BASICS

of
Miniature Packaging
Gene Heftman, Contributing Editor
Design
he packaging of electronic devices is an evolving art driven by
the requirements of smaller, lighter, portable, battery-powered
products, such as cell phones, PDAs, notebook computers, CD-
ROM players, and so forth. With space at a premium to accom-
modate the myriad of electronic devices, component manufactur-
ers are developing miniature packages that occupy minimal area
while maximizing the integration of functions.

A second trend involves reducing the power demands of portable electronics,

enabling longer operational time while running off battery power. The result is
lower-consumption power devices in smaller packages, coupled with an abili-
ty to transfer the heat generated internally away from the package to improve
performance and reliability. A third trend—long underway—is the replace-
ment of through-hole packaging with surface-mount packaging. This allows
for smaller devices, as well as reduces pc-board area and optimizes the board-
trace routing.

Logic Packaging—PicoGate Logic

A
What They Are
A family of miniature surface-mount logic functions for 5-V and lower voltage systems
Much smaller than conventional SO14 package (Fig. 1)
5-, 6-, and 8-pin packages (Fig. 2)
5-pin: SOT353/753, 6-pin: SOT363/457, 8-pin: SOT 765/505-2
Functions available: Single-, dual-, and triple-gate functions
Typical single-gate functions: NAND, NOR, Inverter, buffer, Schmitt Trigger, D-type flip flop, etc.

A Supplement to Electronic Design/December 18, 2003 Sponsored by Philips Semiconductors

Typical dual-gate functions: Similar to single-
gate except two functions in a package (i.e., two SO14 package
NOR gates, two inverters, two buffers, etc.).
Area:
Typical triple-gate functions: three functions in 54 mm 2 Miniature logic package
a package (i.e., three inverters, three buffers). Area: 4.8 mm 2
Logic families available: High-speed CMOS 0.65
(HC/T), Advanced high-speed CMOS (AHC/T),
2.2 mm
Low-voltage CMOS (LVC).
10 times smaller 2.2 mm
Figure 1 than SO14

Where They’re Used Miniature package options

5-pin 6-pin 8-pin 5-pin 6-pin 8-pin

All portable, battery-powered products with

space constraints—cell phones, pagers, CD Single
gate
players, PDAs, notebook computers, and other SOT353 SOT765 SOT753 SOT505-2
electronics that must conserve space (CD-
ROM players, hard-disk drives, and VCRs).
Dual
gate
SOT363 SOT457
SOT765 SOT505-2

Why They’re Needed Triple

gate

Space Savings: To accommodate small pc boards SOT765 SOT505-2

in portable, battery-powered equipment. 3mm 3mm
Time-to-Market Pressures: To prevent costly
modifications to ASICs by permitting simple Figure 2
changes to designs. This is accomplished by
implementing ASIC functions from the original
design that were either omitted or included to enhance product features.
Cost-effectiveness: To simplify pc-board layouts and wiring by allowing logic
functions to be packed densely in the most effective locations, thereby reducing
circuit delays.

Sponsored by Philips Semiconductors

BASICS
of
Miniature Packaging
Design

Logic Packaging— DQFN Logic Packages

B What They Are
Evolution of IC packages

Family of miniature surface-mount logic functions for more complex logic

functions than those in gate-level packages. Increased functionality while DIL
minimizing package size. Packaged in the depopulated very thin quad flat- SO
pack no-leads package (DQFN). Significantly smaller than the conventional SSOP
thin shrink small outline package (TSSOP) (Fig. 3). TSSOP
14-, 16-, 20-, and 24-pin packages. 14-pin package measures 2.5 x 3 mm. Figure 3 DQFN
Package Features: Leadless with solder pads on the bottom surface of the
package. Elimination of perimeter leads reduces the footprint. An exposed
die paddle on the bottom of the package allows for more effective heat
removal from the package than a TSSOP (Fig. 4).
Functions available: Standard logic gates and octal buffer/line drivers, hex
inverter. Schmitt trigger, quad 2-input multiplexer, decoder/demultiplexers,
D flip-flops.
Logic families available: HC/HCT, AHC/AHCT and LVC (low-voltage CMOS).
Figure 4

Where They’re Used

Same applications as for miniature logic, where more complex logic functions and higher gate counts are required. Also
used in automotive electronics market.

