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May 1997
ML2111* Universal Dual High Frequency Filter
GENERAL DESCRIPTION
The ML2111 consists of two independent switched capacitor filters that operate at up to 150kHz and perform second order filter functions such as lowpass, bandpass, highpass, notch and allpass. All filter configurations, including Butterworth, Bessel, Cauer, and Chebyshev can be formed. The center frequency of these filters is tuned by an external clock or the external clock and resistor ratio. The ML2111 frequency range is specified up to 150kHz with 5.0V 10% power supplies. Using a single 5.0V 10% power supply the frequency range is up to 100kHz. These filters are ideal where center frequency accuracy and high Qs are needed. The ML2111 is a pin compatible superior replacement for MF10, LMF100, and LTC1060 filters.
FEATURES
s s s
Specified for operation up to 150kHz Center frequency x Q product 5MHz Separate highpass, notch, allpass, bandpass, and lowpass outputs Center frequency accuracy of 0.4% or 0.8% max. Q accuracy of 4% or 8% max. Clock inputs are TTL or CMOS compatible Single 5V (2.25V) or 5V supply operation
s s s s
* Some Packages Are End Of Life and Obsolete
BLOCK DIAGRAM
7 VA+ INVA 4
+
8 VD+ N/AP/HPA
3 +
5 S1A
2 BPA
1 LPA
S2A
AGND 15 CLKA 10 50/100HOLD 12 LEVEL SHIFT 9 CLKB 11 LEVEL SHIFT NON-OVERLAP CLOCK CONTROL LEVEL SHIFT NON-OVERLAP CLOCK
SA/B 6
INVB 17 VA14 VD13
+
S2B
+
S1B 16
BPB 19
LPB 20
N/AP/HPB 18
1
ML2111
PIN CONFIGURATION
ML2111 20-Pin PDIP (P20) 20-Pin SOIC (S20)
LPA 1 BPA 2 N/AP/HPA 3 INVA 4 S1A 5 SA/B 6 VA+ 7 VD+ 8 LSh 9 CLKA 10 20 LPB 19 BPB 18 N/AP/HPB 17 INVB 16 S1B 15 AGND 14 VA13 VD12 50/100/HOLD 11 CLKB
TOP VIEW
PIN DESCRIPTION
PIN NAME FUNCTION PIN NAME FUNCTION
1 2 3 4 5 6 7 8 9
LPA BPA N/AP/HPA INVA S1A SA/B VA+ V D+ LSh
Lowpass output for biquad A. Bandpass output for biquad A. Notch/allpass/highpass output for biquad A. Inverting input of the summing op amp for biquad A. Auxiliary signal input pin used in modes 1a, 1d, 4, 5, and 6b. Controls S2 input function.
11 12
CLKB
Clock input for biquad B. center-frequency ratio of 50:1 or 100:1, or to stop the clock to hold the last sample of the bandpass or lowpass outputs.
50/100/HOLDInput pin to control the clock-to-
13 14 15 16
V DVAAGND S1B INVB N/AP/HPB BPB LPB
Negative digital supply. Negative analog supply. Analog ground. Auxiliary signal input pin used in modes 1a, 1d, 4, 5, and 6b. Inverting input of the summing op amp for biquad B. Notch/allpass/highpass output for biquad B. Bandpass output for biquad B. Lowpass output for biquad B.
Positive analog supply. Positive digital supply. Reference point for clock input levels. Logic threshold typically 1.4V above LSh voltage. Clock input for biquad A. 17 18 19 20
10
CLKA
2
ML2111
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. Supply Voltage |VA+|, |VD+| - |VA-|, |VD-| ...................................... 13V VA+, VD+ to LSh ..................................................... 13V Inputs ...................... |VA+, VD+| +0.3V to |VA-, VD-| -0.3V Outputs ................... |VA+, VD+| +0.3V to |VA-, VD-| -0.3V |VA+| to |VD+| ........................................................ 0.3V Junction Temperature .............................................. 150C Storage Temperature Range ...................... -65C to 150C Lead Temperature (Soldering, 10 sec) ..................... 300C Thermal Resistance (qJA) 20-Pin PDIP ...................................................... 67C/W 20-Pin SOIC ..................................................... 95C/W
OPERATING CONDITIONS
Temperature Range ML2111CCX .............................................. 0C to 70C ML2111CIP ............................................. -40C to 85C Supply Range ........................................ 2.25V to 6.0V
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, VA+ = VD+ = 5V 10%, VA- = VD- = -5V 10%, CL = 25pF, VIN = 1.41VPK (1.000VRMS), Clock Duty Cycle = 50%, TA = Operating Temperature Range (Note 1)
SYMBOL FILTER f0(MAX) Maximum Center Frequency (Note 2) VIN=1VPK (0.707VRMS) Figure 15 (Mode 1), Q 50, Q Accuracy 25% Figure 15 (Mode 1), Q 20, Q Accuracy 15% f 0(MIN) Minimum Center Frequency (Note 2) VIN=1VPK (0.707VRMS) Figure 15 (Mode 1), Q 50, Q Accuracy 30% Figure 15 (Mode 1), Q 20, Q Accuracy 15% f0 Temperature Coefficient Clock to Center Frequency Ratio Q = 10, Figure 15 (Mode 1) 100:1, fCLK = 5MHz fCLK < 5MHz 50:1, fCLK = 5MHz B Suffix C Suffix B Suffix C Suffix fCLK Clock Frequency Clock Feedthrough Q Accuracy Q 20, Q Accuracy 15% fCLK 5MHz fCLK = 5MHz, Q = 10, 50:1, Figure 15 (Mode 1) fCLK = 5MHz, Q = 10, 100:1, Figure 15 (Mode 1) Q Temperature Coefficient V OS2,3 DC Offset fCLK < 5MHz, Q = 10 50:1, fCLK = 5MHz SA/B = High or Low 100:1, fCLK = 5MHz SA/B =High or Low B Suffix C Suffix B Suffix C Suffix B Suffix C Suffix B Suffix C Suffix 20 7 7 14 14 40 60 60 100 49.65 49.45 99.6 99.2 2.5 10 25 25 -10 49.85 49.85 100.0 100.0 50.05 50.25 100.4 100.8 7500 20 3 5 4 8 kHz mV(P-P) % % % % ppm/C mV mV mV mV 100 150 kHz kHz Hz Hz ppm/C PARAMETER CONDITIONS MIN TYP MAX UNITS
