Filters > 818

818 Series

1 kHz to 1.28 MHz
2" x 4"
8-Pole Filters

Specifications

Pin-out and package data

Ordering Information

Ordering Information


Download PDF File

Download Adobe Acrobat Reader
Download Acrobat Reader

818 Series
8-Bit Programmable
8-Pole Filters
 

 

Purchase

 

 

Description

The 818 Series are digitally programmable low-pass and high-pass active filters that are tunable over a 256:1 frequency range. 818 filters are available with any one of five standard factory-set tuning ranges or 8-bit custom ranges from 1 kHz. to 1.28 MHz. These units contain 8 CMOS logic inputs.

The 818 Series models are convenient, low profile, easy to use fully finished filters which require no external components or adjustments. They feature low harmonic distortion, and near theoretical amplitude characteristics. 818 filters operate from non-critical ±12 to ±18 Vdc power supplies, have a 5 kΩ (min.) input impedance, a 10 Ω (max.) output impedance and low-pass models offer dc voltage offset adjustment.

Features/Benefits:

  • Low harmonic distortion and wide signal-to-noise ratio to 12 bit resolution
  • Digitally programmable corner frequency allows selecting cut-off frequencies specific to each application
  • Plug-in ready-to-use, reducing engineering design and manufacturing cycle time
  • Factory-set tuning range, no external clocks or adjustments needed
  • Broad range of transfer characteristics and corner frequencies to meet a wide range of applications
 

Applications

  • Anti-alias and band-pass filtering
  • Data acquisition systems
  • Satellite and telecommunications
  • Acoustic and vibration analysis and control
  • Aerospace, navigation and sonar
  • Medical research and electronic equipment
  • Engine test and simulation
  • Noise elimination
  • Video systems
  • Signal reconstruction

Available Low-Pass Models:

818L8B
8-pole Butterworth
818L8L
8-pole Bessel
818L8E
8-pole, 6-zero elliptic, 1.77
818L8D80
8-pole, 6-zero constant delay

Available High-Pass Models:

818H8B
8-pole Butterworth
818H8E
8-pole, 6-zero elliptic, 1.77



8-Bit Programmable Filters

 

818 Series

Digital Tuning &
Control Characteristics


Digital Tuning Characteristics

The digital tuning interface circuits are two 4042 quad CMOS latches which accept the following CMOS-compatible inputs: eight tuning bits (D0 - D7 )., a latch strobe bit (C), and a transition

Filter tuning follows the tuning equation given below:

fc = ( fmax/256 ) [ 1 + D7 x 27 + D6 x 26 + D5 x 25 + D4 x 24 + D3 x 23 + D2 x 22 + D1 x 21 + D0 x 20]

where D1 - D7 = "0" or "1", and
f
max = Maximum tuning frequency;
f
c = corner frequency;
Minimum tunable frequency = f
max/256 (D0 thru D7 = 0);
Minimum frequency step (Resolution) = f
max/256

MSB
---
---
---
---
---
---
LSB
Bit
Weight
27
D
7
26
D
6
25
D
5
24
D
4
23
D
3
22
D
2
21
D
1
20
D
0
fc
Corner
Frequency
0
0
0
0
0
0
0
0
fmax/256
0
0
0
0
0
0
0
1
fmax/128
0
0
0
0
0
0
1
1
fmax/64
0
0
0
0
0
1
1
1
fmax/32
0
0
0
0
1
1
1
1
fmax/16
0
0
0
1
1
1
1
1
fmax/8
0
0
1
1
1
1
1
1
fmax/4
0
1
1
1
1
1
1
1
fmax/2
1
1
1
1
1
1
1
1
fmax

 

Data Control Specifications

Data Control Lines
Functions   Latch Strobe (C)
Transition Polarity (P)
Data Control Modes
Mode 1   P = 0; C = 0 frequency follows input codes
P = 0; C = 0
Ý frequency latched on rising edge
Mode 2   P = 1; C = 1 frequency follows input codes
P = 1; C = 1
ß frequency latched on falling edge

Notes:

1.Frequency data must be present before occurrence of strobe edge.

2.Frequency data must be present after occurrence of strobe edge.

