This figure shows the transient responses of the LTC2338-18 18-bit SAR ADC with the internal reference buffer, and with the internal reference buffer overdriven by an external LTC6655-5 5V precision reference. The figure shows that the output voltage change when using the internal reference buffer is less than 1 LSB of the final value. In contrast, bypassing the reference buffer with an external reference take 100 microseconds to settle.

