A DIP-24 comes in two row spacings that share nothing but the 2.54 mm pitch: 7.62 mm and 15.24 mm. Unlike most DIP sizes, both are common at 24 pins, so identifying which one you have is the first job. This page gives verified dimensions for both, the pin-1 rule, and the hole-size arithmetic.

Key takeaways

• Pitch is 2.54 mm (0.100 in). Row spacing is either 7.62 mm (300 mil, JEDEC MS-001) or 15.24 mm (600 mil, JEDEC MS-011).
• 24 pins is the crossover point. Both widths are in active use, which is not true at 20 pins or below.
• Published 300-mil body lengths disagree: Diodes P24 caps D at 29.86 mm, the LTC N24 drawing at 32.512 mm.
• Maximum lead width of 0.57 mm (Diodes P24, dimension B) sets a 0.72 to 0.82 mm finished hole under IPC-2222.
• KiCad ships DIP-24 at four row spacings, more than any other DIP size in the library.
• Through-hole 24-pin logic is going obsolete faster than its SOIC equivalent. Check part status before you commit.

What is a DIP-24 package?

A DIP-24 package is a 24-lead dual in-line package: a rectangular molded body with twelve through-hole leads down each long side on 2.54 mm pitch. The two lead rows sit either 7.62 mm or 15.24 mm apart. It mounts through plated holes or into an IC socket. PDIP-24 denotes the plastic-bodied version.

The naming runs loose. Vendors write DIP24, DIP-24, PDIP-24, DIL-24 and 24-DIP for the same part. Because two widths are in circulation at this pin count, a listing without a row spacing is not enough to order or lay out from. DigiKey disambiguates in the package field: the CD74HC4067E is listed as 24-DIP (0.600 in, 15.24 mm), while the narrow parts read 24-DIP (0.300 in, 7.62 mm).

[IMAGE 1: DIP-24 package outline drawing showing body length D, row spacing, pitch e, and lead dimensions, with 300-mil and 600-mil variants side by side | alt: “DIP-24 package dimensions diagram showing 2.54 mm pitch with 7.62 mm and 15.24 mm row spacing”]

DIP-24 dimensions

The table below is taken from the Diodes P24 outline (document PD-2139, dated 06/14/13), which is a 300-mil 24-pin plastic DIP referencing JEDEC MS-001D variation BE. All values in millimetres as published.

Dimension	Symbol	Min	Max	Note
Overall height	A	3.71	4.31
Standoff	A1	0.51	—	Minimum only
Molded body thickness	A2	3.20	3.60
Lead width	B	0.38	0.57	Sets the drill size
Shoulder width	B1	1.27 BSC	1.27 BSC	Basic dimension
Lead thickness	c	0.20	0.36
Body length	D	29.25	29.86
Molded body width	E	6.20	6.60
Row spacing at shoulders	E1	7.32	7.92	Nominal 7.62
Lead tip spread	E2	8.40	9.00	Splayed, as measured
Lead pitch	e	2.54 BSC	2.54 BSC	Basic dimension
Lead length	L	3.00	3.60

Note the three width figures. E is the molded plastic body at 6.20 to 6.60 mm. E1 is the row spacing measured at the lead shoulders, 7.32 to 7.92 mm, which brackets the 7.62 mm nominal your footprint uses. E2 is the lead tip spread at 8.40 to 9.00 mm, wider because the leads splay outward before insertion. Calipers on a loose part give you E2. Your holes go on E1 nominal.

The two published 300-mil body lengths do not agree

The Diodes P24 drawing caps body length D at 29.86 mm. The Analog Devices / Linear Technology N24 drawing, revision J dated 07/21, gives a maximum of 1.280 in, which is 32.512 mm. That is a 2.65 mm disagreement between two current manufacturer drawings for what both call a 24-lead 300-mil PDIP.

Both are correct for their own parts. JEDEC MS-001 admits several variations at 24 leads, and vendors pick different ones. The consequence for you is practical: a DIP-24 silkscreen outline drawn to one vendor drawing may be overhung by a second-source part from another vendor. Draw the outline to the longest body you might populate, or leave the outline off the ends entirely.

The LTC drawing also notes that its body-length and body-width dimensions exclude mold flash or protrusions, and that flash shall not exceed 0.010 in (0.254 mm). If you are checking a tight slot or a shrouded socket, add that allowance on each side.

MS-001 against MS-011: what the row spacing tells you

The two DIP-24 widths sit under different JEDEC outlines. MS-001 covers PDIP at 2.54 mm pitch with a 6.35 mm body width and 0.3 in row spacing. MS-011 covers PDIP at the same 2.54 mm pitch but with a 12.7 mm body width and 0.6 in row spacing.

Knowing which family a part belongs to tells you the body width before you open the drawing. A 600-mil DIP-24 is roughly twice as wide across the plastic as a 300-mil one, which matters more for board area than the extra 7.62 mm of hole spacing suggests.

DIP-24 pinout and pin 1 identification

Pin 1 sits at one end, marked by a notch in the body, 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 12, across the end, and back up the right side from pin 13 to pin 24.

