3 V to 5 V Single Supply, 200 kSPS a 8-Channel, 12-Bit Sampling ADC AD7858/AD7858L FUNCTIONAL BLOCK DIAGRAM FEATURES Specified for V of 3 V to 5.5 V DD AD7858200 kSPS AD7858L100 kSPS AV DD AGND System and Self-Calibration with Autocalibration on Power-Up AIN1 AD7858/ Eight Single-Ended or Four Pseudo-Differential Inputs I/P T/H AD7858L MUX Low Power DV DD AIN8 AD7858: 12 mW (V = 3 V) DD 2.5V AD7858L: 4.5 mW (V = 3 V) REFERENCE DD COMP Automatic Power-Down After Conversion (25 W) Flexible Serial Interface: DGND REF /REF BUF IN OUT 8051/SPI/QSPI/ P Compatible C 24-Lead DIP, SOIC, and SSOP Packages REF1 CHARGE APPLICATIONS REDISTRIBUTION DAC Battery-Powered Systems (Personal Digital Assistants, CLKIN Medical Instruments, Mobile Communications) C REF2 CONVST SAR AND ADC Pen Computers CONTROL CALIBRATION BUSY Instrumentation and Control Systems MEMORY AND CAL CONTROLLER SLEEP High-Speed Modems GENERAL DESCRIPTION SERIAL INTERFACE/CONTROL REGISTER The AD7858/AD7858L are high-speed, low-power, 12-bit ADCs that operate from a single 3 V or 5 V power supply, the DIN DOUT SCLK SYNC AD7858 being optimized for speed and the AD7858L for low power. The ADC powers up with a set of default conditions at which time it can be operated as a read-only ADC. The ADC PRODUCT HIGHLIGHTS contains self-calibration and system calibration options to en- 1. Specified for 3 V and 5 V supplies. sure accurate operation over time and temperature and have a number of power-down options for low-power applications. 2. Automatic calibration on power-up. The part powers up with a set of default conditions and can 3. Flexible power management options including automatic operate as a read-only ADC. power-down after conversion. The AD7858 is capable of 200 kHz throughput rate while the 4. Operates with reference voltages from 1.2 V to V . DD AD7858L is capable of 100 kHz throughput rate. The input 5. Analog input range from 0 V to V . DD track-and-hold acquires a signal in 500 ns and features a pseudo-differential sampling scheme. The AD7858/AD7858L 6. Eight single-ended or four pseudo-differential input channels. voltage range is 0 to V with straight binary output coding. REF 7. System and self-calibration. Input signal range is to the supply and the part is capable of con- 8. Versatile serial I/O port (SPI/QSPI/8051/ P). verting full power signals to 100 kHz. 9. Lower power version AD7858L. CMOS construction ensures low power dissipation of typically 4.5 mW for normal operation and 1.15 mW in power-down mode with a throughput rate of 10 kSPS (V = 3 V). The part DD is available in 24-lead, 0.3 inch-wide dual-in-line package (DIP), 24-lead small outline (SOIC), and 24-lead small shrink outline (SSOP) packages. See page 31 for data sheet index. SPI and QSPI are trademarks of Motorola, Inc. 