YBa2Cu3O6+x (YBCO) cuprates are semiconducting when oxygen depleted (x < 0.5). We have deposited, by DC sputtering at 150 °C, amorphous YBCO (a-YBCO) semiconducting films to evaluate their potential as sensing layer for thermal detection of infrared (IR) radiation. Low temperature elaboration is a key advantage to integrate a radiation detector on a silicon chip bearing already processed readout electronics. We have studied an a-YBCO/metal planar structure test vehicle in the near-IR, concentrating on the high-pass pyroelectric response observed for the device. This response exhibited interesting features: i) because originating from a capacitance current signal, no DC bias was required, hence a low noise current level; ii) the high-pass pyroelectric cutoff was observed in the 20 to 40 kHz modulation frequency range; iii) the low-pass cutoff, of readout circuitry origin, was pushed towards the MHz range, with a time constant of ~ 2 μs. The use of an analytical model allowed to simulate correctly the device amplitude and phase of the response as a function of the modulation frequency. All the model parameters were introduced, without adjustment, according to the actual geometrical, physical and electrical characteristics of the device and its measurement setup. The low noise and fast response was characterized by a detectivity above 109 cm·Hz1/2·W− 1, in the 500 Hz to 100 kHz range; these features are very promising for fast imaging applications. Migration from near-IR towards mid- and far-IR is also considered.