Page 63 - System on Package_ Miniaturization of the Entire System

40 Cha pte r T w o

2.1 Introduction
With the advances in semiconductor technology, the number of transistors that can be
integrated on a single chip continues to grow. This trend, represented by Moore’s law
(the number of devices on a chip will double every 18 to 24 months), is projected to hold
true through 2010 and beyond per the International Technology Roadmap on
Semiconductors (ITRS) [1]. The increasing level of integration enables the implementation
of electronic systems, which were earlier implemented using multiple chips on a board,
on a single chip—called “system-on-a-chip.”
The definition of SOC is thus evolving, where with each generation more and more
system components are integrated on a single device. As an example, consider the
digital subscriber line (DSL) modem system evolution through three generations, as
shown in Figure 2.1.
From an initial system consisting of five chips, memory, and other discrete
components, the next-generation DSL solution integrated the analog codec, line driver,
and line receiver into a single analog front end (AFE), and in the following generation,
the integration was taken even more forward with the communications processor,
digital PHYsical layer, and AFE all integrated onto a single-chip digital signal processor
(DSP) modem SOC. This journey continues even further, as the system itself evolves
along with the SOC evolution. The DSL system needs to provide voice and video

DSL CPE Modem SOC Integration

Memory
Memory
Comms Memory
processor
Comms
Digital i t i processor
PHY
i t i
Digital
Analog i t i PHY Single-chip
i t i codec DSL modem
i i t
Line AFE
i t i driver i t i
AR5 Line <50
i t i receiver discretes
415
740 discretes
discretes
2000 Today-AR5
BOM 5 chips 3 chips 1 chips
740 discretes 415 discretes <50 discretes
CMOS CMOS CMOS
Manufacturing
process Analog Analog Analog
Flash
Flash
Flash
technology
SDRAM SDRAM SDRAM
i i t Texas Instruments
FIGURE 2.1 Single-chip DSL modem system-on-a-chip.