DATEL ADC-228MM, ADC-228MC, ADC-228, ADC-883 Datasheet

FEATURES

• 8-Bit flash A/D converter

• 20MHz sampling rate

• Complete support circuitry

• Low power, 1.5W

• 7MHz full power bandwidth

• Sample-hold not required

• Three-state outputs

• MIL-STD-883 versions

GENERAL DESCRIPTION

The ADC-228 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-228 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-228 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-228 is housed in a 24-pin ceramic DDIP package
and is available in the commercial, 0 to +70°C, or military,
–55 to +125°C, 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-228

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 NLINV 17 BIT 4

9 NMINV 16 BIT 3
10 –15V SUPPLY 15 BIT 2
11 CS1 14 BIT 1 (MSB)
12 CS1 13 NO CONNECTION

INPUT/OUTPUT CONNECTIONS

13 NO CONNECTION
20 NO CONNECTION
14 BIT 1 (MSB)

15 BIT 2
16 BIT 3
17 BIT 4
21 BIT 5
22 BIT 6

23 BIT 7
24 BIT 8 (LSB)

3 +5V REF. OUT

TRI-STATE

BUFFER

8-BIT
20MHz
FLASH

CONVERTER

LINEARIZATION

& TEMPERATURE

COMPENSATION

NETWORK

INPUT

BUFFER

CS1 11
CS1 12

NLINV 8

NMINV 9

CLOCK 18

ANALOG INPUT 5

+15V SUPPLY 19

GROUND 4

GROUND 7
GROUND 6

–15V SUPPLY 10

+5V SUPPLY 1

VOLTAGE

REFERENCE

NETWORK

GROUND 2

DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.) • Tel: [phone] Fax: [phone] • For immediate assistance [phone]

ADC-228

® ®

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 2.45 2.5 2.55 kΩ
Input Capacitance — 5 10 pF

DIGITAL INPUTS

Logic Levels

Logic 1 +2.0 — — Volts
Logic 0 — — +0.8 Volts

Logic Loading

Logic 1 — — +160 µA
Logic 0 — — –0.5 mA

Clock Pulse Widths

"High" 25 — — ns
"Low" 19 — — 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 — 30 40 ns

Output Hold Time 5 — — ns

PERFORMANCE

Sampling Rate ➀ 20 — — MHz
Differential Linearity ➁

Code Transitions — ±0.5 ±0.75 LSB
Code Centers — ±0.25 ±0.5 LSB

Integral Linearity, +25°C

End-point — ±0.5 ±0.75 LSB
Best-fit Line — ±0.35 ±0.5 LSB
Over Temperature End-point — — ±1 LSB
Best-fit Line — — ±1 LSB

Zero-Scale Offset

Code "0" to "1" Transition
+25°C — — ±0.5 LSB
–55 to +125°C — ±0.5 ±1.5 LSB

Gain error — ±0.5 ±1.5 LSB
Full Scale Absolute Accuracy — ±0.5 ±1.5 LSB
Differential Gain ➂ — 2 — %
Differential Phase ➂ — 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 — –50 –48 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 43 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 45 48 — 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 6.9 7.4 — Bits
5 MHz to 10 MHz 5.6 6.1 — Bits

Input Bandwidth

Full Power 7 — — 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 — — +30 mA
–15V Supply — — –10 mA
+5V Supply — — +230 mA

Power Dissipation

±12V, +5V Nominal — 1.4 1.65 Watts
Over full supply range — 1.6 1.85 Watts
±15V, +5V Nominal — 1.5 1.75 Watts

PHYSICAL/ENVIRONMENTAL

Operating Temp. Range, Case

ADC-228MC 0 to +70°C
ADC-228MM, ADC-228/883 –55 to +125°C

Storage Temp. Range –65 to +150°C
Package Type 24-pin, ceramic DDIP
Weight 0.3 ounces (8.5 grams)

Footnotes:

➀ At full power input and chip selects enabled.
➁ See Technical Note 3.
➂ For 10-step, 40 IRE NTSC ramp test.

