
LTC1863L/LTC1867L
14
1863l7lfc
APPLICATIONS INFORMATION
Figure 7. Example 2, CS/CONV Starts a Conversion With Short Active HIGH Pulse.
With CS/CONV Returning LOW Before the Conversion, the ADC Remains Powered Up
INPUT VOLTAGE (V)
OUTPUT
CODE
1863L7L F09
111...111
111...110
100...001
100...000
000...000
000...001
011...110
011...111
FS – 1LSB
0V
UNIPOLAR
ZERO
FS = 2.5V
1LSB = FS/2n
1LSB (LTC1863L) = 610μV
1LSB (LTC1867L) = 38.1μV
Figure 8. LTC1863L/LTC1867L Bipolar Transfer
Characteristics (Two’s Complement)
Figure 9. LTC1863L/LTC1867L Unipolar Transfer
Characteristics (Straight Binary)
S0
SD
0S
S1
COM UNI
SLP
MSB = D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
CS/CONV
SCK
SDI
SDO
(LTC1867)
Hi-Z
123456789
10
11
12
13
14
15
16
tCONV
D12
MSB = D15
D14
D13
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Hi-Z
1863L7L F07
tCONV
DON'T CARE
NOT NEEDED FOR LTC1863
tACQ
SDO
(LTC1863)
DON'T CARE
INPUT VOLTAGE (V)
0V
OUTPUT
CODE
(T
WO’S
COMPLEMENT)
–1
LSB
1863L7L F08
011...111
011...110
000...001
000...000
100...000
100...001
111...110
1
LSB
BIPOLAR
ZERO
111...111
FS/2 – 1LSB
–FS/2
FS = 2.5V
1LSB = FS/2n
1LSB (LTC1863L) = 610μV
1LSB (LTC1867L) = 38.1μV