3
ML2111
ELECTRICAL CHARACTERISTICS
SYMBOL FILTER (Continued) Gain Accuracy, DC Lowpass Gain Accuracy, Bandpass at f0 R1,R3 = 20kW, R2 = 2kW, 100:1, f0 = 50kHz, Q = 10 R1,R3 = 20kW, R2 = 2kW, 100:1, f0 = 50kHz, Q = 10 Gain Accuracy, DC Notch Output Noise (Note 3) Figure 15 (Mode 1), Q = 1, R1 = R2 = R3 = 2kW Lowpass R1,R3 = 20kW, R2 = 2kW, 100:1, f0 = 50kHz, Q = 10 Bandpass 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 Notch 100kHz, 50:1 50kHz, 100:1 Noise (Note 3) Figure 15 (Mode 1), Q = 10, R3 = 20kW, R2 = 2kW Bandpass, R1 = 20kW Lowpass, R1 = 2kW Notch, R1 = 2kW Crosstalk 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 B Suffix C Suffix 0.01 1 1 0.02 103 121 120 150 115 135 262 333 268 342 64 72 -50 2 4 6 2 % % % % V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS dB PARAMETER
(Continued)
CONDITIONS MIN TYP MAX UNITS
fCLK = 5MHz, f0= 100kHz
FILTER, VA+ = VD+ = 2.25V, VA- = VD- = -2.25V, VIN = 0.707 x VPK (0.5 x VRMS) f 0(MAX) Maximum Center Frequency Figure 15 (Mode 1), Q 50, Q Accuracy 30% Figure 15 (Mode 1), Q 20, Q Accuracy 15% f0(MIN) Minimum Center Frequency Figure 15 (Mode 1), Q 50, Q Accuracy 30% Figure 15 (Mode 1), Q 20, Q Accuracy 15% Clock to Center Frequency Ratio Q = 10, Figure 15 (Mode 1) 100:1, fCLK = 2.5MHz 50:1, fCLK = 2.5MHz B Suffix C Suffix B Suffix C Suffix fCLK Clock Frequency Q Accuracy Q 20, Q Accuracy 15% fCLK = 2.5MHz, Q = 10, 50:1, Figure 15 (Mode 1) fCLK = 2.5MHz, Q = 10, 100:1, Figure 15 (Mode 1) B Suffix C Suffix B Suffix C Suffix 3 6 25 25 49.65 49.45 99.60 99.20 2.5 49.85 49.85 100.0 100.0 50.05 50.25 100.4 100.8 5000 4 8 kHz % % % % 75 100 kHz kHz Hz Hz
4
ML2111
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
(Continued)
CONDITIONS MIN TYP MAX UNITS
FILTER, VA+ = VD+ = 2.25V, VA- = VD- = -2.25V, VIN = 0.707 x VPK (0.5 x VRMS) (Continued) Noise (Note 3) Figure 15 (Mode 1), Q = 1, R1 = R2 = R3 = 2kW Lowpass Bandpass 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 Notch 100kHz, 50:1 50kHz, 100:1 Noise (Note 3) Figure 15 (Mode 1), Q = 10, R3 = 20kW, R2 = 2kW Bandpass, R1 = 20kW Lowpass, R1 = 2kW Notch, R1 = 2kW OPERATIONAL AMPLIFIERS VOS1 AVOL DC Offset Voltage DC Open Loop Gain Gain Bandwidth Product Slew Rate Output Voltage Swing (Clipping Level) Output Short Circuit Current RL = 2kW, |V| from VA+ or VASource Sink CLOCK VCLK Input Low Voltage VCLK Input High Voltage CLKA, CLKB Pulse Width CLKA, CLKB Pulse Width SUPPLY (IA+)+(ID+) Supply Current, (VA+) + (VD+) (IA-)+(ID-) ILSh Supply Current, (VA-) + (VD-) Supply Current, LSh fCLK = 5MHz fCLK = 5MHz fCLK = 5MHz 13 12 0.5 22 21 1 mA mA mA |VD+| - |VD-| 4.5V |VD+| - |VD-| .90V 3.0 100 66 0.6 V V ns ns RL = 1kW 2 95 2.4 2.0 0.5 50 25 1.2 15 mV dB MHz V/s V mA mA 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 100kHz, 50:1 50kHz, 100:1 105 123 122 152 117 138 265 335 270 245 65 73 V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS V RMS
Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions. Note 2: The center frequency is defined as the peak of the bandpass output. Note 3: The noise is meassured with an HP8903A audio analyzer with a bandwidth of 700kHz, which is 7.5 times the f0 at 50:1 and 15 times the f0 at 100:1.
5
ML2111
TYPICAL PERFORMANCE CURVES
0.4 0.0 -0.4 Q = 20 Q = 50 5 4 3 Mode 1 Q = 10 VIN = 0.707VRMS TA = 85C 1 0 -1 -2 -3 TA = 25C
fCLK/f0 Deviation (%)
-0.8 -1.2 -1.6 -2.0 -2.4 -2.8 Mode 1 TA = 25C VIN = 0.707VRMS Q=5 Q = 10
fCLK/f0 Deviation (%)
2
0
2
4
6
8
10
0
2
4
6
8
10
fCLK (MHz)
fCLK (MHz)
Figure 1A. fCLK/f0 vs. fCLK (50:1, VS = 5V)
0.4 Q = 50 0.0 -0.4 Q = 20 0.0 0.5
fCLK/f0 Deviation (%)
fCLK/f0 Deviation (%)
-0.8 -1.2 -1.6 -2.0 -2.4 -2.8 -3.2 0 2 4 6 8 10 Mode 1 TA = 25C VIN = 0.707VRMS Q = 10
TA = 25C -0.5
-1.0
Q=5
-1.5
Mode 1 Q = 10 VIN = 0.707VRMS
TA = 85C
-2.0
0
2
4
6
8
10
fCLK (MHz)
fCLK (MHz)
Figure 1B. fCLK/f0 vs. fCLK (100:1, VS = 5V)
16 14 12
fCLK/f0 Deviation (%)
10
8 Q = 10 Mode 1 TA = 25C VIN = 0.5VRMS
fCLK/f0 Deviation (%)
10 8 6
6 Mode 1 Q = 10 VIN = 0.5VRMS
TA = 85C
4
Q = 20 4 2 0 -2 0 1 2 3 4 5 6 Q = 50 Q=5
2
TA = 25C
0
7
8
9
-2
0
1
2
3
4
5
6
7
8
9
fCLK (MHz)
fCLK (MHz)
Figure 1C. fCLK/f0 vs. fCLK (50:1, VS = 2.5V)
6
ML2111
TYPICAL PERFORMANCE CURVES
