ZHCSBK1C December 2006 – January 2018 DAC8560
PRODUCTION DATA.
The DAC8560 includes a 2.5-V internal reference that is enabled by default. The internal reference is externally available at the VREF pin. TI recommends a minimum 100-nF capacitor between the reference output and GND for noise filtering.
The internal reference of the DAC8560 is a bipolar transistor-based, precision bandgap voltage reference. The basic bandgap topology is shown in Figure 65. Transistors Q1 and Q2 are biased such that the current density of Q1 is greater than that of Q2. The difference of the two base-emitter voltages (VBE1 – VBE2) has a positive temperature coefficient and is forced across resistor R1. This voltage is gained up and added to the base-emitter voltage of Q2, which has a negative temperature coefficient. The resulting output voltage is virtually independent of temperature. The short-circuit current is limited by design to approximately 100 mA.