Microchip Technology MA330031 Data Sheet

 2011-2013 Microchip Technology Inc.

DS70000657H-page 359

25.1.2

OP AMP CONFIGURATION B

 shows a typical inverting amplifier circuit

with the output of the op amp (OAxOUT) externally
routed to a separate analog input pin (ANy) on the
device. This op amp configuration is slightly different in
terms of the op amp output and the ADC input
connection, therefore, R

INT

1 is not included in the

transfer function. However, this configuration requires
the designer to externally route the op amp output
(OAxOUT) to another analog input pin (ANy). See

 for the typical value of R

INT

1. 

 and

 describe the minimum sample time (T

SAMP

)

requirements for the ADC module in this configuration.

 also defines the equation to be used to

calculate the expected voltage at point V

OA

X

OUT

. This

is the typical inverting amplifier equation.

Many useful resources are provided on the main prod-
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this 

, contains the latest updates

and additional information.

25.2.1

KEY RESOURCES

• “Op Amp/Comparator” (DS70357) in the 

• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All Related “dsPIC33/PIC24 Family Reference 

 Sections

• Development Tools

In the event you are not able to access the
product page using the link above, enter
this URL in your browser:

ADC

OAxOUT

R

FEEDBACK(2)

ANy

See 

 for the Typical value.

See 

 for the Minimum value for the feedback resistor.

See 

 and 

 for the minimum sample time (T

SAMP

).

CV

REF1O

 or CV

REF2O

 are two options that are available for supplying bias voltage to the op amps.

–

+

Op Ampx

(V

OA

X

OUT

)

R

INT

1

1

------------------------------









–





=

CxIN1-

CxIN1+

R

1

V

IN

Bias

Voltage