Datasheet

PIC24FV32KA304 FAMILY
DS39995D-page 220  2011-2013 Microchip Technology Inc.
22.3 Transfer Function
The transfer functions of the A/D Converter in 12-bit
resolution are shown in Figure 22-3. The difference of
the input voltages, (V
INH – VINL), is compared to the
reference, ((V
R+) – (VR-)).
• The first code transition occurs when the input
voltage is ((V
R+) – (VR-))/4096 or 1.0 LSb.
•The 0000 0000 0001 code is centered at
V
R- + (1.5 * ((VR+) – (VR-))/4096).
•The ‘0010 0000 0000’ code is centered at
V
REFL + (2048.5 * ((VR+) – (VR-))/4096).
• An input voltage less than
V
R- + (((VR-) – (VR-))/4096)
converts as ‘0000 0000 0000’.
• An input voltage greater than
(V
R-) + (4095 ((VR+) – (VR-))/4096)
converts as ‘1111 1111 1111’.
FIGURE 22-3: 12-BIT A/D TRANSFER FUNCTION
0010 0000 0001 (2049)
0010 0000 0010 (2050)
0010 0000 0011 (2051)
0001 1111 1101 (2045)
0001 1111 1110 (2046)
0001 1111 1111 (2047)
1111 1111 1110 (4094)
1111 1111 1111 (4095)
0000 0000 0000 (0)
0000 0000 0001 (1)
Output Code
0010 0000 0000 (2048)
(VINH – VINL)
V
R-
V
R+
– V
R-
4096
2048 * (V
R+
– V
R-
)
4096
V
R+
V
R-
+
V
R-
+
4095 * (V
R+
– V
R-
)
4096
V
R-
+
0
(Binary (Decimal))
Voltage Level