Description
The 828BP and 828BR Series are 4-pole-pair digitally programmable band-pass and band-reject (notch) active filters. These new filters take advantage of the companys proprietary designs using surface-mount technology to provide a low profile, compact package in minimal board space. 828BP and 828BR filters are factory tuned to one of three factory preset tuning ranges or 8-bit custom ranges from 1 Hz to 25.6 kHz. Each filter type features a near theoretical amplitude/phase response along with low output voltage noise enabling these filters to achieve a 10,000:1 or better dynamic signal range.
Pretuned to within ±2% of the center frequency, band-pass 828BP filters pass all frequencies lying between the upper and lower -3 dB points of the amplitude response curve, while 828BR band-reject (notch) filters sharply attenuate those frequencies that are bound and defined by the bottom of the notch. Available Q's for 828 BP models are 1, 2, 5, or 10 and 828BR filters are 3 or 10.
Features/Benefits:
- Compact 2.0"L x 2.0"W footprint minimizes board space requirements.
- Plugin readytouse, reducing engineering design and manufacturing cycle time.
- Factory tuned, no external clocks or adjustments needed
- Broad range of center frequencies to meet a wide range of applications
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Applications
- Power line interference rejection
- Transducer output filtering
- Production test instrumentation
- Medical electronics equipment and research
- Comb filtering and equalization
- Noise and harmonic analysis
- RMS measurements
- Frequency spectrum analysis
- Programmable Specifications: l
Digital Tuning & Control
Available Band-Pass Models:
- 828BP4 4 pole pair
Available Band-Reject Models:
- 828BR4 4-pole pair
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8-Bit Programmable Filters
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828BP & 828BR Series
Digital Tuning &
Control Characteristics
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Digital Tuning Characteristics
The digital tuning interface circuits are a parallel set of eight (8) 4053 CMOS switches which accept CMOS compatible inputs for the eight tuning bits (D0 - D7 ).
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
fmax = Maximum tuning frequency;
fc = corner frequency;
Minimum tunable frequency = fmax/256 (D0 thru D7 = 0);
Minimum frequency step (Resolution) = fmax/256
MSB
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LSB
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Bit
Weight
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27
D7
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26
D6
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25
D5
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24
D4
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23
D3
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22
D2
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21
D1
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20
D0
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fc
Corner
Frequency
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0
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0
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0
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0
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0
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0
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0
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0
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fmax/256
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0
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0
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0
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0
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0
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0
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0
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1
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fmax/128
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0
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0
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0
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0
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0
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0
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1
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1
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fmax/64
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0
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0
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0
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0
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0
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1
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1
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1
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fmax/32
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0
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0
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0
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0
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1
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1
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1
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1
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fmax/16
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0
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0
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0
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1
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1
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1
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1
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1
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fmax/8
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0
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0
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1
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1
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1
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1
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1
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1
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fmax/4
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0
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1
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1
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1
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1
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1
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1
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1
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fmax/2
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1
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1
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1
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1
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1
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1
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1
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1
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fmax
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Pin-Out Key
IN
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Analog Input Signal
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D7
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Tuning Bit 7 (MSB)
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OUT
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Analog Output Signal
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D6
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Tuning Bit 6
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GND
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Power and Signal Return
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D5
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Tuning Bit 5
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+Vs
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Supply Voltage, Positive
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D4
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Tuning Bit 4
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-Vs
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Supply Voltage, Negative
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D3
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Tuning Bit 3
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Os
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Offset Adjustment
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D2 |
Tuning Bit 2
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D1 |
Tuning Bit 1
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D0 |
Tuning Bit 0 (LSB)
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Data Input Specifications
Input Data Levels
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(CMOS Logic)
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Input Voltage (Vs=15 Vdc ) |
Low Level In |
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0 Vdc min. |
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4 Vdc max. |
High Level In |
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11 Vdc min. |
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15 Vdc max. |
Input Current |
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High Level In |
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-10-5 µA typ. |
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-1 µA max. |
Low Level In |
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+10-5 µA typ. |
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+1 µA max. |
Input Capacitance |
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5 pF typ |
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7.5 pF max. |
Input Data Format
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Frequency Select Bits
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Positive Logic |
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Logic "1" = +Vs |
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Logic "0" = Gnd |
Bit Weight |
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(Binary-Coded) |
D0 |
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LSB (least significant bit) |
D7 |
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MSB (most significant bit) |
Frequency Range 256 : 1, Binary Weighted
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Band-Pass & Band-Reject |
828BP & 828BR Series
8-Bit Programmable
4-Pole Pair Filters
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Model |
828BP4 |
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Model |
828BR4 |
Product Specifications |
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Band-Pass
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Band-Reject
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Size
Range fo
Available "Qs"1
Q Accuracy |
2.0" x 2.0" x 0.5"
1 Hz to 25.6 kHz
1, 2, 5, 10
±10% |
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Size
Range fo
Available "Qs"1
Q Accuracy |
2.0" x 2.0" x 0.5"
1 Hz to 25.6 kHz
3, 10
±10% |
Theoretical Transfer
Characteristics |
Click to view
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Theoretical Transfer
Characteristics |
Click to view
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Notch Attenuation |
45 dB typ. |
Pass-Band Gain
(non-inverting) |
0± 0.25 dB typ.
0± 0.50 dB max. |
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Pass-Band Gain
(non-inverting) |
0± 0.25 dB typ.
0± 0.50 dB max. |
Attenuation Rate |
24 dB/octave |
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Attenuation Rate |
24 dB/octave |
Center Frequency |
fo ±2% max. |
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Center Frequency |
fo ±2% max. |
Stability |
±0.01%/°C |
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Stability |
±0.01%/°C |
Filter Mounting
Assembly |
FMA-02A |
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Filter Mounting
Assembly |
FMA-02A |
Notes 1: Q Quality Factor for band-pass and band-reject filters. Q = fo / (fH - fL)
fo=sq.rt(fH X fL)
Specifications
(@ 25°C and Vs ±15 Vdc)
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Analog Input Characteristics (1)
- Impedance: 10 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 Current(2): ± 2 mA
- Offset Voltage(3):
2 mV typ.
20 mV max.
- Offset Temp. Coeff.: 50 µV / °C
Notes:
- Input and output signal voltage referenced to supply common.
- Output is short circuit protected to common. DO NOT CONNECT TO +/-Vs.
- Adjustable to zero.
- Units operate with or without offset pin connected.
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Power Supply (+/-Vs)
- Rated Voltage: ± 15 Vdc
- Operating Range: ± 5 to ± 18 Vdc
- Maximum Safe Voltage: ± 18 Vdc
- Quiescent Current:
± 25 mA typ., ± 40 mA max.
Temperature
- Operating: 0 to + 70°C
- Storage: -25 to+85°C
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Pin-Out and Package Data
Ordering Information

Power Sequence & ESD
Programmable Filters Modules
- Scope
The following precautions are necessary when handling and installing Frequency Devices programmable filter modules.
- 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.
- (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:
- Connect filter module ground.
- Connect filter module +15 V.
- Connect filter module -15 V.
- Connect the input signal.
All four of the above steps can also occur simultaneously. Power-down should occur in the reverse order.
- 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:
- Only a person wearing a properly grounded wrist strap should handle the modules.
- Any work surface that the modules are placed on must be properly ESD grounded.
- Any insulating materials capable of generating static charge (such as paper) should be kept away from the modules.
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. |