 

  Pin-Out Key

IN
Analog Input Signal
 
D7
Tuning Bit 7 (MSB)
OUT
Analog Output Signal
 
D6
Tuning Bit 6
GND
Power and Signal Return
 
D5
Tuning Bit 5
"P"
Transition Polarity Bit
 
D4
Tuning Bit 4
"C"
Tuning Strobe Bit
 
D3
Tuning Bit 3
+Vs
Supply Voltage, Positive
  D2
Tuning Bit 2
-Vs
Supply Voltage, Negative
  D1
Tuning Bit 1
Os
Optional Offset Adjustment
  D0
Tuning Bit 0 (LSB)
NC
No Connect (Highpass Models)
     

 

 

 

Input Data Levels
 
(CMOS Logic)
Input Voltage (Vs=15 Vdc )  
 
   
Low Level In   0 Vdc min.   4 Vdc max.
High Level In   11 Vdc min.   15 Vdc max.
Input Current        
High Level In   -10-5 µA typ.   -1 µA max.
Low Level In   +10-5 µA typ.   +1 µA max.
Input Capacitance   5 pF typ   7.5 pF max.
Latch Response        
Data Set Up Time1   25 nS    
Data Hold Time2   50 nS    
Strobe Pulse Width   80 nS min.    

Input Data Format
 
Frequency Select Bits
Positive Logic   Logic "1" = +Vs
    Logic "0" = Gnd
Bit Weighting   (Binary-Coded)
  D0   LSB (least significant bit)
  D7   MSB (most significant bit)
Frequency Range   256 : 1, Binary Weighted


8-Bit Programmable                 8-Pole Low-Pass Filters

Model 818L8B 818L8L 818L8E 818L8D80
Product Specifications
Transfer Function


Size

Range fc

8-Pole
Butterworth

2.0” x 4.0” x 0.4”

1 kHz to 1.28 MHz

8-Pole
Bessel

2.0” x 4.0” x 0.4”

1 kHz to 1.28 MHz

8-Pole, 6 zero
Elliptic

2.0” x 4.0” x 0.4”

1 kHz to 1.28 MHz

8-Pole, 6 zero
Constant Delay

2.0” x 4.0” x 0.4”

1 kHz to 1.28 MHz

Theoretical Transfer
Characteristics
Click to view
Click to view
Click to view
Click to view
Passband Ripple
   (theoretical)
0.0 dB 0.0 dB ± 0.035 dB 0.15 dB
DC Voltage Gain
   
(non-inverting)
0 ± 0.1 dB max.
0 ± 0.05 dB typ.
0 ± 0.1 dB max.
0 ± 0.05 dB typ.
0 ± 0.1 dB max.
0 ± 0.05 dB typ.
0 ± 0.1 dB max.
0 ± 0.05 dB typ.
Stopband
Attenuation Rate
48 dB/octave 48 dB/octave 80 dB min. 80 dB min.
Cutoff Frequency
Stability
Amplitude
Phase
fc        ± 3% max.
± 0.01% /°c
-3 dB
-360°
fc        ± 3% max.
± 0.01% /°c
-3 dB
-182°
fr        ± 3% max.
± 0.01% /°c
-3 dB
-323.5°
fc        ± 3% max.
± 0.01% /°c
-3 dB
-306°
Filter Attenuation
   
(theoretical)
0.12 dB       0.80 fc
3.01 dB       1.00 fc
60.0 dB       2.37 fc
80.0 dB       3.16 fc
1.91 dB       0.80 fc
3.01 dB       1.00 fc
60.0 dB       4.52 fc
80.0 dB       6.07 fc
0.035 dB     1.00 fr
3.01 dB       1.13 fr
60.0 dB       1.67 fr
80.0 dB       1.77 fr
3.01 dB       1.00 fc
60.0 dB       3.08 fc
80.0 dB       3.57 fc
Phase Match1
(See below)
(See below)
(See below)
(See below)
Amplitude Accuracy
   