Restated for a DIP-24 specifically:

• Left column, top to bottom: pins 1 through 12
• Right column, bottom to top: pins 13 through 24
• Pin 1 and pin 24 face each other across the body
• Pin 12 and pin 13 face each other at the opposite end

The counterclockwise convention is the same one used for DIP, SOIC, QFN and BGA, with pin 1 always adjacent to the orientation feature. The error it invites is specific to 24-pin parts: because a 4-to-16 decoder or a 16:1 multiplexer exists in both DIP-24 and SOIC-24, and the two share a function map, it is easy to carry a mental image from one to the other. The reference face differs when you hand-solder. Check the datasheet drawing rather than working from memory.

[IMAGE 2: Top-down DIP-24 pinout diagram with notch, pin 1 dot, and numbering 1 to 24 counterclockwise | alt: “DIP-24 pinout diagram showing pin 1 notch and counterclockwise pin numbering to pin 24”]

Silkscreen practice: mark pin 1 with a dot and break the outline at that end. A rotated DIP-24 is 24 joints to desolder, and the wider 600-mil body gives an operator more room to get it wrong before anything looks visually off.

DIP-24 footprint: hole and pad sizing

Twelve holes per row on 2.54 mm pitch, rows at either 7.62 mm or 15.24 mm. Overall hole-pattern length is 11 spaces × 2.54 mm = 27.94 mm in both cases. Everything else follows from lead geometry.

Size the hole from the maximum lead width, not the nominal. The Diodes P24 drawing gives dimension B at 0.38 to 0.57 mm. Use 0.57 mm.

Applying the IPC-2222 density levels:

• Level A: minimum hole = max lead diameter + 0.25 mm → 0.57 + 0.25 = 0.82 mm
• Level B: + 0.20 mm → 0.77 mm
• Level C: + 0.15 mm → 0.72 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: 0.77 + (2 × 0.05) + 0.5 = 1.37 mm pad on a 0.77 mm hole.

Round the hole up to a stocked drill. 0.8 mm is standard and clears a 0.57 mm lead comfortably. A 1.5 mm pad on a 0.8 mm hole is a safe Class 2 default for a general-purpose DIP-24.

Two checks before committing:

• Aspect ratio. Keep board thickness to hole diameter under 10:1 for reliable plating. A 0.8 mm hole is good to 8 mm of board, so this never binds on a 1.6 mm stackup.
• Annular ring class. IPC-6012 Class 3 requires a minimum 0.001969 in external-layer annular ring measured from the finished hole to the land edge. Class 2 permits 90-degree breakout provided the land-conductor junction is teardropped. Building to Class 3 means adding pad, not shaving hole.

Library footprints: DIP-24 has more variants than any other DIP

The KiCad Package_DIP library carries DIP-24 at four distinct row spacings. No other pin count in that library is offered across so many widths:

• DIP-24_W7.62mm — 300 mil, plus LongPads, Socket and Socket_LongPads variants
• DIP-24_W10.16mm — 400 mil, plus LongPads, Socket and Socket_LongPads variants
• DIP-24_W15.24mm — 600 mil, plus LongPads, Socket and Socket_LongPads variants
• DIP-24_W8.89mm, W11.43mm and W16.51mm — SMD socket variants at 350, 450 and 650 mil
• SMDIP-24 at 7.62, 9.53, 11.48 and 15.24 mm — surface-mount DIP versions

The 400-mil entry deserves a note. It is rare in modern parts but real, and its presence in the library means picking the DIP-24 footprint from an autocomplete list is genuinely risky. Type the width, do not scroll to it.

300 mil against 600 mil: which DIP-24 do you have?

	300 mil (7.62 mm)	600 mil (15.24 mm)
Row spacing	7.62 mm	15.24 mm
JEDEC family	MS-001	MS-011
Typical body width	About 6.35 mm	About 12.7 mm
Hole pattern length	27.94 mm	27.94 mm
KiCad stock footprint	Yes	Yes
Common device types	Line transceivers, interface	Decoders, multiplexers, memory
Breadboard	Straddles the centre channel	Too wide for a standard breadboard

Measuring an unknown part settles it in one pass. Span the outside of the lead rows with calipers. A 300-mil DIP-24 reads roughly 8.4 to 9.0 mm across the lead tips per the Diodes E2 dimension. A 600-mil part reads over 15 mm. There is no overlap.

If you only have the part number, the distributor package field is faster than the datasheet. Both DigiKey and Mouser spell out the row spacing in the Package / Case attribute for through-hole DIPs.