Why They’re Needed DQFN-14 compared to PicoPkg-5/8 and MicroPkg-5/8 and TSSOP-14
0.65-mm pitch

Space savings: Over 70% smaller than conven- Lead area

Lead area
tional TSSOP packages. Lead-free design per- Lead area
Lead area
Lead area 5.0 mm
6.4 mm
mits easier assembly on boards because of no 2.0 mm
2.0 mm

3.1 mm 2.5 mm
3.0 mm 2.9 mm
2.8 mm 3 mm
4.0 mm = 32 mm2
= 6.2 mm2 = 7.5 mm2 = 8.12 mm2 = 12.0 mm2
bent leads and co-planarity considerations = 4.2 mm2
Lead area Lead area
(Fig. 5). PicoPkg-5 Lead area DQFN-14
MicroPkg-5 Lead area
PicoPkg-8
Time-to-Market: Same as for gate-level pack- MicroPkg-8 Lead area

ages. 0.5-mm pitch 0.95-mm pitch TSSOP-14

Cost-effectiveness: Same as for gate-level

Figure 5
packages.

1218BASICSco.txt/Figure 5

Sponsored by Philips Semiconductors

 Digital packaging: MCUs

C What They Are

Figure 6

16/32-bit ARM7 MCUs packaged in chip-scale HVQFN (heatsink very thin

quad flat pack) package that can be 48 or 64 pins (Fig.6), depending on
the MCU’s functionality. Devices contain embedded flash and SRAM
memory, memory map and interrupt structure, and peripherals like
timers, UART, SPI bus, Ethernet USB, and others, depending on the model.

Where They’re Used

Point-of-sale terminals, set-top boxes, security systems, medical equipment, embedded systems, vending
machines.

Why They’re Needed

Space savings, greater integration, and cost effectiveness. They replace much larger MCU packages used in
equipment.

Power Packaging: Low Saturation-Voltage

D Bipolar Transistors
Figure 7
What They Are
Family of miniature, surface-mount, bipolar power
transistors possessing very low collector-to-emitter
saturation voltage (VCE(SAT)) and collector-to-emitter
saturation resistance (RCE(SAT)).
Package Features: Supplied in much smaller packages
(SOT666 (Fig. 7), SOT490, SOT883, SOT23….) than con-
ventional (SOT223) power transistors.
Package Dimensions: SOT666: 1.6 x 1.2 x 0.55 mm Why They’re Needed
(length x width x height), SOT490: 1.6 x 0.8 x 0.7 mm,
SOT23: 2.9 x 1.3 x 1.0 mm, SOT223: 6.5 x 3.5 x 1.65 mm. Space saving: Miniature packages replace larger pack-
ages, saving pc-board area and requiring less cooling.
Lead area Types available: Bipolar transistors handle up to 5 A,
depending on package size. Collector current (IC) in Efficiency: Low VCE(SAT) and RCE(SAT) means less power dissi-
5.0 mm
6.4 mm
= 32 mm2 SOT666, SOT23, and SOT223 is 2, 3, and 5 A, respectively. pation in the package. Collector-to-emitter voltage is
low when turned on. Circuit runs cooler, requires less
heatsinking, and makes for a smaller, lighter design.
Lead area
Where They’re Used Greater efficiency also results in longer battery life in
TSSOP-14 DC-DC converters, supply-line switching, LCD back- portable products.
lighting in mobile phones and notebook computers, LED Cost: Bipolar transistors in miniature packages are less
driving, relay and buzzer driving. expensive than MOSFETs and provide equivalent per-
formance.
 Power Packaging: LFPAK and
QLPAK MOSFET Transistors
E
What They Are Figure 8

Reduced-size power packages that replace the industry-

standard S08 with improved thermal and electrical charac-
teristics (Fig. 8). A single LFPAK can replace two SO8s,
cutting board space in power-supply designs. Next step in
the evolution of industry-standard DPAK and D2 PAK
power packages that offer smaller size with equivalent
power-handling capability. Power MOSFET devices are
used that have drain-to-source voltages (VDS) ranging
from 20 to 200 V and on-resistance (RDS(ON)) values below
20 mΩ, depending on voltage rating (Fig. 9).
Figure 9
Where They’re Used
DC-DC converters, other power-supply designs in
telecommunications, mobile equipment, and computing.

