PIC16LF1503 Datasheet, PDF (131/340 Pages) Microchip Technology – 14-Pin Flash, 8-Bit Microcontrollers

PIC16(L)F1503
16.0 DIGITAL-TO-ANALOG
CONVERTER (DAC) MODULE
The Digital-to-Analog Converter supplies a variable
voltage reference, ratiometric with the input source,
with 32 selectable output levels.
The input of the DAC can be connected to:
• External VREF+ pin
• VDD supply voltage
The output of the DAC can be configured to supply a
reference voltage to the following:
• Comparator positive input
• ADC input channel
• DACOUT1 pin
• DACOUT2 pin
The Digital-to-Analog Converter (DAC) can be enabled
by setting the DACEN bit of the DACCON0 register.
16.1 Output Voltage Selection
The DAC has 32 voltage level ranges. The 32 levels
are set with the DACR<4:0> bits of the DACCON1
register.
The DAC output voltage is determined by the following
equations:
EQUATION 16-1: DAC OUTPUT VOLTAGE
IF DACEN = 1
VOUT = _{}VSOURCE+ – VSOURCE-  -D----A----C----2-R--₅--^--4---:--0----^{} + VSOURCE-
IF DACEN = 0 and DACLPS = 1 and DACR[4:0] = 11111
VOUT = VSOURCE +
IF DACEN = 0 and DACLPS = 0 and DACR[4:0] = 00000
VOUT = VSOURCE –
VSOURCE+ = VDD, VREF, or FVR BUFFER 2
VSOURCE- = VSS
16.2 Ratiometric Output Level
The DAC output value is derived using a resistor ladder
with each end of the ladder tied to a positive and
negative voltage reference input source. If the voltage
of either input source fluctuates, a similar fluctuation will
result in the DAC output value.
The value of the individual resistors within the ladder
can be found in Section 28.0 “Electrical
Specifications”.
16.3 DAC Voltage Reference Output
The DAC voltage can be output to the DACOUT1 and
DACOUT2 pins by setting the respective DACOE1 and
DACOE2 pins of the DACCON0 register. Selecting the
DAC reference voltage for output on either DACOUTx
pin automatically overrides the digital output buffer and
digital input threshold detector functions of that pin.
Reading the DACOUTx pin when it has been config-
ured for DAC reference voltage output will always
return a ‘0’.
Due to the limited current drive capability, a buffer must
be used on the DAC voltage reference output for
external connections to either DACOUTx pin.
Figure 16-2 shows an example buffering technique.
 2011 Microchip Technology Inc.
Preliminary
DS41607A-page 131