14-Bit, 170 MSPS/210 MSPS/250 MSPS,

1.8 V Analog-to-Digital Converter (ADC)

Data Sheet

AD9642

Rev. B

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FEATURES

Total power consumption: 390 mW at 250 MSPS

1.8 V supply voltages

LVDS (ANSI-644 levels) outputs

Integer 1-to-8 input clock divider (625 MHz maximum input)

Sample rates of up to 250 MSPS

Internal ADC voltage reference

Flexible analog input range

1.4 V p-p to 2.0 V p-p (1.75 V p-p nominal)

ADC clock duty cycle stabilizer

Serial port control

Energy saving power-down modes

APPLICATIONS

Communications

Diversity radio systems

Multimode digital receivers (3G)

TD-SCDMA, WiMAX, WCDMA,

CDMA2000, GSM, EDGE, LTE

I/Q demodulation systems

Smart antenna systems

General-purpose software radios

Ultrasound equipment

Broadband data applications

FUNCTIONAL BLOCK DIAGRAM

14

REFERENCE

SERIAL PORT

SCLK

SDIO

CSB

CLK+

CLK–

1-TO-8

CLOCK

DIVIDER

AD9642

VIN+

D0±/D1±

D12±/D13±

DCO±

VIN–

VCM

AVDD

AGND

DRVDD

PARALLEL

DDR LVDS

AND

DRIVERS

PIPELINE

14-BIT

ADC

Figure 1.

GENERAL DESCRIPTION

The AD9642 is a 14-bit analog-to-digital converter (ADC) with

sampling speeds of up to 250 MSPS. The AD9642 is designed to

support communications applications, where low cost, small

size, wide bandwidth, and versatility are desired.

The ADC core features a multistage, differential pipelined

architecture with integrated output error correction logic. The

ADC features wide bandwidth inputs that can support a variety

of user-selectable input ranges. An integrated voltage reference

eases design considerations. A duty cycle stabilizer (DCS) is

provided to compensate for variations in the ADC clock duty

cycle, allowing the converter to maintain excellent performance.

The ADC output data is routed directly to the external

14-bit LVDS output port.

Flexible power-down options allow significant power savings,

when desired.

Programming for setup and control is accomplished using a

3-wire SPI-compatible serial interface.

The AD9642 is available in a 32-lead LFCSP and is specified

over the industrial temperature range of −40°C to +85°C. This

product is protected by a U.S. patent.

PRODUCT HIGHLIGHTS

1.

Integrated 14-bit, 170 MSPS/210 MSPS/250 MSPS ADC.

2.

Operation from a single 1.8 V supply and a separate digital

output driver supply accommodating LVDS outputs.

3.

Proprietary differential input maintains excellent SNR

performance for input frequencies of up to 350 MHz.

4.

3-pin, 1.8 V SPI port for register programming and readback.

5.

Pin compatibility with the AD9634, allowing a simple migra-

tion from 14 bits to 12 bits, and with the AD6672.