(theoretical)
0 - 0.6 fc
± 0.5 dB max.
± 0.25 dB typ.
0.6 fc - 1.0 fc
± 1.0 dB max.
± 0.6 dB typ.
0 - fc
± 0.8 dB max.
± 0.4 dB typ.
0 - 0.8 fr
± 0.5 dB max.
± 0.25 dB typ.
0.8 fr - 1.0 fr
± 1.0 dB max.
± 0.5 dB typ.
0 - 0.8 fc
± 0.5 dB max.
± 0.25 dB typ.
0.8 fr - 1.0 fc
± 1.0 dB max.
± 0.5 dB typ.
Total Harmonic
Distortion @ 1 kHz
< - 88 dB typ. < - 88 dB typ. < - 88 dB typ. < - 88 dB typ.
Wide Band Noise
   
(5 Hz - 2 MHz)
300 µVrms typ. 300 µVrms typ. 350 µVrms typ. 350 µVrms typ.
Narrow Band Noise
(5 Hz - 100 kHz)
75 µVrms typ. 75 µVrms typ. 75 µVrms typ. 75 µVrms typ.
Filter Mounting
Assembly
FMA-04A FMA-04A FMA-04A FMA-04A
 

1. Unit to unit match for the same transfer function, set to the same frequency and operating configuration, and from the same manufacturing lot.


8-Bit Programmable                 8-Pole High-Pass Filters

Model 818H8B 818H8E
Product Specifications
Transfer Function


Size

Range fc

8-Pole
Butterworth


2.0” x 4.0” x 0.4”

1.0 Hz to 1.28 MHz
8-Pole, 6 zero
Elliptic


2.0” x 4.0” x 0.4”

1.0 Hz to 1.28 MHz
Theoretical Transfer
Characteristics
Click to view
Click to view
Passband Ripple
   (theoretical)
0.0 dB ± 0.035 dB
Voltage Gain
   
(non-inverting)
0 ± 0.5 dB to 1.28MHz 0 ± 0.5 dB to 1.28MHz
Power Bandwidth (-6 dB) 5 MHz (-6 dB) 5 MHz
Stopband
Attenuation Rate
48 dB/octave 80 dB
Cutoff Frequency
Stability
Amplitude
Phase
fc        ± 3% max.
± 0.01% /°c
-3 dB
-360°
fr        ± 3% max.
± 0.01% /°c
-0.035 dB
-323.5°
Filter Attenuation
   
(theoretical)
80 dB          0.31 fc
60.0 dB       0.42 fc
3.01 dB       1.00 fc
0.00 dB       2.00 fc
80 dB          0.56 fr
60.0 dB       0.60 fr
3.01 dB       0.88 fr
0.03 dB       1.00 fr
0.00 dB       2.00 fr
Amplitude Accuracy
   
(theoretical)
1.0 - 1.25 fc
± 0.5 dB max.
± 0.3 dB typ.
1.25 fc - 1.28MHz
± 1.0 dB max.
± 0.5 dB typ.
1.0 - 1.25 fr
± 0.5 dB max.
± 0.3 dB typ.
1.25 fr - 1.28MHz
± 1.0 dB max.
± 0.5 dB typ.
Total Harmonic
Distortion @ 1 kHz
< - 100 dB typ. < - 88 dB typ.
Wide Band Noise 400 µVrms typ. 450 µVrms typ.
Narrow Band Noise 100 µVrms typ. 100 µVrms typ.
Filter Mounting
Assembly
FMA-04A FMA-04A
 

1. Unit to unit match for the same transfer function, set to the same frequency and operating configuration, and from the same manufacturing lot.


1 kHz to 1.28 MHz

    

818 Series

Phase and Phases
Match Considerations


Phase Deviation from Theoretical:

The phase response of the amplifiers and the capacitance of the frequency control switches of the 818 series contribute to the overall phase response and cause it to deviate from theoretical. For the higher frequency models ( -4 and -5 ), where the cutoff frequencies can be programmed up to 1.28MHz, the deviation from theoretical can be substantial.

Figure 1 is a normalized plot of the phase deviation from theoretical for an 818L8E-5 for programmed cutoff frequencies from 5kHz ( fc min ) to 1.28MHz (fc max ). For fc of 5kHz, the deviation from the 323° theoretical phase shift is 2° but for fc of 1.28MHz the deviation is 78°. This set of curves can be used to estimate the deviation from theoretical phase for other models in the 818 series.

