The LQFP-128 package puts 128 gull-wing leads on a 14 × 14 mm body at 0.40 mm pitch, inside a 16.0 × 16.0 mm lead span and a 1.60 mm maximum height. It occupies exactly the same board area as an LQFP-100 while carrying 28 more nets. The pitch is what you pay for that. Below: the envelope, the pin map, the land pattern, and the two process limits that break 0.40 mm builds.

Key takeaways

• The standard LQFP-128 outline is a 14 × 14 mm body on 0.40 mm pitch, 16.0 mm lead span, 1.40 mm body thickness, 1.60 mm maximum height, per the JEDEC MS-026 family drawing.
• You get no pitch choice at this lead count. Thirty-two leads per side at 0.50 mm would need 15.5 mm of lead field on a 14 mm body. The geometry forces 0.40 mm.
• LQFP-128 and LQFP-100 share a 17.40 mm square courtyard, about 303 mm². Twenty-eight extra I/O cost zero board area.
• A 0.150 mm stencil foil fails the area-ratio check at this pitch, coming out at 0.63 against a 0.66 floor. Specify 0.100 mm to 0.127 mm.
• Non-solder-mask-defined lands leave a 0.06 mm mask web at 0.40 mm pitch. Ganged mask openings stop being a preference and become the only manufacturable option.
• Thermal margin is the real constraint. A 0.825 W device at a typical 45 °C/W leaves under 3 °C of headroom at 85 °C ambient.

What the LQFP-128 package is

LQFP-128 means Low-profile Quad Flat Package with 128 leads. The leads exit all four sides as gull wings, 32 per side. The JEDEC MS-026 outline fixes the body thickness at 1.40 mm and the maximum seated height at 1.60 mm. The standard body is 14 × 14 mm on 0.40 mm pitch.

Vendor naming diverges here more than at lower lead counts. The same outline appears as LQFP-128, TQFP-128 and, in Renesas documentation, LFQFP-128 for low-profile fine-pitch QFP. Only the body thickness distinguishes LQFP from TQFP: 1.40 mm against 1.00 mm. Fine-pitch labelling refers to the 0.40 mm pitch and changes nothing dimensionally.

This is the last stop before board area starts climbing steeply. Above 128 leads, MS-026 moves to a 20 × 20 mm body for 144 leads, which is a different area class entirely.

[IMAGE 1: Isometric render of a 14 × 14 mm LQFP-128 body with the pin-1 chamfer and dimple called out | alt: “LQFP-128 package body showing pin 1 index and 32 gull-wing leads per side”]

LQFP-128 dimensions

The table gives the nominal envelope for the 14 × 14 mm, 0.40 mm pitch variant. These are typical values from the MS-026 family drawing. The controlling numbers for your build sit in the package section of the specific device datasheet.

Table 1 — LQFP-128 mechanical envelope, 14 × 14 mm body, 0.40 mm pitch (typical)

Parameter	Symbol	Typical value	Notes
Body size	D × E	14.00 × 14.00 mm	Square body, plastic moulded
Lead count	—	128	32 leads per side
Lead pitch	e	0.40 mm	Basic dimension, no tolerance
Lead field per side	—	12.40 mm	31 spaces × 0.40 mm
Lead span, tip to tip	HD × HE	16.00 × 16.00 mm ± 0.20 mm	Body + 2 × 1.00 mm lead reach
Body thickness	A2	1.40 mm ± 0.05 mm	The dimension that makes it low profile
Overall height	A	1.60 mm max	Seated height including standoff
Standoff	A1	0.05 mm min, 0.15 mm max	Gap under the body after reflow
Lead width	b	0.18 mm (0.13–0.23 mm)	Narrower than the 0.50 mm pitch family
Lead thickness	c	0.127 mm (0.09–0.20 mm)	Copper alloy plus finish
Foot length	L	0.60 mm (0.45–0.75 mm)	Drives heel and toe fillet targets
Foot angle	θ	0° to 7°	Affects heel fillet formation
Coplanarity	—	0.08 mm max	Critical at this pitch — see the paste height check
Pin 1 index	—	Corner chamfer plus moulded dimple	Chamfer alone is not a reliable index

One line in that table decides the package. Thirty-two leads per side need 31 pitch spaces. At 0.50 mm that is 15.5 mm of lead field, which will not sit on a 14 mm body. At 0.40 mm it is 12.40 mm, leaving 0.80 mm of clearance at each corner.

So the pitch is not a design choice. Anyone quoting an LQFP-128 at 0.50 mm pitch is describing a package with a larger body, and the footprints have nothing in common.

