A DIP-48 is 15.24 mm between lead rows on 2.54 mm pitch, with a hole pattern spanning 58.42 mm. Almost nobody sells a 48-pin IC in this body any more. If you are searching for it, you are most likely fitting a surface-mount part to a DIP-48 adapter, and that changes what you need to know.

Key takeaways

• Pitch is 2.54 mm (0.100 in), row spacing 15.24 mm (0.600 in). Twenty-four leads per side.
• The hole pattern spans 58.42 mm, fixed by 23 spaces × 2.54 mm. That is nearly 6 cm of board length.
• IDT publishes its C48 plastic DIP body as approximately 0.62 in × 2.43 in × 0.15 in, which is 15.7 mm × 61.7 mm × 3.8 mm.
• New 48-pin ICs are not sold in DIP. The CY7C136 dual-port SRAM, once a DIP-48 part, is now stocked only in 52-PLCC and 52-PQFP.
• Sockets remain Active and stocked. The Mill-Max 110-93-648-41-001000 lists at $8.08 in single quantity.
• Most current DIP-48 demand is adapter boards: SSOP-48, TSSOP-48, LQFP-48 and LFCSP-48 all convert to a 600 mil DIP-48 footprint.

What is a DIP-48 package?

A DIP-48 package is a 48-lead dual in-line package: a rectangular body with twenty-four through-hole leads down each long side on 2.54 mm pitch, rows 15.24 mm apart. It mounts through plated holes or into a socket. Plastic and ceramic sidebraze versions both existed, the ceramic ones mostly for military-grade parts.

Forty-eight pins sits above the mainstream DIP range. Common 600 mil counts were 24, 28, 32 and 40; the 36, 48 and 52-pin bodies existed but were always less common. That scarcity is the single most useful thing to know before you start designing around one.

The devices that used it were high-pin-count memory and interface parts. Dual-port SRAMs are the clearest example: IDT built the 7130, 7132 and 7134 families in 48-pin DIP alongside LCC, PLCC and flatpack options.

[IMAGE 1: DIP-48 package outline drawing with body length, row spacing, pitch and lead dimensions, shown against a 40-pin body for scale | alt: “DIP-48 package dimensions diagram showing 2.54 mm pitch and 15.24 mm row spacing”]

DIP-48 dimensions

Manufacturer data for the 48-lead 600 mil package is thin, because few vendors ever published a general package specification for it. The clearest figures come from IDT device datasheets.

Dimension	Value	Source
Lead pitch	2.54 mm (0.100 in)	Adapter and socket listings
Row spacing	15.24 mm (0.600 in)	DigiKey socket package field
Body width (C48 plastic DIP)	approx. 15.7 mm (0.62 in)	IDT 7130/7140 datasheet
Body length (C48 plastic DIP)	approx. 61.7 mm (2.43 in)	IDT 7130/7140 datasheet
Body height (C48 plastic DIP)	approx. 3.8 mm (0.15 in)	IDT 7130/7140 datasheet
Hole pattern length	58.42 mm	Calculated: 23 × 2.54 mm
Adapter PCB footprint	25.4 mm × 60.96 mm	Proto-Advantage DIP-48 adapters

Note how IDT states these. The datasheet says the C48 package body is approximately 0.62 in by 2.43 in by 0.15 in, and adds that the package code is used to reference the package diagram. Those are nominal figures for identification, not toleranced drawing dimensions. If you need limits, you need the specific package drawing.

The hole pattern is the reliable number. Twenty-three spaces at 2.54 mm gives 58.42 mm from the pin 1 hole to the pin 24 hole, and that holds for every DIP-48 regardless of vendor or body variation.

This package is long enough to change how you lay out a board

At 58.42 mm of hole pattern the part is longer than most 100 mm boards are wide. Add the body overhang and you are placing a component about 62 mm long by 15.7 mm wide.

That works out at roughly 9.7 square centimetres of board given to one device before any clearance. A DIP-40 takes about 7 cm²; the TQFP-48 version of a comparable part fits in around 1 cm².

Mechanical handling gets harder too. Forty-eight leads is enough insertion force that the part will not seat without rolling both lead rows inward first, and the long body flexes noticeably if you push at one end only.

DIP-48 pinout and pin 1 identification

Pin 1 sits at one end, marked by a notch, a molded dot, or a chamfered corner. Orient the package with the notch at the top and the leads pointing away from you. Pin 1 is the upper-left lead. Numbering runs down the left side to pin 24, across the end, and back up the right side from pin 25 to pin 48.

