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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

SLAS403A – NOVEMBER 2004 – REVISED DECEMBER 2004

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 errors

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

Figure 21. Positive Voltage Output Circuit

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