LQFP-128 against the alternatives

Compare these by courtyard area rather than body size. Courtyard is what the board actually loses.

Table 2 — High-lead-count package options compared

Package	Body (mm)	Pitch (mm)	Land span (mm)	Courtyard area (mm²)	Where it wins
LQFP-100	14 × 14	0.50	16.90	303	Easiest process window in the family
LQFP-128	14 × 14	0.40	16.90	303	Maximum I/O per unit board area in a QFP
LQFP-144	20 × 20	0.50	22.90	548	Relaxed pitch, if you can spare the area
LQFP-176	24 × 24	0.50	26.90	751	High I/O without leaving leaded packages
TFBGA-144	10 × 10	0.80	—	121	Board area and signal integrity, needs X-ray

Two numbers in that table drive most decisions. Moving from LQFP-100 to LQFP-128 buys 28 nets for no additional courtyard. Moving from LQFP-128 to LQFP-144 buys 16 nets for 81 % more courtyard area.

That makes LQFP-128 the efficiency peak of the leaded family. The cost is not area or price. It is process window, and the next three sections are about spending it carefully.

LQFP-128 pinout and pin numbering

Pin numbering runs counter-clockwise viewed from the top, starting at the corner carrying the moulded dimple. Thirty-two pins per side, no gaps.

Table 3 — LQFP-128 pin allocation by side, top view

Side	Pin range	Direction of count	Corner pins
Left	1 to 32	Top to bottom	Pin 1 at top-left
Bottom	33 to 64	Left to right	Pin 33 at bottom-left
Right	65 to 96	Bottom to top	Pin 65 at bottom-right
Top	97 to 128	Right to left	Pin 97 at top-right

Function assignment is vendor-specific and there is no standard LQFP-128 pinout. Supply and ground pins are normally spread across all four sides so no side carries an unbalanced return current. Build the decoupling plan from the pinout, not from the schematic page order.

Ordering suffixes identify the package more reliably than marketing names. STMicroelectronics uses a T suffix for LQFP, NXP uses FBD, and Microchip uses PT for TQFP outlines. Check the suffix against the mechanical drawing in the datasheet before you commit a footprint, because vendors reuse lead counts across different bodies.

[IMAGE 2: Top-view pinout diagram of an LQFP-128 with pin 1 dimple and the four 32-pin side groups labelled | alt: “LQFP-128 pinout diagram showing counter-clockwise pin numbering from pin 1”]

LQFP-128 PCB footprint and land pattern

The IPC-7351B name for the standard footprint is QFP40P1600X1600X160-128N. That reads as quad flat pack, 0.40 mm pitch, 16.00 × 16.00 mm span, 1.60 mm height, 128 pins, nominal density.

IPC-7351B builds each land from three fillet targets — toe, heel and side — that change with density level. Level A suits low-volume or high-reliability work with manual rework. Level B is the reflow default. Level C is for boards where area is the binding constraint.

Table 4 — IPC-7351B land pattern for LQFP-128, by density level (computed from the nominal envelope)

Density level	Toe fillet (mm)	Heel fillet (mm)	Land size (mm)	Toe-to-toe (mm)	Land gap (mm)
A — most material	0.55	0.45	0.26 × 1.75	17.30	0.14
B — nominal	0.35	0.35	0.24 × 1.50	16.90	0.16
C — least material	0.15	0.25	0.22 × 1.25	16.50	0.18

At density level B the inner land edge sits at a 13.90 mm gap, the land runs 1.50 mm long, and the courtyard closes at 17.40 mm square after the 0.25 mm courtyard excess. Regenerate all of it in your library tool against the real datasheet before release, because foot length tolerance moves the heel further than any other input.

The gap column is the one to read twice. At 0.40 mm pitch and density level B, adjacent lands sit 0.16 mm apart. The equivalent figure on an LQFP-100 is 0.20 mm. That 0.04 mm is where the process difficulty lives.

Solder mask: why ganged openings are mandatory here

Work the mask web. Non-solder-mask-defined lands with the usual 0.05 mm mask expansion consume 0.05 mm on each side of the 0.16 mm gap, leaving a 0.06 mm dam between openings.

Most fabricators will not guarantee a mask web below 0.075 mm to 0.10 mm on liquid photoimageable mask. A 0.06 mm dam either does not image or lifts during assembly, and a lifted mask sliver under a lead is a latent short.

The answer is a single ganged mask opening over each 32-land row. That is standard practice at 0.40 mm pitch and no fab will object. It also removes the last physical barrier to bridging, so paste volume alone now controls the defect rate.

