ADC-228

® ® ADC-228 8-Bit, 20MHz, Complete Flash A/D Converter IN N O V A T I O N a n d E X C E L L E N C E 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. INPUT/OUTPUT CONNECTIONS PIN 1 2 3 4 5 6 7 8 9 10 11 12 FUNCTION +5V SUPPLY GROUND +5V REFERENCE OUT GROUND ANALOG INPUT GROUND GROUND NLINV NMINV –15V SUPPLY CS1 CS1 PIN 24 23 22 21 20 19 18 17 16 15 14 13 FUNCTION BIT 8 (LSB) BIT 7 BIT 6 BIT 5 NO CONNECTION +15V SUPPLY CLOCK INPUT BIT 4 BIT 3 BIT 2 BIT 1 (MSB) NO CONNECTION CS1 11 CS1 12 NLINV 8 NMINV 9 CLOCK 18 ANALOG INPUT 5 INPUT BUFFER +15V SUPPLY 19 –15V SUPPLY 10 GROUND 7 GROUND 6 GROUND 4 GROUND 2 +5V SUPPLY 1 VOLTAGE REFERENCE NETWORK LINEARIZATION & TEMPERATURE COMPENSATION NETWORK 8-BIT 20MHz FLASH CONVERTER TRI-STATE BUFFER 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 Figure 1. Functional Block Diagram 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 ® ® ADC-228 ABSOLUTE MAXIMUM RATINGS PARAMETER Power Supply Voltage, Pin 19 Pin 10 Digital Inputs, Pins 8,9,11,12,18 Analog Input, Pin 5 Digital Outputs Lead Temp. (10 seconds) LIMITS Pin 1 –0.5 to +7V –0.3 to +18V +0.3 to –18V –0.5 to +5.5V –6 to +7.5V –0.5 to +5.5V (short circuit protected to ground) +300°C DYNAMIC PERFORMANCE Total Harm. Distortion, –0.5dB DC to 2.5 MHz 2.5 MHz to 5 MHz 5 MHz to 10 MHz Signal-to-Noise Ratio and Distortion, –0.5dB DC to 2.5 MHz 2.5 MHz to 5 MHz 5 MHz to 10 MHz Signal-to-Noise Ratio w/o Distortion, –0.5 dB DC to 2.5 MHz 2.5 MHz to 5 MHz 5 MHz to 10 MHz Effective Bits, –0.5dB DC to 2.5 MHz 2.5 MHz to 5 MHz 5 MHz to 10 MHz Input Bandwidth Full Power Small Signal (–20dB) POWER SUPPLY Power Supply Range +15V Supply –15V Supply +5V Supply Power Supply Current +15V Supply –15V Supply +5V Supply Power Dissipation ±12V, +5V Nominal Over full supply range ±15V, +5V Nominal PHYSICAL/ENVIRONMENTAL Operating Temp. Range, Case ADC-228MC ADC-228MM, ADC-228/883 Storage Temp. Range Package Type Weight Footnotes: Œ At full power input and chip selects enabled.  See Technical Note 3. Ž For 10-step, 40 IRE NTSC ramp test. 0 to +70°C –55 to +125°C –65 to +150°C 24-pin, ceramic DDIP 0.3 ounces (8.5 grams) +11 –11 +4.75 — — — — — — +15 –15 +5 — — — 1.4 1.6 1.5 +15.75 –15.75 +5.25 +30 –10 +230 1.65 1.85 1.75 Volts Volts Volts mA mA mA Watts Watts Watts MIN. — — — 44 43 35 45 45 42 7.1 6.9 5.6 7 40 TYP. –55 –50 –39 49 46 38 48 48 45 7.75 7.4 6.1 — — MAX. –53 –48 –36 — — — — — — — — — — — UNITS dB dB dB dB dB dB dB dB dB Bits Bits Bits MHz MHz FUNCTIONAL SPECIFICATIONS (Apply over the operating temperature range with 20MHz clock and ±15V and +5V power supply voltages, unless otherwise specified.) ANALOG INPUTS Single-Ended, Non-Isolated Input Range, dc-20MHz Input Resistance Input Capacitance DIGITAL INPUTS Logic Levels Logic 1 Logic 0 Logic Loading Logic 1 Logic 0 Clock Pulse Widths "High" "Low" DIGITAL OUTPUTS Coding Resolution Logic Levels Logic 1 Logic 0 Logic Loading Logic 1 Logic 0 Output Data Valid Delay From Rising Edge Output Hold Time PERFORMANCE Sampling Rate Œ Differential Linearity  Code Transitions Code Centers Integral Linearity, +25°C End-point Best-fit Line Over Temperature End-point Best-fit Line Zero-Scale Offset Code "0" to "1" Transition +25°C –55 to +125°C Gain error Full Scale Absolute Accuracy Differential Gain Ž Differential Phase Ž Aperture Delay Aperture