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APPLICATION INFORMATION

Stability Circuit

_

+

GND

U1

C1

U2

Positive Voltage Output Circuit

GND

OPA277

−2.5 V

GND

OPA277

C1

DAC8801

+2.5V Reference

−

+

−

+

DAC8801

SLAS403B – NOVEMBER 2004 – REVISED FEBRUARY 2007

with the inverting node of the op amp should be as short as possible and according to correct PCB layout

design. For each code change there is a step function. If the GBP of the op amp is limited and parasitic

capacitance is excessive at the inverting node then gain peaking is possible. Therefore, for circuit stability, a

compensation capacitor C1 (4 pF to 20 pF typ) can be added to the design as shown in Figure 20.

Figure 20. Gain Peaking Prevention Circuit With Compensation Capacitor

As shown in Figure 21, in order to generate a positive voltage output, a negative reference is input to the

DAC8801. This design is suggested instead of using an inverting amp to invert the output due to tolerance

ground and a -2.5 V input to the DAC8801 with an op amp.

Figure 21. Positive Voltage Output Circuit

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