For a DIP-48 specifically:

• Left column, top to bottom: pins 1 through 24
• Right column, bottom to top: pins 25 through 48
• Pin 1 and pin 48 face each other across the body
• Pin 24 and pin 25 face each other at the opposite end

There is no shared pin map at this count. A dual-port SRAM, a peripheral controller and an adapter board carrying a QFP have nothing in common electrically. The socket accepts all of them; the schematic must match the specific device.

One point that matters when working from old boards. IDT dual-port parts distinguish MASTER and SLAVE variants by the BUSY pin function: on the IDT7130 it is an open-drain output requiring a pull-up, while on the IDT7140 the same pin is an input. Same package, same pin position, opposite direction.

[IMAGE 2: Top-down DIP-48 pinout diagram with notch, pin 1 dot, and numbering 1 to 48 counterclockwise | alt: “DIP-48 pinout diagram showing pin 1 notch and counterclockwise pin numbering to pin 48”]

DIP-48 footprint: hole and pad sizing

Twenty-four holes per row on 2.54 mm pitch, rows at 15.24 mm. The hole pattern spans 23 × 2.54 mm = 58.42 mm end to end.

Size the hole from the maximum lead width on your specific part or adapter. Plastic DIP lead width maxima in this size range typically fall around 0.51 to 0.58 mm; the worked example uses 0.58 mm as a conservative case. Adapter boards use header pins rather than moulded leads, so check the header specification instead.

Applying the IPC-2222 density levels to a 0.58 mm maximum lead:

• Level A: minimum hole = max lead diameter + 0.25 mm → 0.58 + 0.25 = 0.83 mm
• Level B: + 0.20 mm → 0.78 mm
• Level C: + 0.15 mm → 0.73 mm

Then the pad. Pad diameter = minimum hole size + (2 × minimum annular ring) + minimum fabrication allowance, where the minimum annular ring is 0.05 mm and the fabrication allowance is 0.6 mm for Level A, 0.5 mm for Level B and 0.4 mm for Level C.

Level B worked through: 0.78 + (2 × 0.05) + 0.5 = 1.38 mm pad on a 0.78 mm hole.

Round to a stocked 0.9 mm drill with a 1.6 mm pad. That matches the geometry used on other 600 mil DIPs, so a DIP-40 or DIP-32 footprint scales directly if you extend the pad count.

Routing under a DIP-48

The 15.24 mm row spacing leaves about 13.6 mm of clear gap between opposing pad edges with 1.6 mm pads, running the full 58 mm length. That is a long, wide channel and the most useful space on the board.

For a socketed part it is also the only accessible area once the IC is inserted. Put decoupling there, close to the supply pins, and keep any test points you might want to probe inside the channel rather than under the body.

If the DIP-48 is an adapter carrying a QFP, remember the adapter PCB itself sits above the channel. Proto-Advantage lists its DIP-48 boards at 25.4 mm by 60.96 mm, wider than the 15.24 mm row spacing, so the board overhangs the pads on both sides. Nothing tall goes underneath.

Library footprints

The KiCad Package_DIP library carries DIP-48 in these variants:

• DIP-48_W15.24mm — 600 mil, plus LongPads, Socket and Socket_LongPads variants
• DIP-48_W16.51mm — SMD socket variant at 650 mil
• SMDIP-48_W15.24mm — surface-mount DIP version at 600 mil

Unlike DIP-40, there is no 1000 mil DIP-48 entry and no 400 mil variant. The choice is effectively single: 15.24 mm row spacing. That simplicity is a small compensation for how hard the parts are to find.

Availability: the part is gone, the socket is not

This is the section that matters most for DIP-48, and it is the one no competing page covers.

New 48-pin ICs in DIP are effectively unavailable through mainstream distribution. The clearest evidence is the CY7C136 dual-port SRAM, historically a 48-pin DIP part. DigiKey now lists it only in 52-PLCC (19.13 × 19.13 mm) and 52-PQFP (10 × 10 mm). The DIP option is not offered.

The IDT7130 family tells the same story from the datasheet side. It documents 48-pin sidebraze and plastic DIPs alongside LCCs, flatpacks, 52-pin PLCC and 64-pin TQFP and STQFP. The DIP is listed, but distributor stock has moved to the surface-mount options.

Sockets, by contrast, are healthy:

Part	Type	Row spacing	Status	Qty-1	Stock
110-93-648-41-001000 (Mill-Max)	48-pos DIP socket, gold	0.6 in (15.24 mm)	Active	$8.08	62
48-6554-10 (Aries)	48-pos DIP ZIF socket, tin	0.6 in (15.24 mm)	Active	—	—

The Mill-Max socket carries a 4-week manufacturer lead time and drops from $8.08 at one piece to $4.96290 at 1,000. It is rated 3 A per contact over a −55 °C to +125 °C range with beryllium copper mating contacts and 30 µin gold plating.

