SBOS747C May 2016 – July 2026 REF61
PRODUCTION DATA
The REF61xx family of voltage references are stable with output capacitor values ranging from 10 µF to 47 µF. At a low output-capacitor value of 10 µF, an effective series resistance (ESR) of 20mΩ to 100mΩ is required for stability; whereas, at a higher value of 47 µF, an ESR of 5mΩ to 100mΩ is required. The shaded region in Figure 8-5 shows the stable region of operation for the REF61xx devices.
Figure 8-5 Stable Output Capacitor RangeA capacitor of value 1 µF is required at the FILT pin for stability and noise performance. A low ESR (5mΩ to 20mΩ) is easily achieved by increasing the PCB trace length, thus eliminating the need for a discrete resistor. Higher values of ESR (greater than 20mΩ, but lesser than 100mΩ) can be intentionally added to increase the output bandwidth of the REF61xx. This higher ESR improves the transient performance of the REF61xx, but worsens noise performance because of increased bandwidth.