5 4 3 2 1 Q = 20 0 -1 -2 Q = 10 Q=5 0 1 2 3 4 5 6 7 8 9 -2 0 1 2 3 4 5 6 Q = 50 Mode 1 TA = 25C VIN = 0.5VRMS
(Continued)
12 10 8 6 4 2 0 TA = 25C 7 8 9 Mode 1 Q = 10 VIN = 0.5VRMS TA = 85C
fCLK/f0 Deviation (%)
fCLK (MHz)
fCLK/f0 Deviation (%)
fCLK (MHz)
Figure 1D. fCLK/f0 vs. fCLK (100:1, VS = 2.5V)
0.08 0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06 -40 -0.01 -40 Mode 1 Q = 10 f0 = 100kHz fCLK = 5MHz VIN = 0.707VRMS 0.04 Mode 1 Q = 10 f0 = 50kHz fCLK = 5MHz VIN = 0.707VRMS
0.03
fCLK/f0 Deviation (%)
fCLK/f0 Deviation (%)
100
0.02
0.01
0
-20
0
20
40
60
80
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
Figure 2A. fCLK/f0 Deviation vs. Temperature (50:1, VS = 5V)
0.10 0.08 0.06
fCLK/f0 Deviation (%)
Figure 2B. fCLK/f0 Deviation vs. Temperature (100:1, VS = 5V)
0.06
fCLK/f0 Deviation (%)
0.04 0.02 0.00 -0.02 -0.04 -0.06 -40
Mode 1 Q = 10 f0 = 50kHz fCLK = 2.5MHz VIN = 0.5VRMS
0.04
0.02
0.00 Mode 1 Q = 10 fo = 25kHz fCLK = 2.5MHz VIN = 0.5VRMS
-0.02
-0.04
-20
0
20
40
60
80
100
-0.06 -40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
Figure 2C. fCLK/f0 Deviation vs. Temperature (50:1, VS = 2.5V)
Figure 2D. fCLK/f0 Deviation vs. Temperature (100:1, VS = 2.5V)
7
ML2111
TYPICAL PERFORMANCE CURVES
20 16 12 Mode 1 TA = 25C VIN = 0.707VRMS
(Continued)
20
16 Q = 10 Mode 1 Q = 10 VIN = 0.707VRMS TA = 25C
Q Deviation (%)
8 Q=5 4 0 -4 -8
Q Deviation (%)
12
8
4 TA = 85C
Q = 20 Q = 50 0
0
2
4
6
8
10
-4
0
2
4
6
8
10
fCLK (MHz)
fCLK (MHz)
Figure 2E. Q Error vs. fCLK (50:1, VS = 5V)
20 15 10 Mode 1 TA = 25C VIN = 0.707VRMS 20 Mode 1 Q = 10 VIN = 0.707VRMS
Q = 10
16
Q Deviation (%)
Q Deviation (%)
12 TA = 85C 8
5 Q=5 0 -5 -10 Q = 50 -15 0 2 4 6 8 10 Q = 20
4
0 TA = 25C -4 0 2 4 6 8 10
fCLK (MHz)
fCLK (MHz)
Figure 2F. Q Error vs. fCLK (100:1, VS = 5V)
10 8
5
Q = 10 4
Q Deviation (%)
Q=5
Q = 20
-5
Q Deviation (%)
0
Mode 1 Q = 10 VIN = 0.5VRMS
TA = 25C
0 TA = 85C -4
-10 Mode 1 TA = 25C VIN = 0.5VRMS 0 1 2 3 4 5
Q = 50
-15
-20
6
7
-8
0
1
2
3
4
5
6
7
fCLK (MHz)
fCLK (MHz)
Figure 2G. Q Error vs. fCLK (50:1, VS = 2.5V)
8
ML2111
TYPICAL PERFORMANCE CURVES
16 12 8 Mode 1 TA = 25C VIN = 0.5VRMS Q = 10 Q=5
(Continued)
16 12 8 Mode 1 Q = 10 VIN = 0.5VRMS
Q Deviation (%)
Q Deviation (%)
4 0 -4 -8 -12 0 1 2 3 4
4 0 -4 -8 -12
TA = 85C
Q = 20 Q = 50
TA = 25C
5
6
7
0
1
2
3
4
5
6
7
fCLK (MHz)
fCLK (MHz)
Figure 2H. Q Error vs. fCLK (100:1, VS = 2.5V)
0.4 0.6 0.4 0.2
0.2
Q Deviation (%)
Q Deviation (%)
0.0
0.0 -0.2 -0.4 -0.6 -0.8 -1.0 -40 Mode 1 Q = 10 f0 = 50kHz fCLK = 5MHz VIN = 0.707VRMS -20 0 20 40 60 80 100
-0.2
-0.4 Mode 1 Q = 10 f0 = 100kHz fCLK = 5MHz VIN = 0.707VRMS -20 0 20 40 60 80 100
-0.6
-0.8 -40
Temperature (C)
Temperature (C)
Figure 3A. Q Deviation vs. Temperature (50:1, VS = 5V)
0.2
Figure 3B. Q Deviation vs. Temperature (100:1, VS = 5V)
0.2 Mode 1 Q = 10 f0 = 25kHz fCLK = 2.5MHz VIN = 0.5VRMS
Q Deviation (%)
-0.2
Mode 1 Q = 10 f0 = 50kHz fCLK = 2.5MHz VIN = 0.5VRMS
Q Deviation (%)
20 60 100
0.0
0.0
-0.2
-0.4 -40
-20
0
40
80
-0.4 -40
-20
0
20
40
60
80
100
Temperature (C)
Temperature (C)
Figure 3C. Q Deviation vs. Temperature (50:1, VS = 2.5V)
Figure 3D. Q Deviation vs. Temperature (100:1, VS = 2.5V)
9
ML2111
TYPICAL PERFORMANCE CURVES
4 Mode 1 TA = 25C fCLK = 5MHz VIN = 1VRMS
(Continued)
0.05 Mode 1 TA = 25C 50:1 or 100:1 fCLK = 5MHz VIN = 1VRMS 0.0
fCLK/f0 Deviation (%)
0
100:1 50:1 -4
-8 0.1
fCLK/f0 Deviation (%)
1
10 Ideal Q (R3/R2)
100
-0.05 0.1
1
10 Ideal Q (R3/R2)
100
Figure 4A. fCLK/f0 Deviation vs. Q (VS = 5V)
4
Figure 4A. fCLK/fNOTCH Deviation vs. Q (VS = 5V)
2
0
0
Q Deviation (%)
-4
Q Deviation (%)
-2
-8 Mode 1 TA = 25C f0 = 100kHz fCLK = 5MHz VS = 5V 1 10 Ideal Q (R3/R2) 100
-4 Mode 1 TA = 25C f0 = 50kHz fCLK = 5MHz VS = 5V 1 10 Ideal Q (R3/R2) 100
-12
-6
-16 0.1
-8 0.1
Figure 5A. Q Deviation vs. Q (50:1, VS = 5V)
70
Figure 5B. Q Deviation vs. Q (100:1, VS = 5V)
70
VOUT = 2V
VOUT = 1.41V
VOUT = 0.5V
Single Frequency Distortion Level (dB)
Single Frequency Distortion Level (dB)
60 50 40 30 20 10 0 Mode 1 Q=1 f0 = 100kHz fCLK = 5MHz VS = 5V TA = 25C RL = 2k Low Pass Output 0 20 40 60
60 50 40 30 20 10 0
VOUT = 3V VOUT = 2V VOUT = 4V VOUT = 1.41V VOUT = 0.5V Mode 1 Q=1 f0 = 50kHz fCLK = 5MHz VS = 5V TA = 25C RL = 2k Low Pass Output 0 10 20 30 40 50
VOUT = 3V
VOUT = 4V
80
100
fIN (kHz)
fIN (kHz)
Figure 6A. Distortion vs. fIN (50:1, VS = 5V)
Figure 6B. Distortion vs. fIN (100:1, VS = 5V)
10
ML2111
TYPICAL PERFORMANCE CURVES
250 Mode 1 50:1 R1 = R2 = R3 = 2k BANDPASS OUTPUT VS = 5V f0 = 100kHz fCLK = 5MHz
(Continued)
2500 Mode 1 50:1 R1 = R3 = 20k, R2 = 2k BANDPASS OUTPUT VS = 5V f0 = 100kHz fCLK = 5MHz
200
2000
Noise (nV/Hz)
Noise (nV/Hz)
150
1500
100
1000
50
500
0
