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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
DESCRIPTION
The LF43168 is a high-speed dual FIR filter capable of filtering data at realtime video rates. The device contains two FIR filters which may be used as two separate filters or cascaded to form one filter. The input and coefficient data are both 10-bits and can be in unsigned, two's complement, or mixed mode format. The filter architecture is optimized for symmetric coefficient sets. When symmetric coefficient sets are used, each filter can be configured as an 8-tap FIR filter. If the two filters are cascaded, a 16-tap FIR filter can be implemented. When asymmetric coefficient sets are used, each filter is configured as a 4-tap FIR filter. If both filters are cascaded, an 8-tap filter can be implemented. The LF43168 can decimate the output data by as much as 16:1. When the device is programmed to decimate, the number of clock cycles available to calculate filter taps increases. When configured for 16:1 decimation, each filter can be configured as a 128-tap FIR filter (if symmetric coefficient sets are used). By cascading these two filters, the device can be configured as a 256-tap FIR filter. There is on-chip storage for 32 different sets of coefficients. Each set consists of eight coefficients. Access to more than one coefficient set facilitates adaptive filtering operations. The 28-bit filter output can be rounded from 8 to 19 bits.
FEATURES
u 66 MHz Data and Computation Rate u Two Independent 8-Tap or Single 16-Tap FIR Filters u u u u 10-bit Data and Coefficient Inputs 32 Programmable Coefficient Sets Supports Interleaved Coefficient Sets User Programmable Decimation up to 16:1
u Maximum of 256 FIR Filter Taps, 16 x 16 2-D Kernels, or 10 x 20-bit Data and Coefficients u Replaces Harris HSP43168 u Package Styles Available: * 84-pin Plastic LCC, J-Lead * 100-pin Plastic Quad Flatpack
LF43168 BLOCK DIAGRAM
INB9-0/ OUT8-0
9 10 10
MUX
INA9-0
CSEL4-0 CIN9-0 A8-0 WR
5 10 9
COEFFICIENT BANK A
FILTER CELL A
MUX
COEFFICIENT BANK B
FILTER CELL B
CONTROL
MUX/ADDER
9
19
OUT27-9
OEL OEH
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FIR FILTER A
FIR FILTER B
MUX_CTRL
FIGURE 1.
4
3 LIFO A LIFO A DECIMATION REGISTERS LIFO B DEMUX LIFO B MUX MUX MUX MUX DEMUX 1-16 1-16 1-16
CLK N data CLK N+1 data
MUX
TXFR
DEVICES INCORPORATED
DECIMATION REGISTERS 1-16 1-16 1-16 1-16 1-16 1-16 1-16
SHFTEN
3
TO ALL DECIMATION REGISTERS 1-16 1-16 1-16 1-16
INA9-0
10
3
CLK N data CLK N+1 data
MUX_CTRL
A ALU ALU ALU ALU B A B A B A B A B ALU ALU ALU ALU A B A B A B
FWRD MUX_CTRL
3
TO ALL ALUs
RVRS
3
TO ALL ALUs
COEF BANK 0 COEF BANK 1 COEF BANK 2 COEF BANK 3
LF43168 FUNCTIONAL BLOCK DIAGRAM
COEF BANK 1
COEF BANK 2
COEF BANK 3
ODD/EVEN (TO ALL ALUs)
CONTROL
CIN9-0
10
MUX_CTRL
A8-0 0
9
ROUND_CTRL
WR
MUX
ACCEN
5
MUX1-0
2
6
MUX
CSEL4-0
5
0
4
MUX COEF BANK 0
INB9-0/ OUT8-0
10
9
MUX
3 1-16
2
MUX/ ADDER ROUND_CTRL 2
9 19
OUT27-9 OEH
OEL
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Dual 8-Tap FIR Filter
LF43168
03/28/2000-LDS.43168-H
CLK
NOTE: NUMBERS IN REGISTERS INDICATE NUMBER OF PIPELINE DELAYS.
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
FIGURE 2A. INPUT FORMATS
Data Fractional Unsigned 987 20 2-1 2-2 210 2-7 2-8 2-9 987 20 2-1 2-2 210 2-7 2-8 2-9 Coefficient
SIGNAL DEFINITIONS Power VCC and GND +5 V power supply. All pins must be connected. Clock CLK -- Master Clock The rising edge of CLK strobes all enabled registers. Inputs INA9-0 -- Data Input (FIR Filter A) INA9-0 is the 10-bit registered data input port for FIR Filter A. INA9-0 can also be used to send data to FIR Filter B. Data is latched on the rising edge of CLK. INB9-0 -- Data Input (FIR Filter B) INB9-0 is the 10-bit registered data input port for FIR Filter B. Data is latched on the rising edge of CLK. INB9-1 is also used as OUT8-0, the nine least significant bits of the data output port (see OUT27-0 section). CIN9-0 -- Coefficient/Control Data Input CIN9-0 is the data input port for the coefficient and control registers. Data is latched on the rising edge of WR. A8-0 -- Coefficient/Control Address A8-0 provides the write address for data on CIN9-0. Data is latched on the falling edge of WR. WR -- Coefficient/Control Write The rising edge of WR latches data on CIN9-0 into the coefficient/control register addressed by A8-0. CSEL4-0 -- Coefficient Select CSEL4-0 determines which set of coefficients is sent to the multipliers in both FIR filters. Data is latched on the rising edge of CLK.
