Certain aspects of the present invention provide methods and apparatus for detecting phase shift between signals, such as local oscillating signals in adjacent transceiver paths. One example circuit for phase detection generally includes a mixer configured to mix a first input signal having a first frequency with a second input signal having a second frequency to produce an output signal having frequency components at the sum of and the difference between the first and second frequencies; a filter connected with the mixer and configured to remove one of the frequency components at the sum of the first and second frequencies, thereby leaving a DC component; and an analog-to-digital converter (ADC) (e.g., a comparator) connected with the filter and configured to determine whether the first input signal is in-phase or out-of-phase with the second input signal based on a comparison between the DC component and a reference signal.