SensASIC

Cirel's SensASIC family of custom ASICs addresses custom IC requirements for various sensor conditioning and read out applications. Applications are primarily for consumer and industrial applications and the IC could be delivered either as a known good die or packaged solution.

A platform consisting of various building blocks for these requirements containing low noise PGA, sigma-delta and nyquist rate ADCs, DACS and other building blocks is proven and be used to develop custom solutions.

Case Study of ASIC for battery powered stylus

A leading component provider of human interface solutions wanted to develop an ultra low power IC. The battery operated product was designed as a replacement for an earlier passive device to reduce cost and complexity. Customer had made a prototype using discrete ICs for proof of concept for performance however power consumption of the ASIC was the key challenge. Finding a silicon partner was a challenge for the customer as several vendors did not deem the power budget as practically achievable.

Challenges:

1. Ultra low power requirement to ensure battery life of 24 months operating of a small battery
2. Realization of high voltage functions needed for the device to communicate with the environment
3. Varied functions requiring different skills,viz, ultra low power switched cap DC-Dc regulators, complex power on sequencing, sensor interface and ADC were needed
4. Selecting a process technology providing optimal cost and functionality tradeoff
5. Complex on chip sensors with calibration
6. A detailed understanding of the complete system
7. Aggressive time to market schedule less than 12 months from project start to volume production
8. Total input cap on sensor pins had to be kept very low (less than 2pF) for proper sensor operation calling for careful attention to package and ESD protection circuit design
9. High voltage ESD solution with minimal parasitic capacitance to ensure low power

Solutions:

1. Cirel understood the complete system a key step to ensure the modules specs were derived clearly. All module specs were derived with system implications in mind. Specifications for sensor interfaces were derived with complete understanding of the system issues along with the customer.
2. Cirel provided the key innovation in power consumption by using an innovative solution to generation of a high voltage function on chip which required 5X lower power than conventional technique.
3. A 20V 0.18um low leakage process with triple gate oxide for 20V from Global Foundries was selected as it provided all the voltage elements-transistors and capacitors without compromising the area or power of the core voltage components
4. Availability of wide IP portfolio enabled choosing the right charge pump, PLL and ADC IPs from existing portfolio to use thus minimizing risk and development time
5. In house test development expertise ensured design for test to be embedded in the chip which ensured smooth test development without surprises
6. Cirel's package test and foundry partnerships and control of chip development operations is now ensuring regular production shipments

Imapact

1. Cirel delivered final solution meeting the system functionality and power budget leading to smooth release to mass production of the end product
2. Part is in mass production

Cirel is developing a family of PMICs for portable power management applications. More details will be added shortly.

For more information write us ic@cirelsystems.com