Fractional Two's Complement 987 -20 2-1 2-2
(Sign)
210 2-7 2-8 2-9
987 -20 2-1 2-2
(Sign)
210 2-7 2-8 2-9
FIGURE 2B.
OUTPUT FORMATS
Fractional Two's Complement 27 26 25 -29 28 27
(Sign)
Fractional Unsigned 27 26 25 29 28 27 210 2-16 2-17 2-18
210 2-16 2-17 2-18
Outputs OUT27-0 -- Data Output OUT27-0 is the 28-bit registered data output port. OUT8-0 is also used as INB9-1, the nine most significant bits of the FIR Filter B data input port (see INB9-0 section). If both filters are configured for even-symmetric coefficients, and both input and coefficient data is unsigned, the filter output data will be unsigned. Otherwise, the output data will be in two's complement format. Controls SHFTEN -- Shift Enable When SHFTEN is LOW, data on INA9-0 and INB9-0 can be latched into the device and data can be shifted through the decimation registers. When SHFTEN is HIGH, data on INA9-0 and INB9-0 can not be latched into the device and data in the input and decimation registers is held. This signal is latched on the rising edge of CLK.
FWRD -- Forward ALU Input When FWRD is LOW, data from the forward decimation path is sent to the "A" inputs on the ALUs. When FWRD is HIGH, "0" is sent to the "A" inputs on the ALUs. This signal is latched on the rising edge of CLK. RVRS -- Reverse ALU Input When RVRS is LOW, data from the reverse decimation path is sent to the "B" inputs on the ALUs. When RVRS is HIGH, "0" is sent to the "B" inputs on the ALUs. This signal is latched on the rising edge of CLK. TXFR -- LIFO Transfer Control When TXFR goes LOW, the LIFO sending data to the reverse decimation path becomes the LIFO receiving data from the forward decimation path, and the LIFO receiving data from the forward decimation path becomes the LIFO sending data to the reverse decimation path. The device must see a HIGH to LOW transition of TXFR in order to switch LIFOs. This signal is latched on the rising edge of CLK.
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
TABLE 1.
BITS 0-3
ACCEN -- Accumulate Enable When ACCEN is HIGH, both accumulators are enabled for accumulation and writing to the accumulator output registers is disabled (the registers hold their values). When ACCEN goes LOW, accumulation is halted (by sending zeros to the accumulator feedback inputs) and writing to the accumulator output registers is enabled. This signal is latched on the rising edge of CLK. MUX1-0 -- Mux/Adder Control MUX1-0 controls the Mux/Adder as shown in Table 3. Data is latched on the rising edge of CLK. OEL -- Output Enable Low When OEL is LOW, OUT8-0 is enabled for output and INB9-1 can not be used. When OEL is HIGH, OUT8-0 is placed in a high-impedance state and INB9-1 is available for data input. OEH -- Output Enable High When OEH is LOW, OUT27-9 is enabled for output. When OEH is HIGH, OUT27-9 is placed in a highimpedance state. FUNCTIONAL DESCRIPTION Control Registers There are two control registers which determine how the LF43168 is configured. Tables 1 and 2 show how each register is organized. Data on CIN9-0 is latched into the addressed control register on the rising edge of WR. Address data is input on A8-0. Control Register 0 is written to using address 000H. Control Register 1 is written to using address 001H (Note that addresses 002H to 0FFH are reserved and should not be written to). When a control register is written to, a reset occurs which lasts for 6 CLK cycles from when WR goes HIGH. This reset does not alter any data in the coefficient banks. Control data can be loaded asynchronously to CLK.
