2 LC MOS a 12-Bit, 750 kHz/1 MHz, Sampling ADC AD7886 FEATURES FUNCTIONAL BLOCK DIAGRAM 750 kHz/1 MHz Throughput Rate V 1 ms/750 ns Conversion Time DD CS RD CONVST 12-Bit No Missed Codes Over Temperature R3 R5 VIN1 67 dB SNR at 100 kHz Input Frequency CLOCK 10k 3.5k CONTROL BUSY OSCILLATOR Low Power250 mW typ R4 TIMER AND TIMER Fast Bus Access Time57 ns max VIN2 10k + T/H +5REF APPLICATIONS 4-BIT R1 LATCH Digital Signal Processing 9k 15 Speech Recognition and Synthesis SUM COMPARATORS DB11 R2 4-BIT THREE Spectrum Analysis AND 6.3k LATCH STATE 4-BIT FLASH DB0 DSP Servo Control V REF OUTPUTS LOGIC 4-BIT 4096 LATCH RESISTOR DAC SEGMENT SELECT AD7886 AGND V SS DGND The AD7886 is fabricated in Analog Devices Linear Com- GENERAL DESCRIPTION patible CMOS process, a mixed technology process that The AD7886 is a 12-bit ADC with a sample-and-hold amplifier offering high speed performance combined with low power dissi- combines precision bipolar circuits with low power CMOS logic. pation. The AD7886 is a triple pass flash ADC that uses 15 comparators in a 4-bit flash technique to achieve 12-bit accuracy The AD7886 is available in both a 28-pin DIP and a 28-pin in 1 s/750 ns conversion time. An on-chip clock oscillator pro- leaded chip carrier. vides the appropriate timing for each of the three conversion stages, eliminating the need for any external clocks. Acquisition PRODUCT HIGHLIGHTS time of the sample-and-hold amplifier gives a resulting through- 1. Fast 1.33 s/1 s Throughput Time. put rate of 750 kHz/1 MHz.* Fast throughput time makes the AD7886 suitable for a wide range of data acquisition applications. The AD7886 operates from 5 V power supplies. Pin-strappable inputs offer a choice of three analog input ranges: 0 V to 5 V, 2. Dynamic Specifications for DSP Users. 0 V to 10 V or 5 V. The AD7886 is specified for ac parameters, including In addition to the traditional dc accuracy specifications such as signal-to-noise ratio, harmonic distortion and inter- modulation distortion. Key digital timing parameters are linearity, offset and full-scale errors, the AD7886 is also speci- also tested and guaranteed over the full operating tem- fied for dynamic performance parameters, including harmonic distortion and signal-to-noise ratio. perature range. The AD7886 has a high speed digital interface with three-state 3. Fast Microprocessor Interface. Standard control signals, CS and RD, and fast bus ac- data outputs. Conversion control is provided by a CONVST in- cess times make the AD7886 easy to interface to micro- put. Data access is controlled by CS and RD inputs, standard microprocessor signals. The data access time of less than 57 ns processors. means that the AD7886 can interface directly to most modern 4. Low Power. microprocessors, including DSP processors. 2 LC MOS fabrication process gives low power dissipa- tion of 250 mW. *Contact your local salesperson for further information on the 1 MHz version. REV. B Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties Tel: 617/329-4700 World Wide Web Site: (V = +5 V 6 5%, V = 5 V 6 5%, A6ND = DGND = O V, V = 3.5 V, connected AD7886SPECIFICATIONS DD SS REF as shown in Figure 2. All Specifications T to T unless otherwise noted. Specifications apply for 750 kHz version.) MIN MAX 1 1 1 Parameter J Version K, B Versions T Version Units Test Conditions/Comments 2 DYNAMIC PERFORMANCE 3 Signal-to-Noise Ratio (SNR) 65 67 65 dB min VIN = 100 kHz Sine Wave, f = 750 kHz SAMPLE Total Harmonic Distortion (THD) 75 75 75 dB typ VIN = 100 kHz Sine Wave, f = 750 kHz SAMPLE Peak Harmonic or Spurious Noise 77 77 77 dB typ VIN = 100 kHz Sine Wave, f = 750 kHz SAMPLE Intermodulation Distortion (IMD) Second Order Terms 80 80 80 dB typ f = 96 kHz, f = 103 kHz, f = 750 kHz SAMPLE a b Third Order Terms 80 80 80 dB typ ACCURACY Resolution 12 12 12 Bits Integral Linearity T to T 2 2 LSB max MIN MAX Minimum Resolution for Which No Missing Codes Are Guaranteed 12 12 12 Bits Unipolar Offset Error +25C 5 5 5 LSB max Input Range: 0 V to 5 V or 0 V to 10 V T to T 5 5 5 LSB max MIN MAX Bipolar Offset Error +25C 5 5 5 LSB max Input Range: 5 V T to T 5 5 5 LSB max MIN MAX Unipolar Gain Error +25C 5 5 5 LSB max Input Range: 0 V to 5 V or 0 V to 10 V T to T 5 5 5 LSB max MIN MAX Bipolar Gain Error +25C 5 5 5 LSB max Input Range: 5 V T to T 5+5 5 LSB max MIN MAX ANALOG INPUT Unipolar Input Current 1.5 1.5 1.5 mA max Input Ranges: 0 V to 5 V or 0 V to 10 V Bipolar Input Current 0.75 0.75 0.75 mA max Input Range: 5 V REFERENCE INPUT V 3.5 3.5 3.5 Volts 2% For Specified Performance REF Input Reference Current 10 10 10 mA max R1, Resistance 9 9 9 k nom 25% R2, Resistance 6.3 6.3 6.3 k nom 25% R2/R1 Ratio 0.7 0.7 0.7 nom 0.1% POWER SUPPLY REJECTION V Only, (FS Change) 0.5 0.5 0.5 LSB typ V = 5 V, V = +4.75 V to +5.25 V DD SS DD V Only, (FS Change) 0.5 0.5 0.5 LSB typ V = +5 V, V = 4.75 V to 5.25 V SS DD SS LOGIC INPUTS Input High Voltage, V 2.4 2.4 2.4 V min V = 5 V 5% INH DD Input Low Voltage, V 0.8 0.8 0.8 V max V = 5 V 5% INL DD Input Current, I 10 10 10 A max V = 0 V to V IN IN DD 4 Input Capacitance, C 10 10 10 pF max IN LOGIC OUTPUTS DB11DB0, BUSY Output High Voltage, V 4 4 4 V min I = 200 A OH SOURCE Output Low Voltage, V 0.4 0.4 0.4 V max I = 1.6 mA OL SINK DB11DB0 Floating-State Leakage Current 10 10 10 pA max 4 Floating-State Output Capacitance 15 15 15 pF max POWER REQUIREMENTS V +5 +5 +5 V nom 5% for Specified Performance DD V 5 5 5 V nom 5% for Specified Performance SS I 35 35 35 mA max Typically 25 mA, CONVST = CS = RD = V DD DD I 35 35 35 mA max Typically 25 mA, CONVST = CS = RD = V SS DD Power Dissipation 250 250 250 mW typ CONVST = CS = RD = V DD 350 350 350 mW max NOTES I Temperature ranges are as follows: J, K Versions: 0C to +70C B Version: 40C to +85C T Version: 55C to + 125C. 2 Applies to all three input ranges, V = 0 to FS, pk-to-pk V. IN 3 SNR calculation includes distortion and noise components. 4 Sample tested +25C to ensure compliance. Specifications subject to change without notice. REV. B 2