0 0 100 200 300 400 500 Frequency (kHz)
0
100
200
300
400
500
Frequency (kHz)
Figure 7A. Noise Spectrum Density (Q = 1)
0.8
Figure 7B. Noise Spectrum Density (Q = 10)
100
0.4
80
fCLK/fNotch Deviation (%)
Notch Depth (dB)
0.0
100:1 50:1
100:1 60 50:1 40 Mode 1 TA = 25C Q = 10 VS = 5V VIN = 0.707VRMS 0 2 4 6 8 10
-0.4
-0.8 Mode 1 TA = 25C Q = 10 VS = 5V VIN = 0.707VRMS 0 2 4 6 8 10
-1.2
20
-1.6
0
fCLK (MHz)
fCLK (MHz)
Figure 8. fCLK/fNOTCH vs. fCLK
16 Q = 10 TA = 25C LSh = VSS 50:1 fCLK = 10MHz 14 15
Figure 9. Notch Depth vs. fCLK
14
Supply Current (mA)
fCLK = 5MHz 12 fCLK = 3MHz
Supply Current (mA)
Mode 1 VS = 5V fCLK = 5MHz 50:1
13
12
10
fCLK = 250kHz 11
8
2
3
4 Supply Voltage (V)
5
6
10 -40
-20
0
20
40
60
80
100
Temperature (C)
Figure 10. Supply Current vs. Supply Voltage
Figure 11. Supply Current vs. Temperature
11
ML2111
FUNCTIONAL DESCRIPTION
POWER SUPPLIES The analog (VA+) and digital (VD+) supply pins, in most cases, are tied together and bypassed to AGND with 100nF and 10nF disk ceramic capacitors. The supply pins can be bypassed separately if a high level of digital noise exists. These pins are internally connected by the IC substrate and should be biased from the same DC source. The ML2111 operates from either a single supply from 4V to 12V, or with dual supplies at 2V to 6V. CLOCK INPUT PINS AND LEVEL SHIFT With dual supplies equal to or higher than 4.0V, the LSh pin can be connected to the same potential as either the AGND or the VA- pin. With single supply operation the negative supply pins and LSh pin should be tied to the system ground. The AGND pin should be biased half way between VA+ and VA-. Under these conditions the clock levels are TTL or CMOS compatible. Both input clock pins share the same level shift pin. 50/100/HOLD Tying the 50/100/HOLD pin to the VA+ and VD+ pins makes the filter operate in the 50:1 mode. Tying the pin half way between VA+ and VA- makes the filter operate in the 100:1 mode. The input range for 50/100/HOLD is either 2.5V 0.5V with a total power supply range of 5V, or 5V 0.5V with a total power supply range of 10V. When 50/100/HOLD is tied to the negative power supply input, the filter operation is stopped and the bandpass and lowpass outputs act as a sample/hold circuit which holds the last sample. S1A & S1B These voltage signal input pins should be driven by a source impedance of less than 5kW. The S1A and S1B pins can be used to feedforward the input signal for allpass filter configurations (see modes 4 & 5) or to alter the clock-to-center-frequency ratio (fCLK/f0) of the filter (see modes 1b, 1c, 2a, & 2b). When these pins are not used they should be tied to the AGND pin. SA/B When SA/B is high, the S2 negative input of the voltage summing device is tied to the lowpass output. When the SA/B pin is connected to the negative supply, the S2 input switches to ground. AGND AGND is connected to the system ground for dual supply operation. When operating with a single positive supply the analog ground pin should be biased half way between VA+ and VA-, and bypassed with a 100nF capacitor. The positive inputs of the internal op amps and the reference point of the internal switches are connected to the AGND pin. fCLK/f0 RATIO The ML2111 is a sampled data filter and approximates continuous time filters. The filter deviates from its ideal continuous filter model when the (fCLK/f0) ratio decreases and when the Qs are low. f0 Q PRODUCT RATIO The f0 Q product of the ML2111 depends on the clock frequency and the mode of operation. The f0 Q product is mainly limited by the desired f0 and Q accuracy for clock frequencies below 1MHz in mode 1 and its derivatives. If the clock to center frequency ratio is lowered below 50:1, the f0 Q product can be further increased for the same clock frequency and for the same Q value. Mode 3, (Figure 23) and the modes of operation where R4 is finite, are "slower" than the basic mode 1. The resistor R4 places the input op amp inside the resonant loop. The finite GBW of this op amp creates an additional phase shift and enhances the Q value at high clock frequencies. OUTPUT NOISE The wideband RMS noise on the outputs of the ML2111 is nearly independent of the clock frequency, provided that the clock itself does not become part of the noise. Noise at the BP and LP outputs increases for high values of Q.
FILTER FUNCTION DEFINITIONS
Each filter of the ML2111, along with external resistors and a clock, approximates second order filter functions. These are tabulated below in the frequency domain. 1. Bandpass function: available at the bandpass output pins (BPA, BPB), Figure 12. s w0 Q G(s) = HOBP (1) s w0 s2 + + w02 Q

