Land grid array

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Socket 775 on a motherboard. Sockel 775.jpg
Socket 775 on a motherboard.

The land grid array (LGA) is a type of surface-mount packaging for integrated circuits (ICs) that is notable for having the pins on the socket (when a socket is used) rather than the integrated circuit. [1] An LGA can be electrically connected to a printed circuit board (PCB) either by the use of a socket or by soldering directly to the board.

Integrated circuit electronic circuit manufactured by lithography; set of electronic circuits on one small flat piece (or "chip") of semiconductor material, normally silicon

An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material that is normally silicon. The integration of large numbers of tiny MOS transistors into a small chip results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. The IC's mass production capability, reliability, and building-block approach to circuit design has ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones, and other digital home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs.

CPU socket provides mechanical and electrical connections between a microprocessor and a printed circuit board

In computer hardware, a CPU socket or CPU slot contains one or more mechanical components providing mechanical and electrical connections between a microprocessor and a printed circuit board (PCB). This allows for placing and replacing the central processing unit (CPU) without soldering.

Printed circuit board Board to support and connect electronic components

A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.



The land grid array is a packaging technology with a rectangular grid of contacts on the underside of a package. The contacts are to be connected to a grid of contacts on the PCB. Not all rows and columns of the grid need to be used. The contacts can either be made by using an LGA socket, or by using solder paste. [2]

LGA packaging is related to ball grid array (BGA) and pin grid array (PGA) packaging. Unlike pin grid arrays, land grid array packages are designed to fit either in a socket, or be soldered down using surface mount technology. PGA packages cannot be soldered down using surface mount technology. In contrast with a BGA, land grid array packages in non socketed configurations have no balls, and use flat contacts which are soldered directly to the PCB. BGA packages, however have balls as their contacts in between the IC and the PCBs. The balls are normally attached to the underside of the IC.

Ball grid array

A ball grid array (BGA) is a type of surface-mount packaging used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The traces connecting the package's leads to the wires or balls which connect the die to package are also on average shorter than with a perimeter-only type, leading to better performance at high speeds.

Pin grid array type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the underside of the package

A pin grid array (PGA) is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the underside of the package. The pins are commonly spaced 2.54 mm (0.1") apart, and may or may not cover the entire underside of the package.

Use in microprocessors

The LGA 775 package of a Pentium 4 Prescott CPU. Intel CPU Pentium 4 640 Prescott bottom.jpg
The LGA 775 package of a Pentium 4 Prescott CPU.
Assembly of a CPU with LGA socket.

LGA is used as a physical interface for microprocessors of the Intel Pentium, Intel Xeon, Intel Core and AMD Opteron, Threadripper and Epyc families. Unlike the pin grid array (PGA) interface found on most AMD and older Intel processors, there are no pins on the chip; in place of the pins are pads of bare gold-plated copper that touch protruding pins on the microprocessor's connector on the motherboard. Compared to PGA CPUs, LGA reduces the likelihood of the chip being damaged either before or during installation as there are no pins that can be accidentally bent. By transferring the pins to the motherboard, it is possible to design the socket to physically shield the pins from damage, and the costs of installation damage can be mitigated as motherboards tend to be significantly cheaper than CPUs. [3]

Intel American semiconductor chip manufacturer

Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, in the Silicon Valley. It is the world's second largest and second highest valued semiconductor chip manufacturer based on revenue after being overtaken by Samsung Electronics, and is the inventor of the x86 series of microprocessors, the processors found in most personal computers (PCs). Intel ranked No. 46 in the 2018 Fortune 500 list of the largest United States corporations by total revenue.

Pentium an Intel microprocessor

Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel since 1993. In their form as of November 2011, Pentium processors are considered entry-level products that Intel rates as "two stars", meaning that they are above the low-end Atom and Celeron series, but below the faster Core i3, i5, i7, i9, and workstation Xeon series.

Xeon brand of x86 microprocessors from Intel

Xeon is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded system markets. It was introduced in June 1998. Xeon processors are based on the same architecture as regular desktop-grade CPUs, but have some advanced features such as support for ECC memory, higher core counts, support for larger amounts of RAM, larger cache memory and extra provision for enterprise-grade reliability, availability and serviceability features responsible for handling hardware exceptions through the Machine Check Architecture. They are often capable of safely continuing execution where a normal processor cannot due to these extra RAS features, depending on the type and severity of the Machine Check Exception. Some also support multi-socket systems with two, four, or eight sockets through use of the Quick Path Interconnect bus.

While LGA sockets have been in use as early as 1996 by the MIPS R10000 and HP PA-8000 processors, the interface did not gain widespread use until Intel introduced their LGA platform, starting with the 5x0 and 6x0 sequence Pentium 4 (Prescott) in 2004. All Pentium D and Core 2 desktop processors use LGA 775 socket. As of Q1 2006, Intel switched the Xeon server platform to LGA, starting with the 5000-series models. AMD introduced their server LGA platform starting with the 2000-series Opteron in Q2 2006. AMD offered the Athlon 64 FX series on socket 1207FX through ASUS's L1N64-SLI WS motherboards. It was the only desktop LGA solution offered by AMD.

MIPS is a reduced instruction set computer (RISC) instruction set architecture (ISA) developed by MIPS Computer Systems, now MIPS Technologies, based in the United States.

