Sample-and-hold device for an electrical signal including an input module having two inputs, including a first switching block including two input switches, each input of the input module being connected at the input of one of the input switches, the input module being connected at the input of a first track-and-hold module with two inputs and two outputs, so as to alternately convey the signal from one of the two inputs to one of the two inputs of the first track-and-hold module; the device including a second track-and-hold module connected in parallel with the first track-and-hold module, these track-and-hold modules connected at the output of the first switching block, and an output module including a second switching block including two output switches, the outputs of the first and second track-and-hold modules being connected to the inputs of the output switches, to time interleave the output signals of the track-and-hold modules.