The AD7656 contains six 16-bit, fast, low power, successive approximation ADCs all in the one package. The part AD7656 core operates from a single 4.5 V to 5.5 V power supply and features throughput rates up to 250 kSPS. The part contains low noise, wide bandwidth track-and-hold amplifiers that can handle input frequencies up to 8 MHz.

The conversion process and data acquisition are controlled using CONVST signals and an internal oscillator. Three CONVST pins allow independent simultaneous sampling of the three ADC pairs. The AD7656 has both a high speed parallel and serial interface allowing the devices to interface with microprocessors or DSPs. When in Serial interface mode the AD7656 has a Daisy Chain feature allowing multiple ADCs to connect to a single serial interface. There are no pipelined delays associated with the part.

The AD7656 can accommodate true bipolar input signals in the range ±10V . The AD7656 contains a 2.5V internal reference. The AD7656 can also accept an external reference. If a 3V external reference is applied to the V_REF pin, the ADCs can accommodate a true bipolar ±12V analog input range. V_DD and V_SS supplies of ±12V are required for this ±12V input range.

The AD7656 is fabricated on Analog Devices’ Industrial CMOS process, iCMOS™ , a technology platform combining the advantages of low and high voltage CMOS, bipolar and high voltage DMOS processes. The process enables the AD7656 to accept high voltage bipolar signals in addition to reducing power consumption and package size. The AD7656 can accommodate true bipolar input signals in the ±10V range and ±5V range . It contains a 2.5V internal reference and can also accept an external reference. If a 3V external reference is applied to the VREF pin, the ADC can accommodate a true bipolar ±12V analog input range. V_DD and V_SS supplies of ±12V are required for this ±12V input range.

Product Highlights

1. Six 16-bit 250 kSPS ADCs on board.
2. Six true bipolar high impedance analog inputs.
3. The AD7656 features both a parallel and a high speed serial interface.

Applications

• Power Line Monitoring systems
• Instrumentation and control systems
• Multi-axis positioning systems

Part#	Res	Throughput Rate	# of Inputs	Operating Pwr Diss
AD7656	16	250KSPS	6	143mW
AD7654	16	500KSPS	4	135mW
AD7655	16	1MSPS	4	135mW
AD7657	14	250KSPS	6	143mW
AD7658	12	250KSPS	6	143mW
AD7693	16	500KSPS	1	21.5mW
AD7686	16	500KSPS	1	21.5mW
AD7694	16	250KSPS	1	6.3mW
AD7687	16	250KSPS	1	12.5mW
AD7688	16	500KSPS	1	21.5mW
AD7980	16	1MSPS	1	10mW

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