ZXF103 ZETEX | Alldatasheet

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Technical content

DESCRIPTION

The ZXF103 is a versatile analog high Q bandpass filter. It can be configured to provide pass or notch characteristics. The basic filter section requires 2 resistors and 2 capacitors to set the centre frequency. The frequency range is up to 600kHz. Two external resistors control filter Q Factor. The Q can be varied up to 50.

APPLICATIONS

Many filter applications including: -

  • Sonar and Ultrasonic Systems
  • Line frequency notch
  • Signalling
  • Motion detection
  • Instrumentation
  • Low frequency telemetry FEATURES AND BENEFITS
  • Centre Frequency up to 1MHz
  • Variable Q up to 50
  • Low distortion
  • Low noise
  • Low power 25mW
  • Devices easily cascaded
  • Small QSOP16 package ZXF103 ISSUE 1 - APRIL 2002 VARIABLE Q FILTER R RC C R Q SET ZXF103 Filter Input Filter Output SYSTEM DIAGRAM PART NUMBER PACKAGE PART MARK ZXF103Q16 QSOP16 ZXF103

ORDERING INFORMATION

PART NUMBER CONTAINER INCREMENT ZXF103Q16TA Reel 7” 178mm 500 ZXF103Q16TC Reel 13” 330mm 2500 RC2 GP1 Vcc GP3 BIAS RC1 FI1 GP2 NC Vcc FO FI2 11 6 PINOUT

Voltage on any pin 7.0V (relative to 0V) Operating temperature range 0 to 70 °C Storage temperature -55 to 125 °C

ELECTRICAL CHARACTERISTICS

Test Coνditions: Temperature =25°C, VCC = 5.00V, 0V =0.00V, RL=10k,CL=10pF GENERAL CHARACTERISTICS Parameter Conditions Min. Typical Max. Units Operating current 4.0 5.0 mA Max. operating frequency Vout=1.6V p-p Vout=1.0V p-p 600 1000 kHz Q usable range 0.5 50 Centre Frequency temperature coefficient Q=30, fo = 1kHz 100 ppm/ °C Q temperature coefficient Q=30, fo = 1kHz 0.1 % / °C Voltage noise 1 – 100 kHz 20 nV/ √ Hz Input impedance 10 15 20 kΩ Linear Output Range Output load =10 k Ω 2 V pk-pk Sink current 450 µA Source current 450 µA Pin Name Function

1 R2 Phase retard node

3 RC2 Phase retard node

4 BIAS Internal bias generator

5 RC1 Phase advance node

7 C1 Phase advance node

8 FI1 Filter input mode dependent

9 FI2 Filter input, mode dependent

10 FO Filter output for all modes

11 Vcc +5 Volt supply

12 N/C No connection

13 GP2 Loop gain node

14 GP3 Loop gain node

15 Vcc +5 Volt supply

16 GP1 Loop gain node

Frequency (KHz) Histogram of Centre Frequency (Fo = 11.80KHz Q = 25)

Filter Configurations and Responses Notch Filter 10K 100K 1M 10M-40 -32 -24 -16 Frequency (Hz) Gain (dB) AC Filter Performance 10K 100K 1M45 135 180 225 270 10M Frequency (Hz) Phase (deg) Fo 1 2R C= π where R=R1=R2 and C=C1=C2 Q R4 R3∝ where R1,R2,R3 and R4 /H333562kΩ and C1 and C2 /H3335650pF See “Designing for a value of Q” for more details.

Filter Configurations and Responses (Continued) Inverse Notch Filter (with 0dB Stop Band) 10K 100K 1M 10M0 Frequency (Hz) Gain (dB) AC Filter Performance 10K 100K 1M 10M -270 -225 -180 -135 -90 -45 Frequency (Hz) Fo 1 2R C= π where R=R1=R2 and C=C1=C2 Q R4 R3∝ where R1,R2,R3 and R4 /H333562kΩ and C1 and C2 /H3335650pF

Filter Configurations and Responses (Continued) Inverse Notch Filter (with attenuating skirts) 10K 100K 1M 10M -20 -10 Frequency (Hz) Gain (dB) AC Filter Performance 10K 100K 1M 10M -540 -450 -360 -270 -180 -90 Frequency (Hz) Phase (deg) Fo 1 2R C= π where R=R1=R2 and C=C1=C2 Q R4 R3∝ where R1,R2,R3 and R4 /H333562kΩ and C1 and C2 /H3335650pF See “Designing for a value of Q” for more details. The skirt ‘roll off’ away from the peak is -20dB/Decade regardless of chosed Q. Typical responses from the circuit with component values derived from the diagram.

Designing for a value of Q As mentioned on the configuration pages, there is a proportional relationship between the ratio of R4 and R3, and Q. Q R4 R3∝ These resistors define the gain of an inverting amplifier that determines the peak value of gain and therefore the Q of the filter, as Q is described as; Q = Fo 3dBBandwidth− This value of required gain is quite critical. As the maximum value of Q is approached, too much gain will cause the filter to oscillate at the centre frequency Fo. A small reduction of gain will cause the value of Q to fall significantly. Therefore, for high values of Q factor or tight tolerances of lower values of Q, the resistor ratio must be trimmed. Frequency dependant effects must be accounted for in determining the appropriate gain. As the frequency increases, the effective circuit gain reduces. The required gain is nominally two but at higher frequencies it will need to be slightly greater than two in order to compensate for loss of gain and internal phase shifts. This is not really a problem for circuits where the desired Fo remains constant, as the phase shifts are accounted for permanently. For designs where Q is high and Fo is to be ‘swept’, care must be taken that a gain appropriate at the highest frequency does not cause oscillation at the lowest. Variation in Q increases from device to device, as the value of Q increases, due to internal gain spreads. ZXF103 ISSUE 1 - APRIL 2002

R2 6.8 k R1 6.8k R422 k R310 k VR12 k 100 nF 330 pF C2 330 pF 100 nF 100 nF 100 nF 0 v 5 v Output Input Evaluation Board Schematic Notch J1 and J2 Notch Pass 1 J2 and J3 (0dB Stop Band) Notch Pass 2 J3 only (Attenuating skirts) The evaluation board is designed for operation at 70kHz.

Oldham, OL9 8NP United Kingdom Telephone (44) 161 622 4422 Fax: (44) 161 622 4420 Zetex GmbH Streitfeldstraße 19 D-81673 München Germany Telefon: (49) 89 45 49 49 0 Fax: (49) 89 45 49 49 49 Zetex Inc Suite 315

700 Veterans Memorial Highway

Telephone: (631) 360 2222 Fax: (631) 360 8222 Zetex (Asia) Ltd 3701-04 Metroplaza, Tower 1 Hing Fong Road Kwai Fong, Hong Kong China Telephone: (852) 26100 611 Fax: (852) 24250 494 These offices are supported by agents and distributors in major countries world-wide. This publication is issued to provide outline information only which (unless agreed by the Company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products or services concerned. The Company reserves the right to alter without notice the specification, design, price or conditions of supply of any product or service. For the latest product information, log on to www.zetex.com © Zetex plc 2001 QSOP16 DIM Millimetres Inches MIN MAX MIN MAX A 4.80 4.98 0.189 0.196 B 0.635 0.025 NOM C 0.23 REF 0.009 REF D 0.20 0.30 0.008 0.012 E 3.81 3.99 0.15 0.157 F 1.35 1.75 0.053 0.069 G 0.10 0.25 0.004 0.01 J 5.79 6.20 0.228 0.244 K0 ° 8° 0° 8° Conforms to JEDEC MO-137AB Iss A