Singapore-based Broadcom, which has begun a process to reincorporate in the United States, called the hostile bid its "best and final offer."
The price hike steps up the pressure on California-based Qualcomm, the dominant producer of chips for mobile devices, which is set to hold its annual shareholders meeting next month.
In a letter to Qualcomm board members, Broadcom chief executive Hock Tan called the offer "extremely compelling compared to any other alternative available to Qualcomm" and called on the board to open talks on the proposal. But he said the deal would be off the table if it fails to win approval next month by shareholders.
"We continue to hope you choose to engage with us for the benefit of your stockholders," Tan said.
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"However, we will withdraw this proposal and cease our pursuit of Qualcomm immediately following your upcoming annual meeting unless we have entered into a definitive agreement or the Broadcom-nominated slate is elected."
Broadcom last year proposed a slate of 11 new Qualcomm board members as part of its effort to win approval.
Up to now, Qualcomm has rejected the tie-up, with CEO Steve Mollenkopf arguing last year there was "no real path to value" with Broadcom.
Mollenkopf, in comments in December, maintained that Qualcomm, the leading global supplier of smartphone chips, is well-positioned for emerging technologies for connected devices and 5G, or the fifth generation of wireless networks.
If completed, the deal would be the largest-ever in the tech sector and create a powerful player in the booming sector fueled by growth in smartphones and an array of connected devices from cars to wearables.
Broadcom said its offer stood whether Qualcomm's $47 billion bid for Dutch rival NXP was completed or is terminated. European regulators this month said they had approved the merger subject to conditions.
The Singapore-based firm said it was prepared to pay a "significant" fee to Qualcomm if the two companies agree but the deal is blocked by regulators.