DESCRIPTION GÉNÉRALE

The AD9266 is a monolithic, single-channel 1.8 V supply, 16-bit, 20 MSPS/40 MSPS/65 MSPS/80 MSPS analog-to-digital converter (ADC). It features a high performance sample-andhold circuit and on-chip voltage reference.

The product uses multistage differential pipeline architecture with output error correction logic to provide 16-bit accuracy at 80 MSPS data rates and to guarantee no missing codes over the full operating temperature range.

The ADC contains several features designed to maximize flexibility and minimize system cost, such as programmable clock and data alignment and programmable digital test pattern generation. The available digital test patterns include built-in deterministic and pseudorandom patterns, along with custom user-defined test patterns entered via the serial port interface (SPI).

A differential clock input with a selectable internal 1-to-8 divide ratio controls all internal conversion cycles. An optional duty cycle stabilizer (DCS) compensates for wide variations in the clock duty cycle while maintaining excellent overall ADC performance.

The interleaved digital output data is presented in offset binary, gray code, or twos complement format. A DCO is provided to ensure proper latch timing with receiving logic. Both 1.8 V and 3.3 V CMOS levels are supported.

The AD9266 is available in a 32-lead RoHS-compliant LFCSP and is specified over the industrial temperature range (−40°C to +85°C).

 

CANDIDATURES

Communications

Diversity radio systems

Multimode digital receivers GSM, EDGE, W-CDMA, LTE, CDMA2000, WiMAX, TD-SCDMA

Smart antenna systems

Instruments alimentés par piles

Handheld scope meters

Portable medical imaging

Ultrasound

Radar/LIDAR

PET/SPECT imaging

 

CARACTÉRISTIQUES

1.8 V analog supply operation

1.8 V to 3.3 V output supply SNR

77.6 dBFS at 9.7 MHz input

71.1 dBFS at 200 MHz input SFDR

93 dBc at 9.7 MHz input

80 dBc at 200 MHz input Low power

56 mW at 20 MSPS

113 mW at 80 MSPS

Differential input with 700 MHz bandwidth

On-chip voltage reference and sample-and-hold circuit

2 V p-p differential analog input

DNL = −0.6/+1.1 LSB

Interleaved data output for reduced pin-count interface

Serial port control options

Offset binary, Gray code, or twos complement data format

Optional clock duty cycle stabilizer

Integer 1-to-8 input clock divider

Built-in selectable digital test pattern generation

Energy-saving power-down modes

Data clock output (DCO) with programmable clock and data alignment

 

POINTS FORTS DU PRODUIT

The AD9266 operates from a single 1.8 V analog power supply and features a separate digital output driver supply to accommodate 1.8 V to 3.3 V logic families.

The sample-and-hold circuit maintains excellent performance for input frequencies up to 200 MHz and is designed for low cost, low power, and ease of use.

A standard serial port interface supports various product features and functions, such as data output formatting, internal clock divider, power-down, DCO and data output (D15_D14 to D1_D0) timing and offset adjustments, and voltage reference modes.

The AD9266 is packaged in a 32-lead RoHS-compliant LFCSP that is pin compatible with the AD9609 10-bit ADC, the AD9629 12-bit ADC, and the AD9649 14-bit ADC, enabling a simple migration path between 10-bit and 16-bit converters sampling from 20 MSPS to 80 MSPS.

 

THÉORIE DU FONCTIONNEMENT

The AD9266 architecture consists of a multistage, pipelined ADC. Each stage provides sufficient overlap to correct for flash errors in the preceding stage. The quantized outputs from each stage are combined into a final 16-bit result in the digital correction logic. The pipelined architecture permits the first stage to operate with a new input sample, whereas the remaining stages operate with preceding samples. Sampling occurs on the rising edge of the clock.

Each stage of the pipeline, excluding the last, consists of a low resolution flash ADC connected to a switched-capacitor DAC and an interstage residue amplifier (for example, a multiplying digital-to-analog converter (MDAC)). The residue amplifier magnifies the difference between the reconstructed DAC output and the flash input for the next stage in the pipeline. One bit of redundancy is used in each stage to facilitate digital correction of flash errors. The last stage simply consists of a flash ADC.