TQFP vs LQFP: What is the Difference Between Packages

When working with a PCB design or editing software, you may notice that the LQFP and TQFP have the same footprint.

This means that they both have the same size. After all, they are both quad-flat packages. However, the TQFP has shorter leads than the LQFP.

Why? TQFP vs. LQFP – How are they different, and are these the only differences? The following guide hopes to answer these questions.

Thu will allow you to identify which IC package you should use in your next PCB project.

What is a TQFP?

TQFP housing electronic components

TQFP housing electronic components

The TQFP(thin quad flat pack ) is a low-profile version of the regular quad flat package. Regular QFPs may display up to 4.0 mm of thickness.

Inversely, TQFP packages can have a maximum thickness of 1.4 mm. TQFPs lend themselves well when trying to reduce the overall thickness of your PCB so you can make it more portable.

What is an LQFP?

Simple LQFP IC 

Simple LQFP IC 

As its name implies, the LQFP (low-profile quad flat ) is a low-profile quad version of the regular quad flat package. Both it and the TQFP are surface-mounted packages.

However, one of the key differences is that the LQFP has gull-wing leads that extend from each of its four sides. Nevertheless, they both have a maximum thickness of 1.4 mm.

TQFP vs. LQFP: The Differences

A stack of two IC packages 

A stack of two IC packages 

This section will explore the specifications of each and identify a few more differences.

TQFP Specifications

  • Lead Count Range: 32 to 176
  • Body Size Range: 5 mm x 5 mm to 20 mm x 20 mm
  • Maximum Package Height: 1.4 mm
  • Lead Frame Types: Copper Lead Frames
  • Available Lead Pitches: 0.4 mm, 0.5 mm, 0.65 mm,  0.8 mm, 1.0 mm

TQFP Applications

Blue Transparent Image of TQFP

Blue Transparent Image of TQFP

QFN vs QFP

Although this guide’s main focus is comparing QF packages (TQFP vs LQFP), it’s also important to understand how they differ from Quad Flat No-Leads (QFNs).

QFPs and QFNs use four-sided surface mount technology (SMT) (hence the name quad).

Where these packages differ is in their lead configuration.

QFP pins protrude outward, whereas QFNs don’t have any visible exposed pins. They (QFNs) connect to circuit boards using their exposed pads. 

Because of their lack of pins, QFNs are typically smaller than QFPs. Consequently, designers and fabricators favor QFN packages for smaller PCBs with limited space.

QFP-24 Chip 3D X-Ray Blue Transparent

QFP-24 Chip 3D X-Ray Blue Transparent

How Does a Thin Quad Flat Package (TQFP) Work?

The TQF package is a slim, low-profile QFP sub-type. As with any other integrated circuit (IC) package, it houses, protects and connects a die to a larger circuit board.

What makes the TQFP different is that it is thinner than the Metric Quad Flat Pack (MQFP) and a Low Profile Quad Flat Pack.

Consequently, TFQPs are ideal for compact applications such as single-board computers and microcontrollers.   

What Industry Problems Does the TQF Package Address?

TQF packages address two main problems in the electronics industry: die shrinking and space limitations.

A die shrink is a process that involves scaling down the size of a semiconductor while maintaining its functionality. 

A smaller die must have a package that can accommodate its size. TQF packages can house and encase these smaller semiconductors because of their compact size.

Moreover, because TQF packages have low profiles, they’re portable, and device manufacturers can use them in condensed designs.       

Benefits of the TQF Package

The main purpose of die shrinks is to reduce overall production/fabrication costs. This is also one of the benefits of the TQFP.

Because it is smaller, it requires less material to fabricate. Moreover, this makes it more environmentally friendly.

Most fabricators use green materials to develop and manufacture their TQFPs. You can ensure your TQFPs meet green standards by sourcing them from an ROHS-compliant manufacturer. 

Despite their compactness, TQFPs are highly reliable. Their lead counts range from 32 to 176, which affords them excellent mechanical reliability when soldered and connected correctly. 

What are the TQF Package’s Limitations?

While the TQFP comes with many benefits, they do have one main limitation. They have smaller pitch sizes because they are smaller and have relatively higher pin counts. This means they sit closer to each other. 

The pin lengths are also shorter. They can often be fragile or easily damaged, especially if you mishandle them.

Thus, manufacturers and technicians must store them accordingly. Using a pick-and-place machine, you can automate and reduce errors during the packaging and storage process.

The TQFP’s high pin count and smaller pin size make it harder to connect and solder. They are also highly susceptible to solder bridges.

As such, you must pay special attention during the soldering and connection process.

Closeup Silicon Die Being Extracted Semiconductor

Closeup Silicon Die Being Extracted Semiconductor

Benefits of TQFP’s Surface Mount Technology (SMT)

As we previously mentioned, TQFPs use surface mount technology (SMT). This affords them improved electromagnetic compatibility (EMC), which refers to how well electronic components and devices can function in close proximity. 

How does TQFP Integrate Limited Spacing with More Pin Mounts?

One way to address the spacing limitations of the TQFP is by using a gate array. A good example of this is the TQFP Field Programmable Gate Array (FPGA).

Gate Array packages can help manufacturers increase the pin count as well as ensure more reliable and stable connections.    

What is the Difference between TQFP and SOIC?

While both the TQFP and SOIC packages sport gull-wing-shaped pins, the SOIC package’s leads sit on only two of its sides, the leads are usually positioned on opposite ends. 

This contrasts the TQFP package, whose pins/leads are on all four sides.

Circuit Board Stock

Circuit Board Stock

What are the Different Types of QFPs?

In addition to TQFPs and LQFPs, other QFPs types include:

  • Bumpered Quad Flat Package (BQFP)
  • Bumpered Quad Flat Package with heat Spreader (BQFPH)
  • Ceramic Quad Flat Package (CQFP)
  • Plastic Enhanced Quad Flat Package (EQFP)
  • Fine Pitch Quad Flat Package (FQFP)
  • Metric Quad Flat Package (MQFP)
  • Near Chip-Scale Quad Flat Package (NCQFP)
  • Small Quad Flat Package (SQFP)
  • Very Small Quad Flat Package (VQFP)
  • Very Thin Quad Flat Package (VTQFP)
  • Thin dual Flat No-Lead Package (TDFN)

What are The Costs Associated with TQFPs?

Manufacturing a single TQFP can cost as much as $5 on average. However, this depends on numerous factors. For instance, the pin count. The more leads a TQFP has, the more expensive it is.

Furthermore, different manufacturers and assembly houses charge different prices. American assembly houses typically charge more than their Chinese counterparts.

You’ll also have to consider other costs, such as packaging and shipment. 

TQFP vs LQFP: Conclusion

Both packages are similar in that manufacturers use them in cost-conscious applications. LQFP can have higher lead counts, and its leads are longer.

This makes it easier to mount than TQFP. Nevertheless, we can use both packages in similar applications as they are both low-profile.

TQFPs are more available in smaller packages, while LQFPs are easier to attach to your PCB. 

Additionally, you can purchase them in different die types. They usually share the same moisture level (JEDEC Level 3).

Ultimately, the distinctions between these two packages are so subtle that it barely makes a difference which one you choose.

Nevertheless, please contact us if you have any PCB fabrication inquiries and want to learn more about these topics. 

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Emma Lu
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