At 0.50 mm pitch the same calculation gives a 0.10 mm dam, which is why ganging is a judgement call on an LQFP-100 and a requirement on an LQFP-128.

Stencil design: the area-ratio check that rules out 0.150 mm foil

Fine-pitch paste release is geometry. Area ratio — opening area divided by aperture wall area — must clear 0.66 for reliable transfer.

Take a 0.22 mm × 1.35 mm aperture, the density level B land reduced roughly 8 % in width and 10 % in length:

• Opening area = 0.22 × 1.35 = 0.297 mm²
• Aperture perimeter = 2 × (0.22 + 1.35) = 3.14 mm
• On 0.100 mm foil: wall area = 0.314 mm², area ratio = 0.95 — clears comfortably
• On 0.127 mm foil: wall area = 0.399 mm², area ratio = 0.74 — acceptable
• On 0.150 mm foil: wall area = 0.471 mm², area ratio = 0.63 — below the 0.66 floor

That last line matters because 0.150 mm foil is a common house default for mixed-technology boards. On an LQFP-128 it produces skipped and partial deposits, and the defect appears as random open joints rather than a systematic pattern.

If the board carries connectors or shields that need the thicker foil, use a step stencil or a multi-level electroformed foil rather than compromising the fine-pitch rows.

Coplanarity against paste height

The 0.08 mm coplanarity limit reads harmless until you compare it to what is under the lead. On a 0.100 mm foil the wet paste deposit stands roughly 0.10 mm tall before reflow.

A lead sitting at the 0.08 mm coplanarity limit therefore consumes about 80 % of the available paste height. The lead may touch paste, but there is not enough volume left to wet the foot and form a heel.

This is the mechanism behind the classic LQFP-128 failure: one or two open joints, scattered, passing electrical test intermittently. It is a mechanical problem, not a profile problem, and reflowing again will not fix it.

Handle reels accordingly. Reject any tray-handled part with visible lead deformation and never straighten leads by hand on a 0.40 mm pitch package.

Thermal behaviour and a worked junction-temperature check

A standard LQFP-128 has no exposed pad. Heat leaves through 128 leads into the board, so θJA is mostly a property of your copper.

Typical published figures for a 14 × 14 mm LQFP-128 run 40 °C/W to 50 °C/W on the JESD51-7 four-layer test board and 55 °C/W to 70 °C/W on the JESD51-3 single-layer board. The extra leads help slightly against a 100-lead part in the same body.

Work a realistic case. A 128-pin device drawing 250 mA at 3.3 V dissipates 0.825 W. At 45 °C/W the junction rises 37 °C. At an 85 °C ambient that lands at 122 °C against a 125 °C limit, leaving under 3 °C.

That is not a design margin. To reach 15 °C of headroom you would need to cut dissipation to 0.55 W or push θJA down to about 30 °C/W, which a leadframe package without a thermal pad will not reach on any realistic stack-up.

Three options actually work: cap the specified ambient at 70 °C, pour continuous ground copper on layer 2 across the full 17.40 mm courtyard with a via ring just outside the lands, or move to a package with an exposed pad or a BGA. Adding a heatsink to a 1.60 mm plastic body is not one of them.

Reflow, moisture and escape routing

J-STD-020 classifies by body thickness first. At 1.40 mm the LQFP-128 sits below the 1.60 mm threshold, so the classification peak is 260 °C regardless of package volume. Keep time above 217 °C between 60 s and 150 s.

Moisture sensitivity level 3 is the common rating, giving 168 h of floor life at 30 °C and 60 % RH once the dry bag opens. Past that, bake per J-STD-033 — 24 h at 125 °C for this body class. A 14 mm body with a large die is a popcorn candidate if you skip it.

Routing stays manageable. Four sides at 16.0 mm give 64 mm of perimeter for 128 leads, or 0.50 mm of channel per net. Every lead fans outward without a via, so a two-layer escape remains viable and every joint stays visible to an operator with a microscope.

Keep layer 1 under the body clear of traces. It is the only place a solid return plane can sit directly beneath 128 escapes, and it is also the copper doing your thermal work.

Sourcing, lifecycle and compliance

The 128-lead quad flat outline is common in Renesas, NXP and Microchip microcontroller families, and less common in FPGAs, which tend to jump from 100-lead and 144-lead QFPs straight to BGAs. Confirm the exact orderable and its package drawing before footprinting; this article names no specific part numbers because none were verified against a live datasheet in this session.