Availability: the 24-pin DIP is thinning out

Through-hole 24-pin logic is being discontinued faster than the equivalent surface-mount part. Verified DigiKey listings:

Part	Function	Package	Status	Stock
CD74HC4067E (TI)	Analog mux 16:1, 160 Ω	24-DIP (0.600 in)	Obsolete	None at DigiKey
CD74HC4067M96 (TI)	Same function, SOIC	24-SOIC	Active	16,208
CD4514BE (TI)	Latch / 4-to-16 decoder	24-DIP (0.600 in)	Obsolete	3,227
DM74LS154N (onsemi)	Decoder/demux 1 × 4:16	24-DIP (0.600 in)	Obsolete	4,842 (Rochester)
CD74HC154M96 (TI)	Decoder/demux, SOIC	24-SOIC	Active	10,469

The pattern is worth stating plainly. The CD74HC4067 in DIP-24 is obsolete with no DigiKey stock, while the identical function in SOIC-24 is active with 16,208 units on the shelf at $0.89 in single quantity. The same split shows on the 154 decoder. If your design needs a 24-pin through-hole part for a new build, you are drawing from a shrinking pool.

Two mitigations. First, Rochester Electronics carries authorised end-of-life inventory for several of these, which is a legitimate second source rather than a grey-market flag. The DM74LS154N shows 4,842 units there. Second, a SOIC-24 to DIP-24 adapter board converts the surface-mount part to a 0.6 in DIP footprint, which keeps a socketed or repairable design viable after the through-hole part is gone.

Sockets are still healthy

Socket availability has not followed the ICs down. Mill-Max lists the 110-99-624-41-001000, a 24-position 0.6 in row spacing open-frame socket with tin-lead plating, as active with 247 in stock at $1.87 in single quantity. The gold-plated 111-43-624-41-001000 is also active, 134 in stock at $5.68. Both are rated 3 A per contact with a -55 degC to +125 degC operating range.

The gold-to-tin price ratio is about 3:1 at quantity 1. For a socket that will see one insertion in its life, tin-lead is the honest choice. Gold earns its cost in test fixtures and anywhere the part gets swapped repeatedly.

[IMAGE 3: A 600-mil DIP-24 IC beside a 24-position IC socket and a 300-mil DIP-24 for width comparison | alt: “DIP-24 package in 600 mil and 300 mil widths next to a 24-pin IC socket”]

Design mistakes that cause rework

• Picking the footprint by pin count alone. DIP-24 exists at 300, 400 and 600 mil in the stock KiCad library. Type the width explicitly.
• Silkscreen drawn to one vendor drawing. Published 300-mil body lengths run from 29.86 mm to 32.512 mm. Draw to the longest part you might fit.
• Hole sized from nominal lead width. Nominal is around 0.46 mm; the Diodes P24 maximum is 0.57 mm. Size from maximum.
• Socket footprint used for a bare IC, or the reverse. A socket needs its own pad geometry. KiCad separates them deliberately.
• Assuming the through-hole part will still exist. Check part status at design time. Several common 24-pin DIP logic devices are already obsolete while their SOIC twins are active.
• Ignoring mold flash on a tight fit. The LTC N24 drawing excludes flash from its body dimensions and allows up to 0.254 mm of it per side.

Frequently asked questions

What is a DIP-24 package?

A 24-lead dual in-line package with twelve through-hole leads per side on 2.54 mm pitch. Row spacing is either 7.62 mm or 15.24 mm, and both are common at this pin count. The plastic version is called PDIP-24. It mounts through plated holes or into an IC socket.

What are the dimensions of a DIP-24?

Pitch is 2.54 mm and the hole pattern spans 27.94 mm end to end. For the 300-mil variant, the Diodes P24 drawing gives a body length of 29.25 to 29.86 mm, a body width of 6.20 to 6.60 mm, and an overall height of 3.71 to 4.31 mm. Other vendors publish longer bodies.

Is DIP-24 300 mil or 600 mil?

Both exist and both are common. Decoders, multiplexers and memory tend to use the 600-mil width; line transceivers and interface parts often use 300 mil. Measure across the lead tips: under 9 mm is a 300-mil part, over 15 mm is 600 mil. Or check the distributor package field.

How do I identify pin 1 on a DIP-24?

Look for a notch, molded dot, or chamfer at one end. With the notch at the top and the leads pointing away, pin 1 is the upper-left lead. Numbering runs counterclockwise: down the left to pin 12, then up the right side from 13 to 24.

What hole size should I use for a DIP-24 footprint?

Size from the 0.57 mm maximum lead width in the Diodes P24 drawing. IPC-2222 Level B gives 0.77 mm minimum, Level A gives 0.82 mm. Round to a standard 0.8 mm drill with a 1.5 mm pad for a manufacturable Class 2 default.

Are DIP-24 packages still available?

Fewer every year. Several common 24-pin DIP logic devices are now obsolete while the same function in SOIC-24 remains active and well stocked. Sockets and adapters are still readily available, so socketed and repairable designs stay viable.

What to do next

Before you place anything, settle the width. Read it off the distributor package field or measure across the lead tips. That single check prevents the most expensive DIP-24 mistake, because 300-mil and 600-mil footprints are not recoverable from each other once the board is fabricated.

With the width known, use the matching stock library footprint and stop there. Cut a custom footprint only if you are building to IPC Class 3 and need annular ring margin, or if you are socketing and want the socket-specific pad geometry.Then check part status before you commit the design. If the through-hole device you picked is obsolete and the SOIC version is active, decide now whether to move to surface mount or to design around an adapter. That decision is cheap at schematic stage and expensive after the boards arrive.