To solve this problem, the fact that the LSBs are less critical to speed and accuracy is utilized, and the 7 LSB diodes are replaced with a R-2R network. Also, in order to ensure monotonicity over a wide temperature range, the DAC's 5 MSBs are segmented or split up into 31 equal current sources. Another important definition to understand is conversion rate. This is the speed at which the DAC can make repetitive data conversions. It is mainly effected by propagation delay in counting circuits, ladder switches, comparators, amplifier settling times and slew rates.
Conversion rate is defined as the number of conversions per second.
If conversion rate is specified for less than full resolution, the speck can be misleadingly high. As with all specifications, designers are constantly trying to increase this maximum frequency. Essentially, these HBTs reinvent bipolar semiconductor technology. It can develop 1-V pulses across a load of 50 ohms with rise and fall times of less than 300ps, or 500mV across a load of 25 ohm. DAC's output impedance, resulting from its R2R network, is also 50 ohms.