مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

The AD9267 is a dual continuous time (CT) sigma-delta (Σ - Δ) modulator with -88 dBc of dynamic range over 10 MHz real or 20 MHz complex bandwidth. The combination of high dynamic range, wide bandwidth, and characteristics unique to the continuous time Σ - Δ modulator architecture makes the AD9267 an ideal solution for wireless communication systems. The AD9267 has a resistive input impedance that significantly relaxes the requirements of the driver amplifier. In addition, a 32x oversampled fifth-order continuous time loop filter attenuates out-of-band signals and aliases, reducing the need for external filters at the input. The low noise figure of 15 dB relaxes the linearity requirements of the front-end signal chain components, and the high dynamic range reduces the need for an automatic gain control (AGC) loop. A differential input clock controls all internal conversion cycles. An external clock input or the integrated integer-N PLL provides the 640 MHz internal clock needed for the oversampled continuous time Σ - Δ modulator. The digital output data is presented as 4-bit, LVDS at 640 MSPS in twos complement format. A data clock output (DCO) is provided to ensure proper latch timing with receiving logic. Additional digital signal processing may be required on the 4-bit modulator output to remove the out-of-band noise and to reduce the sample rate. The AD9267 operates on a 1.8 V power supply, consuming 416 mW. The AD9267 is available in a 64-lead LFCSP and is specified over the industrial temperature range (-40°C to +85°C).

Features

• SNR: 83 dB (85 dBFS) to 10 MHz input
• SFDR: −88 dBc to 10 MHz input
• Noise figure: 15 dB
• Input impedance: 1 kΩ
• Power: 416 mW
• 10 MHz real or 20 MHz complex bandwidth
• 1.8 V analog supply operation
• On-chip PLL clock multiplier
• On-chip voltage reference
• Twos complement data format
• 640 MSPS, 4-bit LVDS data output
• Serial control interface (SPI)

Applications

• Baseband quadrature receivers: CDMA2000, W-CDMA, multicarrier GSM/EDGE, 802.16x, and LTE
• Quadrature sampling instrumentation