a FEATURES Specified for V DD of 3 V to 5.5 V AD7859–200 kSPS; AD7859L–100 kSPS System and Self-Calibration Low Power Normal Operation AD7859: 15 mW (VDD = 3 V) AD7859L: 5.5 mW (V DD = 3 V) Using Automatic Power-Down After Conversion (25 W) AD7859: 1.3 mW (VDD = 3 V 10 kSPS) AD7859L: 650 W (VDD = 3 V 10 kSPS) Flexible Parallel Interface: 16-Bit Parallel/8-Bit Parallel 44-Pin PQFP and PLCC Packages APPLICATIONS Battery-Powered Systems (Personal Digital Assistants, Medical Instruments, Mobile Communications) Pen Computers Instrumentation and Control Systems High Speed Modems
3 V to 5 V Single Supply, 200 kSPS 8-Channel, 12-Bit Sampling ADCs AD7859/AD7859L* FUNCTIONAL BLOCK DIAGRAM AVDD
AIN1 I/P MUX
AIN8 2.5V REFERENCE COMP REFIN/ REFOUT
CHARGE REDISTRIBUTION DAC CLKIN
SAR + ADC CONTROL
CALIBRATION MEMORY AND CONTROLLER
CONVST BUSY SLEEP
PARALLEL INTERFACE/CONTROL REGISTER
The AD7859/AD7859L are high speed, low power, 8-channel, 12-bit ADCs which operate from a single 3 V or 5 V power supply, the AD7859 being optimized for speed and the AD7859L for low power. The ADC contains self-calibration and system calibration options to ensure accurate operation over time and temperature and have a number of power-down options for low power applications. The AD7859 is capable of 200 kHz throughput rate while the AD7859L is capable of 100 kHz throughput rate. The input track-and-hold acquires a signal in 500 ns and features a pseudodifferential sampling scheme. The AD7859 and AD7859L input voltage range is 0 to VREF (unipolar) and –VREF/2 to +VREF/2 about VREF/2 (bipolar) with both straight binary and 2s complement output coding respectively. Input signal range is to the supply and the part is capable of converting full-power signals to 100 kHz. CMOS construction ensures low power dissipation of typically 5.4 mW for normal operation and 3.6 µW in power-down mode. The part is available in 44-pin, plastic quad flatpack package (PQFP) and plastic lead chip carrier (PLCC).
DB15 – DB0
1. Operation with either 3 V or 5 V power supplies. 2. Flexible power management options including automatic power-down after conversion. 3. By using the power management options a superior power performance at slower throughput rates can be achieved. AD7859: 1 mW typ @ 10 kSPS AD7859L: 1 mW typ @ 20 kSPS 4. Operates with reference voltages from 1.2 V to the supply. 5. Analog input ranges from 0 V to VDD. 6. Self and system calibration. 7. Versatile parallel I/O port. 8. Lower power version AD7859L.
- Patent pending. See page 28 for data sheet index.
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