The PLCC-52 package is a square plastic leaded chip carrier with 52 J-leads at the standard 1.27 mm PLCC pitch. It’s less common than PLCC-20, -28, -32, or -44 — Microchip’s own PLCC packaging-specification documents skip 52 leads entirely, jumping from 44 straight to 68 — but it’s still a real, current package: Atmel’s AT89C5131 USB microcontroller family shipped in PLCC-52 into the 2010s, and PLCC-52 sockets remain in production from at least two connector manufacturers.

Key takeaways

• Body span roughly 19.25 mm square, per distributor listings for the AT89C5131A-S3SUM, cross-checked across three regional RS Online pages — this is the most reliable dimension source, since Microchip’s own package-drawing set doesn’t include a 52-lead outline.
• Lead pitch is the standard 1.27 mm (0.05 in) fixed across every PLCC size, including 52.
• PLCC-52 doesn’t have one fixed pinout — it depends on the IC. The AT89C5131 8051-based USB microcontroller is a documented example, with signal groups covering Ports 0-4, USB D+/D-, clock, and power.
• The AT89C5131 datasheet’s own PLCC-52 pin diagram includes 4 explicit NC (no-connect) positions, similar in spirit to the corner-skip pattern seen on smaller PLCC sizes.
• Yamaichi’s IC120-0524-307 (through-hole, test-grade) and 3M’s 8452-21B1-RK-TP (SMT) are both active PLCC-52 socket options, though the 3M part carries a Last Time Buy date.

PLCC-52 Dimensions

Unlike PLCC-20, -28, -32, and -44, Microchip’s own packaging-specification documents don’t include a 52-lead PLCC outline — their PLCC lineup goes 20, 28, 32, 44, then jumps to 68. PLCC-52 is still a JEDEC-registered size and other manufacturers do ship it, but the most reliable dimension source available is distributor data for an actual part, not a manufacturer package drawing.

Parameter	Value	Source
Lead count	52	RS Online AT89C5131A-S3SUM listing
Body span (width x length)	19.25 mm x 19.25 mm, square	RS Online, cross-checked across UK/DE/JP listings
Overall height	4.06 mm (one listing) to 4.57 mm (another listing)	RS Online — variation likely reflects different revisions or measurement points
Lead pitch	1.27 mm (0.05 in)	Consistent across every PLCC size; confirmed by Yamaichi and 3M socket specs below

Treat the height figure as approximate: two independent distributor listings for the same part number differ by half a millimeter, which is normal when distributors pull specs from different datasheet revisions rather than a single controlled JEDEC drawing. For a design that’s sensitive to exact body height, get the specific part’s own mechanical drawing rather than relying on a distributor’s summary field.

Worked example: lead width on PLCC packages runs 0.33–0.53 mm regardless of lead count (the same range documented on every other PLCC size in this series). At the fixed 1.27 mm pitch, that leaves a minimum 0.74 mm gap between adjacent lead edges. A 0.6–0.7 mm solder pad keeps a hand-soldered joint inspectable without bridging — the same rule applies whether the package has 20 leads or 52.

PLCC-52 Pinout

PLCC-52 has no universal pinout — function depends entirely on the IC. The clearest documented example is Atmel’s AT89C5131, an 8051-core microcontroller with an integrated full-speed USB device controller, offered in PLCC52, VQFP64, MLF48, and SO28 packages. Its datasheet groups every pin by function across twelve signal-description tables:

Signal group	Pins	Notes
Port 0 (P0.0-P0.7)	8	Multiplexed address/data bus (AD0-AD7) for external memory access
Port 1 (P1.0-P1.7)	8	Keypad inputs, PCA capture/compare, SPI, Timer 2 — shared with the keyboard interrupt interface
Port 2 (P2.0-P2.7)	8	Address bus MSB (A8-A15) for external memory access
Port 3 (P3.0-P3.7)	8	RxD, TxD, external interrupts, timer inputs, RD/WR, LED drive
Port 4 (P4.0-P4.1)	2	TWI (I2C-style) SCL/SDA
USB	3	D+, D-, VREF
Clock	3	XTAL1, XTAL2, PLLF (PLL loop filter)
System control	4	RST, ALE, PSEN, EA
Power	4	VDD, VSS, AVDD, AVSS
No connect	4	Explicit NC positions per the datasheet’s own PLCC-52 pin diagram

