LTC1096 Linear Technology, LTC1096 Datasheet - Page 15

• Manufacturer Part Number: LTC1096
• Description: Micropower Sampling 8-Bit Serial I/O A/D Converters
• Manufacturer: Linear Technology

A
the A/D conversion result is output on the D
Bringing CS high resets the LTC1096(L) for the next data
exchange.
Input Data Word
The LTC1096(L) requires no D
configured to have a single differential input. The conver-
sion result, in which output on the D
sequence, followed by LSB sequence providing easy inter-
face to MSB- or LSB-first serial ports.
The LTC1098(L) clocks data into the D
edge of the clock. The input data words are defined as
follows:
Start Bit
The first “logical one” clocked into the D
goes low is the start bit. The start bit initiates the data
transfer. The LTC1098(L) will ignore all leading zeros
which precede this logical one. After the start bit is
received, the remaining bits of the input word will be
clocked in. Further inputs on the D
until the next CS cycle.
Multiplexer (MUX) Address
The bits of the input word following the START bit assign
the MUX configuration for the requested conversion. For
a given channel selection, the converter will measure the
voltage between the two channels indicated by the “+” and
“–” signs in the selected row of the followintg tables. In
single-ended mode, all input channels are measured with
respect to GND.
SINGLE-ENDED MUX MODE
DIFFERENTIAL MUX MODE
PPLICATI
LTC1098(L) Channel Selection
O
U
START
SGL/DIFF
S
MUX ADDRESS
1
1
0
0
I FOR ATIO
SGL/
DIFF
U
ADDRESS
MUX
ODD/SIGN
IN
ODD/
SIGN
0
1
0
1
word. It is permanently
MSB-FIRST/
LSB-FIRST
IN
LTC1096/8 • AI02
MSBF
W
OUT
pin are then ignored
IN
0
+
+
–
CHANNEL #
input on the rising
IN
line is MSB-first
input after CS
1
+
–
+
LTC1096/8 • AI03
U
GND
OUT
–
–
line.
MSB-First/LSB-First (MSBF)
The output data of the LTC1098(L) is programmed for
MSB-first or LSB-first sequence using the MSBF bit.
When the MSBF bit is a logical one, data will appear on
the D
filled in indefinitely following the last data bit. When the
MSBF bit is a logical zero, LSB-first data will follow the
normal MSB-first data on the D
Sequence)
Unipolar Transfer Curve
The LTC1096(L)/LTC1098(L) are permanently config-
ured for unipolar only. The input span and code assign-
ment for this conversion type are shown in the follow-
ing figures for a 5V reference.
Operation with D
The LTC1098(L) can be operated with D
together. This eliminates one of the lines required to
communicate to the microprocessor (MPU). Data is trans-
mitted in both directions on a single wire. The processor
pin connected to this data line should be configurable as
either an input or an output. The LTC1098(L) will take
control of the data line and drive it low on the 4th falling
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 0
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
•
•
•
OUT
line in MSB-first format. Logical zeros will be
OUTPUT CODE
1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 0
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
•
•
•
IN
Unipolar Transfer Curve
Unipolar Output Code
and D
LTC1096/LTC1096L
LTC1098/LTC1098L
INPUT VOLTAGE
V
V
REF
REF
OUT
1LSB
0V
– 1LSB
– 2LSB
•
•
•
Tied Together
OUT
INPUT VOLTAGE
(V
line. (see Operating
REF
4.9805V
4.9609V
0.0195V
= 5.000V)
IN
0V
•
•
•
LTC1096/8 • AI05
and D
OUT
15
LTC1096/8 • AI04
tied
V
IN