Jitter No Missing Codes Power Supply Rejection 20 — — — — — — — ±0.5 ±0.25 ±0.5 ±0.35 — — — ±0.75 ±0.5 ±0.75 ±0.5 ±1 ±1 MHz LSB LSB LSB LSB LSB LSB Straight bin., comp. bin., two's comp., comp. two's comp. 8 bits +2.4 — — Volts — — +0.4 Volts — — — 5 — — 30 — –1 +1 40 — mA mA ns ns +2.0 — — — 25 19 — — — — — — — +0.8 +160 –0.5 — — Volts Volts µA mA ns ns MIN. 0 2.45 — TYP. — 2.5 5 MAX. +5.0 2.55 10 UNITS Volts kΩ pF — — ±0.5 LSB — ±0.5 ±1.5 LSB — ±0.5 ±1.5 LSB — ±0.5 ±1.5 LSB — 2 — % — 1 — deg. — 8 — ns — 50 — ps Over the operating temperature range ±0.02% FSR/ %VS maximum 2 ® ® ADC-228 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. +5V 0.1µF 74HC86 4.7µF + 1 CLOCK IN 250Ω CLOCK OUT 100pF NLINV 8 –15V 0.1µF 10 4.7µF + 14 15 B1 (MSB) B2 B3 B4 B5 B6 B7 B8 (LSB) NO CONNECTION NMINV 9 16 17 50ns CS1 11 21 ADC-228 CS1 12 CLOCK 18 ANALOG INPUT VIN 5 DATA N VALID 19 0.1µF 2, 4, 6, 7 22 23 24 13, 20 3 25ns PULSES DATA N SAMPLED +5V REFERENCE OUT 51Ω 9kΩ *Optional + 4.7µF 0.1µF 40ns Figure 2. ADC-228 Single Clock Pulse Circuit and Operation * Use optional resistor only if amp is not used to drive input. R = VEE /1.667mA + 4.7µF +15V Figure 3. ADC-228 Typical Connections Table 1. ADC-228 Unipolar Output Coding STRAIGHT BIN. NMINV = 0 NLINV = 0 1111 1110 1100 0000 1000 0000 0100 0000 0000 0001 0000 0000 COMP. BIN. NMINV = 1 NLINV = 1 0000 0001 0011 1111 0111 1111 1011 1111 1111 1110 1111 1111 Table 2. ADC-228 Bipolar Output Coding (Assumes analog input is externally offset) TWO’S COMP. NMINV = 1 NLINV = 0 0111 1111 0100 0000 0000 0001 0000 0000 1100 0000 1000 0001 1000 0000 COMP. TWO’S COMP. NMINV = 0 NLINV = 1 1000 0000 1011 1111 1111 1110 1111 1111 0011 1111 0111 1110 0111 1111 ANALOG INPUT +4.96V +3.75V +2.50V +1.25V +0.02V 0.00V CODE +FS – 1 LSB + 3/4 FS + 1/2 FS + 1/4 FS + 1 LSB ZERO ANALOG INPUT +2.480V +1.250V +0.020V +0.000V –1.250V –2.480V –2.500V CODE +FS – 1 LSB +1/2 FS +1 LSB ZERO –1/2 FS –FS + 1 LSB –FS 3 ® ® ADC-228 Table 3. Chip Select Truth Table CS1 Pin 12 0 0 1 1 CS1 Pin 11 0 1 0 1 Bits 1-8 Three State Mode Three State Mode Data Outputted Three State Mode CLOCK SAMPLE N SAMPLE N+1 OUTPUT DELAY SAMPLE N+2 DIGITAL OUTPUT DATA N–1 DATA N DATA N+1 OUTPUT HOLD TIME Figure 4. ADC-228 Timing Diagram MECHANICAL DIMENSIONS INCHES (mm) 1.31 MAX. (33.27) Dimension Tolerances (unless otherwise indicated): 2 place decimal (.XX) ±0.010 (±0.254) 3 place decimal (.XXX) ±0.005 (±0.127) 0.80 MAX. (20.32) 1 12 Lead Material: Kovar alloy Lead Finish: 50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating 24 13 0.100 TYP. (2.540) 1.100 (27.940) 0.235 MAX. (5.969) 0.200 MAX. (5.080) 0.010 –0.001 (0.254) 0.190 MAX. (4.826) 0.018 ±0.002 (0.457) 0.100 (2.540) 0.040 (1.016) +0.002 SEATING PLANE 0.025 (0.635) 0.600 ±0.010 (15.240) 0.100 (2.540) ORDERING INFORMATION MODEL ADC-228MC ADC-228MM ADC-228/883 TEMPERATURE RANGE 0 to +70°C –55 to +125°C –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 ® ® ISO 9001 R E G I S T E R E D IN N O V A T I O N a n d E X C E L L E N C E DS-0211B 10/96 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 Data Sheet Fax Back: (508) 261-2857 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 München, Germany Tel: 89-544334-0 DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-354-2025 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.