SCAN921821 Datasheet, PDF (1/11 Pages) National Semiconductor (TI) – Dual 18-Bit Serializer with Pre-emphasis, IEEE 1149.1(JTAG), and At-Speed BIST

November 2004
SCAN921821
Dual 18-Bit Serializer with Pre-emphasis, IEEE 1149.1
(JTAG), and At-Speed BIST
General Description
The SCAN921821 is a dual channel 18-bit serializer featur-
ing signal conditioning, boundary SCAN, and at-speed BIST.
Each serializer block transforms an 18-bit parallel LVCMOS/
LVTTL data bus into a single Bus LVDS data stream with
embedded clock. This single serial data stream with embed-
ded clock simplifies PCB design and reduces PCB cost by
narrowing data paths that in turn reduce PCB size and
layers. The single serial data stream also reduces cable
size, the number of connectors, and eliminates clock-to-data
and data-to-data skew.
Each channel also has an 8-level selectable pre-emphasis
feature that significantly extends performance over lossy
interconnect. Each channel also has its own powerdown pin
that saves power by reducing supply current when the chan-
nel is not being used.
The SCAN921821 also incorporates advanced testability
features including IEEE 1149.1 and at-speed BIST PRBS
pattern generation to facilitate verification of board and link
integrity
Features
n 15-66 MHz Dual 18:1 Serializer with 2.376 Gbps total
throughput
n 8-level selectable pre-emphasis on each channel drives
lossy cables and backplanes
n >15kV HBM ESD protection on Bus LVDS I/O pins
n Robust BLVDS serial data transmission with embedded
clock for exceptional noise immunity and low EMI
n Power saving control pin for each channel
n IEEE 1149.1 "JTAG" Compliant
n At-Speed BIST - PRBS generation
n No external coding required
n Internal PLL, no external PLL components required
n Single +3.3V power supply
n Low power: 260 mW (typ) per channel at 66 MHz with
PRBS-15 pattern
n Single 3.3 V supply
n Fabricated with advanced CMOS process technology
n Industrial −40 to +85˚C temperature range
n Compact 100-ball FBGA package
Block Diagram
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