Datasheet

MSP430F47x
MIXED SIGNAL MICROCONTROLLER
SLAS629A -- MARCH 2009 -- REVISED APRIL 2009
47
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature (unless otherwise
noted) (continued)
12-bit DAC, linearity specifications (see Figure 20)
PARAMETER TEST CONDITIONS V
CC
MIN TYP MAX UNIT
INL
Integral nonlinearity
(see Note 1)
V
REF,DAC12
=1.2VorV
REF,ext
=2.5V
DAC12AMPx = 7, DAC12IR = 1
2.7V ±2.0 ±8.0 LSB
D
N
L
Differential nonlinearity
V
REF,ext
=1.2V
DAC12AMPx = 7, DAC12IR = 1
2.7V -- 1 ±0.4 +1.3 LSB
DN
L
D
i
f
f
e
r
e
n
t
i
a
l
n
o
n
l
i
n
e
a
r
i
t
y
(see Note 1)
V
REF,ext
=2.5V
DAC12AMPx = 7, DAC12IR = 1
2.7V ±0.4 ±1.0 LSB
E
Offset voltage w/o calibration
(see Notes 1, 2)
V
REF, DAC12
= 1.2 V, DAC12AMPx = 7,
DAC12IR = 1
2.7 V ±20
m
V
E
O
Offset voltage with calibration
(see Notes 1, 2)
V
REF, DAC12
= 1.2 V, DAC12AMPx = 7,
DAC12IR = 1
2.7 V ±2.5
m
V
d
E(O)
/d
T
Offset error temperature
coefficient (see Note 1)
2.7 V ±30 µV/C
E
G
Gain error (see Note 1) V
REF, DAC12
=1.2V 2.7 V ±3.50 %FSR
d
E(G)
/d
T
Gain temperature coefficient
(see Note 1)
2.7 V 10
ppm of
FSR/°C
T
i
m
e
f
o
r
o
f
f
s
e
t
c
a
l
i
b
r
a
t
i
o
n
DAC12AMPx = 2 2.7 V 100
t
O
f
f
set Cal
Time for offset calibration
(
s
e
e
N
o
t
e
3
)
DAC12AMPx = 3, 5 2.7 V 32
ms
t
O
f
f
s
e
t
_
C
a
l
(see Note 3)
DAC12AMPx = 4, 6, 7 2.7 V 6
m
s
NOTES: 1. Parameters calculated from the best-fit curve from 0x0A to 0xFFF. The best-fit curve method is used to deliver coefficients “a” and
“b” of the first order equation: y = a + b*x. V
DAC12_xOUT
=E
O
+(1+E
G
)*(V
REF, DAC12
/4095) * DAC12_xDAT, DAC12IR = 1.
2. The offset calibration works on the output operational amplifier . Offset Calibration is triggered setting bit DAC12CALON
3. The offset calibration can be done if DAC12AMPx = {2, 3, 4, 5, 6, 7}. The output operational amplifier is switched off with DAC12AMPx
= {0, 1}. It is recommended that the DAC12 module be configured prior to initiating calibration. Port activity during calibration may
effect accuracy and is not recommended.
Positive
Negative
V
R+
Gain Error
Offset Error
DAC Code
DAC V
OUT
Ideal transfer
function
R
Load
=
AV
CC
C
Load
= 100pF
2
DAC Output
Figure 20. Linearity Test Load Conditions and Gain/Offset Definition