ABSOLUTE MAXIMUM RATINGS

PARAMETER LIMITS

Power Supply Voltage, Pin 1 –0.5 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 –6 to +7.5V
Digital Outputs –0.5 to +5.5V (short circuit protected to ground)
Lead Temp. (10 seconds) +300°C

Over the operating temperature range

±0.02% FSR/%V

S

maximum

Straight bin., comp. bin., two's

comp.,

comp. two's comp.

8 bits

2

® ®

ADC-228

Table 2. ADC-228 Bipolar Output Coding

(Assumes analog input is externally offset)

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 4.7µF, 25V tantalum
electrolytic capacitor in parallel with a 0.1µF ceramic
capacitor.

3. DATEL uses conservative definitions when specifying
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.

4. Single conversions (one-shot mode) would require another
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.

STRAIGHT BIN. COMP. BIN.

ANALOG NMINV = 0 NMINV = 1

INPUT CODE NLINV = 0 NLINV = 1

+4.96V +FS – 1 LSB 1111 1110 0000 0001
+3.75V + 3/4 FS 1100 0000 0011 1111
+2.50V + 1/2 FS 1000 0000 0111 1111
+1.25V + 1/4 FS 0100 0000 1011 1111
+0.02V + 1 LSB 0000 0001 1111 1110

0.00V ZERO 0000 0000 1111 1111

Table 1. ADC-228 Unipolar Output Coding

TWO’S COMP.

COMP. TWO’S COMP.

ANALOG NMINV = 1 NMINV = 0

INPUT CODE NLINV = 0 NLINV = 1

+2.480V +FS – 1 LSB 0111 1111 1000 0000
+1.250V +1/2 FS 0100 0000 1011 1111
+0.020V +1 LSB 0000 0001 1111 1110
+0.000V ZERO 0000 0000 1111 1111
–1.250V –1/2 FS 1100 0000 0011 1111
–2.480V –FS + 1 LSB 1000 0001 0111 1110
–2.500V –FS 1000 0000 0111 1111

CLOCK

OUT

74HC86

CLOCK

IN

100pF

50ns

40ns

25ns
PULSES

DATA N
SAMPLED

DATA N
VALID

250

Ω

Figure 3. ADC-228 Typical Connections

Figure 2. ADC-228 Single Clock Pulse

Circuit and Operation

24

23

B8 (LSB)

B7

9k

Ω

51

Ω

19

V

IN 5

+15V

*Optional

+

2, 4, 6, 7

+5V REFERENCE OUT

NO CONNECTION

3

13, 20

22

B6

21

B5

17

B4

16

B3

CS1 12

CLOCK 18

ANALOG

INPUT

15

B2

14

+

+

B1 (MSB)

4.7µF

NLINV 8

NMINV 9

0.1µF

101

–15V

+5V

CS1 11

* Use optional resistor only if
amp is not used to drive input.

ADC-228

+

0.1µF

0.1µF

0.1µF

4.7µF

4.7µF

4.7µF

EE

R = V /1.667mA

3

Table 3. Chip Select Truth Table

Figure 4. ADC-228 Timing Diagram

SAMPLE

N + 2

SAMPLE

N + 1

SAMPLE

N

OUTPUT

HOLD TIME

DATA
N – 1

DATA

N

DATA
N + 1

CLOCK

DIGITAL

OUTPUT

OUTPUT

DELAY

CS1 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

ADC-228

® ®

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
ADC-228MC 0 to +70°C

ADC-228MM –55 to +125°C
ADC-228/883 –55 to +125°C

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-0211B 10/96

ISO 9001

ISO 9001

REGISTERED

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: [phone] [phone] Fax: [phone]
Internet: www.datel.com E-mail:[e-mail]
Data Sheet Fax Back: [phone]

DATEL (UK) LTD. Tadley, England Tel: [phone]
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: [phone]
DATEL GmbH München, Germany Tel: [phone]
DATEL KK Tokyo, Japan Tel: [phone], Osaka Tel: [phone]