In this paper, we present a novel cross-correlator chip suitable for "smart" ECG electrodes. Sophisticated QRS-detection is feasible exploring multicomponent-based cross-correlation and by exploiting the simplicity offered by bitstream processing. The chip is evaluated using real ECG signals as an example application. Power-efficient running cross correlation is obtained with novel asynchronous circuit solutions consuming approximately 730 μ W while processing ECG data sampled at a rate of 250 Hz. The implemented generic cross-correlator may be explored for other pattern-matching applications in wireless sensor networks or other low-power applications.