Aries offers a 48-position ZIF socket at the same 0.6 in row spacing, listed Active. ZIF matters here because forty-eight leads is enough insertion force to make repeated swaps genuinely awkward in a friction socket.

What people actually use DIP-48 for now

Adapter boards. The commercial DIP-48 market today is dominated by SMD-to-DIP converters, and the range tells you what engineers are fitting.

• SSOP-48 at 0.635 mm pitch to DIP-48
• TSSOP-48 at 0.5 mm pitch to DIP-48
• LQFP-48 at 0.65 mm pitch, 10 × 10 mm body, to DIP-48
• LFCSP-48 and QFN-48 at 0.5 mm pitch, 7 × 7 mm body, to DIP-48, including thermal-pad versions

All of these convert to a 600 mil DIP-48 footprint on 0.1 in pin pitch. Proto-Advantage builds most on a 25.4 mm by 60.96 mm FR-4 board, 1.6 mm thick.

The use case is prototyping and bench work: taking a fine-pitch part you cannot hand-solder, mounting it on a carrier, and plugging the carrier into a socket or breadboard. That is a legitimate reason to place a DIP-48 footprint on a board, and probably the most common one left.

[IMAGE 3: A DIP-48 socket on a board next to an LQFP-48 to DIP-48 adapter carrying a surface-mount part | alt: “DIP-48 socket beside an LQFP-48 to DIP-48 adapter board”]

Design mistakes that cause rework

• Designing a new product around a DIP-48 IC. Check distributor availability first. Parts that were once DIP-48 are now sold only in PLCC or QFP.
• Budgeting board area from a DIP-40 footprint. DIP-48 is 58.42 mm of hole pattern against 48.26 mm, roughly 9.7 cm² against 7 cm².
• Treating IDT body figures as toleranced. The datasheet says approximately and points to a separate package diagram. Get limits from the drawing.
• Using a friction socket for a part you will swap often. Forty-eight leads is enough force to justify ZIF, and Aries lists one at the same row spacing.
• Placing tall parts under an adapter board. A DIP-48 adapter PCB is wider than the row spacing and overhangs the pads on both sides.
• Assuming MASTER and SLAVE dual-port parts are interchangeable. On the IDT7130 the BUSY pin is an open-drain output needing a pull-up; on the IDT7140 it is an input.

Frequently asked questions

What is a DIP-48 package?

A 48-lead dual in-line package with twenty-four through-hole leads per side on 2.54 mm pitch, rows 15.24 mm apart. It was used for high-pin-count memory and interface devices such as dual-port SRAMs. New ICs are rarely offered in it today.

What are the dimensions of a DIP-48?

The hole pattern spans 58.42 mm, fixed by 23 spaces at 2.54 mm. IDT gives its C48 plastic DIP body as approximately 0.62 in by 2.43 in by 0.15 in, which is about 15.7 mm by 61.7 mm by 3.8 mm. Those are nominal identification figures, not toleranced limits.

Are DIP-48 chips still available?

Rarely as new parts. The CY7C136 dual-port SRAM, once a DIP-48 device, is now stocked only in 52-PLCC and 52-PQFP. Sockets and SMD-to-DIP-48 adapter boards remain Active and readily available.

How do I identify pin 1 on a DIP-48?

Look for a notch, molded dot, or chamfer at one end. With the notch at the top and leads pointing away, pin 1 is the upper-left lead. Numbering runs counterclockwise: down the left to pin 24, then up the right side from 25 to 48.

What hole size should I use for a DIP-48 footprint?

Size from the maximum lead width on your part or adapter header. For a 0.58 mm maximum, IPC-2222 Level B gives 0.78 mm minimum and Level A gives 0.83 mm. Round to a 0.9 mm drill with a 1.6 mm pad.

What is a DIP-48 adapter used for?

Mounting a fine-pitch surface-mount part on a carrier board that plugs into a DIP-48 socket or breadboard. Adapters exist for SSOP-48, TSSOP-48, LQFP-48, LFCSP-48 and QFN-48, all converting to a 600 mil DIP-48 footprint on 0.1 in pitch.

What to do next

Check part availability before you draw anything. If the 48-pin device you have in mind is only stocked in PLCC or QFP, the DIP-48 footprint is the wrong starting point and you will find that out faster from a distributor search than from a datasheet.

If you are placing the footprint for an adapter, use the 15.24 mm library entry, set the drill at 0.9 mm, and leave the area under the adapter board clear. The adapter overhangs the pad rows on both sides.

If you are repairing or reproducing existing hardware, budget the board area honestly at about 9.7 cm² and specify a ZIF socket if the part will come out more than once. The sockets are still made, still stocked, and cheaper than the frustration of a bent lead row on a part you cannot replace.