Technology, Process and Cost

Broadcom AFEM8231 – 4G-5G MBHB LPAD

By Yole SystemPlus — Mar 2023

A complete investigation of the latest 4G-5G mid-band/high-band LPAD from Broadcom included in the Apple iPhone 14 series

SPR23731

Key Features

Detailed photos
Precise measurements
Materials analysis
Manufacturing process flow
Supply chain evaluation
Manufacturing cost analysis
Estimated selling price
Technical and cost comparison with MB/HB L-PAMiD devices from Broadcom since 2017

What's new

Broadcom innovation and technology reduces the component’s footprint and increases its performance
Beyond dual side molding BGA, the innovation in the packaging is the use of integrated passive devices for LNA circuit decoupling or PA output matching

Staying true to its choices for each previous iPhone series iteration, Apple has again selected an innovative radio frequency (RF) front-end module (FEM) for its flagship. Each year Broadcom, its faithful supplier, has advanced its filters and innovative packaging technology to compete with other market players and retain its contract. This year, for the fourth time, Broadcom chose dual side molding ball grid array (BGA) packaging, coupled to new electromagnetic interference (EMI) shielding to enable a very high density system-in-package (SiP) with frequency band sharing. The packaging includes integrated passive device (IPD) components on both sides of the printed circuit board (PCB) substrate, and the filter design integrates single 2-in-1 or duplexer type filters in the bulk acoustic wave (BAW) filter.

Broadcom remains the only supplier of the same module for several versions of the latest Apple iPhone series 14 and 14 Pro Max. Like its predecessor, the AFEM-8214, the AFEM-8231 is a mid- and high-band (MB and HB) long-term evolution (LTE) and 5G low-noise power amplifier integrated duplexer (LPAD). It features several dies: a power amplifier (PA), a silicon-on-insulator (SOI) switch, silicon capacitors, IPDs and film bulk acoustic resonator (FBAR) filters. The filters still use Avago’s Microcap bonded wafer chip-scale packaging (CSP) technology, with through-silicon vias (TSVs) enabling electrical contacts and scandium doped aluminum nitride (AlScN) as a piezoelectric material.

For this new version, Broadcom innovates on several points. Thanks to the dual side molding BGA technology, the density of the packaging has grown. The critical dies, the master switches, power management integrated circuit (PMIC), low-noise amplifier (LNA), and decoupling capacitor, have been completely isolated from the filtering part. To enhance the yield and reduce the cost, Broadcom chose a silicon capacitor from a third-party company to replace the Surface Mount Device (SMD) component. On the EMI management, compartmental shielding using gold/silver wire bonding has hugely reduced the packaging cost. To go further in reducing the packaging size, the IPD die has been used in the output matching path of the PA to reduce the footprint of the inductance on the PCB substrate. Finally, with the latest filtering design, some FBAR-BAW filters integrated in the module are single die two-in-one filters on the transmit (Tx), receive (Rx), and even in the receive/transmit (RxTx) path. Thanks to all these innovations, Broadcom managed to deliver a miniaturized package despite the added complexity of 5G.

This report contains a complete analysis of the FEM SiP, including a detailed analysis of the PA, the switches, the LNA, the IPDs, the filtering dies, and the internal/external EMI shielding. This report also features a cost analysis and a price estimation of the component. Finally, it includes a comparison with the AFEM8072, in the Apple iPhone X, the AFEM8092, in the Apple iPhone XS, the AFEM8100, in the Apple 11 series, the AFEM8200, in the Apple 12 series and the AFEM8214 in the Apple 13 series.

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Broadcom AFEM8231 – 4G-5G MBHB LPAD

A complete investigation of the latest 4G-5G mid-band/high-band LPAD from Broadcom included in the Apple iPhone 14 series