UAF
42 UAF42
UAF
42
UNIVERSAL ACTIVE FILTER
FEATURES APPLICATIONS
VERSATILE TEST EQUIPMENT
LOW-PASS, HIGH-PASS COMMUNICATIONS EQUIPMENT
BAND-PASS, BAND-REJECT
MEDICAL INSTRUMENTATION
SIMPLE DESIGN PROCEDURE
DATA ACQUISITION SYSTEMS
ACCURATE FREQUENCY AND Q
MONOLITHIC REPLACEMENT FOR UAF41
INCLUDES ON CHIP 1000pF 0.5%
CAPACITORS
DESCRIPTION
The UAF42 is a universal active filter which can be three) can be used to form additional stages, or for
configured for a wide range of low-pass, high-pass, special filters such as band-reject and Inverse
and band-pass filters. It uses a classical state-variable Chebyshev.
analog architecture with an inverting amplifier and The classical topology of the UAF42 forms a time-
two integrators. The integrators include on-chip 1000pF continuous filter, free from the anomalies and switch-
capacitors trimmed to 0.5%. This solves one of the ing noise associated with switched-capacitor filter
most difficult problems of active filter design types.
obtaining tight tolerance, low-loss capacitors.
The UAF42 is available in 14-pin plastic DIP and
A DOS-compatible filter design program allows easy SOL-16 surface-mount packages, specified for the
implementation of many filter types such as 25C to +85C temperature range.
Butterworth, Bessel, and Chebyshev. A fourth, un-
committed FET-input op amp (identical to the other
High-Pass Band-Pass Low-Pass
Out Out Out
R
R 1000pF(1) 1000pF(1) V+
In1
In2
R R V
In3
R = 50k 0.5% NOTE: (1) 0.5% GND
International Airport Industrial Park Mailing Address: PO Box 11400, Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 Tel: (520) 746-1111 Twx: 910-952-1111
Internet: http://www.burr-brown.com/ FAXLine: (800) 548-6133 (US/Canada Only) Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
1990 Burr-Brown Corporation PDS-1070H Printed in U.S.A. January, 1998
SPECIFICATIONS
ELECTRICAL
At TA = +25C, VS = 15V, unless otherwise noted.
UAF42AP, AU
PARAMETER CONDITIONS MIN TYP MAX UNITS
FILTER PERFORMANCE
Frequency Range, fn 0 to 100 kHz
Frequency Accuracy f = 1kHz 1 %
vs Temperature 0.01 %/C
Maximum Q 400
Maximun (Q Frequency) Product 500 kHz
Q vs Temperature (fO Q) < 104 0.01 %/C
(fO Q) < 105 0.025 %/C
Q Repeatability (fO Q) < 105 2 %
Offset Voltage, Low-Pass Output 5 mV
Resistor Accuracy 0.5 1% %
OFFSET VOLTAGE(1)
Input Offset Voltage 0.5 5 mV
vs Temperature 3 V/C
vs Power Supply VS = 6 to 18V 80 96 dB
INPUT BIAS CURRENT(1)
Input Bias Current VCM = 0V 10 50 pA
Input Offset Current VCM = 0V 5 pA
NOISE
Input Voltage Noise
Noise Density: f = 10Hz 25 nV/Hz
f = 10kHz 10 nV/Hz
Voltage Noise: BW = 0.1 to 10Hz 2 Vp-p
Input Bias Current Noise
Noise Density: f = 10kHz 2 fA/Hz
INPUT VOLTAGE RANGE(1)
Common-Mode Input Range 11.5 V
Common-Mode Rejection VCM = 10V 80 96 dB
INPUT IMPEDANCE(1)
Differential 1013 || 2 || pF
Common-Mode 1013 || 6 || pF
OPEN-LOOP GAIN(1)
Open-Loop Voltage Gain VO = 10V, RL = 2k 90 126 dB
FREQUENCY RESPONSE(1)
Slew Rate 10 V/s
Gain-Bandwidth Product G = +1 4 MHz
Total Harmonic Distortion G = +1, f = 1kHz 0.0004 %
OUTPUT(1)
Voltage Output RL = 2k 11 11.5 V
Short Circuit Current 25 mA
POWER SUPPLY
Specified Operating Voltage 15 V
Operating Voltage Range 6 18 V
Current 6 7 mA
TEMPERATURE RANGE
Specification 25 +85 C
Operating 25 +85 C
Storage 40 +125 C
Thermal Resistance, JA 100 C/W
Same as specification for UAF42AP.
NOTES: (1) Specifications apply to uncommitted op amp, A 4. The three op amps forming the filter are identical to A4 but are tested as a complete filter.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the users own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
UAF42 2
PIN CONFIGURATION
Top View
Plastic DIP, P U Package
SOL-16, 16-Pin SOIC
Low-Pass VO 1 14 Frequency Adj2 Low-Pass VO 1 16 Frequency Adj2
VIN3 2 13 High-Pass VO NC 2 15 NC
VIN2 3 12 VIN1 VIN3 3 14 High-Pass VO
Auxiliary Op Amp, +In 4 11 Ground VIN2 4 13 VIN1
Auxiliary Op Amp, In 5 10 V+ Auxiliary Op Amp, +In 5 12 Ground
Auxiliary Op Amp, VO 6 9 V Auxiliary Op Amp, In 6 11 V+
Bandpass VO 7 8 Frequency Adj1 Auxiliary Op Amp, VO 7 10 V
Bandpass VO 8 9 Frequency Adj1
NOTE: NC: No Connection. For best
performance connect all NC pins to
ground to minimize inter-lead capacitance.
ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDERING INFORMATION
Power Supply Voltage ....................................................................... 18V PACKAGE
Input Voltage ............................................................................. VS 0.7V DRAWING TEMPERATURE
Output Short Circuit ................................................................. Continuous PRODUCT PACKAGE NUMBER(1) RANGE
Operating Temperature:
Plastic DIP, P; SOIC, U ................................................. 40C to +85C UAF42AP Plastic 14-pin DIP 010 25C to +85C
Storage Temperature: UAF42AU SOL-16 211 25C to +85C
Plastic DIP, P; SOIC, U ............................................... 40C to +125C NOTE: (1) For detailed drawing and dimension table, please see end of data
Junction Temperature: sheet, or Appendix C of Burr-Brown IC Data Book.
Plastic DIP, P; SOIC, U .............................................................. +125C
Lead Temperature (soldering, 10s) ................................................ +300C
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
ESD damage can range from subtle performance degradation
to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric
changes could cause the device not to meet its published
specifications.
3 UAF42
APPLICATIONS INFORMATION
The UAF42 is a monolithic implementation of the proven The basic building element of the most commonly used filter
state-variable analog filter topology. Pin-compatible with types is the second-order section. This section provides a
the popular UAF41 Analog Filter, it provides several complex-conjugate pair of poles. The natural frequency, n,
improvements. and Q of the pole pair determines the characteristic response
Slew Rate of the UAF42 has been increased to 10V/s of the section. The low-pass transfer function is
versus 1.6V/s for the UAF41. Frequency Q product of
VO(s) ALPn2
the UAF42 has been improved, and the useful natural = (1)
frequency extended by a factor of four to 100kHz. FET- VI(s) s2 + s n/Q + n2
input op amps on the UAF42 provide very low input bias
current. The monolithic construction of the UAF42 provides The high-pass transfer function is
lower cost and improved reliability. VHP(s) AHPs2
= (2)
VI(s) s2 + s n/Q + n2
DESIGN PROGRAM
Application Bulletin AB-035 and a computer-aided design The band-pass transfer function is
program, available from Burr-Brown, make it easy to design
and implement many kinds of active filters. The DOS- VBP(s) ABP(n/Q) s
compatible program guides you through the design process = (3)
VI(s) s2 + s n/Q + n2
and automatically calculates component values.
Low-pass, high-pass, band-pass and band-reject (notch) A band-reject response is obtained by summing the low-pass
filters can be designed. The program supports the three most and high-pass outputs, yielding the transfer function
commonly used all-pole filter types: Butterworth, Chebyshev
and Bessel. The less-familiar Inverse Chebyshev is also VBR(s) ABR(s2 +n2)
supported, providing a smooth passband response with ripple = (4)
in the stop-band. VI(s) s2 + s n/Q + n2
With each data entry, the program automatically calculates The most commonly used filter types are formed with one or
and displays filter performance. This allows a spreadsheet- more cascaded second-order sections. Each section is de-
like what if design approach. For example, you can quickly signed for n and Q according to the filter type (Butterworth,
determine, by trial and error, how many poles are required Bessel, Chebyshev, etc.) and cutoff frequency. While tabu-
for a desired attenuation in the stopband. Gain/phase plots lated data can be found in virtually any filter design text, the
may be viewed for any response type. design program eliminates this tedious procedure.
Second-order sections may be non-inverting (Figure 1) or
inverting (Figure 2). Design equations for these two basic
configurations are shown for reference. The design program
solves these equations, providing complete results, includ-
ing component values.
UAF42 4
HP Out BP Out LP Out
RF1 RF2
12 13 8 7 14 1
R1
50k
R2
50k C1 C2
2
1000pF 1000pF
50k
RG A1 A2 A3
VIN 3
R4
50k
RQ UAF42
11
NOTE: If RG = 50k, you can eliminate the external
gain-setting resistor by connecting VIN to pin 2. Pin numbers are for DIP
package. SOL-16 pinout
is different.
Design Equations
R1
1+
R2 R2
1. n2 = 4. ALP =
R1 RF1 RF2 C1 C2
1 1 1
RG + +
RG RQ R4
R4 (RG + RQ)
1+ 1/2
R G RQ R2 RF1 C1 R2
2. Q= 1+
R2 R1 RF2 C2 R2 R1
1+ 5. AHP = ALP =
R1 R1
1 1 1
RG + +
RG RQ R4
1/2
R1 R1 RF1 C1
3. QALP = QAHP = ABP
R2 R2 RF2 C2 R4
6. ABP =
RG
FIGURE 1. Non-Inverting Pole-Pair.
5 UAF42
HP Out BP Out LP Out
RG RF1 RF2
VIN
12 13 8 7 14 1
R1
50k
R2
50k C1 C2
2
1000pF 1000pF
50k
A1 A2 A3
3
R4
50k
RQ UAF42
11
NOTE: If RQ = 50k, you can eliminate the external
Q-setting resistor by connecting pin 2 to ground. Pin numbers are for DIP
package. SOL-16 pinout
is different.
Design Equations
R2 R1
1. n2 = 4. ALP =
R1 RF1 RF2 C1 C2 RG
1/2
R4 1 RF1 C1 R2 R2
2. Q= 1 + 5. AHP = ALP =
RQ R1 R2 RF2 C2 R1 RG
1 1 1
+ +
R1 R2 RG
1/2
R1 R1 RF1 C1 R4 1
3. QALP = QAHP = ABP 6. ABP = 1 +
R2 R2 RF2 C2 RQ
1 1 1
RG + +
R1 R2 RG
FIGURE 2. Inverting Pole-Pair.
UAF42 6
