Intel Atom Z2420 socket: BGA 617

What the Atom Z2420 is

Intel Atom Z2420 is a single core Penwell phone SoC that Intel launched in January 2013 for the Medfield and Lexington platforms. It uses the Saltwell core design on a 32 nm process with Hyper-Threading, so one core provides 2 threads. Clock behavior is 1.2 GHz (no boost). The cache is 512 KB L2. Power is 3 W for the whole SoC. Graphics come from PowerVR SGX540 (400 MHz).

Saltwell is an in order design with Burst Technology that lifts short clocks for touch response. The SoC integrates a dual channel LPDDR2 controller, PowerVR graphics and phone I/O on die, which suits small bodies with soldered memory. It is a 32 bit design, so modern 64 bit app support is the binding limit on surviving devices.

At 3 W the Atom Z2420 belongs to the Atom Z2400 Penwell group. The fixed 1.2 GHz clock suits calls, messaging, reading and video on small displays with passive cooling. Devices pair it with eMMC storage and soldered LPDDR2. The How to find your CPU socket type guide shows how to confirm the package before ordering parts.

Socket and motherboard compatibility

The Atom Z2420 solders to BGA 617 with 617 balls in a 12 by 12 mm FC-MB4617 footprint and cannot be moved to another board. Phone makers qualify each model with a specific board and Android build, so even another Penwell part is not a drop in upgrade. The Clover Trail Plus parts share the 617-ball count in a larger 14 by 14 mm package, but boards never mix across the two designs.

Firmware decides service results more than speed. The board build must list the exact Atom Z2420 string, and Android support stays on older branches for this 32 bit family. The CPU cooler compatibility by socket guide notes that soldered phone parts have no desktop mount pattern. Socket vs chipset: what decides whether a CPU works covers Intel pairing basics.

Memory, PCIe and cooling

Memory support is lpddr2-800, two channels, up to 1 gb, soldered next to the SoC. The dual channel layout feeds the PowerVR graphics block that shares system RAM. Capacity locks at purchase, with 1 GB common on phones of this era.

I/O is on device rather than PCIe slots. Storage, wireless, cameras, sensors and touch controllers follow the device wiring, so the maker spec sheet is the final word on ports. USB and display output vary by model, and there is no graphics card slot to consider.

Cooling uses the phone chassis, fully passive at 3 W. There is no fan curve to adjust and no retail heatsink to fit. Sustained speed follows case temperature, so a warm pocket throttles sooner than a cool desk.

Upgrade paths

There is no CPU upgrade path on soldered BGA 617. The Atom Z2420 cannot be removed, so a faster Penwell part means a new board or a new device. Within the family Intel Atom Z2480 shows the other Penwell option, but phone boards and firmware rarely mix.

A platform move means a new phone. Current devices use 64 bit SoCs with LPDDR4 or newer memory and current OS support, which no BGA 617 board can reach. Recycle the old device through a proper e waste path once data is wiped.