Figure 1 represents a "maximum deviation from theoretical phase" situation. Other models (i.e. -1 to -4) will exhibit a similar set of phase deviation curves with the phase scale being reduced by the ratio of the f max of the model to the f max of the -5. For example, an L8E-1, whose programming frequency range is from 1kHz to 256kHz (1/5 of the range of the -5 model) will have a similar set of phase deviation curves but the maximum phase deviation, at the highest frequency setting (fc max), will be approximately 1/5 that of the -5 model (78/5 = 15.6°). The other programmed settings of the -1 will also produce proportionally reduced phase deviations.

Unit to Unit Phase Match2

The actual phase shift through a filter at a frequency " f " is determined by its programmed frequency " fc ", the theoretical phase response of the transfer function (B, L, E, or D80) and the phase deviation from theoretical which in turn depends upon component tolerances, the model # (i.e. -1 through -5) and frequency to which it is programmed. It is therefore not possible to have a meaningful unit to unit phase match that is specified by a single number.

For a group of the same model type and number, programmed to the same frequency, the unit to unit phase match can be approximated as a percentage of the theoretical phase shift with a correction term added to accommodate amplifier induced phase deviations.

  EXAMPLE: Phase Match Calculation

  (f)max = 0.02° x (f)   + 4.0° x f/fc x fmax/1.28MHz
 
   
   
       4.0° - L8L
   3.0° - L8B & L8D80
   2.0° - L8L

(f)typ =0.5 x (f)max

where:

    (f) = phase match at frequency f
    (f) = theoretical phase shift at f
    f = frequency of interest
    f max = maximum fc of the model
    fc = frequency to which the filter is programmed

Eg. - for an 818L8E-3, the phase deviation from theoretical at a frequency of 192kHz, when the cutoff frequency fc is programmed to 384kHz is:

    f/fc = 192kHz/384kHz = 0.5, fmax = 768kHz
    (f) = 133° (from data table at f/fc = 0.5)

Phase Match:

(f)max = 0.02° x (f) + 4.0° x f/fc x fmax/1.28MHz

    = 0.02 x (-133°) + 4.0° x 0.5 x 768kHz/1.28MHz
    = 2.66° + 1.20° = +3.86°

    (f)typ =0.5 x (f)max = 0.5° x 3.86° = 1.93°

 

818L8E Phase Deviation (in degrees “°”) from Theoretical vs. Normalized Input Frequency

programmed setting of fc
f/fc 5kHz 10kHz 20kHz 40kHz 80kHz 160kHz 320kHz 640kHz 1.28MHz
0.10
0.15
0.18
0.17
0.08
-0.12
-0.52
-1.18
-2.57
-5.32
0.20
0.30
0.32
0.30
0.17
-0.39
-1.03
-2.41
-5.17
-10.76
0.30
0.34
0.42
0.40
-0.18
-0.57
-1.59
-3.66
-7.89
-16.29
0.40
0.20
0.40
0.50
-0.20
-0.90
-2.30
-5.10
-10.80
-22.10
0.50
0.20
0.32
0.60
-0.40
-1.20
-3.00
-6.70
-14.00
-28.20
0.60
0.00
0.00
-0.10
-0.80
-1.90
-4.10
-8.70
-17.70
-35.10
0.70
-0.21
-0.30
-0.60
-1.30
-2.70
-5.40
-11.00
-21.80
-42.60
0.80
-0.50
-0.60
-1.30
-2.10
-3.80
-7.20
-13.90
-26.90
-51.30
0.85
-0.80
-1.00
-1.80
-2.80
-4.70
-8.40
-15.80
-30.10
-56.40
0.90
-1.20
-1.60
-2.50
-3.70
-5.80
-10.00
-18.40
-33.80
-62.30
0.95
-1.90
-2.40
-3.50
-4.80
-7.30
-12.00
-21.10
- 38.30
-69.20
1.00
-2.50
-3.30
-4.60
-6.20
-8.90
-14.10
-24.30
-43.30
-77.50


Phase Deviation from Theoretical


Specifications

(@ 25°C and Vs ±15 Vdc)

Analog Input Characteristics1
  • Impedance: 5 kΩ min.
  • Voltage Range: ± 10 Vpeak
  • Max. Safe Voltage: ± Vs

Analog Output Characteristics

  • Impedance(Closed Loop):
    1 Ω typ.
    10 Ω max.
  • Linear Operating Range: ± 10 V
  • Maximum Current2: ± 5 mA
  • Offset Voltage3:
    2 mV typ.

