ADC-228/883 ETC [List of Unclassifed Manufacturers], ADC-228/883 Datasheet - Page 3

• Manufacturer Part Number: ADC-228/883
• Description: 8-Bit, 20MHz, Complete 8-Bit, 20MHz, Complete Flash A/D Converter
• Manufacturer: ETC [List of Unclassifed Manufacturers]

TECHNICAL NOTES
1. Rated performance requires using good high-frequency
2. Bypass all the analog and digital supplies and the +5V
ANALOG
CLOCK
techniques. The analog and digital ground pins are
connected to each other internally. Avoid ground related
problems by connecting the grounds to one point, the
ground plane beneath the converter. Due to the inductance
and resistance of the power supply return paths, return the
analog and digital ground separately to the power supplies.
REFERENCE (pin 3) to ground with a 4.7µF, 25V tantalum
electrolytic capacitor in parallel with a 0.1µF ceramic
capacitor.
+4.96V
+3.75V
+2.50V
+1.25V
+0.02V
Figure 2. ADC-228 Single Clock Pulse
INPUT
®
0.00V
IN
DATA N
SAMPLED
Circuit and Operation
Table 1. ADC-228 Unipolar Output Coding
250
+FS – 1 LSB
50ns
+ 3/4 FS
+ 1/2 FS
+ 1/4 FS
+ 1 LSB
CODE
ZERO
100pF
40ns
74HC86
25ns
PULSES
®
STRAIGHT BIN.
DATA N
VALID
NMINV = 0
NLINV = 0
1000 0000
0100 0000
0000 0001
0000 0000
1100 0000
1111 1110
CLOCK
OUT
COMP. BIN.
NMINV = 1
NLINV = 1
0000 0001
0011 1111
1011 1111
0111 1111
1111 1110
1111 1111
ANALOG
* Use optional resistor only if
amp is not used to drive input.
R = V /1.667mA
INPUT
EE
51
3
CLOCK 18
9k
*Optional
3. DATEL uses conservative definitions when specifying
4. Single conversions (one-shot mode) would require another
NMINV 9
NLINV 8
CS1 11
CS1 12
ANALOG
V
Figure 3. ADC-228 Typical Connections
+2.480V
+1.250V
+0.020V
+0.000V
–1.250V
–2.480V
–2.500V
4.7µF
integral linearity (end-point) and differential linearity (code
transition). The specifications using the less conservative
definitions have also been provided as a comparative
specification for products specified this way.
clock edge to read out data. Users desiring to provide just
a single clock pulse could use the circuit shown in Figure 2
to obtain the data.
IN
INPUT
5
+
0.1µF
(Assumes analog input is externally offset)
+15V
Table 2. ADC-228 Bipolar Output Coding
+
+5V
+FS – 1 LSB
–FS + 1 LSB
19
4.7µF
1
+1/2 FS
–1/2 FS
+1 LSB
CODE
ZERO
0.1µF
–FS
ADC-228
–15V
2, 4, 6, 7
10
0.1µF
NMINV = 1
NLINV = 0
0100 0000
0000 0001
0000 0000
1000 0001
1000 0000
1100 0000
0111 1111
TWO’S
4.7µF
COMP.
4.7µF
13, 20
14
15
16
17
21
22
23
24
+
3
+
B1 (MSB)
B2
B3
B4
B5
B6
B7
B8 (LSB)
NO CONNECTION
0.1µF
+5V REFERENCE OUT
ADC-228
TWO’S COMP.
NMINV = 0
NLINV = 1
1000 0000
1011 1111
0011 1111
0111 1110
1111 1110
0111 1111
1111 1111
COMP.