External Reference Voltage

VVREFP is an external reference voltage applied on the pin VREFP. The quality of the reference voltage VVREFP is critical to the performance of the AFE. A DC variation of the reference voltage VVREFP is converted to a gain error by the AFE. The noise generated by VVREFP is converted by the AFE to count noise.

Table 1. VREFP Electrical Characteristics
Symbol Parameter Conditions Min. Typ. Max. Unit
VVREFP Voltage Range Full operational 1.7 VDDIN V
RMS Noise (see Note 2) Bandwidth up to 1.74MHz VREFP=1.7V 120 µV
RVREFP Input DC Impedance AFE reference resistance bridge (see Note 1) 4.7 kOhm
Vin Input Linear Range (see Note 3) Operational Range 2 - 98 %VVREFP
IVREFP Current VVREFP = 3.3V 0.8 mA
Notes:
  1. 1.When the AFE is in Sleep mode, the VREFP impedance has a minimum of 10 MOhm.
  2. 2.Requested noise on VREFP.
  3. 3.Electrical parameters specified inside the operational range. Exceeding this range can introduce additional INL error up to +/- 5 LSB and temperature dependency up to +/-10 LSB.