A voltage-to-current converter includes a first differential pair of transistors, a second differential pair of transistors, and a first resistor. The first differential pair of transistors includes a first transistor and a second transistor. An emitter of the first transistor is directly connected to an emitter of the second transistor. The second differential pair of transistors includes a third transistor and a fourth transistor. An emitter of the third transistor is directly connected to an emitter of the fourth transistor. The first resistor is connected to the emitter of the first transistor, the emitter of the second transistor, the emitter of the third transistor, and the emitter of the fourth transistor.