An LQFP package is a plastic, gull-wing surface-mount package with leads on all four sides, a 1.40 mm molded body, and a 1.60 mm maximum seated height. It is registered under JEDEC outline MS-026 and ships in 32 to 256 leads, across 7 × 7 mm to 28 × 28 mm bodies, at 0.4 mm to 0.8 mm pitch. What follows is the dimensional data, measured thermal performance, land-pattern math, and failure modes you need before committing a footprint.

Key Takeaways

• The 1.40 mm figure describes the molded body only. Seated height is 1.60 mm maximum, which includes a nominal 0.10 mm standoff under the leads.
• LQFP and TQFP fall under the same JEDEC registration, MS-026, the low/thin profile plastic quad flat package outline. Body thickness separates them; the land pattern does not.
• Measured θJA spans 67.8 °C/W for a 32-lead 7 × 7 mm part on a single-layer board in still air, down to 18.1 °C/W for a 208-lead 28 × 28 mm part on a multilayer board (Amkor DS232G).
• At 0.5 mm pitch, an IPC-7351B Level B land leaves roughly 0.12 mm of copper between adjacent pads. Confirm that against your fabricator’s minimum solder-mask web before release.
• Gull-wing leads take at least a quarter of each thermal cycle’s deformation as elastic bending, which is why LQFP joints outlast leadless joints on boards that swing temperature.
• Commercial LQFP lines are characterized to moisture sensitivity level 3 and qualified to AEC-Q100. Dry-pack handling is part of the specification, not a warehouse detail.

What Is an LQFP Package?

An LQFP (low-profile quad flat package) is a plastic surface-mount IC package with gull-wing leads on all four sides, a 1.40 mm nominal body thickness, and a 1.60 mm maximum seated height. JEDEC outline MS-026 defines it. Standard offerings run from 32 to 256 leads at 0.4 mm to 0.8 mm pitch.

Inside the mold compound sits a copper-alloy leadframe. The die is attached to the paddle with adhesive and connected to the lead fingers by copper, silver, or gold wire. The leads exit the body, bend outward, then bend down to form the gull wing that lands on the board. Pins are numbered counter-clockwise from the pin-1 index mark.

Amkor’s process data for its LQFP line gives the practical details that matter downstream: die thickness of 14.5 ± 0.5 mil, matte tin or pre-plated Ni/Pd lead finish, laser marking, and shipment in JEDEC CO-124 low-profile trays or on tape and reel.

[IMAGE 1: cutaway of an LQFP showing leadframe, die paddle, bond wires, mold compound, and the gull-wing lead form | alt: “LQFP package cutaway showing leadframe, die, bond wires, and gull-wing leads”]

Where the “Low Profile” Actually Applies

The number engineers quote most often, 1.4 mm, is the body. It is not the height the package occupies above the board. Analog Devices’ drawing for a 64-lead LQFP with exposed pad (SW-64-2, 10 × 10 mm body, 0.5 mm pitch, compliant to MS-026-BCD-HD) gives the full stack: body 1.35 / 1.40 / 1.45 mm, overall height 1.60 mm maximum, standoff 0.05 / 0.10 / 0.15 mm, lead foot 0.45 / 0.60 / 0.75 mm, and a 1.00 mm reference lead form.

Three more dimensions from that drawing decide whether the part solders: lead width 0.17 / 0.22 / 0.27 mm, lead thickness 0.09 / 0.15 / 0.20 mm, and coplanarity 0.08 mm maximum, with the lead exit angle between 0° and 7°.

Pages that describe LQFP body thickness as “1.0 mm to 1.4 mm” are collapsing two package families. A 1.0 mm body is TQFP. If you are height-constrained, read the mechanical drawing rather than the acronym, and budget the 1.60 mm seated maximum plus board thickness against the enclosure gap. That figure is what rules out the 2.0 mm to 3.6 mm PQFP bodies the LQFP replaced.

Body Size, Lead Count, and the Pitch Each Combination Implies

Amkor’s configuration table pins body size against lead count but does not print pitch. Pitch follows from geometry: leads per side minus one, multiplied by pitch, has to fit inside the body edge. Table 1 lists the pitch each combination resolves to. Treat it as a shortlisting tool and confirm against the device drawing before you build a footprint.

