Analog Devices extends its portfolio of 3 V data converters with the introduction of two low-power analog-to-digital converters (ADCs). The AD9218 is the industry's fastest 3 V 10-bit dual ADC, offering a sample rate of 105 mega samples per second (MSPS), which is more than 160 percent faster than other 10-bit dual ADCs with similar power consumption. The AD9235 is a 3 V, 12-bit 65 MSPS ADC, and is 30 percent faster than other 12-bit converters in its class. In addition, the AD9235 enables intermediate frequency (IF) sampling up to 100 MHz in small or portable applications, such as pico-cell cellular base stations.

"As manufacturers strive to meet customer demand for smaller portable devices, they are increasingly looking for low-power components that can lower cost and reduce printed circuit board complexity," said Dave Robertson, product line director, High Speed Converters, Analog Devices. "ADI is addressing manufacturers' requirements by offering the broadest portfolio of 3 V high-speed analog-to-digital converters to provide low-power operation without compromising speed or performance. With the introduction of the AD9218 and AD9235, we are setting a new benchmark for low-power converters that offer both high speed and the highest levels of dynamic performance."

The AD9218 is a dual 10-bit monolithic sampling ADC that is optimized for applications requiring low power and printed circuit board space savings. It operates at conversion rates of 40/65/80/105 MSPS, and has a signal to noise ratio (SNR) of 56 dBc at 105 MSPS and an input frequency of 41 MHz. The AD9218 is ideal for low-cost oscilloscopes, portable instruments, In-phase and Quadrature (I&Q) communications, and broadband (wired and wireless) applications. This low-power solution needs only a 3 V (2.7 V to 3.6 V) power supply and a differential clock to operate. It reduces power supply demands by consuming only 265 mW per channel during full operation at 105 MSPS. The AD9218 has digital outputs that are TTL and LVCMOS compatible, and support interfacing with 3.3 V or 2.5 V logic. The device provides user-selectable options that support a combination of power-down modes, digital data formats, and digital timing schemes. In addition, its dual ADC channels can be operated independently of each other. The AD9218 also provides designers with a cost-effective solution for migrating from 8-bit to 10-bit performance, while saving space and power, by offering pin-compatibility with Analog Devices' AD9288, an 8-bit 40/80/100 MSPS dual ADC.

The AD9235 is a monolithic, single 3 V 12-bit, 20/40/65 MSPS analog-to-digital converter that combines low power and supports IF sampling up to 100 MHz input frequencies. It achieves an SNR of 70.4 dBc and a spurious-free dynamic range (SFDR) of 84 dBc and is ideal for a number of applications, including cellular base stations, portable instrumentation, high-end imaging and transportable ultrasound equipment. The design has been optimized for each speed grade resulting in power dissipation of 90 mW, 165 mW and 300 mW, respectively. The AD9235 includes a patented input sampling network, voltage reference, and multistage differential pipelined architecture with output error correction logic for 12-bit accuracy at 65 MSPS data rates, with no missing codes. It also offers a clock duty-cycle stabilizer to maintain performance over a wide range of clock pulse widths, which is important to portable applications where the clock source may be less than ideal.

Analog Devices, One Technology Way, Norwood, MA 02062-9106. Phone: 781-329-4700 or 800-262-5643

Analog Devices has introduced yet another duo of ADCs with low power requirements and high resolution. These two are for 3 V applications that need 10- or 12-bit resolution. The AD9218 is a dual 10-bit monolithic sampling ADC and is designed for low-cost oscilloscopes, portable instruments, in-phase and quadrature communications, and wired and wireless broadband applications. It operates at conversion rates of 40/65/80/105 MSPS, and has a signal-to-noise ratio of 56 dBc at the highest sampling rate and an input frequency of 41 MHz. The ADC requires only a single 3.0 V power supply and an encode clock to operate. The company says that for most applications you don't need an external reference or driver component. The digital outputs are TTL/CMOS compatible and to broaden its appeal the chip is offered with a separate output power supply pin that supports interfacing with 3.3 V or 2.5 V logic.

The AD9218 uses input buffers that are differential with both sets of inputs internally biased. This allows for flexible use of AC or DC and differential or single ended input modes. The chip uses a track/hold circuit, which is essentially a mixer, so any noise, distortion, or timing jitter on the clock is combined with the desired signal at the A/D output. For that reason, you should take care when choosing a clock source.

The AD9235 family features a high performance sample-and-hold amplifier (SHA) and voltage reference. The converter is suitable for multiplexed systems that switch full-scale voltage levels in successive channels and for sampling single-channel inputs at frequencies beyond the Nyquist rate. A single-ended clock input is used to control all internal conversion cycles. A duty cycle stabilizer compensates for wide variations in the clock duty cycle while maintaining performance. The company's patented SHA input maintains its performance for input frequencies up to 200 MHz, and can be configured for single-ended or differential operation.

Both ADCs operate over the extended industrial range of -40°C and +85°C and are available in production quantities now.

The AD9218 is packaged in a 48-lead 7x7 mm LQFP (low-profile quad flat pack) and is priced at the following in 1,000-piece quantities: $9.25 (40 MSPS), $11.76 (65 MSPS), $13.36 (80 MSPS) and $17.12 (105 MSPS).

The AD9235 is packaged in a 28-lead TSSOP (thin shrink small-outline package) and is priced at the following in 1,000-piece quantities: $12.38 (20 MSPS), $15.08 (40 MSPS) and $17.02 (65 MSPS).

AD9218 Data Sheet (linked above)
www.analog.com/pdf/AD9218_pre.pdf

AD9235 Data Sheet:
www.analog.com/pdf/AD9235_0.pdf