CONTROL REGISTER 0 - ADDRESS 000H
FUNCTION DESCRIPTION No Decimation, Delay by 1 Decimate by 2, Delay by 2 Decimate by 3, Delay by 3 Decimate by 4, Delay by 4 Decimate by 5, Delay by 5 Decimate by 6, Delay by 6 Decimate by 7, Delay by 7 Decimate by 8, Delay by 8 Decimate by 9, Delay by 9 Decimate by 10, Delay by 10 Decimate by 11, Delay by 11 Decimate by 12, Delay by 12 Decimate by 13, Delay by 13 Decimate by 14, Delay by 14 Decimate by 15, Delay by 15 Decimate by 16, Delay by 16 Decimation Factor/ 0000 = Decimation Register Delay Length 0001 = 0010 = 0011 = 0100 = 0101 = 0110 = 0111 = 1000 = 1001 = 1010 = 1011 = 1100 = 1101 = 1110 = 1111 = Filter Mode Select Coefficient Symmetry Select FIR Filter A: Odd/Even Taps FIR Filter B: Odd/Even Taps FIR Filter B Input Source Interleaved/Non-Interleaved Coefficient Sets
4 5 6 7 8 9
0 = Single Filter Mode 1 = Dual Filter Mode 0 = Even-Symmetric Coefficients 1 = Odd-Symmetric Coefficients 0 = Odd Number of Filter Taps 1 = Even Number of Filter Taps 0 = Odd Number of Filter Taps 1 = Even Number of Filter Taps 0 = Input from INA9-0 1 = Input from INB9-0 0 = Non-Interleaved Coefficient Sets 1 = Interleaved Coefficient Sets
Bits 0-3 of Control Register 0 control the decimation registers. The decimation factor and decimation register delay length is set using these bits. Bit 4 determines if FIR filters A and B operate separately as two filters or together as one filter. Bit 5 is used to select even or odd-symmetric coefficients. Bits 6 and 7 determine if there are an even or odd number of taps in filters A and B respectively. When the FIR filters are set to operate as two separate filters, bit 8 selects either INA9-0 or INB9-0 as the filter B input source. Bit 9 determines if the coefficient set used is interleaved or noninterleaved (see Interleaved Coefficient Filters section). Most applications use non-interleaved coefficient sets (bit 9 set to "0").
Bits 0 and 1 of Control Register 1 determine the input and coefficient data formats respectively for filter A. Bits 2 and 3 determine the input and coefficient data formats respectively for filter B. Bit 4 is used to enable or disable data reversal on the reverse decimation path. When data reversal is enabled, the data order is reversed before being sent to the reverse decimation path. Bits 5-8 select where rounding will occur on the output data (See Mux/Adder section). Bit 9 enables or disables output rounding. Coefficient Banks The coefficient banks supply coefficient data to the multipliers in both FIR filters. The LF43168 can store 32 different coefficient sets. A coefficient
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
grammed to decimate by 2 to 16 (see Decimation section and Table 1). SHFTEN enables and disables the shifting of data through the decimation registers. When SHFTEN is LOW, data on INA9-0 and INB9-0 can be latched into the device and data can be shifted through the decimation registers. When SHFTEN is HIGH, data on INA9-0 and INB9-0 can not be latched into the device and data in the input and decimation registers is held. Data feedback circuitry is positioned between the forward and reverse decimation registers. It controls how data from the forward decimation path is fed to the reverse decimation path. The feedback circuitry can either reverse the data order or pass the data unchanged to the reverse decimation path. The mux/demux sends incoming data to one of the LIFOs or the data feedback decimation register. The LIFOs and decimation register feed into a mux. This mux determines if one of the LIFOs or the decimation register sends data to the reverse decimation path. If the data order needs to be reversed before being sent to the reverse decimation path (for example, when decimating), Data Reversal Mode should be enabled by setting bit 4 of Control Register 1 to "0". When Data Reversal is enabled, data from the forward decimation path is written into one of the LIFOs in the data feedback section while the other LIFO sends data to the reverse decimation path. When TXFR goes LOW, the LIFO sending data to the reverse decimation path becomes the LIFO receiving data from the forward decimation path, and the LIFO receiving data from the forward decimation path becomes the LIFO sending data to the reverse decimation path. The device must see a HIGH to LOW transition of TXFR in order to switch LIFOs. The size of data blocks sent to the reverse decimation path is determined by how often TXFR goes LOW. To send data blocks of size 8 to
TABLE 2.
BITS 0 1 2 3 4 5-8
CONTROL REGISTER 1 - ADDRESS 001H
FUNCTION FIR Filter A Input Data Format FIR Filter A Coefficient Format FIR Filter B Input Data Format FIR Filter B Coefficient Format Data Order Reversal Enable Output Round Position DESCRIPTION 0 = Unsigned 1 = Two's Complement 0 = Unsigned 1 = Two's Complement 0 = Unsigned 1 = Two's Complement 0 = Unsigned 1 = Two's Complement 0 = Enabled 1 = Disabled 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 = = = = = = = = = = = = 2-10 2-9 2-8 2-7 2-6 2-5 2-4 2-3 2-2 2-1 20 21
9
Output Round Enable
0 = Enabled 1 = Disabled
set consists of 8 coefficient values. Each bank can hold 32 10-bit values. CSEL4-0 is used to select which coefficient set is sent to the filter multipliers. The coefficient set fed to the multipliers may be switched every CLK cycle if desired. Data on CIN9-0 is latched into the addressed coefficient bank on the rising edge of WR. Address data is input on A8-0 and is decoded as follows: A1-0 determines the bank number ("00", "01", "10", and "11" correspond to banks 0, 1, 2, and 3 respectively), A2 determines which filter ("0" = filter A, "1" = filter B), A7-3 determines which set number the coefficient is in, and A8 must be set to "1". For example, an address of "100111011" will load coefficient set 7 in bank 3 of filter A with data. Coefficient data can be loaded asynchronously to CLK.
