Datasheet

MCP3903

5.3.2 MODULATOR INPUT RANGE AND

SATURATION POINT

For a specified voltage reference value of 2.4V, the

modulator specified differential input range is ±500 mV.

The input range is proportional to V

REF

and scales

according to the V

REF

voltage. This range ensures the

stability of the modulator over amplitude and frequency.

Outside of this range, the modulator is still functional,

however its stability is no longer guaranteed and

therefore it is not recommended to exceed this limit.

The saturation point for the modulator is V

REF

/3 since

the transfer function of the ADC includes a gain of 3 by

default (independent from the PGA setting. See

Section 5.5 “ADC OUTPUT CODING”).

5.3.3 BOOST MODE

The Delta-Sigma modulators also include an

independent BOOST mode for each channel. If the

corresponding BOOST<1:0> bit is enabled, the power

consumption of the modulator is multiplied by 2 and its

bandwidth is increased to be able to sustain AMCLK

clock frequencies up to 8.192 MHz while keeping the

ADC accuracy. When disabled, the power consumption

returns back to normal and the AMCLK clock

frequencies can only reach up to 5 MHz without

affecting ADC accuracy.