A BQFP (Bumpered Quad Flat Package) is a plastic quad flat package with small protective tabs — bumpers — molded at its four corners. The bumpers hold the fine gull-wing leads off the work surface so they survive handling before reflow. It is a high-pin-count package from the late 1980s and 1990s, now effectively obsolete: for new designs you specify LQFP, TQFP, or a BGA instead. Here is what it is, why the bumpers exist, and what to migrate to.
| Legacy-package cautionBQFP was registered by JEDEC in many body sizes and lead counts. Dimensions below are representative ranges for the family, not one part. If you are maintaining or reworking a board that uses one, pull the exact outline from that device’s datasheet. |
Key takeaways
- The corner bumpers are the whole point: they protect coplanarity of the leads during shipping and pick-and-place, before the joints are formed.
- BQFP is a QFP variant — gull-wing leads on all four sides, high pin count, molded plastic body.
- Pitch and pins: Typical lead pitch is 0.025 in (0.635 mm); some families used 0.8 mm. Lead counts commonly ran from ~84 to 244.
- It is a legacy part. Prefer LQFP / TQFP / PQFP or BGA for anything new; keep BQFP only for repair and second-source of existing hardware.
- The bumpers add corner footprint, so a BQFP land occupies more board area than a same-pin-count LQFP.
What the bumper actually does
The leads on a high-pin-count QFP are thin and closely spaced. Bend or lift one and the part will not sit flat, which shows up as an open joint after reflow. The failure is coplanarity: if the feet do not all touch the pads within tolerance, solder cannot bridge the gap on the high ones.
The bumper is a molded plastic standoff at each of the four corners, projecting slightly beyond the lead tips. When the package rests on a tray, a rail, or a nozzle’s staging surface, the bumpers take the load, not the leads. That preserves lead coplanarity from the molding line through shipping to placement.
Once the part is soldered, the bumpers do nothing electrical or thermal. They are pure mechanical insurance for the pre-assembly life of the device. That is also why the concept faded: thinner packages (TQFP, LQFP) and carrier-tape handling reduced the damage risk, and bumpers cost board area.
[IMAGE 1: top view of a BQFP showing gull-wing leads on four sides with molded bumpers at the corners projecting past the lead tips | alt: “Bumpered Quad Flat Package BQFP top view with corner bumpers protecting the leads”]
BQFP dimensions and construction
Because the family spans many JEDEC outlines, treat the table as typical ranges, not a single datasheet. The defining geometry is the corner bumper plus four-sided gull-wing leads.
| Attribute | Typical for the BQFP family |
| Body | Molded plastic (thermoset/thermoplastic), square |
| Leads | Gull-wing, all four sides |
| Lead pitch | 0.025 in (0.635 mm); some at 0.8 mm |
| Lead count | Commonly ~84 to 244 |
| Corner feature | Four molded bumpers projecting past the lead tips |
| Overall height | Taller than TQFP/LQFP; varies by outline |
| Mounting | Surface mount, reflow |
Ranges reflect the JEDEC BQFP family across body sizes. Exact D, E, pitch, and height come from the device’s own mechanical drawing.
BQFP vs the packages that replaced it
If you are choosing a quad flat package today, or deciding what to substitute for an obsolete BQFP, this is the comparison that matters. Values are typical for each family, not specific parts.
| Package | Pitch (typ) | Corner bumper | Position today |
| BQFP | 0.635 mm | Yes | Legacy — repair/second-source only |
| PQFP | 0.635 mm | No | Legacy, still found in industrial parts |
| TQFP | 0.4–0.8 mm | No | Active — thin profile, general use |
| LQFP | 0.4–0.8 mm | No | Active — the default fine-pitch QFP |
| BGA | 0.5–1.0 mm | No | Active — highest pin density |
PQFP = Plastic QFP; TQFP = Thin QFP; LQFP = Low-profile QFP. Pitches are family-typical.
The migration logic is simple. A BQFP and a same-pin-count LQFP carry the same net list; the LQFP is thinner, has no bumpers, and fits a smaller land. If the original board’s mechanical drawing allowed for the bumper keep-outs, dropping in an LQFP frees that corner area. Confirm the pinout maps one-to-one before you assume a straight swap.
Working with a BQFP on an existing board
Sourcing. New BQFP silicon is rare. Expect to buy from brokers or old stock, which raises the counterfeit risk. Verify date codes, check top-mark laser quality, and X-ray a sample for the correct lead frame before committing a build.
Moisture sensitivity. Plastic QFPs carry an MSL rating per JEDEC J-STD-020. Old stock may have exceeded its floor life, so bake per the device’s MSL before reflow or you risk popcorning the package.
Rework. The bumpers make the part sit higher, which helps hot-air rework nozzles clear the leads. Reflow to the datasheet’s classification temperature, and re-check coplanarity on any part you have handled loose — that is exactly the damage the bumper was meant to prevent.
Frequently asked questions
What does BQFP stand for?
BQFP stands for Bumpered Quad Flat Package. It is a plastic, surface-mount quad flat package with gull-wing leads on all four sides and small molded bumpers at the four corners that protect the leads from damage before the part is soldered down.
Why does a BQFP have bumpers?
The bumpers act as corner standoffs. They keep the fine gull-wing leads from touching trays, rails, or nozzles during shipping and pick-and-place, preserving lead coplanarity. Poor coplanarity is a leading cause of open joints on high-pin-count QFPs, and the bumper reduces that risk.
Is BQFP the same as PQFP?
They are close relatives. Both are plastic quad flat packages with four-sided gull-wing leads. The difference is the bumper: a BQFP has molded corner bumpers, a plain PQFP does not. Otherwise their pitch and lead-count ranges overlap heavily.
Can I replace a BQFP with an LQFP?
Often yes, if a same-pin-count LQFP exists with a matching pinout. The LQFP is thinner and has no bumpers, so it needs a smaller land and less corner clearance. Confirm the pin assignment maps one-to-one and re-lay the footprint; do not reuse the BQFP land as-is.
Is BQFP still used in new designs?
Rarely. It is a legacy package kept alive mainly for repair and second-sourcing of 1990s-era hardware. New designs use LQFP, TQFP, or BGA, which are thinner, denser, and better supported by current parts and assembly lines.
What to do next
If you are designing something new, do not specify BQFP; choose an LQFP or TQFP for fine-pitch quad flat needs, or a BGA when pin density is the constraint. If you are maintaining a board that already carries a BQFP, buy from verified stock, bake to the MSL rating, respect the corner bumper keep-outs on the existing footprint, and re-check lead coplanarity on every hand-handled part before reflow.