Decimation Registers The decimation registers are provided to take advantage of symmetric filter coefficients and to provide data storage for 2-D filtering. The outputs of the registers are fed into the ALUs. Both inputs to an ALU need to be multiplied by the same filter coefficient. By adding or subtracting the two data inputs together before being sent to the filter multiplier, the number of filter taps needed is cut in half. Therefore, an 8-tap FIR filter can be made with only four multipliers. The decimation registers are divided into two groups, the forward and reverse decimation registers. As can be seen in Figure 1, data flows left to right through the forward decimation registers and right to left through the reverse decimation registers. The decimation registers can be pro-
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
Decimation Decimation by N is accomplished by only reading the LF43168's output once every N clock cycles. For example, to decimate by 10, the output should only be read once every 10 clock cycles. When not decimating, the maximum number of taps possible with a single filter in dual filter mode is eight. When decimating by N, there are N - 1 clock cycles between output readings when the filter output is not read. These extra clock cycles can be used to calculate more filter taps. As the decimation factor increases, the number of available filter taps increases also. When programmed to decimate by N, the number of filter taps for a single filter in dual filter mode increases to 8N. Arithmetic Logic Units The ALUs can perform the following operations: B + A, B - A, pass A, pass B, and negate A (-A). If FWRD is LOW, the forward decimation path provides the A inputs to the ALUs. If FWRD is HIGH, the A inputs are set to "0". If RVRS is LOW, the reverse decimation path provides the B inputs to the ALUs. If RVRS is HIGH, the B inputs are set to "0". FWRD, RVRS, and the filter configuration determine which ALU operation is performed. If FWRD and RVRS are both set LOW, and the filter is set for even-symmetric coefficients, the ALU will perform the B + A operation. If FWRD and RVRS are both set LOW, and the filter is set for odd-symmetric coefficients, the ALU will perform the B - A operation. If FWRD is set LOW, RVRS is set HIGH, and the filter is set for evensymmetric coefficients, the ALU will perform the pass A operation. If FWRD is set LOW, RVRS is set HIGH, and the filter is set for odd-symmetric coefficients, the ALU will perform the negate A operation. If FWRD is set HIGH, RVRS is set LOW, and the filter is set for either even or odd-symmetric coefficients, the ALU will perform the pass B operation. Accumulators The multiplier outputs are fed into an accumulator. Each filter has its own accumulator. The accumulator can be set to accumulate the multiplier outputs or sum the multiplier outputs and send the result to the accumulator output register. When ACCEN is HIGH, both accumulators are enabled for accumulation and writing to the accumulator output registers is disabled (the registers hold their values). When ACCEN goes LOW, accumulation is halted (by sending zeros to the accumulator feedback inputs) and writing to the accumulator output registers is enabled. Mux/Adder When the LF43168 is configured as two FIR filters, the Mux/Adder is used to determine which filter drives the output port. When the LF43168 is configured as a single FIR filter, the Mux/Adder is used to sum the outputs of the two filters and send the result to the output port. If 10-bit data and 20-bit coefficients or 20-bit data and 10-bit coefficients are required, the Mux/Adder can facilitate this by scaling filter B's output by 2-10 before being added to filter A's output. MUX1-0 determines what function the Mux/Adder performs (see Table 3). The Mux/Adder is also used to round the output data before it is sent to the output port. Output data is rounded by adding a "1" to the bit position selected using bits 5-8 of Control Register 1 (see Table 2). For example, to round the
the reverse decimation path, TXFR would have to be set LOW once every 8 CLK cycles. Once a data block size has been established (by asserting TXFR at the proper frequency), changing the frequency or phase of TXFR assertion will cause unknown results. If data should be passed to the reverse decimation path with the order unchanged, Data Reversal Mode should be disabled by setting bit 4 of Control Register 1 to "1" and TXFR must be set LOW. When Data Reversal is disabled, data from the forward decimation path is written into the data feedback decimation register. The output of this register sends data to the reverse decimation path. The delay length of this register is the same as the forward and reverse decimation register's delay length. When the LF43168 is configured to operate as a single FIR filter, the forward and reverse decimation paths in filters A and B are cascaded together. The data feedback section in filter B routes data from the forward decimation path to the reverse decimation path. The configuration of filter B's feedback section determines how data is sent to the reverse decimation path. Data going through the feedback section in filter A is sent through the decimation register. The point at which data from the forward decimation path is sent to the data feedback section is determined by whether the filter is set to have an even or odd number of filter taps. If the filter is set to have an even number of taps, the output of the third forward decimation register is sent to the feedback section. If the filter is set to have an odd number of taps, the data that will be output from the third forward decimation register on the next CLK cycle is sent to the feedback section.