where: HOBP = Gain at w = w 0 f0 = w 0/2p. The center frequency of the complex pole pair is f0. It is measured as the peak frequency of the bandpass output. Q = the Quality factor of the complex pole pair. It is the ratio of f0 to the -3dB bandwidth of the 2nd order bandpass function. The Q is always measured at the filter BP output.
12
ML2111
FILTER FUNCTION DEFINITIONS (Continued)
2. Lowpass function: available at the LP output pins, Figure 13. G(s) = HOLP s2 + where: HOLP = DC gain of the LP output 3. Highpass function: available only in mode 3 at N/AP/HPA and N/AP/HPB, Figure 14.
G(s) = HOHP s s w0 + w 02 s2 + Q
fL f0 fH
BANDPASS OUTPUT
GAIN (V/V)
s w + w Q
0
w02
0
2
(2)
HOBP 0.707 HOBP

2

f (LOG SCALE)
(3)
Q=
HOHP = Gain of the HP output for f (R) fCLK/2.
f0 ; f0 = fL fH fH - fL
fL = f0
fH = f0
-1 2Q + 1 2Q +
1 2Q 1 2Q
2
+1
2
+ 1
Figure 12.
LOWPASS OUTPUT HIGHPASS OUTPUT
HOP
GAIN (V/V)
HOLP 0.707 HOLP HOP
GAIN (V/V)
HOHP 0.707 HOHP
fP f (LOG SCALE)
fC
fC = f0
1 - 1 + 1 - 1 2Q 2Q
2 2
fC
fP
2
+1
fC = f0
fP = f0 1 -
1 2Q 2
1
HOP = HOLP
1 1 1 2Q + 1- 2Q ! 1 "# f = f 1! 2Q $#
f (LOG SCALE)
2
2
2
-1
"# + 1# #$
-1
P
0
2
1 1 1Q 4Q 2
HOP = HOHP
1
1 1 1Q 4Q 2
Figure 13.
Figure 14.
13
ML2111
FILTER FUNCTION DEFINITIONS
4. Notch function: available at N/AP/HPA and N/AP/HPB for several modes of operation.
G(s) = HON2 s2
OPERATION MODES
There are three basic modes of operation -- Modes 1, 2, and 3 , each of which has derivatives; and four secondary modes of operation -- Modes 4, 5, 6, and 7, each of which also has derivatives. In Figure 15, the input amplifier is outside the resonant loop. Because of this, mode 1 and its derivatives (modes 1a, 1b, 1c, and 1d) are faster than modes 2 and 3. Mode 1 provides a clock tunable notch. It is a practical configuration for second order clock tunable bandpass/ notch filters. In mode 1, a band pass output with a very high Q, together with unity gain can be obtained with the dynamics of the remaining notch and lowpass outputs. Mode 1a (Figure 16) represents the simplest hookup of the ML2111. It is useful when voltage gain at the bandpass output is required. However, the bandpass voltage gain is equal to the value of Q, and second order, clock tunable, BP resonator can be achieved with only 2 resistors. The filter center frequency directly depends on the external clock frequency. Mode 1a is not practical for high order filters as it requires several clock frequencies to tune the overall filter response. Modes 1b and 1c, Figures 17 and 18, are similar. They both produce a notch with a frequency which is always equal to the filter center frequency. The notch and the center frequency can be adjusted with an external resistor ratio.
4s + w 9 s w + w + Q
2 n 2 0
0
2
(4)
HON2 = Gain of the notch output for f (R) fCLK/2. HON1 = Gain of the HP output for f (R) 0 fn = w n/2p. The frequency of the notch occurrence is f n. 5. Allpass function: available at N/AP/HPA and N/AP/ HPB for modes 4 and 4a.
G(s) = HOAP s w0 + w02 Q s w0 s2 + + w02 Q s2 -
(5)
HOAP = Gain of the allpass output for 0 < f < fCLK/2 For allpass functions, the center frequency and the Q of the numerator complex zero pair is the same as the denominator. Under these conditions the magnitude response is a straight line. In mode 5, the center frequency fZ of the numerator complex zero pair is different than f0. For high numerator Q's, the magnitude response will have a notch at fZ.
1/2 ML2111
R3 R2
1/2 ML2111
VIN
R3
N 3 (18) S1A 5 (16) BP 2 (19) LP 1 (20)
R2
BP2 3 (18)
S1A 5 (16)
BP1 2 (19)
LP 1 (20)
R1 VIN 4 (17)
+ +
4 (17)
+ +
SA/B 6
15
SA/B
V+
6
15
V+
f0 =
fCLK R2 R3 ; fn = f0 ; HOLP = ; HOBP = ; 100(50) R1 R1 HON1 = R2 R3 ;Q = R1 R2
f0 =
fCLK R3 R3 ;Q = ; HOBP1 = ; 100(50) R2 R2
HOBP2 = 1non - inverting); HOLP = -1 (
Figure 16. Mode 1a: 2nd Order Filter Providing Bandpass, Lowpass
Figure 15. Mode 1: 2nd Order Filter Providing Notch, Bandpass, Lowpass
14
ML2111
MODE 6a 6b 7 BPA, BPB LP LP LP N/AP/HPA, N/AP/HPB HP LP AP fC fCLK R2 100(50) R3 fCLK R2 100(50) R3 fCLK R2 100(50) R3 fCLK R2 100(50) R3 fZ
Table 1. First Order Functions.
MODE 1 1a 1b
LPA, LPB LP LP LP
BPA, BPB BP BP BP
N/AP/HPA&B Notch BP Notch fCLK 100(50) fCLK 100(50)
f0
fN f0
fCLK R6 1+ R5 + R6 100(50) fCLK R6 R5 + R6 100(50)
fCLK 100(50)
fCLK R6 1+ R5 + R6 100(50) fCLK R6 R5 + R6 100(50)
1c
LP
BP
Notch
1d 2
LP LP
BP BP Notch
fCLK R2 1+ R4 100(50)
fCLK R2 R6 1+ + R4 R5 + R6 100(50) fCLK R2 R6 + R4 R5 + R6 100(50) fCLK R2 R4 100(50)
fCLK 100(50)
fCLK R6 1+ R5 + R6 100(50) fCLK R6 R5 + R6 100(50)
2a
LP
BP
Notch
2b
LP
BP
Notch
3
LP
BP
HP
3a
LP
BP
Notch
fCLK R2 R4 100(50)
fCLK 100(50)
R fCLK h Rl 100(50)
4 4a
LP LP
BP BP
AP AP
fCLK R2 R4 100(50) fCLK R2 1+ R4 100(50) fCLK R2 1R4 100(50)
5
LP
BP
CZ
Table 2. Second Order Functions
15
ML2111
R6 R3 R2 R5
f0 =
N 3 (18) S1A 5 (16) BP 2 (19) LP 1 (20)
fCLK R6 1+ ; fn = f0 R5 + R6 100(50)
Q=
R1 VIN 4 (17)
R3 R6 1+ ;R5 < 5kW R2 R5 + R6
+ +
HON1 f 0 = HON2 f
1
6

fCLK R2 =2 R1

SA/B 6
15
HOBP = -
R3 -R2 / R1 ; HOLP = R1 1 + R6 / R5 + R6
0
5
V+
Figure 17. Mode 1b: 2nd Order Filter Providing Notch, Bandpass, Lowpass
R6 R3 R2
R5
f0 =
N 3 (18) S1A 5 (16) BP 2 (19) LP 1 (20)
fCLK R6 ; fn = f0 R5 + R6 100(50)
Q=
R1 VIN 4 (17)
R3 R6 ; R2 R5 + R6
+ +
HON1 f 0 = HON2 f
1
6