Body size (mm)	Lead counts	Implied pitch (mm)	Tip-to-tip (mm)	Standoff (mm)	Foot (mm)
7 × 7	32 / 48 / 64	0.80 / 0.50 / 0.40	9.0	0.10	0.60
10 × 10	44 / 52 / 64 / 80	0.80 / 0.65 / 0.50 / 0.40	12.0	0.10	0.60
12 × 12	80	0.50	14.0	0.10	0.60
14 × 14	64 / 80 / 100 / 128	0.80 / 0.65 / 0.50 / 0.40	16.0	0.10	0.60
20 × 20	128 / 144 / 176	0.50 / 0.50 / 0.40	22.0	0.10	0.60
24 × 24	160 / 176 / 216	0.50 / 0.50 / 0.40	26.0	0.10	0.60
28 × 28	208 / 256	0.50 / 0.40	30.0	0.10	0.60

Table 1. Body size, lead count, lead span, standoff, and foot length from Amkor data sheet DS232G. Body thickness is 1.40 mm on every row. Pitch is derived from lead count per side and body edge, not quoted by the source.

The useful reading is diagonal. A 64-lead device exists at 0.40 mm pitch in a 7 × 7 mm body, 0.50 mm in a 10 × 10 mm body, and 0.80 mm in a 14 × 14 mm body. Each step up in body size buys process margin. If the board has 49 mm² to spare, spending it on the 10 × 10 mm variant removes an entire class of bridging defects.

Body size also drives shipping quantity, which matters when you are planning line changeovers or a first build. Amkor ships the 7 × 7 mm bodies in a 10 × 25 tray matrix at 250 units per tray, the 14 × 14 mm bodies at 90, and the 28 × 28 mm bodies at 36. A 176-lead device in a 24 × 24 mm body arrives 40 to a tray, so a 5,000-piece build is 125 trays of handling.

LQFP vs TQFP, QFN, and BGA

Attribute	LQFP	TQFP	QFN	BGA
Termination	Gull-wing leads, 4 sides	Gull-wing leads, 4 sides	Bottom lands, no leads	Solder balls, area array
Standard outline	JEDEC MS-026	JEDEC MS-026 (thin variants)	JEDEC MO-220	Device-specific
Body thickness	1.40 mm	1.00 mm typical	Sub-1 mm typical	Varies
Pitch range	0.40–0.80 mm	0.40–0.80 mm	0.40–0.65 mm typical	0.40–1.00 mm
Joint inspection	Visible fillet, AOI	Visible fillet, AOI	X-ray required	X-ray only
Rework	Hot air, lead by lead	Hot air, lead by lead	Full reball or replace	Full reball
Cyclic strain	Lead absorbs ≥25%	Lead absorbs ≥25%	Low standoff raises strain	Ball height dependent
Main thermal path	Leads, or exposed pad	Leads, or exposed pad	Exposed pad to board	Balls and vias

Table 2. Package comparison. Cyclic-strain entries reflect published finite-element work on gull-wing versus leadless terminations, cited below.

The decision path is short:

1. Enclosure clearance under about 2 mm above the board, and joints that have to be inspectable optically: LQFP.
2. More than 256 I/O, or an I/O density that peripheral leads cannot reach: BGA. LQFP has no path there.
3. Sustained dissipation above roughly 1.5 W: an exposed-pad LQFP or a QFN, not a plain LQFP. [INTERNAL LINK: exposed-pad LQFP construction → HLQFP package article]
4. High vibration, wide temperature excursions, field repair, or low build volume: LQFP, and take the larger body if the layout allows it.

That last row is why the package refuses to disappear. Amkor lists its LQFP line as the target package for ASICs, power management controllers, microprocessors, gate arrays including FPGA and PLD devices, and chipsets. Peripheral leads cap the I/O count, but everything below that cap gets a joint an operator can see, probe, and repair.

Thermal Data and the Power Budget It Buys

Most pages on this package describe its thermal behavior qualitatively. Table 3 gives measured numbers on JEDEC test boards, at three air velocities, for both single-layer and multilayer boards.