TABLE 3. MUX1-0 FUNCTION
MUX1-0 00 01 10 11 FUNCTION Filter A + Filter B (Filter B Scaled by 2-10) Filter A + Filter B Filter A Filter B
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
FIGURE 3.
SYMMETRIC COEFFICIENT SET EXAMPLES
8765 87654321 7654321 4321
Even-Tap, Even-Symmetric Coefficient Set
Odd-Tap, Even-Symmetric Coefficient Set
Even-Tap, Odd-Symmetric Coefficient Set
FIGURE 4.
EVEN-SYMMETRIC COEFFICIENT FILTER CONFIGURATIONS (NO DECIMATION)
DATA IN
DATA IN
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
COEF 0 COEF 1 COEF 2 COEF 3
COEF 0 COEF 1 COEF 2 COEF 3 2
EVEN-TAP FILTER
ODD-TAP FILTER
output to 16 bits, bits 5-8 of Control Register 1 should be set to "0011". This will cause a "1" to be added to bit position 2-7. Symmetric Coefficients The LF43168 filter architecture is optimized for symmetric filter coefficient sets. Figure 3 shows examples of the different types of symmetric coefficient sets. In even-symmetric sets, each coefficient value appears twice (except in odd-tap sets where the middle value appears only once). In odd-symmetric sets, each coefficient appears twice, but one value is positive and one is negative. If the
two data input values that will be multiplied by the same coefficient are added or subtracted before being sent to the filter multiplier, the number of multipliers needed for an N-tap filter is cut in half. Therefore, an 8-tap filter can be implemented with four multipliers if a symmetric coefficient set is used. FILTER CONFIGURATIONS Figures 4-6 show the data paths from filter input to filter multipliers for all symmetric coefficient filters. Figure 7 shows the interleaved coefficient filter configuration. Each diagram shows
one of the two FIR filters when the device is configured for dual filter mode. The diagrams can be expanded to include both filters when the device is configured for single filter mode. Even-Symmetric Coefficient Filters Figure 4 shows the two possible configurations when the device is programmed for even-symmetric coefficients and no decimation. Note that coefficient 3 on the oddtap filter must be divided by two to get the correct result (The coefficient must be input to the device already divided by two).
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
FIGURE 5.
DECIMATING, EVEN-SYMMETRIC COEFFICIENT FILTER CONFIGURATIONS
LIFO A LIFO A
N = Delay Length (Decimation Factor)
MUX
N = Delay Length (Decimation Factor)
DEMUX MUX
N
N
N
N
N
N
LIFO B
DATA IN
N
N
N
DATA IN
N
N
N
Delay Stage N - 1 Output
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
A B+A
B
COEF 0 COEF 1 COEF 2 COEF 3
COEF 0 COEF 1 COEF 2 COEF 3
EVEN-TAP FILTER
ODD-TAP FILTER
FIGURE 6.
ODD-SYMMETRIC COEFFICIENT FILTER CONFIGURATIONS
LIFO A
N = Delay Length (Decimation Factor)
MUX
LIFO B
N
N
N
DATA IN
DATA IN
N
N
N
A B-A
B
A B-A
B
A B-A
B
A B-A
B
A B-A
B
A B-A
B
A B-A
B
A B-A
B
COEF 0
COEF 0
COEF 1
COEF 1
COEF 2
COEF 2
COEF 3
COEF 3
EVEN-TAP FILTER (NO DECIMATION)
DECIMATING, EVEN-TAP FILTER
Figure 5 shows the two possible configurations when the device is programmed as a decimating, evensymmetric coefficient filter. The delay length of the decimation registers will be equal to the decimation factor that the device is programmed for. Since only four coefficients (effectively eight) can be sent to the filter multipli-
ers on a clock cycle, it may be necessary (depending on the coefficient set) to change the coefficients fed to the multipliers on different CLK cycles for filters with more than eight taps. Note that for the odd-tap filter, the middle coefficient of the coefficient set must be divided by two to get the correct result.
Odd-Symmetric Coefficient Filters Figure 6 shows the two possible configurations when the device is programmed for odd-symmetric coefficients. Note that odd-tap, oddsymmetric coefficient filters are not possible.
