Integrated circuits

An integrated circuit (IC) is an electronic circuit built on a semiconductor wafer, usually made of silicon. On this wafer, there are millions of miniaturized transistors, resistors, and capacitors, which are connected by metal traces. The ICs are powered by an external power supply for their operations. ICs perform specific functions such as data processing and signal processing. The entire physical size of the IC wafer is extremely small compared to that of discrete circuits hence it is called a microchip or simply chips. Because of their small size, ICs have low power consumption.

Types of ICs

ICs are categorized as digital, analog, and mixed-signal ICs based on their circuit functionality.

Digital ICs

Digital ICs can be divided into further two categories for the sake of simplicity:

• Simple ICs: Timer, counter, register, switches, digital logic gates, adder, etc.
• Complex ICs: Microprocessor, memories, switching ICs, ethernet MAC/PHY.

A microprocessor/microcontroller is an integrated circuit, which can process the digital data. For example, temperature sensor data can be read by a microprocessor and using its internal logic to perform control functions such as switching an air-conditioner ON or OFF. The ability to program a microprocessor gives it the flexibility to be used in a wide range of applications. Some of the applications are consumer electronics (microwave, washing machine, TV), industrial applications (motor control, process control), communication applications (wireless communication, telephony, satellite communication).

A microprocessor is a complex IC having an inbuilt central processing unit (CPU) consisting of an arithmetic logic unit (ALU), registers, buffer memory, clock. The processor does not have inbuilt memory and needs to interface RAM and ROM externally. Applications: computers, laptops, servers, basically for high-end processing.

A microcontroller is an integrated circuit that has CPU, inbuilt memory, general-purpose IO’s, communication interface such as SPI, I2C, UART, ADC, DAC, PWM. Depending on the size of memory and interface microcontrollers are targeted for specific applications. Applications: Embedded devices such as washing machines, weighing scales, CNC machines, etc.

Digital signal processing (DSP) controllers are a type of processor which are used in high-computing applications such as image processing, speech processing, video compression, etc.

Analog ICs

Operational amplifiers, differential amplifiers, instrumentation amplifiers, RF devices, ADCs, DACs.

Interfacing ICs – RS232 driver, ethernet, CAN bus drivers, buffers, and level converters.

Power ICs – Voltage regulators such as linear regulators, LDOs, switching regulators

Field programmable gate array – FPGA, mixed-signal FPGA

IC packages

IC’s are available in different packages and pin counts such as DIP and SMD. Below are some of the popular and widely used packages.

Typical selection parameters

While selecting an IC in any circuit user need to consider about following parameters apart from the application/usage.

Digital ICs

• Operating voltage (Vcc): +2.5V, +3.3V, +1.8V, +5V, +12V/-12V
• Maximum operating frequency
• Switching time and maximum data rates
• IO voltage level (TTL5V, CMOS), max tolerance, VIH, VIL, VOH, VOL
• IO setup time, hold time, data valid time
• Type of IO: Digital or analog pin
• Open collector or totem pole output
• Total number of IOs required for application
• Type of communication interfaces such as SPI or I2C and speed
• Power dissipation.
• Commercial 0° C to 60° C, mil-grade -55° C to 125° C, industrial -40° C to 85° C
• Size

Analog ICs

• Operating voltage (Vcc): +2.5V, +3.3V, +1.8V, +5V, +12V/-12V
• Ref voltages
• Maximum and minimum output voltage
• Offset voltages and current
• CMRR, PSRR
• Input signal magnitude range
• Type of digital communication interface and speed
• Power dissipation
• Commercial 0° C to 60° C, mil-grade -55° C to 125° C, industrial -40° C to 85° C
• Size