I am currently designing an improved Howland current source to sink current from a TIA. The specifications of the circuit is as follows:

Bandwidth = 200MHz

Maximum current it should sink = 2mA

Load(TIA input impedance) = 100 to 500 ohms

I have chosen TI opamp LMH6629, suppling it with +2.5V and -2.5V and implemented it as follows:

The circuit is working perfect, just for the matter that the bandwidth of this circuit is below 100MHz - both in simulations and hardware implementation. I am been trying to improve the circuit bandwidth using few techniques. But nothing works better. I know I have to use a better opamp to be able to sink in current upto 2mA. But for the starters, I am looking for any bandwidth improvement techniques. If anybody could suggest any, it would be great.

Thanks in advance!