A Controller Area Network, CAN, transceiver (500, 700, 1400) comprising: a transmitter (511, 711) for transmitting, based on an input signal, a transmitter output voltage to a CAN bus (504, 704); another transmitter (511a, 711a) configured to generate, from the input signal, a copy of the transmitter output voltage to provide an expected differential bus voltage; and an error frame detection unit (515, 715) configured to: measure a differential bus voltage from the CAN bus; and detect an error frame on the CAN bus based on a comparison between the measured differential bus voltage and the expected differential bus voltage, in which the error frame detection unit comprises a first transconductance amplifier and a second transconductance amplifier, in which: the first transconductance amplifier is configured to convert the expected differential voltage signal to a first current; and the second transconductance amplifier is configured to convert the measured differential bus voltage signal from the CAN bus (504, 704) to a second current, in which the error frame detection unit (515, 715) is configured to determine a difference between the first current and the second current in order to compare the expected differential voltage signal and the measured differential bus voltage signal. a transmitter (511, 711) for transmitting, based on an input signal, a transmitter output voltage to a CAN bus (504, 704); another transmitter (511a, 711a) configured to generate, from the input signal, a copy of the transmitter output voltage to provide an expected differential bus voltage; and an error frame detection unit (515, 715) configured to: measure a differential bus voltage from the CAN bus; and detect an error frame on the CAN bus based on a comparison between the measured differential bus voltage and the expected differential bus voltage, measure a differential bus voltage from the CAN bus; and detect an error frame on the CAN bus based on a comparison between the measured differential bus voltage and the expected differential bus voltage, in which the error frame detection unit comprises a first transconductance amplifier and a second transconductance amplifier, in which: the first transconductance amplifier is configured to convert the expected differential voltage signal to a first current; and the second transconductance amplifier is configured to convert the measured differential bus voltage signal from the CAN bus (504, 704) to a second current, in which the error frame detection unit (515, 715) is configured to determine a difference between the first current and the second current in order to compare the expected differential voltage signal and the measured differential bus voltage signal. the first transconductance amplifier is configured to convert the expected differential voltage signal to a first current; and the second transconductance amplifier is configured to convert the measured differential bus voltage signal from the CAN bus (504, 704) to a second current, in which the error frame detection unit (515, 715) is configured to determine a difference between the first current and the second current in order to compare the expected differential voltage signal and the measured differential bus voltage signal.