LF2249 Datasheet, PDF (1/8 Pages) LOGIC Devices Incorporated – 12 x 12-bit Digital Mixer

DEVICES INCORPORATED
DEVICES INCORPORATED
LF2249
12 x 12-bi_Lt D_Fig₂ita₂l ₄Mi₉xer
12 x 12-bit Digital Mixer
FEATURES
DESCRIPTION
u 40 MHz Data and Computation Rate ^{The LF2249 is a high-speed digital}
u Two 12 x 12-bit Multipliers with
mixer comprised of two 12-bit
user control for subtraction of prod-
ucts. The sum of the products can
1
Individual Data Inputs
multipliers and a 24-bit accumulator. also be internally rounded to 16 bits
u Separate 16-bit Input Port for
Cascading Devices
u Independent, User-Selectable 1–16
Clock Pipeline Delay for Each Data
Input
u User-Selectable Rounding of Products
All multiplier inputs are user acces-
sible, and each can be updated on
every clock cycle. The LF2249 utilizes
a pipelined architecture with fully
registered inputs and outputs and an
asynchronous three-state output
enable control for optimum flexibility.
during the accumulation process.
A separate 16-bit input port con-
nected to the accumulator is included
to allow cascading of multiple
LF2249s. Access to all 24 bits of the
accumulator is gained by switching
between upper or lower 16-bit words.
2
3
u Fully Registered, Pipelined
Independent input register clock
The accumulated output data is
4
Architecture
enables allow the user to hold the
updated on every clock cycle.
u Three-State Outputs
u Fully TTL Compatible
u Replaces TRW/Raytheon/Fairchild
TMC2249
u 120-pin PQFP
data inputs over multiple clock cycles.
Each multiplier input also includes a
user-selectable 1-16 clock pipeline
delay. The output of each multiplier
can be independently negated under
All inputs and outputs of the LF2249
are registered on the rising edge of
clock, except for OE. Internal pipeline
registers for all data and control
inputs are provided to maintain
5
6
LF2249 BLOCK DIAGRAM
7
ADEL3-0 A11-0 ENA
BDEL3-0 B11-0 ENB
CDEL3-0 C11-0 ENC
DDEL3-0 D11-0 END
8
CLK
NEG1
RND
FT
CAS15-0
CASEN
SWAP
1–16
1–16
1–16
1–16
4
4
16
2's COMP
2's COMP
16
24
3
MS 16
16 LS
1
0
2:1
0
1
2:1
4
NEG2
4
ACC
9
10
11
OE
NOTE: NUMBERS IN REGISTERS INDICATED
NUMBER OF PIPELINE DELAYS.
16
S15-0
Video Imaging Products
1
08/16/2000–LDS.2249-J