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LIFO B
DEMUX
DEMUX
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
FIGURE 7. INTERLEAVED COEFFICIENT FILTER CONFIGURATION
N = Delay Length (Decimation Factor)
Interleaved Coefficient Filters Figure 7 shows the filter configuration when the device is programmed for interleaved coefficients. An interleaved coefficient set contains two separate odd-tap, even-symmetric coefficient sets which have been interleaved together (see Figure 8). If two data sets are interleaved into the same serial data stream, they can both be filtered by different coefficient sets if the two coefficient sets are also interleaved. The LF43168 is configured as an interleaved coefficient filter by programming the device for interleaved coefficient sets, evensymmetric coefficients, odd number of filter taps, and data reversal disabled. Note that coefficient 3, in Figure 7, must be divided by two to get the correct result. Asymmetric Coefficient Filters It is possible to have asymmetric coefficient filters. Asymmetric coefficient sets do not exhibit even or odd symmetric properties. A 4-tap asymmetric filter is possible by putting the device in even-tap, pass A mode and then feeding the asymmetric coefficient set to the multipliers. An 8-tap asymmetric filter is possible if the device is clocked twice as fast as the input data rate. It will take two CLK cycles to calculate the output. On the first CLK cycle, the reverse decimation path is selected to feed data to the filter multipliers. On the second CLK cycle, the coefficients sent to the multipliers are changed (if necessary) and the forward decimation path is selected to feed data to the filter multipliers.
N
N
N
N
DATA IN
N
N
N
A B+A
B
A B+A
B
A B+A
B
A B+A
B
COEF 0 COEF 1 COEF 2 COEF 3 2
ODD-TAP INTERLEAVED FILTER
FIGURE 8.
INTERLEAVED COEFFICIENT SET EXAMPLE
7654321
Odd-Tap, Even-Symmetric Coefficient Set A 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Interleaved Coefficient Set Consisting of Sets A and B 7654321
Odd-Tap, Even-Symmetric Coefficient Set B
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
MAXIMUM RATINGS Above which useful life may be impaired (Notes 1, 2, 3, 8)
Storage temperature ........................................................................................................... -65C to +150C Operating ambient temperature ........................................................................................... -55C to +125C VCC supply voltage with respect to ground ............................................................................ -0.5 V to +7.0 V Input signal with respect to ground ............................................................................... -0.5 V to VCC + 0.5 V Signal applied to high impedance output ...................................................................... -0.5 V to VCC + 0.5 V Output current into low outputs ............................................................................................................. 25 mA Latchup current ............................................................................................................................... > 400 mA
OPERATING CONDITIONS To meet specified electrical and switching characteristics
Mode Active Operation, Commercial Active Operation, Military Temperature Range (Ambient) 0C to +70C -55C to +125C Supply Voltage 4.75 V VCC 5.25 V 4.50 V VCC 5.50 V
ELECTRICAL CHARACTERISTICS Over Operating Conditions (Note 4)
Symbol VOH VOL VIH VIL IIX IOZ ICC1 ICC2 CIN COUT Parameter Output High Voltage Output Low Voltage Input High Voltage Input Low Voltage Input Current Output Leakage Current VCC Current, Dynamic VCC Current, Quiescent Input Capacitance Output Capacitance
(Note 3)
Test Condition VCC = Min., IOH = -2.0 mA VCC = Min., IOL = 4.0 mA
Min 2.6
Typ
Max
Unit V
0.4 2.0 0.0 VCC 0.8 10 10 300 500 12 12
V V V A A mA A pF pF
Ground VIN VCC (Note 12) Ground VOUT VCC (Note 12)
(Notes 5, 6) (Note 7)
TA = 25C, f = 1 MHz TA = 25C, f = 1 MHz
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LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
SWITCHING CHARACTERISTICS COMMERCIAL OPERATING RANGE Notes 9, 10 (ns)
30
Symbol Parameter Min Max
LF43168- 22
Min Max Min
15
Max
tCYC tPW tS tH tWP tWPW tWHCH tCWS tCWH tAWS tAWH tD tENA tDIS
Cycle Time Clock Pulse Width Input Setup Time Input Hold Time Write Period Write Pulse Width Write High to Clock High CIN9-0 Setup Time CIN9-0 Hold Time Address Setup Time Address Hold Time Output Delay Three-State Output Enable Delay (Note 11) Three-State Output Disable Delay (Note 11)
30 12 15 0 30 12 5 12 0 10 0 14 12 12
22 8 12 0 22 10 3 10 0 8 0 12 12 12
15 7 5 0 15 7 2 5 0 5 0 11 12 12
SWITCHING WAVEFORMS
tCYC tPW CLK INPUTS/ CONTROLS* WR tAWS A8-0 tCWS CIN9-0 OEL OEH tDIS OUT27-0
HIGH IMPEDANCE
tPW
tS
tH
tWP tAWH
tWHCH
tWPW
tWPW
tCWH
tENA
tD
*includes INA9-0, INB9-0, CSEL4-0, ACCEN, MUX1-0, SHFTEN, FWRD, RVRS, and TXFR.
