DAC8562SDSCT Datasheet, PDF (28/58 Pages) Texas Instruments – DUAL 16-/14-/12-BIT, ULTRALOW-GLITCH, LOW-POWER, BUFFERED, VOLTAGE-OUTPUT DAC WITH 2.5-V, 4-PPM/°C INTERNAL REFERENCE IN SMALL 3-MM × 3-MM SON

DAC8562, DAC8563
DAC8162, DAC8163
DAC7562, DAC7563
SLAS719D – AUGUST 2010 – REVISED AUGUST 2012
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INTERNAL REFERENCE
The DAC756x, DAC816x, and DAC856x include a 2.5-V internal reference that is disabled by default. The
internal reference is externally available at the V_REFIN/V_REFOUT pin. The internal reference output voltage is 2.5 V
and can sink and source up to 20 mA.
A minimum 150-nF capacitor is recommended between the reference output and GND for noise filtering.
The internal reference of the DAC756x, DAC816x, and DAC856x is a bipolar transistor based precision bandgap
voltage reference. Figure 90 shows the basic bandgap topology. 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 (V_BE1 – V_BE2) has
a positive temperature coefficient and is forced across resistor R₁. This voltage is amplified 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.
V_REFIN/V_REFOUT
Reference
Enable
Q₁
Q₂
R₁
R₂
Figure 90. Bandgap Reference Simplified Schematic
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