LTC1391IGN Linear Technology, LTC1391IGN Datasheet - Page 7

• Manufacturer Part Number: LTC1391IGN
• Description: IC MULTIPLEXER 8X1 16SSOP
• Manufacturer: Linear Technology

Specifications of LTC1391IGN

• Function: Multiplexer
• Circuit: 1 x 8:1
• On-state Resistance: 75 Ohm
• Voltage Supply Source: Dual Supply
• Voltage - Supply, Single/dual (±): ±2.7 V ~ 5 V
• Current - Supply: 15µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP (0.150", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
bits clocked into the LTC1391 shift register before CS is
taken low select the MUX channel that is turned on. This
allows a series of devices, with the D
connected to the D
with a single data stream.
Multiplexer Expansion
Several LTC1391s can be daisy-chained to expand the
number of multiplexer inputs. No additional interface
ports are required for the expansion. Figure 5 shows two
LTC1391s connected at their analog outputs to form a
16-to-1 multiplexer at the input to an LTC1400 A/D converter.
D
CLK
OUT
D
IN
ANALOG
ANALOG
INPUTS
INPUTS
Figure 4. Digital Data Transfer Operation
D1
1
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
S0
S1
S2
S3
S4
S5
S6
S7
S0
S1
S2
S3
S4
S5
S6
S7
D2
IN
2
U
LTC1391
LTC1391
of the next device, to be programmed
D3
A
B
5V
3
0.1 F
INFORMATION
D
D
GND
GND
U
CLK
CLK
OUT
OUT
D
D
D4
CS
CS
V
V
V
V
IN
IN
D
D
+
–
+
–
4
D1
16
15
14
13
12
11
10
16
15
14
13
12
11
10
9
9
D5
D2
W
Figure 5. Daisy-Chaining Two LTC1391s for Expansion
OUT
D3
OPTIONAL A/D
INPUT FILTER
0.1 F
of one device
D4
–5V
U
D5
1391 • F04
+
10 F
To ensure that only one channel is switched on at any one
time, two sets of channel selection bits are needed for
DATA as shown in Figure 6. The first data sequence is used
to switch off one MUX and the second data sequence is
used to select one channel from the other MUX or
vice versa. In other words, if bit “ENA” is high and bit
“ENB” is low, one channel of MUX A is switched on and all
channels of MUX B are switched off. If bit “ENA” is low and
bit “ENB” is high, all channels at MUX A are switched off
and one channel of MUX B is switched on. Care should be
taken to ensure that only one LTC1391 is enabled at any
one time to prevent two channels from being enabled
simultaneously.
CLK
D
CS
IN
0.1 F
Figure 6. Data Sequence for MUX Expansion
1
2
3
4
ENA
V
A
V
GND
CC
IN
REF
1
LTC1400
A2
2
CONV
D
CLK
V
OUT
A1
SS
3
8
7
6
5
A0
4
ENB
5
+
B2
0.1 F
10 F
6
+
B1
LTC1391
7
10 F
0.1 F
B0
8
DATA
OUT
DATA IN
CS
CLK
sn1391 1391fas
5V
– 5V
1391 • F05
1391 • F06
7