IEEE 802.11ac (WiFi) and IEEE 802.11ad (60-GHz WiGig) are emerging gigabit-per-second standards providing complementary services but different nature of signals. The 802.11ac targets high-resolution and narrow-to-medium bandwidth channels, while 802.11ad aims to provide broadband communications with simple modulation schemes. This work proposes a single-physical-layer transmitter baseband architecture for both 11ac and 11ad standards. The core of the proposed transmitter is a configurable mixed-signal digital-to-analog converter (DAC), which has an embedded semidigital filtering tailored for four WiFi modes (20, 40, 80, and 160 MHz) and the 1.76-GHz bandwidth of the 60-GHz WiGig standard. The DAC operates on the oversampled WiFi and raw WiGig data at a common 3.52-GHz clock frequency. System-level simulations of the finite impulse response DAC-based architecture show that the requirements of the standards can be met with maximum hardware sharing and reduced area penalty.