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: 781/329-4700 World Wide Web Site: 1, 2 AD7858/AD7858LSPECIFICATIONS (AV = DV = +3.0 V to +5.5 V, REF /REF = 2.5 V External DD DD IN OUT Reference unless otherwise noted, f = 4 MHz (1.8 MHz B Grade (0 C to +70 C), 1 MHz A and B Grades (40 C to +85 C) for L Version) f = CLKIN SAMPLE 200 kHz (AD7858), 100 kHz (AD7858L) SLEEP = Logic High T = T to T , unless otherwise noted.) Specifications in ( ) apply to the AD7858L. A MIN MAX 1 1 Parameter A Version B Version Units Test Conditions/Comments DYNAMIC PERFORMANCE 3 Signal to Noise + Distortion Ratio 70 71 dB min Typically SNR is 72 dB (SNR) V = 10 kHz Sine Wave, f = 200 kHz (100 kHz) IN SAMPLE Total Harmonic Distortion (THD) 78 78 dB max V = 10 kHz Sine Wave, f = 200 kHz (100 kHz) IN SAMPLE Peak Harmonic or Spurious Noise 78 78 dB max V = 10 kHz Sine Wave, f = 200 kHz (100 kHz) IN SAMPLE Intermodulation Distortion (IMD) Second Order Terms 78 80 dB typ fa = 9.983 kHz, fb = 10.05 kHz, f = 200 kHz (100 kHz) SAMPLE Third Order Terms 78 80 dB typ fa = 9.983 kHz, fb = 10.05 kHz, f = 200 kHz (100 kHz) SAMPLE Channel-to-Channel Isolation 90 90 dB typ V = 25 kHz IN DC ACCURACY Any Channel Resolution 12 12 Bits Integral Nonlinearity 1 1 LSB max 2.5 V External Reference V = 3 V, V = 5 V (B Grade Only) DD DD 1 0.5 LSB max 5 V External Reference V = 5 V DD (1) LSB max (L Version, 5 V External Reference, V = 5 V) DD (1) LSB max (L Version) Differential Nonlinearity 1 1 LSB max Guaranteed No Missed Codes to 12 Bits. 2.5 V External Reference V = 3 V, 5 V External Reference, V = 5 V DD DD Total Unadjusted Error 1 1 LSB typ Unipolar Offset Error 5 5 LSB max Typically 2 LSBs 2.5 2.5 LSB max 5 V External Reference, V = 5 V DD (3) (3) LSB max (L Version) (1.5) (1.5) LSB max (L Version, 5 V External Reference, V = 5 V) DD Unipolar Offset Error Match 1.5 1.5 LSB max Positive Full-Scale Error 4 4 LSB max 1.5 1.5 LSB max 5 V External Reference, V = 5 V DD Positive Full-Scale Error Match 1 1 LSB max ANALOG INPUT Input Voltage Ranges 0 to V 0 to V Volts i.e., AIN(+) AIN() = 0 to V , AIN() can be biased REF REF REF up but AIN(+) cannot go below AIN() Leakage Current 1 1 A max Input Capacitance 20 20 pF typ REFERENCE INPUT/OUTPUT REF Input Voltage Range 2.3/V 2.3/V V min/max Functional from 1.2 V IN DD DD Input Impedance 150 150 k typ REF Output Voltage 2.3/2.7 2.3/2.7 V min/max OUT REF Tempco 20 20 ppm/C typ OUT LOGIC INPUTS Input High Voltage, V 2.4 2.4 V min AV = DV = 4.5 V to 5.5 V INH DD DD 2.1 2.1 V min AV = DV = 3.0 V to 3.6 V DD DD Input Low Voltage, V 0.8 0.8 V max AV = DV = 4.5 V to 5.5 V INL DD DD 0.6 0.6 V max AV = DV = 3.0 V to 3.6 V DD DD Input Current, I 10 10 A max Typically 10 nA, V = 0 V or V IN IN DD 4 Input Capacitance, C 10 10 pF max IN LOGIC OUTPUTS Output High Voltage, V I = 200 A OH SOURCE 4 4 V min AV = DV = 4.5 V to 5.5 V DD DD 2.4 2.4 V min AV = DV = 3.0 V to 3.6 V DD DD Output Low Voltage, V 0.4 0.4 V max I = 0.8 mA OL SINK Floating-State Leakage Current 10 10 A max 4 Floating-State Output Capacitance 10 10 pF max Output Coding Straight (Natural) Binary CONVERSION RATE Conversion Time 4.6 (18) 4.6 s max (L Versions Only, 40C to +85C, 1 MHz CLKIN) (10) s max (L Versions Only, 0C to +70C, 1.8 MHz CLKIN) Track/Hold Acquisition Time 0.4 (1) 0.4 (1) s min (L Versions Only) 2 REV. B