LTC1594 Linear Technology, LTC1594 Datasheet - Page 15

• Manufacturer Part Number: LTC1594
• Description: 4- and 8-Channel/ Micropower Sampling 12-Bit Serial I/O A/D Converters
• Manufacturer: Linear Technology

APPLICATIONS
BOARD LAYOUT CONSIDERATIONS
Grounding and Bypassing
The LTC1594/LTC1598 are easy to use if some care is
taken. They should be used with an analog ground plane
and single point grounding techniques. The GND pin
should be tied directly to the ground plane.
The V
a 10 F tantalum capacitor with leads as short as possible.
If the power supply is clean, the LTC1594/LTC1598 can
also operate with smaller 1 F or less surface mount or
ceramic bypass capacitors. All analog inputs should be
referenced directly to the single point ground. Digital
inputs and outputs should be shielded from and/or
routed away from the reference and analog circuitry.
CSADC = CSMUX = CS
CC
MUXOUT = ADCIN
pin should be bypassed to the ground plane with
CH0 TO CH7
D
COM
CLK
OUT
D
IN
U
INFORMATION
U
Figure 7. LTC1594/LTC1598 ADCIN and COM Input Settling Windows
EN
W
D2
U
D1
SAMPLE-AND-HOLD
Both the LTC1594/LTC1598 provide a built-in sample-
and-hold (S&H) function to acquire signals through the
selected channel, assuming the ADCIN and MUXOUT
pins are tied together. The S & H of these parts acquire
input signals through the selected channel relative to
COM input during the t
Single-Ended Inputs
The sample-and-hold of the LTC1594/LTC1598 allows
conversion of rapidly varying signals. The input voltage
is sampled during the t
The sampling interval begins after t
is pulled low and continues until the second falling CLK
edge after the CS is low (see Figure 7). On this falling CLK
D0
t
ON
1ST BIT TEST “COM” INPUT MUST
SAMPLE
SETTLE DURING THIS TIME
“ANALOG” INPUT MUST
SETTLE DURING
THIS TIME
t
SMPL
SMPL
SMPL
LTC1594/LTC1598
time (see Figure 7).
time as shown in Figure 7.
HOLD
DON‘T CARE
ON
t
CONV
time once the CS
1594/98 F07
B11
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