ADS8343E2K5 Datasheet, PDF (10/23 Pages) Burr-Brown (TI) – 16-Bit, 4-Channel Serial Output Sampling ANALOG-TO-DIGITAL CONVERTER

TYPICAL CHARACTERISTICS: +2.7V (Cont.)
At T_A = +25°C, +V_CC = +2.7V, V_REF = +1.25V, f_SAMPLE = 100kHz, and f_CLK = 24 • f_SAMPLE = 2.4MHz, unless otherwise noted.
SUPPLY CURRENT vs SAMPLING FREQUENCY
1.4
f_CLK = 2.4MHz
1.2
1.0
V_SS = 5.0V
0.8
0.6
V_SS = 2.7V
0.4
0.2
Power-Down After Conversion Mode.
0
External Clock Gated HIGH After Conversion.
10 20 30 40 50 60 70 80 90 100
Sampling Frequency (kHz)
THEORY OF OPERATION
The ADS8343 is a classic Successive Approximation Register
(SAR) A/D converter. The architecture is based on capacitive
redistribution which inherently includes a sample-and-hold func-
tion. The converter is fabricated on a 0.6µm CMOS process.
The basic operation of the ADS8343 is shown in Figure 1.
The device requires an external reference and an external
clock. It operates from a single supply of 2.7V to 5.25V. The
external reference can be any voltage between 500mV and
+V_CC/2. The value of the reference voltage directly sets the
input range of the converter. The average reference input
current depends on the conversion rate of the ADS8343.
+ 1µF
to
10µF
+2.7V to +5V
ADS8343
0.1µF
1 +V_CC
2 CH0
DCLK 16
CS 15
Single-ended
or differential
analog inputs.
3 CH1
4 CH2
5 CH3
DIN 14
BUSY 13
DOUT 12
6 COM GND 11
7 SHDN GND 10
V_REF
8 V_REF
+V_CC 9
1µF
Serial/Conversion
Clock
Chip Select
Serial Data In
Serial Data Out
FIGURE 1. Basic Operation of the ADS8343.
The analog input to the converter is differential and is
provided via a 4-channel multiplexer. The input can be
provided in reference to a voltage on the COM pin (which is
generally V_REF) or differentially by using two of the four input
channels (CH0-CH3). The particular configuration is select-
able via the digital interface.
ANALOG INPUT
The analog input is bipolar and fully differential. There are
two general methods of driving the analog input of the
ADS8343: single-ended or differential, as shown in Figure 2.
±V_REF(1)
Common-Mode
Voltage
(typically V_REF)
CHX
ADS8343
COM
Single-Ended Input
Common-Mode
Voltage
± ^VREF(1)
2
± ^VREF(1)
2
CHX+
ADS8343
CHX–
Differential Input
NOTE: (1) Relative to common-mode voltage.
FIGURE 2. Methods of Driving the ADS8343—Single-Ended
or Differential.
10
ADS8343
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