fCLK R2 =; 2 R1

SA/B 6
15
HOBP = -
R3 -R2 / R1 ; HOLP = ; R5 < 5kW R1 R6 / R5 + R6
0
5
V-
Figure 18. Mode 1c: 2nd Order Filter Providing Notch, Bandpass, Lowpass
R3B R2
R3A
N 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
R1 VIN 4 (17)
f0 =
+ +
fCLK R3 R2 ; Q = 1 + A ; HOBP = Q; R3B R1 100(50)
HOLP = -
R2 R2 ; VN VIN R1 R1
SA/B 6
15
V+
Figure 19. Mode 1d: 2nd Order Filter Providing Bandpass and Lowpass for Qs Greater Than or Equal To 1.
16
ML2111
R4 R3 R2
f0 =
N 3 (18) S1A 5 (16) BP 2 (19) LP 1 (20)
fCLK f R2 1+ ; fn = CLK ; 100(50) 100(50) R4
R3 R2 -R2 / R1 1+ ; HOLP = ; R2 R4 1 + R2 / R4
R1 VIN 4 (17)
Q=
0
5
+ +
HOBP =
-R3 -R2 / R1 ; HON1 f 0 = ; R1 1 + R2 / R 4
1
6
0
5
SA/B 6
15
HON2 f

fCLK -R2 = 2 R1

V+
Figure 20. Mode 2: 2nd Order Filter Providing Notch, Bandpass, Lowpass
R4 R6 R3 R2 R5
f0 =
fCLK R2 R6 R3 1+ + ; HOBP = ; 100(50) R 4 R5 + R6 R1
fCLK f R6 R2 1+ ; HON2 f CLK = ; 100(50) R5 + R6 2 R1
fn =
N 3 (18) S1A 5 (16) BP 2 (19) LP 1 (20)

R1 VIN 4 (17)
Q=
+ +
R3 R2 R6 1+ + ; R2 R 4 R5 + R6
HON1 f 0 = -
1
6
1 + R6 / R5 + R6 R2 ; R1 1 + R2 / R4 + R6 / R5 + R6
% &0 '
5
0
5
( ) *
SA/B 6
15
HOLP =
-R2 / R1 1 + R2 / R4 + R6 / R5 + R6
V+
0
5
0
5
Figure 21. Mode 2a: 2nd Order Filter Providing Notch, Bandpass, Lowpass
R4 R6 R3 R5
f0 =
fCLK R2 R6 + ; R 4 R5 + R6 100(50) fCLK R6 R3 R2 R6 ;Q = + ; 100(50) R5 + R6 R2 R4 R5 + R6
fn =
R2 N 3 (18) R1 VIN 4 (17) S1A 5 (16) BP 2 (19) LP 1 (20)
HON1 f 0 = + +
1
6
R2 R1
HON2 f

fCLK R2 R3 =; HOBP = ; R1 R1 2

% R6 / 0R5 + R65 (; & 0R2 / R45 + R6 / R5 + R6 ) ' *
SA/B 6
15
HOLP =
V-
0
-R2 / R1 R2 / R4 + R6 / R5 + R6
5
0
5
17
Figure 22. Mode 2b: 2nd Order Filter Providing Notch, Bandpass, Lowpass
ML2111
OPERATION MODES
(Continued) Modes 2, 2a, and 2b (Figures 20, 21, and 22) have notch outputs whose frequency, fn, can be tuned independently from the center frequency, f0. However, for all cases fn < f0. These modes are useful when cascading second order functions to create an overall elliptic highpass, bandpass or notch response. The input amplifier and its feedback resistors R2 and R4 are now part of the resonant loop. Because of this, mode 2 and its derivatives are slower than mode 1 and its derivatives. In Mode 3 (Figure 23) a single resistor ratio, R2/R4, can tune the center frequency below or above the fCLK/100 (or fCLK/50) ratio. Mode 3 is a state variable configuration since it provides a highpass, bandpass, lowpass output through progressive integration. Notches are acquired by summing the highpass and lowpass outputs (mode 3a, Figure 24). The notch frequency can be tuned below or The clock to center frequency ratio range is:
500 fCLK 100 50 or (mode 1c) 1 1 1 f0 100 50 fCLK 100 50 or or (mode 1b) 1 1 f0 2 2
(6) (7)
The input impedance of the S1 pin is clock dependent, and in general R5 should not be larger than 5kW for fCLK < 2.5MHz and 2kW for fCLK > 2.5MHz. Mode 1c can be used to increase the clock-to-center-frequency ratio beyond 100:1. The limit for the (fCLK/f0) ratio is 500:1 for this mode. The filter will exhibit large output offsets with larger ratios. Mode 1d (Figure 19) is the fastest mode of operation: center frequencies beyond 20kHz can easily be achieved at a 50:1 ratio.
R4 R3 R2
HP 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
R1 VIN 4 (17)
f0 =
fCLK R2 R3 R2 ;Q = ; R4 R2 R4 100(50)
+ +
HOHP = -
R2 R4 R3 ; HOLP = ; HOBP = R1 R1 R1
SA/B 6
15
V-
Figure 23. Mode 3: 2nd Order Filter Providing Highpass, Bandpass, Lowpass -- 1/2 ML2111
R2 R3 R4 R2
Q=
R4 R3 R2
f0 =
Rh fCLK f R2 ; fn = CLK ; 100(50) 100(50) R4 Rl
R2 R3 R4 ; HOBP = ; HOLP = ; R1 R1 R1
HP 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
HOHP = -
R1 VIN 4 (17)
+ +
HON f = f0 = Q
Rg External Op Amp NOTCH
1
6
R R
g l
HOLP -
Rg Rh
HOHP ;

Rl SA/B 6 15 Rh
HON2 f

R g R2 fCLK = ; 2 R h R1

V-
HON1 f 0 =
1
6
Figure 24. Mode 3a: 2nd Order Filter Providing Highpass, Bandpass, Lowpass, Notch -- 1/2 ML2111
18
+
Rg Rl
R4 R1
ML2111
OPERATION MODES
(Continued) frequency. Mode 4a (Figure 26) gives a non-inverting output, but requires an external op amp. Mode 5 is recommended if this response is unacceptable. Mode 5 (Figure 27) gives a flatter response than mode 4 if R1 = R2 = 0.02 R4. Modes 6 and 7 are used to construct 1st order filters. Mode 6a (Figure 28) gives a lowpass and a highpass single pole response. Mode 6b (Figure 29) gives an inverting and non-inverting lowpass single pole filter response. Mode 7 (Figure 30) gives an allpass and lowpass single pole response. above the center frequency through the resistor ratio Rh/ Rl. Because of this, modes 3 and 3a are the most versatile and useful modes for cascading second order sections to obtain high order elliptic filters. For very selective bandpass/bandreject filters the mode 3a approach , as in Figure 24, yields better dynamic range since the external op amp helps to optimize the dynamics of the output nodes of the ML2111. Modes 4 and 5 are useful for constructing allpass response filters. Mode 4, Figure 25, gives an allpass response, but due to the sampled nature of the filter, a slight 0.5 dB peaking can occur around the center
R3 R2
AP 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
R1 = R2 VIN 4 (17)
+ +
SA/B 6
15
V+
fo =
fCLK R3 R3 R2 ; Q= ; HOAP = - ; HOLP = -2; HOBP = -2 100 50 R2 R2 R1
05