Package	1-layer, 0 LFPM	1-layer, 200	1-layer, 500	Multi, 0 LFPM	Multi, 200	Multi, 500
32-lead, 7 × 7 mm	67.8	55.9	50.1	47.9	42.1	39.4
100-lead, 14 × 14 mm	41.5	33.4	29.5	31.7	26.8	24.7
144-lead, 20 × 20 mm	38.0	31.2	28.1	31.7	26.9	24.9
176-lead, 24 × 24 mm	38.3	31.9	29.0	31.9	27.3	25.4
208-lead, 28 × 28 mm	not published	—	—	18.1	15.3	14.4

Table 3. θJA in °C/W by airflow, from Amkor data sheet DS232G. The 208-lead row was measured on pre-JEDEC boards at 1 W.

Run the numbers for a 100-lead, 14 × 14 mm device with a 125 °C maximum junction temperature in an 85 °C ambient, so ΔT = 40 K. On a single-layer board in still air, 40 / 41.5 gives 0.96 W. Move it to a multilayer board and 40 / 31.7 gives 1.26 W. Add 200 LFPM to the multilayer board and it reaches 1.49 W.

Note which lever is stronger. Board copper cut θJA by 24 percent in still air; the first 200 LFPM of airflow on the single-layer board cut it by 20 percent. Copper is free at layout time and does not depend on a fan surviving five years in the field.

Amkor also publishes simulated lead parasitics at 100 MHz, which almost nobody quotes. On the 32-lead 7 × 7 mm body the longest lead is 0.904 nH and 9.2 mΩ. On the 176-lead 24 × 24 mm body it is 9.51 nH, 89.0 mΩ, and 1.27 pF. A 100 mA edge with a 1 ns transition through 9.5 nH develops about 0.95 V of bounce, which is the arithmetic reason a large LQFP needs decoupling on every side rather than one bulk capacitor at a corner.

[IMAGE 2: chart of θJA versus airflow for 32, 100, 144, 176, and 208-lead LQFP bodies on single-layer and multilayer boards | alt: “LQFP package thermal resistance chart by lead count and airflow”]

The Land Pattern and Stencil Numbers That Decide Yield

IPC-7351B sets solder fillet goals for gull-wing terminations at three density levels. Toe extension is 0.55 / 0.35 / 0.15 mm for Level A, B, and C. Heel is 0.45 / 0.35 / 0.25 mm. Side is 0.05 / 0.03 / 0.01 mm. Courtyard excess is 0.5 / 0.25 / 0.1 mm per side.

Apply Level B to the 64-lead, 10 × 10 mm, 0.5 mm pitch part dimensioned above, using maximum lead width 0.27 mm, maximum foot 0.75 mm, and a 0.05 mm fabrication allowance:

• Pad width = 0.27 + (2 × 0.03) + 0.05 = 0.38 mm
• Pad length = 0.75 + 0.35 toe + 0.35 heel + 0.05 = 1.50 mm
• Pad centers sit 5.25 mm from the package center on each axis

That leaves 0.50 − 0.38 = 0.12 mm of copper between neighbouring pads. Most fabricators will not hold a solder-mask dam below 0.15 mm, so specify non-solder-mask-defined lands and let stencil design control bridging. If a mask dam is mandatory for your process, drop the side fillet to Level C, which narrows the pad to 0.34 mm and opens the gap to 0.16 mm.

Stencil design then has to clear two IPC-7525 thresholds: area ratio ≥ 0.66 and aspect ratio ≥ 1.5. A 0.28 × 1.35 mm aperture in 0.12 mm foil gives an area ratio of (0.28 × 1.35) / (2 × (0.28 + 1.35) × 0.12) = 0.97 and an aspect ratio of 2.3. Both pass comfortably. Step the same aperture up to 0.15 mm foil and the ratio falls to 0.77, still legal, but the extra paste volume is exactly where 0.4 mm pitch parts start bridging.

What Actually Fails

Coplanarity out of spec. The limit is 0.08 mm across all leads. Past that, corner leads sit above the paste and open. Loose parts stacked outside their CO-124 trays are the usual cause. Reject bent-lead parts rather than re-forming 0.4 mm pitch leads by hand.

Popcorning after a floor-life breach. Amkor characterizes its commercial LQFP line to moisture sensitivity level 3, with a 30 °C / 60% RH, 192-hour soak. Lead-free peak reflow lands between 245 °C and 260 °C for SAC305 alloys, which is more than enough to flash absorbed moisture into delamination.

