enter image description hereI am designing an Operational Transconductance Amplifier whose maximum output current should be 15mA. Using Super Class AB amplifier, I was able to get a maximum output current of up to 2mA. The supply voltage is 5V. So to boost the output current, I need to cascade it with a current amplifier with a small gain. What would be the best way to do so? Can I get a current in mA range using CMOS current mirror technique? Or should I design another opamp and a mosfet/bjt at the output the boost the current?

  • \$\begingroup\$ Can you post a schematic of what you have so far? \$\endgroup\$ Commented Jul 9, 2018 at 16:05
  • \$\begingroup\$ Updated the post with a screenshot of the schematic of the OTA. \$\endgroup\$
    – Raghu
    Commented Jul 9, 2018 at 16:13

1 Answer 1


To boost the (output current) of an OTA, either 1) make the output devices wider (more stripes) 2) increase the internal transconductance 3) add external current mirrors 4) increase the VDD, so you have more headroom; this requires the FETS are able to exploit the extra headroom without velocity saturation


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