Figure 25. Mode 4: 2nd Order Filter Providing Allpass, Bandpass, Lowpass -- 1/2 ML2111
R4 R3 R2
HP 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
f0 =
fCLK R2 R3 R2 ;Q = ; 100(50) R4 R2 R4
R5 R2 ; HOHP = ; 2R R1 R4 ; R1 R3 R1
R1 VIN 4 (17)
HOAP =
+ +
R5
HOLP = HOBP = -
SA/B 6
15
R
External Op Amp
V-
Figure 26. Mode 4a: 2nd Order Filter Providing Highpass, Bandpass, Lowpass, Allpass -- 1/2 ML2111
+
2R
19
ML2111
R3
R4
R2
R3 R2
HP 3 (18)
S1A 5 (16)
LP 2 (19) 1 (20)
CZ 3 (18)
S1A 5 (16)
BP 2 (19)
LP 1 (20)
R1 VIN 4 (17)
+ +
R1 VIN 4 (17)
+ +
SA/B 6
15
SA/B 6
15
V-
V+
f0 =
fCLK f R2 R1 1+ ; f Z = CLK 1 ; 100(50) 100(50) R4 R4
fC =
fCLK R2 R3 R2 ; HOLP = ; HOHP = 100(50) R3 R1 R1
Q=
R3 R2 R3 R1 1+ ;QZ = 1; R2 R4 R1 R4
HOBP =
R 4 / R1 - 1 R3 R2 1+ ; HOZ f 0 = ; R2 R1 R4 / R2 + 1

1
HOZ f

fCLK R2 = ; HOLP 2 R1

6 00 55 1 + 0R2 / R15 = 1 + 0R2 / R 45
Figure 28. Mode 6a: 1st Order Filter Providing Highpass, Lowpass -- 1/2 ML2111
Figure 27. Mode 5: 2nd Order Filter Providing Numerator Complex Zeroes, Bandpass, Lowpass -- 1/2 ML2111
R3 R2
VIN
R3
LP1 3 (18)
S1A 5 (16)
LP2 2 (19) 1 (20)
R1 = R2
R2 = R1
AP 3 (18)
S1A 5 (16)
LP 2 (19) 1 (20)
4 (17)
+ +
VIN 4 (17)
+ +
SA/B 6
SA/B
15
6
15
V-
V-
fC =
fCLK R2 R3 ; HOLP1 = 1; HOLP2 = 100(50) R3 R2
fP = fZ =
fCLK R2 R2 ; HOLP = 2 100(50) R3 R3
|GAIN AT OUTPUT| = 1 FOR 0 f Figure 29. Mode 6b: 1st Order Filter Providing Lowpass -- 1/2 ML2111
fCLK 2
Figure 30. Mode 7: 1st Order Filter Providing Allpass, Lowpass -- 1/2 ML2111
20
ML2111
1 LPA R31 R21 2 BPA 3 HPA 4 INVA VIN 1Vp-p 5V 5 S1A 6 SA/B 7 VA + 8 V D+ 9 LSh 10 CLKA CLKB 50/100 11 VD12 V A13 -5V 5V AGND 14 S1B 15 Q1 = 0.541 Q2 = 1.302 INVB 16 HPB 17 BPB 18 R22 LPB 19 R32 20 VOUT
0 -10 -20
VOUT/VIN (dB)
101,777Hz -3.058dB
-30 -40 -50 -60 -70 -80 10k
Clock 5MHz
100k FREQUENCY (Hz)
1M
1% RESISTOR VALUES R21 = 3746 R31 = 2003 R22 = 1996 R32 = 2604
Figure 31. 4th Order, 100kHz Lowpass Butterworth Filter Obtained by Cascading Two Sections in Mode 1a.
VOUT 1 LPA R31 R21 VIN 2.82Vp-p (1VRMS) R11 2 BPA 3 HPA 4 INVA 5 S1A 5V 6 SA/B 7 VA + 8 VD+ 9 LSh 10 CLKA CLKB 50/100 11 VD12 V A13 -5V 5V AGND 14 S1B 15 INVB 16 VOUT/VIN (dB) Q1 = Q2 = 10 HPB 17 BPB 18 R22 LPB 19 20 R12 R32
0 -10 -20 -30 -40 -50 -60 -70 -80 10k 149,871Hz -0.31dB
100k FREQUENCY (Hz)
1M
Clock 7.5MHz RESISTOR VALUES R12 = 20k R22 = 2k R32 = 20k
R11 = 20k R21 = 2k R31 = 20k
Figure 32. Cascasding 2 Sections Connected in Mode 1, each with Q = 10, to obtain a Bandpass Filter with Q = 15.5, and f0 = 150kHz (fCLK = 7.5MHz).
21
ML2111
R12 1 LPA 2 BPA R21 3 HPA 4 INVA R11 VIN 1Vp-p 5V 5 S1A 6 SA/B 7 VA+ 8 V D+ 9 LSh 10 CLKA CLKB 50/100 11
-70 10k 100k FREQUENCY (Hz) 1M
20 LPB 19 BPB 18 HPB 17 16 S1B 15 AGND 14 V A13 VD12 -5V 5V INVB R22
VOUT
10 0 -10 166,224Hz -3.121dB
VOUT/VIN (dB)
-20 -30 -40 3-50 -60
Clock 7.51MHz RESISTOR VALUES R11 = R21 = R12 = R22 = 2.0k
Figure 33. Cascading Two Sections in Mode 1d, Each with Q =1, (Independent of Resistor Ratios) to Create a Sharper 4th Order Lowpass Filter.
VIN 2.82Vp-p
R23
R22
1 LPA 2 LPB BPA R24 3 HPA 4 INVA INVB HPB BPB
20 19 18 17 16 S1A S1B 15 SA/B AGND 14 VA + V A13 VD + VD 12 LSh 50/100 11 CLKA CLKB -5V 5V R21
VOUT
0 -5 -10 -15
VOUT/VIN (dB)
R31
R32
5 6
-20 -25 -30 -35 -40 -45 -50 127 130 FREQUENCY (kHz) 133 129,070Hz
R34 5V
7 8 9 10
Clock 6.5MHz 1% RESISTOR VALUES R21 = R22 = R23 = R24 = 2k R32 = 4.9k R31 = 80k R34 = 100
Figure 34. Notch Filter with Q = 50 and f0 = 130kHz. This Circuit Uses Side A in Mode 1d and the Side B Op Amp to Create a Notch Whose Depth is Controlled by R31. The Notch is Created by Subtracting the Bandpass from V IN. The Bandpass of Side A is Subtracted Using the Op Amp of Side B.
22
ML2111
OPERATION MODES
(Continued)
OFFSETS
Switched capacitor integrators generally exhibit higher input offsets than discrete RC integrators. These offsets are mainly the charge injection of the CMOS switchers into the integrating capacitors. The internal op amp offsets also add to the overall offset budget.Figure 35 shows half of the ML2111 filter with its equivalent input offsets VOS1, VOS2, & VOS3. The DC offset at the filter bandpass output is always equal to VOS3. The DC offsets at the remaining two outputs (Notch and LP) depend on the mode of operation and external resistor ratios. Table 3 illustrates this. It is important to know the value of the DC output offsets, especially when the filter handles input signals with large dynamic range. As a rule of thumb, the output DC offsets increase when: 1. The Qs decrease 2. The ratio (fCLK/fo) increases beyond 100:1. This is done by decreasing either the (R2/R4) or the R6/(R5 + R6) resistor ratios.
Mode 1a is a good choice when Butterworth filters are desired since they have poles in a circle with the same f0. Figure 31 shows an example of a 4th order, 100kHz lowpass Butterworth filter clocked at 5MHz. A monotonic passband response with a smooth transition band results, showing the circuit's low sensitivity, even though 1% resistors are used which results in an approximate value of Q. Figure 32 gives an example of a 4th order bandpass filter implemented by cascading 2 sections, each with a Q of 10. This figure shows the amplitude response when fCLK = 7.5MHz, resulting in a center frequency of 150kHz and a Q of 15.5. Figure 33 uses mode 1d of a 4th order flter where each section has a Q of 1, independent of resistor ratios. In this mode, the input amplifier is outside the damping (Q) loop. Therefore, its finite bandwidth does not degrade the response at high frequency. This allows the amplifier to be used as an anti-aliasing and continuous smoothing fliter by placing a capacitor across R2.
(18) 3 4 (17) VOS1
(16) 5 2
(19)
(20) 1
+ + +
15
VOS2
+ + +
VOS3
Figure 35. Equivalent Input Offsets of 1/2 of an ML2111 Filter.
+
23
ML2111
MODE VOSN N/AP/HPA, N/AP/HPB 1, 4 1a 1b VOS1 [(1/Q) + 1 + ||HOLP||] - VOS3/Q VOS1 [1 + (1/Q)] - VOS3/Q VOS1 [(1/Q)] + 1 + R2/R1] - VOS3/Q VOSBP BPA, BPB V OS3 V OS3 V OS3 VOSN - VOS2 VOSN - VOS2 ~(VOSN - VOS2) (1 + R5/R6) VOSLP LPA, LPB
1c
VOS1 [(1/Q)] + 1 + R2/R1] - VOS3/Q
V OS3
~ VOSN - VOS2
1
6 RR55++2RR66
1d 2, 5
VOS1 [1 + R2/R1] [VOS1 (1 + R2/R1 + R2/R3 + R2/R4) - VOS3(R2/R3)] [R4/(R2 + R4)] + VOS2[R2/(R2 + R4)]
V OS3
VOSN - VOS2 - VOS3/Q
V OS3
VOSN - VOS2
2a
[VOS1 (1 + R2/R1 + R2/R3 + R2/R4) - VOS3(R2/R3)]
OS2
R411+ k6 "# + V R2 "# ;k = R6 !R2 + R411+ k6 $# !R2 + R411+ k6 $# R5 + R6
R 41k 6 "# + V R 2 "# ; k = R 6 ! R 2 + R 41k 6 $# ! R 2 + R 41k 6 $# R 5 + R 6
O S2
V OS3
~ VOSN - VOS2
1
1
6 RR55++2RR66
6
R5 R6
2b
[VOS1 (1 + R2/R1 + R2/R3 + R2/R4) - VOS3(R2/R3)]
V OS3
~ VOSN - VOS2 1+

