the new buzzword for design engineers who are on the lookout for efficient features when developing products that aim towards making life simpler and safer.
Modern day’s life is full of electronics, they are everywhere around us. From the time we wake up in the morning to the time we sleep at night, we come across various simple and complex electronic devices and products.
A few decades ago, with the advent of computers and more so with personal computers, designers started focusing on digitizing the world, and electronics were seen as a tool for digital revolution and became synonymous with the word digital. Anything and everything which contained some kind of display was considered digital, while the real world was still dominated by analog. Interaction with the real world happens through analog, while the processing of data may be in digital. In general, humans experience the world analogically. Vision, for example, is an analog experience where we perceive infinitely smooth gradations of shapes and colors. A foundational element in nearly every digital application, analog chips convert “real-world” signals, such as voice, sound, pressure, temperature and electricity, into digital ones and zeros, manipulate and cleanse them, and deliver them as clearer, sharper and more precise signals that we rely on.
Resurrection
Of late, designers have re-discovered the beauty of Analog world and have started recognizing the power of Analog circuits in their designs. Analog integrated circuits comprise one of the largest segments of the semiconductor industry. Analog ICs are also vital parts of most of the circuit and product designs. For instance, for every embedded processor in a customer’s electronic system, 10 analog components are typically required, although the count varies by system. And if an electronic device uses a battery or plugs into a wall, it will likely require at least one power management chip.
Most of the design engineers these days, design with the key ideology of making the products simple and safe to use, so as to gain mass appeal for the product, thereby generating a rich user experience. These designers have recognized that the world is analog and even though they cannot escape processing the data and inputs digitally, they need to keep the input and output interfaces analog.
Instances
A classic example would be in the field of medical test and measurement with the most common equipment being an Electro Cardio Graph (ECG). The input to this equipment is always analog i.e. electrical signals being picked up by probes attached to a patient’s body and the basic functions of an ECG machine including ECG waveform display, either through LCD screen or printed paper media, and heart rhythm indication as well as simple user interface through buttons. The key challenge here for a designer is not on how to process the data received from the probes, but more of signal acquisition due to the presence of the large DC offset and various interference signals. This potential can be up to 300mV for a typical electrode. The interference signals include the 50-/60-Hz interference from the power supplies, motion artifacts due to patient movement, radio frequency interference from electro-surgery equipments, defibrillation pulses, pace maker pulses, other monitoring equipment, etc.
A smart designer would rather focus on the simplicity of the analog signal acquisition than on display / print of the ECG graph as that determines the accuracy of the test equipment. Some of the 50Hz/60Hz common mode interference can be cancelled with a high-input-impedance instrumentation amplifier (INA121U), which removes the AC line noise common to both inputs. To further reject line power noise, the signal is inverted and driven back into the patient through the right leg by an amplifier. Only a few micro amps or less are required to achieve significant Common Mode Rejection (CMR) improvement and stay within the UL544 (UL Standard for Safety Medical and Dental Equipment) limit. In addition, 50/60Hz digital notch filters are used to reduce this interference further. High levels of integration and cost reductions are possible by using the TI’s new Analog Front End parts for the application eg. ADS1298 which help designers reduce the overall size of the board as well as power consumption, thereby making the machine portable and low cost. This surely makes the life of doctors and patients simpler and safer while providing far greater access to technology and medical diagnostics.
Another example of a consumer product which is finding wide acceptance amongst consumers of varied ages, needs and interests is the tablet computer. A tablet is a handheld electronic device primarily designed to run multimedia and web-based applications which require considerable processing power. Its main advantage over a laptop PC or a Notebook PC is its portability which is achieved by having a small form factor and less number of peripheral devices. Additionally, it uses a touch screen as the primary interface to control and interact with the product.
Again, apart from the heart of this product which is the applications processor, the designers have realized the importance of focusing on Analog for differentiating their products with competition and offering a rich user experience. This is evident from the use of light sensors in displays to continuously monitor the ambient light and alter the brightness of the display in order to conserve the battery power thereby enabling longer hours of use.
