FEATURES
8-Bit flash A/D converter
20MHz sampling rate
Complete support circuitry
Low power, 900mW
Sample-hold not required
Three-state outputs
MIL-STD-883 versions
GENERAL DESCRIPTION
The ADC-228A combines analog front-end circuitry and a flash
A/D converter to digitize high-speed analog signals at a rate of
20 million samples per second. The ADC-228A contains an 8-
bit, 20MHz, flash A/D, a wideband analog input buffer, a
precision voltage reference, temperature compensation
circuitry, reference trims, and a three-state output buffer in a
24-pin package.
The ADC-228A offers significant savings by combining all of
the circuitry in a single package. Valuable board real estate is
saved, and design time and manufacturing costs are reduced.
The ADC-228A is housed in a 24-pin ceramic DDIP package
and is available in the commercial, 0 to +70C, or military,
55 to +125C, temperature ranges. A MIL-STD-883 version
is also available. Operation is from 15V and +5V power
supplies.
INNOVATION and EX C ELL E N C E
ADC-228A
8-Bit, 20MHz, Complete
Flash A/D Converter
Figure 1. Functional Block Diagram
PIN
FUNCTION
PIN
FUNCTION
1
+5V SUPPLY
24
BIT 8 (LSB)
2
GROUND
23
BIT 7
3
+5V REFERENCE OUT
22
BIT 6
4
GROUND
21
BIT 5
5
ANALOG INPUT
20
NO CONNECTION
6
GROUND
19
+15V SUPPLY
7
GROUND
18
CLOCK INPUT
8
NO CONNECTION
17
BIT 4
9
NO CONNECTION
16
BIT 3
10
15V SUPPLY
15
BIT 2
11
CS1
14
BIT 1 (MSB)
12
CS2
13
NO CONNECTION
INPUT/OUTPUT CONNECTIONS
DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.)
Tel: (508) 339-3000 Fax: (508) 339-6356
For immediate assistance (800) 233-2765
1 3 N O C O N N E C T I O N
2 0 N O C O N N E C T I O N
1 4 B I T 1 ( M S B )
1 5 B I T 2
1 6 B I T 3
1 7 B I T 4
2 1 B I T 5
2 2 B I T 6
2 3 B I T 7
2 4 B I T 8 ( L S B )
3 + 5 V R E F . O U T
T R I - S T A T E
B U F F E R
8 - B I T
2 0 M H z
F L A S H
C O N V E R T E R
L I N E A R I Z A T I O N
& T E M P E R A T U R E
C O M P E N S A T I O N
N E T W O R K
I N P U T
B U F F E R
C S 1 1 1
C S 2 1 2
N O C O N N E C T I O N 8
N O C O N N E C T I O N 9
C L O C K 1 8
A N A L O G I N P U T 5
+ 1 5 V S U P P L Y 1 9
G R O U N D 4
G R O U N D 7
G R O U N D 6
1 5 V S U P P L Y 1 0
+ 5 V S U P P L Y 1
V O L T A G E
R E F E R E N C E
N E T W O R K
G R O U N D 2
PRELIMINARY PRODUCT DATA
ADC-228A
FUNCTIONAL SPECIFICATIONS
(Apply over the operating temperature range with 20MHz clock and 15V and +5V
power supply voltages, unless otherwise specified.)
ANALOG INPUTS
MIN.
TYP.
MAX.