R10000 MIPS microprocessor

The R10000, code-named "T5", is a RISC microprocessor implementation of the MIPS IV instruction set architecture (ISA) developed by MIPS Technologies, Inc. (MTI), then a division of Silicon Graphics, Inc. (SGI). The chief designers are Chris Rowen and Kenneth C. Yeager. The R10000 microarchitecture is known as ANDES, an abbreviation for Architecture with Non-sequential Dynamic Execution Scheduling. The R10000 largely replaces the R8000 in the high-end and the R4400 elsewhere. MTI was a fabless semiconductor company; the R10000 was fabricated by NEC and Toshiba. Previous fabricators of MIPS microprocessors such as Integrated Device Technology (IDT) and three others did not fabricate the R10000 as it was more expensive to do so than the R4000 and R4400.

Hewlett-Packard American information technology company

The Hewlett-Packard Company or Hewlett-Packard was an American multinational information technology company headquartered in Palo Alto, California. It developed and provided a wide variety of hardware components as well as software and related services to consumers, small- and medium-sized businesses (SMBs) and large enterprises, including customers in the government, health and education sectors.

The most recent Intel desktop LGA socket is dubbed LGA 1151 (Socket H4), which is used with Intel's Skylake, Kaby Lake and Coffee Lake series Core i3, i5, and i7 families, as well as their lower-end Pentium and Celeron families. Their Skylake-X Core i7 and Core i9 families use the LGA 2066 socket. The LGA setup provides higher pin densities, allowing more power contacts and thus a more stable power supply to the chip.

LGA 1151 CPU socket type by Intel

LGA 1151, also known as Socket H4, is an Intel microprocessor compatible socket which comes in two distinct versions: the first revision which supports both Intel's Skylake and Kaby Lake CPUs, and the second revision which supports Coffee Lake CPUs exclusively.

Skylake (microarchitecture) Intel processor microarchitecture

Skylake is the codename used by Intel for a processor microarchitecture that was launched in August 2015 succeeding the Broadwell microarchitecture. Skylake is a microarchitecture redesign using the same 14 nm manufacturing process technology as its predecessor, serving as a "tock" in Intel's "tick–tock" manufacturing and design model. According to Intel, the redesign brings greater CPU and GPU performance and reduced power consumption. Skylake CPUs share its microarchitecture with Kaby Lake, Coffee Lake and Cannon Lake CPUs.

Kaby Lake is an Intel codename for a processor microarchitecture Intel announced on August 30, 2016. Like the preceding Skylake, Kaby Lake is produced using a 14 nanometer manufacturing process technology. Breaking with Intel's previous "tick–tock" manufacturing and design model, Kaby Lake represents the optimized step of the newer "process-architecture-optimization" model. Kaby Lake began shipping to manufacturers and OEMs in the second quarter of 2016, and mobile chips have started shipping while Kaby Lake (desktop) chips were officially launched in January 2017.

AMD introduced its first consumer LGA socket, called Socket TR4 (LGA 4094) for its high end desktop platform Ryzen Threadripper processors. This socket is physically identical to their Socket SP3 for their Epyc server CPUs even though SP3 CPUs are not compatible with the desktop X399 chipset and vice versa.

The previous AMD server LGA socket was designated Socket G34 (LGA 1944). Like Intel, AMD decided to use LGA sockets for their higher pin densities, as a 1944-pin PGA would simply be too large for most motherboards.



See also

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Socket G1

Socket G1, also known as rPGA 988A, is Intel's CPU socket for their line of mobile Core i7, the successor to the Core 2 line. It is based on Intel's Nehalem architecture which was first available for the 1366-pin "Socket B", which, like its predecessor, LGA775, uses the LGA socket configuration. Later followed the updated LGA-1156 socket, which moved the QPI and PCI-express controller off the Northbridge and onto the CPU. As a result of the lower pin count, LGA-1156 systems, and later, socket G1 systems, can only run in Dual-channel memory mode, as opposed to the Triple-channel mode which is unique to the LGA-1366 platform. The Nehalem's mobile variant was released on September 23, 2009 in the form of the i7-720QM, 820QM, and 920XM models, followed by the i7-740QM, 840QM, and 940XM models on June 21, 2010. The newer CPUs use the new Clarksfield core, which maintained the same 45 nm manufacturing process as the desktop-based Nehalems. Nehalem received a die shrink on January 7, 2010, under the core name of Westmere. With the Intel GMA HD Graphics Ironlake core packaged onto the CPU substrate, but not integrated directly to the processor die, it goes on to create the Arrandale-based line. The current CPUs to use this package are the Core i7-6x0M series, the Core i5-4x0M series, the Core i5-5x0M series, the Core i3-3x0M series, and finally the Pentium P6x00 series and Celeron P4x00 series which were released on March 28, 2010. However, not all of these are available for Socket G1, as some of them are only available in a BGA package. They are also known as PGA988 socket processors.

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Coffee Lake Intel processor family

Coffee Lake is Intel's codename for the second 14 nm process node refinement following Broadwell, Skylake, and Kaby Lake. The integrated graphics on Coffee Lake chips allow support for DP 1.2 to HDMI 2.0 and HDCP 2.2 connectivity. Coffee Lake natively supports DDR4-2666 MHz memory in dual channel mode when used with Xeon, Core i5, i7 and i9 CPUs, DDR4-2400 MHz memory in dual channel mode when used with Celeron, Pentium, and Core i3 CPUs, and LPDDR3-2133 MHz memory when used with mobile CPUs.

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  1. "Definition of:LGA". PC Magazine. Retrieved October 1, 2015.
  2. "Land Grid Array (LGA) Socket and Package Technology" (PDF). Intel. Retrieved October 1, 2015.
  3. Prices of the most expensive Intel Core i7 and AMD Threadripper CPUs vs their most expensive corresponding motherboards on eBuyer as of 16th of Feb 2018