19 Quality and environment control Principal customers We have an uncompromising approach to  quality assurance in every area of our operations  and goal of zero failures of our products in the  field. Active employee participation in error  prevention approaches has enabled us to win  the approval of our major customers and to beat their parts per million (ppm) failure rate expectations. The overall objective of our  quality management system is to provide all  our customers with the assurance that our  products and services not only fulfil their  current contractual requirements, but will  also meet their future needs.  Many of Dialog’s principal customers are leading  portable device digital cordless, automotive  and industrial equipment manufacturers that  purchase both ASIC and ASSP solutions.  Customers with a significant contribution to  revenue include (in order of contribution) Apple,  Gigaset, Panasonic, Bosch and Samsung. These  top five customers represented 91% of revenue  in 2012. Samsung has also become increasingly  important for a growing range of our products  targeting smartphone and portable media  player platforms. We are committed to minimising our impact on  the environment by developing and promoting  environmentally compatible products, and  operate in accordance with the ISO 14001  international environmental quality standard.  We continuously promote awareness and  knowledge of environmental and social  responsibility throughout the organisation to  ensure that they become a natural part of the  decision-making process. As we demand the  same standards from our suppliers we only  form supply partnerships with those who are  accredited to the same international standards.  For more detailed information on specific  products, please see our website:  www.dialog-semiconductor.com. Given the rapidly evolving nature of the  technology used in Dialog’s target markets,  the Company strives to develop long-term  relationships with its major customers and  seeks to adopt a partnership approach for  both standard products and custom solutions.  Customers look to Dialog for high integration,  innovation and technical expertise, while close  working relationships with customers provide  Dialog with an opportunity to develop and  refine market-leading products with recognised  industry leaders. Dialog has an uncompromising approach to quality  assurance in every area of our operations and goal  of zero failures of our products in the field. Given the rapidly evolving nature of the technology  used in Dialog’s target markets, the Company  strives to develop long-term relationships with its  major customers and seeks to adopt a partnership  approach for both standard products and  custom solutions. From left: 