UNITS
Single-Ended, Non-Isolated
Input Range, dc-20MHz
0
--
+5.0
Volts
Input Resistance
1.95
2
--
k
Input Capacitance
--
5
10
pF
DIGITAL INPUTS
Logic Levels
Logic 1
+2.0
--
--
Volts
Logic 0
--
--
+0.8
Volts
Logic Loading
Logic 1
--
--
+160
A
Logic 0
--
--
0.5
mA
Clock Pulse Widths
"High"
20
--
--
ns
"Low"
20
--
--
ns
DIGITAL OUTPUTS
Coding
Resolution
Logic Levels
Logic 1
+2.4
--
--
Volts
Logic 0
--
--
+0.4
Volts
Logic Loading
Logic 1
--
--
1
mA
Logic 0
--
--
+1
mA
Output Data Valid Delay
From Rising Edge
--
--
40
ns
Output Hold Time
6
--
--
ns
PERFORMANCE
Sampling Rate
20
--
--
MHz
Differential Linearity
Code Transitions
--
0.5
0.75
LSB
Integral Linearity, +25C
End-point
--
0.5
1
LSB
Best-fit Line
--
0.35
0.75
LSB
Over Temperature End-point
--
--
1.75
LSB
Best-fit Line
--
--
1
LSB
Zero-Scale Offset
Code "0" to "1" Transition
+25C
--
0.5
1
LSB
55 to +125C
--
0.5
1.5
LSB
Gain error
--
0.5
1.5
LSB
Full Scale Absolute Accuracy
--
0.5
1.5
LSB
Differential Gain
--
2
--
%
Differential Phase
--
1
--
deg.
Aperture Delay
--
8
--
ns
Aperture Jitter
--
50
--
ps
No Missing Codes
Power Supply Rejection
DYNAMIC PERFORMANCE
MIN.
TYP.
MAX.
UNITS
Total Harm. Distortion, 0.5dB
DC to 2.5 MHz
--
55
53
dB
2.5 MHz to 5 MHz
--
49
44
dB
5 MHz to 10 MHz
--
39
36
dB
Signal-to-Noise Ratio
and Distortion, 0.5dB
DC to 2.5 MHz
44
49
--
dB
2.5 MHz to 5 MHz
41
46
--
dB
5 MHz to 10 MHz
35
38
--
dB
Signal-to-Noise Ratio
w/o Distortion, 0.5 dB
DC to 2.5 MHz
45
48
--
dB
2.5 MHz to 5 MHz
44
49
--
dB
5 MHz to 10 MHz
42
45
--
dB
Effective Bits, 0.5dB
DC to 2.5 MHz
7.1
7.75
--
Bits
2.5 MHz to 5 MHz
6.8
7.4
--
Bits
5 MHz to 10 MHz
5.6
6.1
--
Bits
Input Bandwidth
Large Signal (3dB)
15
--
--
MHz
Small Signal (20dB)
40
--
--
MHz
POWER SUPPLY
Power Supply Range
+15V Supply
+11
+15
+15.75
Volts
15V Supply
11
15
15.75
Volts
+5V Supply
+4.75
+5
+5.25
Volts
Power Supply Current
+15V Supply
--
+12
+20
mA
15V Supply
--
13
20
mA
+5V Supply
--
+70
+80
mA
Power Dissipation
15V, +5V Nominal
--
0.7
0.9
Watts
PHYSICAL/ENVIRONMENTAL
Operating Temp. Range, Case
ADC-228AMC
0 to +70C
ADC-228AMM, ADC-228A/883
55 to +125C
Storage Temp. Range
65 to +150C
Package Type
24-pin, ceramic DDIP
Weight
0.3 ounces (8.5 grams)
Footnotes:
At full power input and chip selects enabled.
For 10-step, 40 IRE NTSC ramp test.
ABSOLUTE MAXIMUM RATINGS
PARAMETER
LIMITS
Power Supply Voltage,
Pin 1
0.3 to +7V
Pin 19
0.3 to +18V
Pin 10
+0.3 to 18V
Digital Inputs, Pins 8,9,11,12,18
0.5 to +5.5V
Analog Input, Pin 5
3.8 to +6.6V
Digital Outputs
0.5 to +5.5V
(short circuit protected to ground)
Lead Temp. (10 seconds)+300C
Over the operating temperature range
0.02% FSR/%V
S
maximum
2
Straight Binary
8 Bits
ADC-228A
TECHNICAL NOTES
1. Rated performance requires using good high-frequency
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.
2. Bypass all the analog and digital supplies and the +5V
REFERENCE (pin 3) to ground with a 4.7F, 25V
tantalum electrolytic capacitor in parallel with a 0.1F
ceramic capacitor.