    10 mV max.
  • Offset Temp. Coeff.: 50 µV / °C

Notes:

  1. Input and output signal voltage referenced to supply common.
  2. Output is short circuit protected to common. DO NOT CONNECT TO +/-Vs.
  3. Adjustable to zero
  4. Units operate with or without offset pin connected.
Power Supply (+/-V)
  • Rated Voltage: ± 15 Vdc
  • Operating Range: ± 12 to ± 18 Vdc
  • Maximum Safe Voltage: ± 18 Vdc
  • Quiescent Current:
    100 mA typ
    120 mA max.

Temperature

  • Operating: 0 to + 70°C
  • Storage: -25 to+85°C


Pin-Out and Package Data

Filter Mounting Assembly-See FMA-04A


Ordering Information

Model Number
Tuning Range (Hz)
Minimum Step (kHz)

1

1kHz to 256kHz
1kHz

2

2kHz to 512kHz
2kHz

3

3kHz to 768kHz
3kHz

4

4kHz to 1,024kHz
4kHz

5

5kHz to 1,280kHz
5kHz


Power Sequence & ESD
Programmable Filters Modules

818, 824, 828, 828BP, 828BR, 854, 858, R854, R858, 824BP, D824, D828

  1. Scope
    The following precautions are necessary when handling and installing Frequency Devices programmable filter modules.

  2. Digital Circuit Description
    The digital input pins connect directly to 4000 series CMOS logic, such as the 4053 analog switch. The power supply (Vss) for the digital logic on the module comes directly from the +15 Volt pin on the module. This sets the threshold voltage at 11.0 V minimum to 15.0 V maximum for a "1" (High) level and 0.0 V minimum to 4.0 V maximum for a "0" (Low) level. Applying a voltage between 4.0 and 11.0 V will produce unpredictable operation. Connecting 5 Volt or 3.3 V logic devices directly to the filter module without using a voltage translator will result in erratic operation of the filter.

  3. (VERY IMPORTANT) Power-Up and Power-Down Sequence
    Do not plug-in or un-plug module while power is applied. It is imperative that power is supplied to the + 15 V pin on the filter module before or at the same instance that any digital pin is pulled High (> 0.0 V). Failure to do this will result in excessive current flowing through the digital input pin and through a protection diode internal to the 4000 logic, which will result in damage to the module. The proper power-up and power-down sequence is:
    1. Connect filter module ground.
    2. Connect filter module +15 V.
    3. Connect filter module -15 V.
    4. Connect the input signal.


    All four of the above steps can also occur simultaneously. Power-down should occur in the reverse order.

  4. ESD Issues
    Like most modern electronic equipment, the modules can be damaged by electrostatic discharge (ESD). The modules are shipped from the factory in sealed, anti-static packaging and should be kept in the sealed package prior to mounting on a circuit board. The following additional rules should also be observed when handling the modules after they are removed from the factory packaging:
    1. Only a person wearing a properly grounded wrist strap should handle the modules.
    2. Any work surface that the modules are placed on must be properly ESD grounded.
    3. Any insulating materials capable of generating static charge (such as paper) should be kept away from the modules.


    Static generating clothing should be covered with an ESD-protective smock.


We hope the information given here will be helpful. The information is based on data and our best knowledge, and we consider the information to be true and accurate. Please read all statements, recommendations or suggestions herein in conjunction with our conditions of sale which apply to all goods supplied by us. We assume no responsibility for the use of these statements, recommendations or suggestions, nor do we intend them as a recommendation for any use which would infringe any patent or copyright.


Frequency Devices, Inc.
Your engineering partner for signal conditioning
  1784 Chessie Lane
Ottawa, IL 61350

Fax: (815) 434-8176
e-mail: sales@freqdev.com

 

Phone: (815) 434-7800
or (800) 252-7074 (U.S. only)

Copyright © 2001-2014 Frequency Devices
All Rights Reserved