Check three things at sourcing. The package suffix must map to the drawing you footprinted. AEC-Q100 qualification is granted per part and per package, so automotive grade in a sibling package proves nothing. RoHS and REACH declarations must be current for the specific orderable, not the family.

Counterfeit risk is real on high-pin-count QFPs. The top surface is large and flat enough to re-mark cleanly, and 0.40 mm pitch leads show handling damage from reworked parts. Compare laser mark depth and font against a known-good unit, check date code consistency across the reel, and reject any part with re-formed leads.

Design mistakes that cause returns

• Assuming a 0.50 mm pitch because the body is 14 mm. The LQFP-100 and LQFP-128 have identical spans and identical courtyards, and the footprints are not interchangeable.
• Letting the house default 0.150 mm stencil foil onto a 0.40 mm pitch row, which fails the area-ratio floor at 0.63.
• Specifying non-solder-mask-defined lands at 0.40 mm pitch and getting a 0.06 mm dam the fab cannot image.
• Reducing stencil aperture width instead of length to control bridging, which starves the heel fillet that carries thermal cycling load.
• Using a four-layer datasheet θJA figure on a two-layer board, then discovering the margin at qualification.
• Hand-straightening leads on a returned or tray-handled part. At 0.08 mm coplanarity you have already lost most of the paste height.

Frequently asked questions

What does LQFP-128 stand for?

Low-profile Quad Flat Package with 128 leads. Low profile is a JEDEC height class meaning a 1.40 mm body and a 1.60 mm maximum seated height. Quad flat means gull-wing leads on all four sides. The 128 is the lead count, 32 per side.

What is the size of an LQFP-128 package?

The standard variant has a 14 × 14 mm body and a 16.0 × 16.0 mm lead span on 0.40 mm pitch, standing 1.60 mm tall at maximum. The lead field occupies 12.40 mm of each 14 mm side, leaving 0.80 mm of corner clearance.

What is the pin pitch of an LQFP-128?

0.40 mm, and there is no alternative on a 14 mm body. Thirty-two leads per side require 31 pitch spaces, which at 0.50 mm would need 15.5 mm of lead field. Any 128-lead QFP quoted at 0.50 mm pitch uses a larger body and a different footprint.

Is LQFP-128 the same as TQFP-128?

The pitch, span and land pattern are identical, so the footprint transfers directly. Body thickness differs: 1.40 mm for LQFP against 1.00 mm for TQFP, with maximum heights of 1.60 mm and 1.20 mm. Renesas documentation calls the same outline LFQFP-128.

What land pattern should I use for an LQFP-128?

Start from IPC-7351B QFP40P1600X1600X160-128N at density level B: 0.24 mm × 1.50 mm lands on 0.40 mm pitch, 16.90 mm toe-to-toe, 17.40 mm courtyard. Use ganged solder mask openings per row. Regenerate against the datasheet before release.

Can you hand-solder an LQFP-128?

Yes, but expect it to be slow. At 0.40 mm pitch, drag soldering works with plenty of flux and fine braid, and every joint stays inspectable. Budget several bridges per part and check heel fillets under magnification, since a bridge-free row can still hide a starved joint.

What to do next

If you need more than 100 nets and your board area is fixed, specify the LQFP-128. It is the only package in the leaded family that adds I/O without adding courtyard, and the 303 mm² it occupies is identical to the LQFP-100 you are probably replacing.

Then spend the process budget deliberately. Specify 0.100 mm or 0.127 mm stencil foil in the fabrication notes, gang the mask openings per row, and reduce aperture length rather than width.

If your dissipation is above about 0.6 W at an 85 °C ambient, stop and reconsider the package. A leaded body without a thermal pad will not give you the margin, and finding that out at qualification costs more than the BGA would have.

References

• JEDEC Solid State Technology Association — MS-026, plastic quad flat package family outline. https://www.jedec.org/standards-documents
• IPC — IPC-7351B, Generic Requirements for Surface Mount Design and Land Pattern Standard. https://www.ipc.org/
• IPC / JEDEC — J-STD-020, Moisture/Reflow Sensitivity Classification for Nonhermetic Surface Mount Devices. https://www.jedec.org/standards-documents
• IPC / JEDEC — J-STD-033, Handling, Packing, Shipping and Use of Moisture/Reflow Sensitive Surface Mount Devices.
• JEDEC — JESD51-3 and JESD51-7, thermal test board definitions for package thermal measurement.
• IPC — IPC-7525, Stencil Design Guidelines (area ratio and aperture reduction).

Note: these documents were not retrieved live in this session. Verify every figure against your controlled copy of the standard and the device datasheet before publishing.