ANALOG
INPUT
CODE
STRAIGHT BIN.
+4.96V
+FS 1 LSB
1111 1110
+3.75V
+ 3/4 FS
1100 0000
+2.50V
+ 1/2 FS
1000 0000
+1.25V
+ 1/4 FS
0100 0000
+0.02V
+ 1 LSB
0000 0001
0.00V
ZERO
0000 0000
Table 1. ADC-228A Unipolar Output Coding
Table 2. Chip Select Truth Table
Figure 2. ADC-228A Timing Diagram
CS2
CS1
Pin 12
Pin 11
Bits 1-8
0
0
Three State Mode
0
1
Three State Mode
1
0
Data Outputted
1
1
Three State Mode
Figure 3. ADC-228A Typical Connections
S A M P L E
N + 2
S A M P L E
N + 1
S A M P L E
N
O U T P U T
H O L D T I M E
D A T A
N
D A T A
N + 1
D A T A
N + 2
C L O C K
D I G I T A L
O U T P U T
O U T P U T
D E L A Y
2 4
2 3
B 8 ( L S B )
B 7
9 k
9
5 1
9
1 9
V
I N
5
+ 1 5 V
* O p t i o n a l
+
2 , 4 , 6 , 7
+ 5 V R E F E R E N C E O U T
N O C O N N E C T I O N
3
8 , 9 , 1 3 , 2 0
2 2
B 6
2 1
B 5
1 7
B 4
1 6
B 3
C S 1 1 2
C L O C K 1 8
A N A L O G
I N P U T
1 5
B 2
1 4
+
+
B 1 ( M S B )
4 . 7 F
0 . 1 F
1 0
1
1 5 V
+ 5 V
C S 1 1 1
* U s e o p t i o n a l r e s i s t o r o n l y i f
a m p i s n o t u s e d t o d r i v e i n p u t .
A D C - 2 2 8 A
+
0 . 1 F
0 . 1 F
0 . 1 F
4 . 7 F
4 . 7 F
4 . 7 F
E E
R = V / 1 . 6 6 7 m A
3
ADC-228A
MECHANICAL DIMENSIONS INCHES (mm)
0.200 MAX.
(5.080)
0.235 MAX.
(5.969)
0.600 0.010
(15.240)
0.80 MAX.
(20.32)
0.100 TYP.
(2.540)
0.100
(2.540)
0.018 0.002
(0.457)
0.100
(2.540)
0.040
(1.016)
1.31 MAX.
(33.27)
1
12
13
24
1.100
(27.940)
0.190 MAX.
(4.826)
0.010
(0.254)
+0.002
0.001
SEATING
PLANE
0.025
(0.635)
Dimension Tolerances (unless otherwise indicated):
2 place decimal (.XX) 0.010 (0.254)
3 place decimal (.XXX) 0.005 (0.127)
Lead Material: Kovar alloy
Lead Finish: 50 microinches (minimum) gold plating
over 100 microinches (nominal) nickel plating
ORDERING INFORMATION
MODEL
TEMPERATURE RANGE
SAMPLING RATE
ADC-228AMC
0 to +70C
20MSPS
ADC-228AMM
55 to +125C
20MSPS
ADC-228A/883 *
55 to +105C
15MSPS
Receptacle for PC board mounting can be ordered through AMP Inc., part # 3-331272-8
(component lead socket), 24 required. Contact DATEL for 883 product specifications
INNOVATION and EX C ELL E N C E
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein
do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.
DS-0513 Preliminary
5/03
ISO 9001
ISO 9001
R
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G
I
S
T
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DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
Internet: www.datel.com E-mail:sales@datel.com
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 1-34-60-01-01
DATEL GmbH Mnchen, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
DATEL's initial qualification was done at 15MSPS and as a Mil-STD-883 Class G product per
customer request. Mil-STD-883 Class G allows for a reduced temperature range (55C to
+105C) that applies to this device. Contact DATEL if a 20MSPS rate or a Mil-STD-883
Class H (55C to +125C) temperature range is desired.
*
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