Video Imaging Products
11
03/28/2000-LDS.43168-H
4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4321098765432121098765432109876543210987654321 4
Min
*DISCONTINUED SPEED GRADE
DEVICES INCORPORATED
Symbol
MILITARY OPERATING RANGE Notes 9, 10 (ns)
SWITCHING WAVEFORMS
SWITCHING CHARACTERISTICS
tDIS
tENA
tD
tAWH
tAWS
tCWH
tCWS
tWHCH
tWPW
tWP
tH
tS
tPW
tCYC
INPUTS/ CONTROLS*
OUT27-0
CIN9-0
OEL OEH
CLK
A8-0
WR
Parameter
Three-State Output Disable Delay (Note 11)
Three-State Output Enable Delay (Note 11)
Output Delay
Address Hold Time
Address Setup Time
CIN9-0 Hold Time
CIN9-0 Setup Time
Write High to Clock High
Write Pulse Width
Write Period
Input Hold Time
Input Setup Time
Clock Pulse Width
Cycle Time
*includes INA9-0, INB9-0, CSEL4-0, ACCEN, MUX1-0, SHFTEN, FWRD, RVRS, and TXFR.
tDIS
tS
tWP
tH
tAWS
HIGH IMPEDANCE
tAWH
tCWS
12
tCWH
tENA
tPW
17
15
15
15
39
39
10
8
0
0
0
tCYC
tWHCH
39*
tPW
Max
12
12
17
Video Imaging Products
tD
Min
15
12
12
12
30
30
10
LF43168- 30*
5
0
0
0
tWPW
Dual 8-Tap FIR Filter
Max
12
12
15
tWPW
03/28/2000-LDS.43168-H
Min
12
10
10
22
22
3
0
8
0
0
8
LF43168
22*
Max
12
12 12
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
NOTES
1. Maximum Ratings indicate stress specifications only. Functional operation of these products at values beyond those indicated in the Operating Conditions table is not implied. Exposure to maximum rating conditions for extended periods may affect reliability. 9. AC specifications are tested with input transition times less than 3 ns, output reference levels of 1.5 V (except tDIS test), and input levels of nominally 0 to 3.0 V. Output loading may be a resistive divider which provides for specified IOH and IOL at an output voltage of VOH min and VOL max respectively. Alternatively, a diode bridge with upper and lower current sources of IOH and IOL respectively, and a balancing voltage of 1.5 V may be used. Parasitic capacitance is 30 pF minimum, and may be distributed. 11. For the tENA test, the transition is measured to the 1.5 V crossing point with datasheet loads. For the tDIS test, the transition is measured to the 200mV level from the measured steady-state output voltage with 10mA loads. The balancing voltage, VTH, is set at 3.5 V for Z-to-0 and 0-to-Z tests, and set at 0 V for Zto-1 and 1-to-Z tests.
2. The products described by this specification include internal circuitry designed to protect the chip from damaging substrate injection currents and ac12. These parameters are only tested at cumulations of static charge. Neverthethe high temperature extreme, which is less, conventional precautions should the worst case for leakage current. be observed during storage, handling, FIGURE A. OUTPUT LOADING CIRCUIT and use of these circuits in order to This device has high-speed outputs caavoid exposure to excessive electrical pable of large instantaneous current stress values. pulses and fast turn-on/turn-off times. S1 As a result, care must be exercised in the 3. This device provides hard clamping of testing of this device. The following DUT IOL transient undershoot and overshoot. In- measures are recommended: VTH CL put levels below ground or above VCC IOH will be clamped beginning at -0.6 V and a. A 0.1 F ceramic capacitor should be VCC + 0.6 V. The device can withstand installed between VCC and Ground indefinite operation with inputs in the leads as close to the Device Under Test FIGURE B. THRESHOLD LEVELS range of -0.5 V to +7.0 V. Device opera- (DUT) as possible. Similar capacitors tENA tDIS tion will not be adversely affected, how- should be installed between device VCC OE 1.5 V 1.5 V ever, input current levels will be well in and the tester common, and device ground and tester common. excess of 100 mA.
Z 0 3.5V Vth Z Z
4. Actual test conditions may vary from b. Ground and VCC supply planes those designated but operation is guar- must be brought directly to the DUT anteed as specified. socket or contactor fingers. 5. Supply current for a given applica- c. Input voltages should be adjusted to tion can be accurately approximated by: compensate for inductive ground and VCC noise to maintain required DUT input NCV2 F levels relative to the DUT ground pin. 4 where 10. Each parameter is shown as a minN = total number of device outputs C = capacitive load per output V = supply voltage F = clock frequency 6. Tested with all outputs changing every cycle and no load, at a 20 MHz clock rate. 7. Tested with all inputs within 0.1 V of VCC or Ground, no load. 8. These parameters are guaranteed but not 100% tested. imum or maximum value. Input requirements are specified from the point of view of the external system driving the chip. Setup time, for example, is specified as a minimum since the external system must supply at least that much time to meet the worst-case requirements of all parts. Responses from the internal circuitry are specified from the point of view of the device. Output delay, for example, is specified as a maximum since worst-case operation of any device always provides data within that time.