That accounts for all 52 physical leads (8+8+8+8+2+3+3+4+4+4 = 52). Many pins carry alternate functions depending on which peripheral is active — P1, for instance, doubles as keypad inputs, PCA I/O, and SPI depending on configuration. For the exact pin-number assignment, pull the manufacturer’s own top-view diagram directly rather than a secondhand pin list; dense 52-lead diagrams are easy to transcribe incorrectly, and getting a power or ground pin wrong is a board-killing mistake.

PLCC-52 Sockets

PLCC-52 sockets are less common than smaller sizes but still in production. Two real, currently available parts:

Parameter	Yamaichi IC120-0524-307 (THT)	3M 8452-21B1-RK-TP (SMT)
Application	Test / burn-in socket	Board-mount socket
Mounting	Through hole	Surface mount
Mating pitch	1.27 mm	0.050 in (1.27 mm)
Contact material / plating	Beryllium copper, gold over nickel	Copper alloy, tin, 160 µin thick
Current rating	1 A	1 A
Voltage rating	100 V AC rms / 150 V DC	not stated by this distributor listing
Insulation resistance	1,000 MΩ	not stated by this distributor listing
Operating temperature	−40 °C to +107 °C	−40 °C to +105 °C
Lifecycle status	Active	Last Time Buy (3/31/2026)

The 3M part’s Last Time Buy date is worth flagging on its own: if a design currently specifies the 8452-21B1-RK-TP, that window is closing, and a replacement SMT source should be lined up before it’s gone. The Yamaichi part is a gold-plated test/burn-in socket rather than a low-cost board-mount part, so it isn’t a direct like-for-like substitute — it’s the right choice for programming and test fixtures, not necessarily for a production board.

Choosing a Socket or Direct Solder

• Production board, part won’t be swapped after assembly → solder the PLCC-52 directly; confirm current board-mount socket availability first if a socket is genuinely required.
• Bring-up board, or the part is a field-programmable microcontroller reprogrammed occasionally → an SMT or through-hole commercial socket, lifecycle-checked before the build — not assumed available given how few PLCC-52 socket options remain active.
• Test, burn-in, or programmer fixture → a gold-contact test socket like the Yamaichi IC120 series, rated for a stated high mating-cycle count.

FAQ

What are the dimensions of a PLCC-52 package?

Distributor data for the AT89C5131A-S3SUM gives a body span of approximately 19.25 mm square, with overall height reported between 4.06 mm and 4.57 mm depending on the listing. Microchip’s own package-drawing set doesn’t include a 52-lead PLCC outline, so distributor part data is the most practical dimension source.

Does PLCC-52 have a standard pinout?

No — pin function depends on the IC. The AT89C5131 USB microcontroller is a documented example, with Ports 0-4, USB D+/D-, clock, and power pins accounting for all 52 leads, including four explicit no-connect positions.

What socket fits a PLCC-52 package?

Any socket built at the standard 1.27 mm PLCC pitch with 52 positions. Yamaichi’s IC120-0524-307 through-hole test socket and 3M’s 8452-21B1-RK-TP SMT socket are both real current options, though the 3M part has a Last Time Buy date.

What is the lead pitch on a PLCC-52?

1.27 mm (0.05 in), the same fixed pitch used across every JEDEC PLCC size from 20 to 84 leads.

Is PLCC-52 still used in current designs?

It’s uncommon compared to PLCC-44 or -68, and Microchip’s own packaging documentation doesn’t include it, but it isn’t obsolete — the AT89C5131 family shipped in PLCC-52 into the 2010s, and sockets for the size remain in production.

The Decision

Treat PLCC-52 as a package size worth double-checking before committing to it: it’s real and current parts still use it, but it sits outside the mainstream PLCC lineup that most manufacturers document directly, so dimensions and sockets both need part-specific verification rather than assumption. Pull exact pin assignments from the manufacturer’s own top-view diagram, confirm socket lifecycle status before finalizing a BOM, and budget extra sourcing time compared with the more common 28-, 32-, and 44-lead sizes.