Datasheet

MSP430F673x
MSP430F672x
www.ti.com SLAS731C –DECEMBER 2011–REVISED FEBRUARY 2013
SD24_B, Performance (continued)
f
SD24
= 1 MHz, SD24OSRx = 256, SD24REFS = 1
PARAMETER TEST CONDITIONS V
CC
MIN TYP MAX UNIT
SD24GAIN: 1, with external reference (1.2 V) 3 V -1 +1
E
G
Gain error
(1)
SD24GAIN: 8, with external reference (1.2 V) 3 V -2 +2 %
SD24GAIN: 32, with external reference (1.2 V) 3 V -2 +2
Gain error temperature
ΔE
G
/ΔT coefficient
(2)
, internal SD24GAIN: 1/8/32 (with internal reference) 3 V 50 ppm/°C
reference
SD24GAIN: 1 0.15
ΔE
G
/ΔV
CC
Gain error vs V
CC
(3)
SD24GAIN: 8 0.15 %/V
SD24GAIN: 32 0.4
SD24GAIN: 1 (with Vdiff = 0V) 3 V 2.3
E
OS
[V] Offset error
(4)
SD24GAIN: 8 3 V 0.73 mV
SD24GAIN: 32 3 V 0.18
SD24GAIN: 1 (with Vdiff = 0V) 3 V -0.2 0.2
E
OS
[FS] Offset error
(4)
SD24GAIN: 8 3 V -0.5 0.5 % FS
SD24GAIN: 32 3 V -0.5 0.5
SD24GAIN: 1 3 V 1
Offset error temperature
ΔE
OS
/ΔT SD24GAIN: 8 3 V 0.15 uV/°C
coefficient
(5)
SD24GAIN: 32 3 V 0.1
SD24GAIN: 1 600
ΔE
OS
/ΔV
CC
Offset error vs V
CC
(6)
SD24GAIN: 8 100 uV/V
SD24GAIN: 32 50
SD24GAIN: 1 3 V -110
Common mode rejection
CMRR,DC SD24GAIN: 8 3 V -110 dB
at DC
(7)
SD24GAIN: 32 3 V -110
(1) The gain error E
G
specifies the deviation of the actual gain G
act
from the nominal gain G
nom
: E
G
= (G
act
- G
nom
)/G
nom
. It covers process,
temperature and supply voltage variations.
(2) The gain error temperature coefficient ΔE
G
/ ΔT specifies the variation of the gain error E
G
over temperature (E
G
(T) = (G
act
(T) -
G
nom
)/G
nom
) using the box method (i.e. min. and max. values):
ΔE
G
/ ΔT = (MAX(E
G
(T)) - MIN(E
G
(T) ) / (MAX(T) - MIN(T)) = (MAX(G
act
(T)) - MIN(G
act
(T)) / G
nom
/ (MAX(T) - MIN(T))
with T ranging from -40°C to +85°C.
(3) The gain error vs V
CC
coefficient ΔE
G
/ ΔV
CC
specifies the variation of the gain error E
G
over supply voltage (E
G
(V
CC
) = (G
act
(V
CC
) -
G
nom
)/G
nom
) using the box method (i.e. min. and max. values):
ΔE
G
/ ΔV
CC
= (MAX(E
G
(V
CC
)) - MIN(E
G
(V
CC
) ) / (MAX(V
CC
) - MIN(V
CC
)) = (MAX(G
act
(V
CC
)) - MIN(G
act
(V
CC
)) / G
nom
/ (MAX(V
CC
) -
MIN(V
CC
))
with V
CC
ranging from 2.4V to 3.6V.
(4) The offset error E
OS
is measured with shorted inputs in 2's complement mode with +100% FS = V
REF
/G and -100% FS = -V
REF
/G.
Conversion between E
OS
[FS] and E
OS
[V] is as follows: E
OS
[FS] = E
OS
[V]×G/V
REF
; E
OS
[V] = E
OS
[FS]×V
REF
/G.
(5) The offset error temperature coefficient ΔE
OS
/ ΔT specifies the variation of the offset error E
OS
over temperature using the box method
(i.e. min. and max. values):
ΔE
OS
/ ΔT = (MAX(E
OS
(T)) - MIN(E
OS
(T) ) / (MAX(T) - MIN(T))
with T ranging from -40°C to +85°C.
(6) The offset error vs V
CC
ΔE
OS
/ ΔV
CC
specifies the variation of the offset error E
OS
over supply voltage using the box method (i.e. min.
and max. values):
ΔE
OS
/ ΔV
CC
= (MAX(E
OS
(V
CC
)) - MIN(E
OS
(V
CC
) ) / (MAX(V
CC
) - MIN(V
CC
))
with V
CC
ranging from 2.4V to 3.6V.
(7) The DC CMRR specifies the change in the measured differential input voltage value when the common mode voltage varies:
DC CMRR = -20log(Δ
MAX
/FSR) with Δ
MAX
being the difference between the minium value and the maximum value measured when
sweeping the common mode voltage (for example, calculating with 16-bits FSR = 65536 a maximum change by 1 LSB results in -
20log(1/65536) ≈ -96 dB) .
The DC CMRR is measured with both inputs connected to the common mode voltage (i.e. no differential input signal is applied), and the
common mode voltage is swept from -1V to V
CC
.
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