1.5 V
VOL*
0.2 V
0 1
1.5 V
VOH*
0.2 V
Z
1
0V Vth VOL* Measured VOL with IOH = -10mA and IOL = 10mA VOH* Measured VOH with IOH = -10mA and IOL = 10mA
Video Imaging Products
13
03/28/2000-LDS.43168-H
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
ORDERING INFORMATION
84-pin
CIN8 CIN9 CSEL4 CSEL3 CSEL2 CSEL1 CSEL0 VCC A8 A7 A6 A5 A4 A3 A2 A1 A0 GND WR MUX1 MUX0
CIN7 CIN6 CIN5 CIN4 GND CIN3 CIN2 CIN1 CIN0 INA9 INA8 INA7 INA6 INA5 VCC INA4 INA3 INA2 INA1 INA0 INB9
11 10 9 8 7 6 5 4 3 2 1 84 83 82 81 80 79 78 77 76 75 12 74 13 73 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 72 71 70 69 68 67 66
Top View
65 64 63 62 61 60 59 58 57 56
55 32 54 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
RVRS FWRD SHFTEN TXFR ACCEN VCC CLK GND OEH OUT27 OUT26 OUT25 OUT24 OUT23 OUT22 OUT21 OUT20 OUT19 OUT18 OUT17 VCC
Speed
0C to +70C -- COMMERCIAL SCREENING
30 ns 22 ns 15 ns LF43168JC30 LF43168JC22 LF43168JC15
-40C to +85C -- COMMERCIAL SCREENING
INB8 INB7 INB6 INB5 GND INB4 INB3 INB2 INB1 INB0 OEL OUT9 OUT10 VCC OUT11 OUT12 OUT13 OUT14 OUT15 OUT16 GND
Plastic J-Lead Chip Carrier (J3)
Video Imaging Products
14
03/28/2000-LDS.43168-H
LF43168
DEVICES INCORPORATED
Dual 8-Tap FIR Filter
ORDERING INFORMATION
100-pin
CIN9 CSEL4 CSEL3 CSEL2 CSEL1 CSEL0 VCC VCC A8 A7 A6 A5 A4 A3 A2 A1 A0 GND GND WR CIN8 NC CIN7 NC CIN6 CIN5 CIN4 GND GND CIN3 CIN2 CIN1 CIN0 INA9 INA8 INA7 INA6 INA5 VCC VCC INA4 INA3 INA2 INA1 INA0 NC NC INB9 INB8 INB7 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Top View
MUX1 MUX0 RVRS NC FWRD SHFTEN TXFR ACCEN VCC VCC CLK GND GND OEH OUT27 OUT26 OUT25 OUT24 OUT23 OUT22 OUT21 OUT20 OUT19 OUT18 OUT17 NC VCC VCC GND GND
Speed
0C to +70C -- COMMERCIAL SCREENING
30 ns 22 ns 15 ns LF43168QC30 LF43168QC22 LF43168QC15
-40C to +85C -- COMMERCIAL SCREENING
INB6 INB5 GND GND INB4 INB3 INB2 INB1 INB0 OEL OUT9 OUT10 VCC VCC OUT11 OUT12 OUT13 OUT14 OUT15 OUT16
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
Plastic Quad Flatpack (Q2)
Video Imaging Products
15
03/28/2000-LDS.43168-H
121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321 1 1210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
DEVICES INCORPORATED
Speed
-55C to +125C -- MIL-STD-883 COMPLIANT
-55C to +125C -- COMMERCIAL SCREENING
0C to +70C -- COMMERCIAL SCREENING
ORDERING INFORMATION
84-pin
G
H
D
C
K
E
B
A
F
L
J
CIN0
CIN3
CIN4
CIN5
CIN8 CSEL4 CSEL3 CSEL1
INB9
INA1
INA2
INA4
INA6
VCC
1
GND
CIN6
CIN7
CIN1
INB6
INB8
INA0
INA3
INA5
INA9
2
CIN2
CIN9 CSEL2 VCC
INB5
INB7
INA7
INA8
3
Ceramic Pin Grid Array (G6)
Discontinued Package
GND
INB4
4
(i.e., Component Side Pinout)
CSEL0
INB1 OUT11 OUT10 OUT12 OUT14 OUT15 GND
INB2
INB3
16
A8
5
Through Package
Top View
INB0
OEL
A6
A2
A7
6
OUT9
VCC OUT13 OUT16 VCC OUT18
A5
A3
A4
7
A0
A1
8
OUT25 OUT23 OUT24
OUT26 OUT22 OUT27
MUX1 MUX0 SHFTEN
GND
CLK
9
ACCEN VCC
OUT17 OUT19
OUT20 OUT21
FWRD TXFR
GND
WR
10
Video Imaging Products
RVRS OEH
11
Dual 8-Tap FIR Filter
03/28/2000-LDS.43168-H
LF43168

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