3, 4a
VOS2
V OS3
VOS1 1 +
!
R 4 R 4 R4 R4 R4 + + - VOS2 - VOS3 R1 R2 R3 R2 R3
"# $
Table 3.
24
ML2111
PHYSICAL DIMENSIONS
inches (millimeters)
Package: P20 20-Pin PDIP
1.010 - 1.035 (25.65 - 26.29) 20
PIN 1 ID
0.240 - 0.260 0.295 - 0.325 (6.09 - 6.61) (7.49 - 8.26)
0.060 MIN (1.52 MIN) (4 PLACES)
1 0.055 - 0.065 (1.40 - 1.65) 0.100 BSC (2.54 BSC) 0.015 MIN (0.38 MIN)
0.170 MAX (4.32 MAX)
0.125 MIN (3.18 MIN)
0.016 - 0.022 (0.40 - 0.56)
SEATING PLANE
0 - 15
0.008 - 0.012 (0.20 - 0.31)
Package: S20 20-Pin SOIC
0.498 - 0.512 (12.65 - 13.00) 20
0.291 - 0.301 0.398 - 0.412 (7.39 - 7.65) (10.11 - 10.47) PIN 1 ID
1 0.024 - 0.034 (0.61 - 0.86) (4 PLACES) 0.050 BSC (1.27 BSC) 0.095 - 0.107 (2.41 - 2.72) 0 - 8
0.090 - 0.094 (2.28 - 2.39)
0.012 - 0.020 (0.30 - 0.51)
SEATING PLANE
0.005 - 0.013 (0.13 - 0.33)
0.022 - 0.042 (0.56 - 1.07)
0.007 - 0.015 (0.18 - 0.38)
25
ML2111
ORDERING INFORMATION
PART NUMBER ML2111CCP (EOL) ML2111CCS ML2111CIP (OBS) TEMPERATURE RANGE 0C to 70C 0C to 70C -40C to 85C PACKAGE 20-Pin PDIP (P20) 20-Pin SOIC (S20) 20-Pin PDIP (P20)
Micro Linear Corporation 2092 Concourse Drive San Jose, CA 95131 Tel: (408) 433-5200 Fax: (408) 432-0295
(c) Micro Linear 1999. is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their respective owners. Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116; 5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376; 5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174; 5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223; 5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending. Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents of this publication and reserves the right to makes changes to specifications and product descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted by this document. The circuits contained in this document are offered as possible applications only. Particular uses or applications may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged to perform its own engineering review before deciding on a particular application. Micro Linear assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear products including liability or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property right. Micro Linear products are not designed for use in medical, life saving, or life sustaining applications.
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DS2111-01

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