Datasheet

LTC2415/LTC2415-1
15
sn2415 24151fs
Table 2. LTC2415/LTC2415-1 Output Data Format
Differential Input Voltage Bit 31 Bit 30 Bit 29 Bit 28 Bit 27 Bit 26 Bit 25 … Bit 0
V
IN
* EOC DMY SIG MSB
V
IN
* ≥ 0.5 • V
REF
** 00110 0 0…0
0.5 • V
REF
** – 1LSB 00101 1 1…1
0.25 • V
REF
** 00101 0 0…0
0.25 • V
REF
** – 1LSB 0 0100 1 1…1
0 00100 0 0…0
–1LSB 0 0011 1 1…1
–0.25 • V
REF
** 00011 0 0…0
–0.25 • V
REF
** – 1LSB 00010 1 1…1
–0.5 • V
REF
** 00010 0 0…0
V
IN
* < –0.5 • V
REF
** 00001 1 1…1
*The differential input voltage V
IN
= IN
+
– IN
–
. **The differential reference voltage V
REF
= REF
+
– REF
–
.
Figure 3. Output Data Timing
APPLICATIO S I FOR ATIO
WUU
U
MSBSIG“0”
12345 262732
BIT 0BIT 27 BIT 5
LSB
24
BIT 28BIT 29BIT 30
SDO
SCK
CS
EOC
BIT 31
SLEEP DATA OUTPUT CONVERSION
2415 F03
Hi-Z
V
CC
(V)
2.5
OFFSET (ppm)
50
0
–50
–100
–150
–200
–250
3.0
3.5 4.0 4.5
2415 F04
5.0 5.5
V
REF
= 2.5V
T
A
= 25°C
PART NO.1
PART NO.2
PART NO.3
TEMPERATURE (°C)
–50
OFFSET ERROR (ppm OF V
REF
)
–103.8
–104.0
–104.2
–104.4
–104.6
–25 0 25 50
2415 F05
75 100
V
CC
AND V
REF
(V)
2.7
OFFSET ERROR (ppm OF V
REF
)
–103.0
–103.5
–104.0
–104.5
–105.0
–105.5
3.5
4.3
4.7
2415 F06
3.1
3.9
5.1
5.5
V
CC
= 5V
V
REF
= 5V
REF
+
= 5V
REF
–
= GND
V
IN
= 0V
IN
+
= GND
IN
–
= GND
F
O
= GND
T
A
=100°C
T
A
= –50°C
T
A
=25°C
Figure 4. Offset vs V
CC
Figure 5. Offset vs Temperature Figure 6. Offset vs V
CC
(V
REF
= V
CC
)
While the variation in offset with supply voltage is propor-
tional to V
CC
(see Figure 4), several characteristics of this
variation can be used to eliminate the effects. First, the
variation with respect to supply voltage is linear. Second,
the magnitude of the offset error decreases with de-
creased supply voltage. Third, the offset error increases
with increased reference voltage with an equal and oppo-
site magnitude to the supply voltage variation. As a result,
by tying V
CC
to V
REF
, the variation with supply can be
nearly eliminated, see Figure 6. The variation with supply
is less than 2ppm over the entire 2.7V to 5.5V supply
range.