Broadcom had proposed acquiring all outstanding shares of Qualcomm for $82 per share, which breaks down to $60.00 in cash and $22 in Broadcom stock.
Qualcomm's response attempts to strike a balance between continued resistance of Broadcom's takeover attempt and heeding the calls of some Qualcomm shareholders, who urged the company in recent days to engage with its rival in case it can clinch an attractive deal.
He said the Qualcomm board would be open to meeting with Broadcom to explore "all options for maximizing shareholder value", but reiterated the board's view that the proposal is "inferior" relative to Qualcomm's prospects as an independent company.
In the letter, Qualcomm board said it is seeking clarity on whether Tan would be willing to up the price.
Qualcomm's proposed acquisition of NXP was approved by European Union antitrust regulators last month. Boards of public companies have a fiduciary duty to consider shareholders, so Qualcomm needed to justify why it was turning this down.
Singapore-based Broadcom is mainly a manufacturer whose connectivity chips are used in products ranging from mobile phones to servers. Management has argued that leadership in smartphones will help Qualcomm expand into new areas such as server chips, personal-computer processors and automotive chips.
The merger would create a tech giant whose products would be used in almost all of the world's smartphones. Qualcomm primarily licenses its technology for the delivery of broadband and data, a business that would significantly benefit from the rollout of 5G wireless technology.
The deal would be the largest-ever technology acquisition to date, eclipsing Dell's acquisition of EMC for about $65 billion. That $47 billion deal is close to securing final regulatory approval.