PLCC

Q:What defines the physical structure of PLCC?

A:Key features include:
- J-lead design: Gull-wing leads bent inward for surface mounting
- Central cavity: Accommodates IC die with epoxy encapsulation
- Pin layout: 20 to 84 pins arranged in perimeter rows (standard: 32/44/68-pin)
- Body thickness: 3.5–4.0 mm robust plastic housing

Q:Why choose PLCC over alternatives?

A:Critical advantages:
- Space efficiency: 30% denser than DIP packages in PCB area
- Mechanical durability: J-leads absorb thermal stress better than QFP leads
- Electrical isolation: Plastic body reduces crosstalk vs. ceramic carriers
- Reliability: UL94 V-0 flame-retardant material

Q:What are common technical specs?

A:Standard configurations (consult datasheets):
- Body size: 9.0×9.0 mm to 28.0×28.0 mm (e.g., 16×16 mm for 44-pin)
- Pin pitch: 1.27 mm (uniform across all variants)
- Material: Plastic composite with copper-alloy leads
- Temp range: -40°C to +85°C (industrial grade)

Q:Where is PLCC typically applied?

A:Dominant use cases:
- Legacy embedded systems: BIOS chips (e.g., Intel 28F010)
- Telecom interfaces: ISDN/ADSL modules (e.g., Motorola MC145572)
- Industrial controls: PLCs and sensor hubs (e.g., TI MSP430 variants)

Q:What are critical assembly guidelines?

A:Key recommendations:
- PCB design: 0.2 mm clearance for J-lead soldering
- Solder paste: Type 3 (particle size 25–45 μm) for reliable fillets
- Reflow profile: Ramp rate ≤2°C/s, peak 235°C (SnPb) or 250°C (Pb-free)
- Inspection: Optical post-reflow for lead coplanarity checks