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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

AFE7920, AFE7921, AFE7988, AFE7989

SBAS971C – DECEMBER 2019 – REVISED JUNE 2020

AFE79xx Quad-Channel RF Transceiver With Feedback Path

1

1 Features

1

•

Quad RF sampling 12-GSPS transmit DACs

•

Quad RF sampling 3-GSPS receive ADCs

•

Dual RF sampling 3-GSPS feedback ADCs

(AFE792x only)

•

Maximum RF signal bandwidth:

–

TX/FB: 1200 MHz (AFE7920/88) or 400 MHz

(AFE7989) or 800MHz (AFE7921)

–

RX: 600 MHz (AFE7920/88) or 400 MHz

(AFE7921/AFE7989)

•

Digital Step Attenuators (DSA):

–

TX: 40 dB range, 1-dB analog and 0.125-dB

digital steps

–

RX: 25 dB range, 0.5-dB steps

–

FB: 25 dB range, 0.5-dB steps

•

Single or dual-band DUC/DDCs (AFE7920/88

only) for TX and RX

•

Dual NCOs for fast frequency switching

•

Supports TDD operation with fast switching

between TX and RX

•

Internal PLL/VCO to generate DAC/ADC clocks

•

Optional external CLK at DAC or ADC rate

•

SerDes data interface:

–

JESD204B and JESD204C compliant

–

8 SerDes transceivers up to 29.5 Gbps

–

8b/10b and 64b/66b encoding

–

12-bit, 16-bit, 24-bit, and 32-bit resolution

–

Subclass 1 multi-device synchronization

•

Package: 17-mm × 17-mm FCBGA, 0.8-mm pitch

2 Applications

•

Macro remote radio unit (RRU)

•

Active antenna system mMIMO (AAS)

•

Small cell base station

•

Repeater

•

Distributed Antenna Systems (DAS)

3 Description

The AFE79xx is a family of high performance, wide bandwidth multi-channel transceivers, integrating four RF

sampling transmitter chains, four RF sampling receiver chains, and up to two RF sampling digitizing auxiliary

chains (feedback paths). The high dynamic range of the transmitter and receiver chains allows the device to

generate and receive 3G, 4G, and 5G signals from wireless base stations, while the wide bandwidth capability of

the AFE79xx devices is designed for multi-band 4G and 5G base stations.

Each receiver chain includes a 25-dB range DSA (Digital Step Attenuator), followed by a 3-GSPS ADC (analog-

to-digital converter). Each receiver channel has an analog peak power detector and various digital power

detectors to assist an external or internal autonomous automatic gain controller, and RF overload detectors for

device reliability protection. The single or dual digital down converters (DDC) provide up to 600 MHz of combined

signal BW. In TDD mode, the receiver channel can be configured to dynamically switch between the traffic

receiver (TDD RX) and wideband feedback receiver (TDD FB), with the capability of re-using the same analog

input for both purposes.

Each transmitter chain includes a single or dual digital up converters (DUCs) supporting up to 1200-MHz

combined signal bandwidth. The output of the DUCs drives a 12-GSPS DAC (digital to analog converter) with a

mixed mode output option to enhance 2nd or 3rd Nyquist operation. The DAC output includes a variable gain

amplifier (TX DSA) with 40-dB range and 1-dB analog and 0.125-dB digital steps.

The feedback path includes an 25-dB range DSA driving a 3-GSPS RF sampling ADC, followed by a DDC with

up to 1200-MHz bandwidth.

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE

AFE7989

FC-BGA

17.00 mm × 17.00 mm

AFE7920

FC-BGA

17.00 mm × 17.00 mm

AFE7988

FC-BGA

17.00 mm × 17.00 mm

AFE7921

FC-BGA

17.00 mm × 17.00 mm

(1) For more information, see Mechanical, Packaging, and Orderable Information.