Parallel high-speed current driver using OPA660

As shown in the figure, it is a parallel high-speed current drive circuit. The input signal Vin is added to the base B (pin 3) of the equivalent special transistor OTA in the OPA660 device through a 180Ω resistor. The two collectors C (pin 8) are directly connected and connected to the load, and current is provided to the load at the same time. Therefore, the current flowing through the load is twice that of a single OTA. Because the maximum output current of the OTA in the OPA660 is ±15mA, and the maximum output current that the parallel circuit can provide is ±30mA. When a larger current is required, multiple OPA660 op amps can be connected in parallel to obtain the required load current. The 180Ω resistor connected to the input end (B pole) has a current limiting effect, and can also prevent the amplifier from self-oscillation and reduce the peaking phenomenon of the frequency characteristic. The negative feedback resistor RE (tens of ohms to hundreds of ohms) connected to the emitter can improve the linearity, input impedance and stability of the amplifier and other dynamic indicators, but the transconductance of the OTA will decrease. It can be seen that the output current can be adjusted by appropriately changing the resistance value of RE.