LTC1402
U
TYPICAL APPLICATION
Using Quad Cable Drivers/Receivers in Remote
unshielded cable. Using these devices, the LTC1402’s
serial data can be transmitted up to 100 feet without data
corruption. Because the SCK, CONV and DOUT signals
originate at the LTC1402, they arrive at the serial port with
similar delays and remain synchronized. When the data is
received at the serial port of the DSP or other controller,
the port must be programmed to respond to the appropri-
ate SCK and CONV edges. It is also necessary to check
where the 12-bit output DATA resides in the 16-bit data
frame. The TMS320C54x serial port READ instructions
canshiftthe12-bitdatatothepreferredpositionwithinthe
16-bit data frame.
LTC1402 Applications
In some applications, the host controller or main proces-
sor may be located some distance from the sensor, the
signal conditioning circuitry, and the ADC. In these appli-
cations, maintaining serial data integrity over long cable
distances can be a challenge. The circuit in Figure 15
showsonewaytoconveytheLTC1402’shigh-speedserial
data over a long distance. The circuit uses the LTC1688
quad cable driver and an LTC1520 quad cable receiver to
transmit/receive the LTC1402’s high-speed 35.2Mbps
serial data to the DSPs serial port over category-5
5V
5V
DV
DD
10µF
11
16
15
10
9
16
0V
DD
16
2
1
2
V
DD
3
4
1
3
5
+
–
100Ω
100Ω
100Ω
100Ω
100Ω
100Ω
BFSR
A
CONV
SCK
IN
3
TMS320C54x
BCLKR
SIGNAL
6
6
7
9
A
D
OUT
IN
7
5
OGND
LTC1402
10
10
11
BDR
GND
9
8
4
11
8
CATEGORY-5
UNSHIELDED CABLE
UP TO 100 FEET
REMEE PART NO.
5A244UTPM30BU
CONV
2.2Msps
4
15
12
14
14
15
13
CLK
13
35.2MHz
PIN 4 = ENA
PIN12 = ENB
LTC1688
QUAD DRIVER
LTC1520
QUAD RECEIVER
Figure 15. The LTC1402 3-Wire Serial Port Sends Data Over 100 Feet of Category-5
Twisted Pair with the LTC1688/LTC1520 Quad Driver/Receiver Pairs
22
Linear [ Linear ]