Why They’re Needed

To increase efficiency in DC-DC converter designs, the
thermal and electrical performance of the transistors must
be improved. Thermal limitations of the SO8 package are a
problem because of its internal construction. In an SO8
package, the power MOSFET is completely surrounded by
the plastic mold compound of the package, which is a poor
thermal conductor. The only thermal path to the circuit
LFPAK and SO8 internal structures
board is through the package’s source leads (gold wires) Gold wires Chip
SO8
(Fig. 10). Two improvements in the LFPAK lead to much
better thermal performance. One is the relatively large
copper plate that replaces the SO8’s gold leads and con-
ducts heat away from the chip more effectively. The sec-
ond is the metal mounting base (leadframe), which makes Lead frame Plastic
a lower thermal resistance path (better heat conduction) Zero-resistance source contact Chip
than the SO8’s plastic package out to pc board. LFPAK

Plastic
Electrical performance is improved because a lower RDS(ON)
results from using a copper-plate source lead instead of
gold wires. Lower RDS(ON) means less power is dissipated in Two-part lead frame
the MOSFET, so the power supply is more efficient. Lead
inductance is also reduced, making the LFPAK a better Figure 10
choice in DC-DC converters that operate at high frequen-
cies (hundreds of kilohertz).

For additional copies, go to www.semiconductors.philips.com

Document # 9397 750 12193
BASICS
of
Miniature Packaging
Design
 16/32-BIT FLASH
MICROCONTROLLERS

Big performance. Small package.

Why not see for yourself with

a free sample?

Visit www.philips.com/LPC2100
or call 1-800- 447-1500, ext. 2818.

Available in both
HVQFN64 and LQFP64

The Philips LPC2100 family of 16/32-bit ARM7TDMI-S TM Flash microcontrollers

can help you with your application challenges by providing you with:

• The industry’s highest-performance embedded Flash memory

- 128/256KB of high-performance Flash
- 60 MHz code execution from either Flash or RAM, no dynamic loading necessary
- JTAG in-system programming and in-application programming via serial ports

• Ultra-low power operation up to 60 MHz

- 1.8V process technology offers leading-edge 1 mW/MHz operating power

• Miniature 64-pin packages

- Both LPC2124 and LPC2114 are available in LQFP64 and HVQFN64

When a portfolio gives you this much design freedom, it’s more than a part of
your product, it’s living technology. And it’s only from Philips.

© Koninklijke Philips Electronics N.V., 2003. All rights reser ved.

 DQFN & PICOGATE LOGIC

Big portfolio. Small packages.

Why not see for yourself with

a free evaluation package?

Visit www.philips.com/lvlogic
or call 1-800- 447-1500, ext. 2820.

The Philips family of Logic devices can help with your application challenges by providing
you with:

• An ultra-small DQFN footprint

- DQFN is the world’s smallest package on the market for gates, octals and MSI functions.

• An ultra-small PicoGate footprint

- PicoGate is about 10x smaller than the conventional SO14 package.

• A diverse portfolio of choices

- DQFN and PicoGate in 5V, 3.3V and 1.8V technologies.

When a portfolio gives you this much design freedom, it’s more than a part of your product,
it’s living technology. And it’s only from Philips.

Actual Size

© Koninklijke Philips Electronics N.V., 2003. All rights reser ved.

 LOW VCEsat BISS TRANSISTORS
AND LOW VF MEGA SCHOTTKY
BARRIER RECTIFIERS

Best-in-class performance.
Highest efficiency in ultra-small packages.

Why not see for yourself with

a free product launch pack?

Visit www.philips.com/BISS-MEGA
or call 1-800- 447-1500, ext. 2819.

The Philips family of Low VCEsat BISS transistors and Low VF MEGA Schottky
barrier rectifiers provide you with industry-leading performance because they feature:

• High Current Capability

- Collector current of 2 A for PBSS5240V (transistor)
- Forward current of 2 A for PMEG1020EV (rectifier)

• High Application Efficiency

- Low collector emitter saturation voltage – VCEsat < 530 mV @ 2 A / 200 mA (transistor)
- Low forward voltage drop – VF < 460 mV @ 2A (rectifier)

• High Space Efficiency

- E.g., the 1612 sized SOT666 package offers best-in-class performance at 41% less
required PCB as compared to standard SOT23 devices or combinations of transistors
and rectifiers in one package (PMEM series)

When a por tfolio gives you this much design freedom, it’s more than a par t of your
product, it’s living technology. And it’s only from Philips.

© Koninklijke Philips Electronics N.V., 2003. All rights reser ved.