Thermal fatigue at the outer leads. A typical QFP has an in-plane CTE near 11 ppm/K against roughly 14 ppm/K for the board. Finite-element work on a 176-lead, 24 mm package with 0.2 × 0.22 mm² copper leads found that at least 25 percent of the deformation from each temperature cycle is absorbed by elastic bending of the lead itself. That compliance is why daisy-chained LQFP64 assemblies cycled between −40 °C and +125 °C ran past 3,500 cycles without significant failures.

Solder wicking into a via. A via inside or touching a land drains paste during reflow and starves the heel fillet. Move vias outside the courtyard, or fill and cap them.

Sourcing, Second Sources, and Counterfeits

LQFP remains the most widely stocked package for mid-range microcontrollers, and it is cheap. LCSC lists the STM32F103RCT6 in LQFP64 from about $1.50 at the time of writing.

Do not assume the same die in a different package is a drop-in. An LQFP land pattern is driven by the 12.00 mm lead span of a 10 × 10 mm body; the QFN version of the same die is driven by the body outline. They are different footprints, and dual-footprint layouts cost more in courtyard area than they save in flexibility.

For automotive work, note that standard LQFP assembly lines carry AEC-Q100 qualification, along with temperature cycling from −65 °C to +150 °C for 500 cycles and 1,000-hour high-temperature storage at 150 °C. Ask for the package qualification report, not just the device one.

Materials are worth one line on the purchase order. Standard LQFP construction uses Pb-free, RoHS-compliant materials, with copper, silver, or gold bond wire depending on the assembly house and the device. Wire metallurgy is invisible on the outside and is not always stated on a distributor page, so if the product sees sustained high junction temperatures, ask the supplier which one it is before qualifying a second source.

On counterfeit screening, three checks catch most reworked parts: marking method, since production parts are laser marked rather than ink printed; lead finish, which should be matte tin or a pre-plated Ni/Pd frame with no re-tinned meniscus; and coplanarity measured on incoming samples against the 0.08 mm limit. Date codes that disagree with tray labels are the fourth.

Frequently Asked Questions

What does LQFP stand for?

LQFP stands for low-profile quad flat package. “Quad flat” describes leads on all four sides of a flat plastic body; “low profile” describes the JEDEC height class, which for this outline means a 1.40 mm body and a 1.60 mm maximum seated height. The registered outline is MS-026.

What is the difference between LQFP and TQFP?

Body thickness. LQFP bodies are 1.40 mm; TQFP bodies are typically 1.00 mm. Both are registered under the same JEDEC outline, MS-026, and both use gull-wing leads at the same pitches, so a given lead count and body size shares a land pattern. Check the drawing before assuming heights are interchangeable.

What pitch does an LQFP package use?

Four pitches are standard: 0.80, 0.65, 0.50, and 0.40 mm. Pitch is set by lead count and body size together. A 64-lead device appears at 0.40 mm in a 7 × 7 mm body, 0.50 mm in a 10 × 10 mm body, and 0.80 mm in a 14 × 14 mm body.

Can you hand-solder an LQFP?

At 0.65 mm and 0.80 mm pitch, yes, with flux, a fine tip, and drag soldering. At 0.50 mm it is possible but slow. At 0.40 mm, use paste, a stencil, and hot air or a reflow oven. Hand rework at 0.40 mm damages leads more often than it fixes joints.

How much power can an LQFP dissipate?

Around 1 W for a mid-size body without help. A 100-lead, 14 × 14 mm package on a multilayer board in still air has a θJA near 31.7 °C/W, which allows 1.26 W for a 40 K junction-to-ambient rise. Beyond about 1.5 W, move to an exposed-pad variant.

What to Specify

Default to the largest body your layout can absorb at the lowest pitch that meets the pin count, and stop there. A 0.5 mm pitch part in a 10 × 10 mm body is a routine build for any contract manufacturer; a 0.4 mm pitch part in a 7 × 7 mm body needs solder paste inspection, a controlled stencil, and a conversation with the assembly house before you release Gerbers.

Take a multilayer board with copper under the package if you need more than 1 W, and only then consider airflow. Above 1.5 W sustained, stop specifying plain LQFP and move to an exposed-pad variant. If the design needs more than 256 I/O, or the enclosure gives you less than 2 mm above the board, LQFP is the wrong family and the decision moves to BGA or a thinner package class.

One last rule: put the coplanarity limit, the moisture sensitivity level, and the tray or reel format on the purchasing specification. Those three lines prevent more field failures than any layout change you can make afterwards.