ZXF103Q16, ZXF103EV
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 2 - JULY 2002
VARIABLE Q FILTER
1
R R
C C
RQ 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
R2
0V
RC2
GP1
Vcc
GP3
BIAS
RC1
0V
C1
FI1
GP2
NC
Vcc
FO
FI2
116
PINOUT
ABSOLUTE MAXIMUM RATINGS
Voltage on any pin 7.0V (relative to 0V)
Operating temperature range 0 to 70°C
Storage temperature -55 to 125°C
ZXF103
ISSUE 2 - JULY 2002
2
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 kΩ2V pk-pk
Sink current 450 µA
Source current 450 µA
Output impedance 10 ⍀
ELECTRICAL CHARACTERISTICS Test Conditions: Temperature =25°C, VCC = 5.00V, 0V =0.00V,
RL=10k,CL=10pF
Pin Name Function
1 R2 Phase retard node
2 0V 0 Volts
3 RC2 Phase retard node
4 BIAS Internal bias generator
5 RC1 Phase advance node
6 0V 0 Volts
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
11.78 11.79 11.80 11.81 11.82
Number of Devices
Frequency (KHz)
Histogram of Centre Frequency
(Fo = 11.80KHz Q = 25)
ZXF103
ISSUE 2 - JULY 2002
3
Filter Configurations and Responses
Notch Filter
10K 100K 1M 10M
-40
-32
-24
-16
-8
0
Frequency (Hz)
Gain (dB)
AC Filter Performance
10K 100K 1M
45
90
135
180
225
270
10M
Frequency (Hz)
Phase (deg)
Fo 1
2RC
=π
where R=R1=R2
and C=C1=C2
QR4
R3
∝
where R1,R2,R3 and R4 艌2kΩ
and C1 and C2 艌50pF
See “Designing for a value of Q”
for more details.
ZXF103
ISSUE 2 - JULY 2002
4
Filter Configurations and Responses (Continued)
Inverse Notch Filter (with 0dB Stop Band)
10K 100K 1M 10M
0
6
12
18
24
30
Frequency (Hz)
Gain (dB)
AC Filter Performance
10K 100K 1M 10M
-270
-225
-180
-135
-90
-45
Frequency (Hz)
Fo 1
2RC
=π
where R=R1=R2
and C=C1=C2
QR4
R3
∝
where R1,R2,R3 and R4 艌2kΩ
and C1 and C2 艌50pF
ZXF103
ISSUE 2 - JULY 2002
5
Filter Configurations and Responses (Continued)
Inverse Notch Filter (with attenuating skirts)
AC Filter Performance
Fo 1
2RC
=π
where R=R1=R2
and C=C1=C2
QR4
R3
∝
where R1,R2,R3 and R4 艌2kΩ
and C1 and C2 艌50pF
See “Designing for a value of Q”
for more details.
The skirt ‘roll off’away from the
peak is -20dB/Decade regardless
of chosen 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.
QR4
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 2 - JULY 2002
66
EVALUATION BOARD
An evaluation board (ZXF103EV) is available to assist
with in-system or stand-alone performance evaluation.
The board can be set, by simple jumper links, to
perform any of the filter characterisitics responses.
Evaluation boards can be purchased from our
catalogue distributors.
Digi-Key North America www.digikey.com
Tel: 1-800344-4539
Europe - Farnell www.farnell.com
Tel: 44-113-263-6311
ZXF103
ISSUE 2 - JULY 2002
7
R2
1
0 v
RC2
Bias
RC1
0 v
C1
FI 1
GP1
Vcc
GP3
GP2
N/C
Vcc
FO
FI 2
ZXF103
R2 6.8 k
R1 6.8k
R422 k
R310 k
VR12 k
C4
100 nF
C1
330 pF
C2 330 pF
C3
100 nF
C6
100 nF
C5
100 nF
0 v
5 v
Output
Input
J1
J2
J3
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.
ZXF103
ISSUE 2 - JULY 2002
8
Europe
Zetex plc
Fields New Road
Chadderton
Oldham, OL9 8NP
United Kingdom
Telephone (44) 161 622 4422
Fax: (44) 161 622 4420
uk.sales@zetex.com
Zetex GmbH
Streitfeldstraße19
D-81673 München
Germany
Telefon: (49) 89 45 49 49 0
Fax: (49) 89 45 49 49 49
europe.sales@zetex.com
Americas
Zetex Inc
700 Veterans Memorial Hwy
Hauppauge, NY11788
USA
Telephone: (631) 360 2222
Fax: (631) 360 8222
usa.sales@zetex.com
Asia Pacific
Zetex (Asia) Ltd
3701-04 Metroplaza, Tower 1
Hing Fong Road
Kwai Fong
Hong Kong
Telephone: (852) 26100 611
Fax: (852) 24250 494
asia.sales@zetex.com
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 2002
QSOP16 PACKAGE OUTLINE
Conforms to JEDEC MO-137AB Iss A
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°
QSOP16 PACKAGE DIMENSIONS
